Patran 2010 Reference Manual Part 4: Functional Assignments

Patran 2010

Reference ManualPart 4: Functional Assignments

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C o n t e n t sFunctional Assignments

1 Introduction to Functional Assignment Tasks

Orientation 4

Naming Conventions 6

2 Loads and Boundary Conditions Application

Overview of the Loads and Boundary Conditions Application 8Purpose 8Definitions 8Capabilities 9Summary of Key Features 10

Rules for Creating/Modifying/Applying Loads and Boundary Conditions 11

Structural Analysis Loads/BCs Set Inputs 15Thermal Analysis Loads/BCs Set Inputs (other than Patran Thermal) 18Thermal Analysis Loads/BCs Set Inputs (Patran Thermal) 20Fluid Dynamics (CFD) Analysis Loads/BCs Set Inputs 21

Loads and Boundary Conditions Form 23Create Structural LBCs Sets 23Create Thermal LBCs Sets 26Create Fluid Dynamics LBCs Sets 29Modify LBCs Sets 40Delete LBCs Sets 42Show LBCs Sets Tabular Format 44Plot Contours of LBCs Set Data 46Plot LBCs Set Markers 48

Loads and Boundary Conditions Global Display Parameters 55

3 Element Properties Application

Overview of the Element Properties Application 58Purpose 58Definitions 58

Functional Assignments

2

Capabilities 59Summary of Key Features 60

Rules for Creating/Modifying/Applying Element Properties 61

Element Properties Forms 63Create Element Property Sets 64Modify Element Property Sets 69Delete Element Property Sets 71Show Element Property Sets 73

4 Materials Application

Overview of the Materials Application 84Purpose 84Definitions 84Capabilities 85Summary of Key Features 85

Rules for Creating/Modifying Materials 86

Materials Forms 87Create Materials 87Show Materials 99Modify Materials 105Delete Materials 109

Composite Materials Construction 112Laminated Composite 112Rule-of-Mixtures Composite 117Halpin-Tsai Continuous Fiber Composite 119Halpin-Tsai Discontinuous Fiber Composite 122Halpin-Tsai Continuous Ribbon Composite 124Halpin-Tsai Discontinuous Ribbon Composite 126Halpin-Tsai Particulate Composite 129Short Fiber Composite (1D) 131Short Fiber Composite (2D) 133Composite Material Properties 135

Theory - Composite Materials 138Laminated Composite Materials 138Rule-of-Mixtures Composite Materials 143Halpin-Tsai Composite Materials 146Short Fiber Composite Materials 153

3CONTENTS

5 Load Cases Application

Overview of the Load Cases Application 158Purpose 158Definitions 159Capabilities 159Summary of Key Features 160

Rules for Creating/Modifying Load Cases 161

Load Cases Forms 162Create Load Cases 162Modify Load Cases 165Delete Load Cases 168Show Load Cases 170Show Assigned Loads/BCs 171Prioritize Loads/BCs Within Load Cases 173

6 Fields Application

Overview of The Fields Function 188Purpose 188Definitions 188Capabilities 189Summary of Key Features 189

Procedures for Using Fields 191Create 191Modify a Field 199Common Spreadsheet Functionality 200Delete a Field 204Show a Field 205

Fields Forms 206Fields Create (Spatial, PCL Function) 208Fields Create (Spatial, Tabular Input) 212Time Spatial Fields Create (Patran Thermal only) 230Fields Create (Material Property, Tabular Input) 234Fields Create (Non-Spatial, Tabular Input) 239Non-Spatial Field 2D Data Input Table 243Non Spatial Field 3D Data Input Table 244Fields Create (Non-Spatial, Discrete FEM) (SAMCEF Only) 249Fields Create (General Field) 253Fields Create (Spatial, Discrete FEM) 258


4

Fields Create (Spatial, Continuous FEM) 264Fields Show 268Fields Modify (Spatial, PCL Function) 278Fields Modify (Spatial, Tabular Input) 280Fields Modify (Material Property) 282Fields Modify (Non-Spatial) 284Fields Modify (Non-Spatial, Discrete FEM) (SAMCEF Only) 286Fields Modify (General Field) 288Fields Delete 294

Fields Example 297Spatial PCL Function 297

Index

Ch. 1: Introduction to Functional Assignment TasksPatran Reference Manual

1 Introduction to Functional Assignment Tasks

Orientation 4

Naming Conventions 6

Patran Reference ManualOrientation

4

1.1 Orientation Functional Assignments are necessary to turn a collection of finite elements into a complete finite element model. The five Functional Assignment Applications assign element properties, material properties, loads and boundary conditions, load cases, as well as assign those features as a function of a mathematical field.

The diagram below describes the basic flow of finite element analysis and its relationship to the application of Functional Assignments. The five Functional Assignment Application tasks are the topic of this chapter.

Each of the five Functional Assignments are accessed by a menu selection in the main form. Each Functional Assignment area deals with groups of items, typically called sets, that have names and may be of different types.

A Field is a special kind of Functional Assignment. Fields define spatial and time- or temperature-dependent distributions of scalar or vector quantities. These functions can be defined by tables or general PCL expressions in real or parametric space. They are extremely useful tools in defining complex distributions of element properties, material properties, loads or boundary conditions. Examples include: the temperature or stress dependence of a material property, the thickness distribution of a shell, and a time-dependent pressure pulse.

This area is called Functional Assignments. They include all the actions that are necessary to turn a collection of finite elements into a complete, ready-for-analysis model.

Load Cases Element Properties

Material Properties Loads and Boundary Conditions

Geometry

Fields

FEM Model Analysis Results

5Ch. 1: Introduction to Functional Assignment TasksOrientation

An important feature of Patran is the ability to apply element properties and LBCs to the geometry prior to meshing. This eliminates the need to reapply them if the finite element model is remeshed.

The primary Functional Assignment actions are Create, Delete, Modify, and Show. These actions refer both to the contents of the sets themselves, and to their associativity to the geometric and FEM entities that make up the model.

An important characteristic of the Patran approach to finite element analysis is the ability to retain information in the database. Thus, the model database includes not only the current analysis but also elements of all previous analyses: different loads, materials, configurations, etc. This archival ability adds an important new dimension to analysis: a record of its history.

Many of the actions that are taken in Functional Assignments are analysis code specific. The types of element properties that can be created, the property input forms, and the types of loads that can be applied all depend on the code preference selected. It is important that this selection be made before working in the Functional Assignments areas.

A database inherently assumes that a single code and analysis type are being used. If the analysis code preference is changed, Patran will attempt to convert all code specific information to the new preference. Switching the analysis code preferences back and forth will, in general, not result in a complete translation. To use an existing database with an alternate analysis code, it is recommended that the database be duplicated.

Create Used to create the element property sets, material property sets, loads and boundary conditions sets, load cases, and the various fields used to define these sets.

Delete Used to remove the Functional Assignment sets.

Modify Used to edit the Functional Assignments sets.

Show Provides the capability of displaying information in both tabular and plot format. The most common plot type is contour plot of the selected data on the model, although in fields and materials XY plotting of data is also supported. Displays other than contours are also available such as Marker displays, where annotated symbols that indicate a material type or load direction are shown.

Patran Reference ManualNaming Conventions

6

1.2 Naming ConventionsSince all Functional Assignments deal with named items or groups of items (sets or cases), it is important that users be aware of the conventions and restrictions that exist for names. These are summarized below.

• Length - 1 to 31 characters

• Permitted Characters - A to Z, a to z, 0 to 9, underscore, hyphen, period

• Not Allowed - Spaces, parenthesis, brackets, commas, +, !, ?, =, etc.

• Case Sensitive - Yes

It is recommended that the user provide names that describe the FA being created.

When a field is to be used as input to a databox, the field name must be preceded by “f:.” This identifies it as a field. Similarly, materials are preceded by “m:” when they are entered into element property databoxes.

Ch. 2: Loads and Boundary Conditions ApplicationPatran Reference Manual

2 Loads and Boundary Conditions Application

Overview of the Loads and Boundary Conditions Application 8

Rules for Creating/Modifying/Applying Loads and Boundary Conditions 11

Loads and Boundary Conditions Form 23

Loads and Boundary Conditions Global Display Parameters 55

Patran Reference ManualOverview of the Loads and Boundary Conditions Application

8

2.1 Overview of the Loads and Boundary Conditions Application

PurposeThe Loads and Boundary Conditions application (Loads/BCs) provides the ability to apply a variety of static and dynamic loads and boundary conditions to finite element models. Loads/BCs may be associated with geometric entities as well as FEM entities. When associated with geometric entities, they can be transferred to finite elements created on the geometry. Loads and boundary conditions are intended to be created in multiple single purpose groups referred to as sets. These sets are grouped into load cases in the Load Cases application. Fields can be used in the definition of loads and boundary conditions. Loads/BCs sets remain in the database unless specifically deleted and thus provide an archival record.

DefinitionsLoads/BC Set: A Loads/BC set is comprised of a collection of data (which may include fields) that are associated with both an analysis type and geometric and/or FEM entities. Typical examples are displacements associated with nodes in a structural analysis, or heat fluxes associated with surfaces in a thermal analysis.

Load Case: A Load Case is a group of Loads/BCs sets that together define a single analysis case. Load Cases are assembled from the entire array of Loads/BCs sets in the Load Cases Application.

Analysis Type: Analysis types currently supported are Structural, Thermal, and Fluid Dynamics (CFD).

Nodal: This refers to the case where loads or boundary conditions are associated with finite element nodes. A typical case is a specified displacement at a node of a structural finite element.

Element Uniform: This refers to the case where the loads or boundary condition is associated with the element itself and is assumed to be uniform over the element face, or element edge. A typical case is an element temperature.

Element Variable: This refers to the case where the loads or boundary condition is associated with an element, but varies in magnitude over the element, element face or element edge. It may thus have different values at the element’s nodes. This leads to the case where nodes that are common to adjacent elements may be multi-valued in the loads or boundary conditions. A typical example is pressure applied over an element.

Target Element Type: Target Elements are elements selected to be actual or eventual recipients of the desired loads or boundary condition. All elements in a set must be of the same type: either 1D, 2D, or 3D. If more than one type is involved, make a separate set for each. Target Element Types are only required for Element Uniform or Element Variable Loads/BCs sets.

Dynamic Loads/BCs Sets: Dynamic loads and boundary conditions sets are those which have a time-dependent component. They must be associated with a time dependent Load Case, which must be the current case when the set is created. Time and spatial dependencies are assumed to be uncoupled.

9Ch. 2: Loads and Boundary Conditions ApplicationOverview of the Loads and Boundary Conditions Application

Dynamic sets are comprised of a static spatial component multiplied by a time varying component. Fields must be used to define the time dependency.

Markers: These are the graphic symbols (e.g., arrows, circles) that appear on the screen and provide visual feedback of the location, type, magnitude and direction of the loads or boundary condition. Their display can be turned on or off in the Plot Marker form, or in the Display/Functional Assignment top menu form. See Rules for Creating/Modifying/Applying Loads and Boundary Conditions, 11 for more details.

Type Prefix: As a convenience, each set is given a type prefix that is displayed when sets of different types are listed together. This prefix is the first five letters of the set type followed by an underscore. For example, a set of displacements named “set_1” would appear as “displ_set_1” when displayed with sets of other types.

CapabilitiesThe Loads/BCs application has the capability of creating, deleting, modifying, and displaying loads and boundary condition sets. Three Analysis Types are supported: Structural, Thermal, and Fluid Dynamics (CFD).

The sets can be either Static or Time Dependent (dynamic). Time dependency is introduced either through the inclusion of a time dependent field multiplier, or through use of initial condition options (e.g., initial displacements).

The loads and boundary condition set types that can be created depend on the analysis selected. The Loads/BCs set types available are a function for the analysis code set in “Analysis Preferences.” For example, if MSC Nastran is the current analysis code selection then only Structural Loads/BC set types will be available. For structural analyses, nine different set types are supported: displacement, force, pressure, temperature, inertial load, initial displacement, initial velocity, velocity and acceleration. For thermal analyses, sets can include temperature (thermal), convection, heat flux, heat source, and initial temperature. Fluid analysis set types are: inflow (incomp), outflow (incomp), solid wall (incomp), symmetry, inflow (comp), outflow (comp), open flow (comp), solid wall (comp), volumetric and total heat load.

Loads and boundary conditions are created and stored in the database as sets. Each set has a unique name and is associated with one analysis type (e.g., structural), one loads and boundary conditions type (e.g., pressure), and one target element type (e.g., 2D), if applicable. All sets are associated with a load case, which by default is the Current Load Case when the set is created.

Sets can be visually displayed on the screen by markers which show the location, type, magnitude, and direction of the applied loads or boundary condition. Only the static portion of a dynamic Loads/BCs set is reflected in the marker display. Sets can also be displayed as tables.

A powerful capability is the display of any set scalar data directly on the model as a fringe plot. For display purposes, data are treated as “results,” with full user control over the spectrum, method, shading, etc. Data display is scalar, but the data can be pressures, vector component magnitudes, and vector resultant magnitudes. Fringe plots can only be displayed on finite elements. Fringes of a dynamic Loads/BCs set may be displayed at user-specified times.

Patran Reference ManualOverview of the Loads and Boundary Conditions Application

10

The use of PCL functions in defining loads and boundary conditions is supported through the use of Fields. Use the PCL option in the Fields function to create the desired input data distribution. The field can be used in the Loads/BCs application by simply selecting it from a listbox display.

Loads/BCs can be defined on geometric entities. These are subsequently evaluated on FEM entities associated to that geometry. This is convenient because remeshing the geometry has no effect on the loads and boundary conditions.

Summary of Key FeaturesThe Loads/BCs function provides:

• A straightforward, convenient means for taking data, whether from fields or direct input, and associating it with either FEM or geometric entities. Data are grouped as uniquely named sets. These sets, in turn, can be grouped into load cases in the Load Cases Application.

• Archival records in the model database of all previous loads and boundary conditions unless specifically deleted.

• Loads and boundary conditions to be associated with geometric entities (e.g., surfaces). These sets can then be evaluated on the FEM model. This permits remeshing without impacting the loads and boundary conditions.

• A means of creating new sets that are modifications of existing sets.

• Full support of the use of Fields in defining data input. This, for example, permits access to PCL functions in defining Loads/BCs.

• Support for structural, thermal, and fluid dynamics (CFD) analysis types. Loads/BCs associativity can be nodal, uniform over the element, or variable over the element. It also provides the addition of time dependence through the use of time-dependent fields or initial conditions (e.g., initial displacements).

• The ability to create, delete, modify and show sets. Visual display of sets includes showing the type, location, magnitude, and direction of applied loads and boundary conditions. Sets can also be shown in a table format.

• Scalar data (e.g., pressure, temperature, vector components) which can also be displayed as fringe plots on the model. The data are treated as “results,” with full control over the display (e.g., spectrum, shading, type, etc.).

11Ch. 2: Loads and Boundary Conditions ApplicationRules for Creating/Modifying/Applying Loads and Boundary Conditions

2.2 Rules for Creating/Modifying/Applying Loads and Boundary ConditionsAll Loads/BCs sets created are associated with the Current Load Case. This load case will be the one named “Default” unless a different one is specified. The current load case can be changed from within the Loads/BCs application.

The scope of an individual set is limited to a single analysis type (e.g., structural), a single loads or boundary condition definition (e.g., displacement), a single data set, and either FEM or geometry entity types.

Loads/BCs sets can be created, modified, deleted, and displayed. Set modification is completely general in that this action essentially deletes the original set and replaces it with the modified set. The Create option may also be used to modify a set. The only difference is that you will be prompted with a message warning that the set already exists, and asking whether it can be overwritten.

Creating a new set that is a modification of an existing set is accomplished by selecting an existing set, renaming it, and making the desired modifications using the Create action.

In many cases, a Scale Factor may be specified in the Input Data form. All data in the set will be multiplied by this value. The default scale factor is 1.0.

The region of application on the model of the defined set is established using the standard selection tools. If more than one entity can be selected, a select menu will be displayed. The ID of selected items is displayed in the selection region databox.

It is important that the analysis code to be used is selected prior to creating Loads BCs sets.

Fields are created in the separate Fields Application (Ch. 6). Fields must be created before they can be assigned in the Input Data form.

Important: A common strategy is to create all sets within the default load case and break them out into separate named load cases later.

Important: It is intended that multiple sets be used to define the complete load case. Avoid large complex sets. This reduces the chance for error and makes modification and set manipulation easier.

Important: All loads and boundary conditions sets are integrally related to the specific analysis type and code selected.

Patran Reference ManualRules for Creating/Modifying/Applying Loads and Boundary Conditions

12

Depending on the specific analysis code and Loads/BCs type, the loads or boundary condition is associated with either the elements themselves or the nodes. If values are associated with elements, they can be either applied uniformly across the element, element face, or element edge (Element Uniform), or vary across the element based on values at associated nodes (Element Variable). The selection between these two options depends on the method used by the analysis code. Determine what is required before attempting to define element loads.

Local Coordinate System Definition

Loads/BCs applied to elements are defined in terms of local coordinate systems as follows: The 1, 2, and 3 directions are defined to be either consistent with the geometric entity C1, C2, and C3 directions or with respect to the element nodal connectivity as shown.

For a rectangular surface, the C1, C2, and C3 directions form a right-handed coordinate system. The top surface is the side in the plus C3 direction.

For elements, connectivity is used to define a coordinate system. If the connectivity is I-J-K-L, the 1-axis corresponds to the I-to-J direction, the 2-axis the I-to-L direction, and the 3-axis normal to the plane defined by 1 and 2 in a right-handed sense. The top surface is on the positive 3-direction side of the element.

Important: The use of fields to define complex data distributions makes this task easier and is encouraged.

Important: For element variable loads, a node may have multiple load values, if the node is associated to multiple elements.

K

JI

L

C1

C2C3

1

2

3

Top Surface

Bottom Surface


Sign Conventions

Displacements, forces, velocities, and accelerations are positive in the positive directions of the Analysis Coordinate Frame displayed in the Input Data form.

Positive pressures are those that act inward toward the entity. Negative pressures act outward from the entity and represent a surface “suction.”

Markers

When loads and boundary conditions are created, they are automatically displayed with markers. Markers may be arrows, circles, squares, etc. Use the Graphics Preferences form to select the marker options. In general, arrows (also referred to as graphical vectors) are used to display quantities which have a direction. All other types of markers are used to display scalar quantities. Arrow markers can have one, two, or three heads. For example, translational displacements, forces, pressures, and translational velocities are displayed as single-headed arrows. Moments and rotations are displayed as double-headed arrows. Rotational accelerations are displayed as triple-headed arrows. Displacement constraint markers may have one-, two-, or three-headed arrows with no tail. For example, if only a translational constraint is specified, a single-headed arrow will be displayed in the appropriate direction. If only a rotational constraint is specified, then a double-headed arrow will be displayed. If both a translational and rotational constraint are specified in the same direction, then a triple-headed arrow will be displayed.

Marker colors can be changed in the Display/Functional Assignment form in the main form. Marker display for each Loads/BCs set type can be selectively turned ON and OFF from this form.

Units

The Loads/BCs application is nondimensional. Input data units are those required by the analysis code selected. Scale factors can be used for conversion if model units differ from code required units (e.g., metric to English).

Set Names

Set names can be up to 31 characters long and must be unique. Use descriptive names with words separated by underscores. As a convenience, each set is given a type prefix that is displayed when sets of different types are listed together. This prefix is the first five letters of the set type followed by an underscore. For example, a set of displacements named “set_1” would appear as “displ_set_1” when displayed with sets of other types. If only displacement sets are listed, the type prefix is omitted.

Plotting Loads and Boundary Conditions as Contours

A powerful capability is the display of any set scalar data directly on the model as a fringe plot. For display purposes, data are treated as “results,” with full user control over the spectrum, display method, shading, etc. Data display is scalar, of course, but the data to be plotted can be pressures, vector component magnitudes, and vector resultant magnitudes.


14

Set Types

The loads and boundary condition set types that can be created depend on the type of analysis being performed. Three different types are currently supported: Structural, Thermal, and Fluid Dynamics (CFD).

For structural analyses, nine different set types are supported: Displacement, Force, Pressure, Temperature, Inertial Load, Initial Displacement, Initial Velocity, Velocity, and Acceleration. Thermal analyses sets can include Temp (Thermal), Convection, Heat Flux, Heat Source, and Initial temperature. Fluid analysis set types include: Inflow (Incomp), Outflow (Incomp), Solid Wall (Incomp), Symmetry, Inflow (Comp), Outflow (Comp), Open Flow (Comp), and Solid Wall (Comp), Volumetric Heat and Total Heat Load.

Each set type can, in turn, have different element associativities, target element types, and required inputs. The tables on the following pages provide maps of all possibilities and options.

Structural Analysis Loads/BCs Set Inputs

Set Type Association Element Inputs

Displacement Nodal --- Translations <T1 T2 T3>

Rotations < R1 R2 R3>

Analysis Coordinate Frame

Element Uniform 2D Surf Translations <T1 T2 T3>

Surf Rotations < R1 R2 R3>

Edge Translations <T1 T2 T3>

Edge Rotations < R1 R2 R3>


3D Translations <T1 T2 T3>


Element Variable 2D Surf Translations <T1 T2 T3>

Surf Rotations < R1 R2 R3>

Edge Translations <T1 T2 T3>

Edge Rotations < R1 R2 R3>


3D Translations <T1 T2 T3>


Force Nodal --- Force <F1 F2 F3>

Moment < M1 M2 M3>

16

Pressure Element Uniform 2D Top Surf Pressure

Bot Surf Pressure

Edge Pressure

3D Pressure

Element Variable 2D Top Surf Pressure

Bot Surf Pressure

Edge Pressure

3D Pressure

Temperature Nodal --- Temperature

Element Uniform 1D Temperature

2D Temperature

3D Temperature

Element Variable 1D Centroid Temperature

Axis-1 Gradient

Axis-2 Gradient

2D Top Surface Temperature

Bottom Surface Temperature

3D Temperature

Inertial Load not element dependent

(applies to entire model)

Trans Accel <A1 A2 A3>

Rotationa l Veloc <w1 w2 w3>

Rotational Accel <a1 a2 a3>


Initial Displacement Nodal --- Translations <T1 T2 T3>

Rotations <R1 R2 R3>


Initial Velocity Nodal --- Trans Veloc <v1 v2 v3>

Rotationa l Veloc <w1 w2 w3>

Distributed Load Element Uniform 1D Distr Load <f1 f2 f3>

Distr Moment <m1 m2 m3>

2D Edge Distr Load <f1 f2 f3>

Edge Distr Moment <m1 m2 m3>

Element Variable 1D Distr Load <f1 f2 f3>

Distr Moment <m1 m2 m3>

2D Edge Distr Load <f1 f2 f3>

Edge Distr Moment <m1 m2 m3>

Contact Element Uniform --- Friction Coefficient (MU1)

Stiffness in Stick (FSTIF)

Penalty Stiffness Scaling Factor (SFAC)

Slideline Width (W!)

A Vector Pointing from Master to Slave Surface


18

Thermal Analysis Loads/BCs Set Inputs (other than Patran Thermal)


Temp (Thermal) Nodal --- Temperature

Convection Element Uniform 2D Top Surf Convection

Bot Surf Convection

Edge Convection

Ambient Temperature

3D Convection

Ambient Temperature

Element Variable 2D Top Surf Convection

Bot Surf Convection

Edge Convection

Ambient Temperature

3D Convection

Ambient Temperature

Heat Flux Element Uniform 2D Top Surf Heat Flux

Bot Surf Heat Flux

Edge Heat Flux

3D Heat Flux

Element Variable 2D Top Surf Heat Flux

Bot Surf Heat Flux

Edge Heat Flux

3D Heat Flux

Heat Source Nodal --- Heat Source

Element Uniform 2D Heat Source

3D Heat Source


Initial Temperature Nodal --- Temperature

Voltage Nodal --- Voltage



20

Thermal Analysis Loads/BCs Set Inputs (Patran Thermal)


View Factor Element Uniform 1D

2D

3D

View Factor

View Factor

View Factor

Convection Element Uniform 1D

2D

3D

Convection

Convection

Convection

Element Variable 1D

2D

3D

Convection

Convection

Convection

Heat Flux Element Uniform 1D

2D

3D

Heat Flux

Heat Flux

Heat Flux

Element Variable 1D

2D

3D

Heat Flux

Heat Flux

Heat Flux

Heat Source Nodal --- Heat Source

Element Uniform 1D

2D

3D

Heat Source

Heat Source

Heat Source

Element Variable 1D

2D

3D

Heat Source

Heat Source

Heat Source

Fixed Temperature Nodal --- Temperature

Initial Temperature Nodal --- Temperature

Variable Temperature Nodal --- Temperature Scale Factor

Fluid Dynamics (CFD) Analysis Loads/BCs Set Inputs

Mass Flow Nodal --- Mass Flow Rate

Fixed Pressure Nodal --- Pressure

Initial Pressure Nodal --- Pressure

Variable Pressure Nodal --- Pressure Scale Factor


Inflow (Incomp) Element Uniform 2D Velocity )

Pressure

3D Velocity 

Pressure

Outflow (Incomp) Element Uniform 2D Pressure

3D Pressure

Solid Wall (Incomp) Element Uniform 2D Heat Flux

3D Temperature

Heat Flux

Heat Transfer Coefficient

Ambient Temperature

Symmetry Element Uniform 2D None

3D None

Inflow (Comp) Element Uniform 2D Velocity )

Pressure

Absolute Temperature

3D Velocity 

Pressure

22

Outflow (Comp) Element Uniform 2D Velocity 

Pressure


3D Velocity 

Pressure


Open Flow (Comp) Element Uniform 2D Velocity 

Pressure


3D Velocity 

Pressure


Solid Wall (Comp) Element Uniform 2D Temperature

Heat Flux

3D Temperature

Heat Flux

Volumetric Heat Element Uniform 2D Heat Source

3D Heat Source

Total Heat Load Element Uniform 2D

3D

23Ch. 2: Loads and Boundary Conditions ApplicationLoads and Boundary Conditions Form

2.3 Loads and Boundary Conditions FormThe functions of the Loads/BCs menu are listed and described below in the order in which they appear on the menu.

Create Structural LBCs SetsThis form is used to create all structural loads and boundary conditions sets. Existing sets can be recalled and used as templates for new sets. Separate forms are used for data input and selection of a region on the model for application.

Menu Pick Action

Create Structural Sets • Create a new set using structural analysis set type options.

Create Thermal Sets • Create a new set using thermal analysis set type options.

Create Fluid Dynamics Sets • Create a new set using fluid dynamic analysis set type options.

Modify • Change any property or characteristic of a set.

Delete • Remove selected sets from the database.

Show Tabular • View set data displayed in a table format.

Plot Contours • Display contour plots of selected set data on the model.

Plot Markers • Control display of markers (arrows, etc.) on groups.

Patran Reference ManualLoads and Boundary Conditions Form

24


Action A new loads and boundary conditions set will be created.

Object The available types of structural sets include:

• Displacement

• Force

• Pressure

• Temperature

• Inertial Load

• Initial Displacement

• Initial Velocity

• Distributed Load

• Contact

Type Sets are ultimately associated with either nodes (Nodal) or elements. Sets can be associated with the element itself (Element Uniform) or the element’s nodes (Element Variable).

Analysis Type The analysis type is Structural. The form changes if an alternative analysis type is selected.

Current Load Case The set will be assigned to this Current Load Case named “Default.” To change, select this button and make a new selection in the form that appears. Time-dependent sets require a time dependent load case.

Existing Pressure Sets The names of all sets of the type selected are displayed here. Selecting one retrieves it from the database.

New Set Name Each new set requires a unique name (31 characters maximum, no spaces).

Target Element Type For element associated sets, select the element type (1D, 2D, or 3D). If more than one type, create different sets for each. Not used for Nodal types.

Input Data Select this box to bring up the Input Data form containing the appropriate variables for the set type selected.


26

Create Thermal LBCs SetsThis form is used to create all thermal loads and boundary conditions sets. Existing sets can be recalled and used as templates for new sets. Separate forms are used for data input and selection of a region on the model for application.

Select Application Region

Select this box to bring up forms for selecting the entities to which this set applies. Standard selection methods are used.

Note: The new set is not created until OK is selected.

• Auto Select This tool is available for creating Pressures only when the application region is FEM. This is a tool that you can use to select connected free faces of solid elements by selecting a single reference free face and specifying an angle range such that all adjacent free faces with normals within this range relative to the normal of the reference element are selected. By pressing the Overwrite button on this subordinate form, the selected element faces will be overwritten from any previous query. If the Append button is pressed, than faces from additional queries are added to previous queries. When the form is canceled, the list of faces selected from this tool appear in the select databox on the main form for selecting an application region. Simply add the element faces to the application region and create the pressure LBC.

Here are a couple of examples of picking you can do with this tool:

• Picking free faces of one-quarter of a solid sphere

• Picking the free faces of a hole of a solid plate for bolt bearing analysis.

More Help: Preference Guides Application Modules

• Patran ABAQUS

• Patran ANSYS

• Patran LS-DYNA

• Patran MSC.Marc

• Patran MSC.Dytran

• Patran MSC Nastran

• Patran PAMCRASH

• Patran SAMCEF

• Patran P2NF

• Patran FEA

• Patran Thermal

• Patran Advanced FEA


28


Object The available types of thermal sets include:

*Denotes Patran Thermal only.

• Temp (Thermal)

• Convection

• Heat Flux

• Heat Source

• Initial Temperature

• Volumetric Heat (PatranT*)

• Pressure (Patran T*)

• Mass Flow (Patran T*)

• Viewfactors (Patran T*)

• Voltage (Thermal)

Type Sets are ultimately associated with either nodes (Nodal) or elements. With elements, they can be associated with the element itself or the element’s nodes (Element Uniform or Element Variable).

Analysis Type The analysis type is Thermal. The form changes if an alternative analysis type is selected.

Current Load Case The set will be assigned to this Current Load Case named “Default.” To change, select this databox and make a new selection in the form that appears. Time dependent sets require a time-dependent Load Case. (Note: Not applicable to Patran Thermal.)

Existing Heat Flux Sets The names of all sets of the type selected are displayed here. Selecting one retrieves it from the database.






Note: Note: The new set is not created until Apply is selected.


Create Fluid Dynamics LBCs SetsThis form is used to create all fluid dynamics loads and boundary condition sets. Existing sets can be recalled and used as templates for new sets. Separate forms are used for data input and selection of a region on the model for application.


• Patran ABAQUS

• Patran ANSYS

• Patran LS-DYNA

• Patran MSC.Marc



• Patran PAMCRASH

• Patran SAMCEF

• Patran P2NF

• Patran FEA

• Patran Thermal



30

Load/Boundary Conditions

Create Action:

Analysis Type:

Inflow(Incomp) Object:

Element Uniform Type :

2D Target Element Type:

Default...

Type: Static

Current Load Case:

Existing Sets

New Set Name

Input Data...

Select Application Region...

-Apply-

Fluid Dynamics



Object The available types of Fluid Dynamics sets include:

• Inflow (Incomp)

• Outflow (Incomp)

• Solid Wall (Incomp)

• Symmetry

• Inflow (Comp)

• Outflow (Comp)

• Open Flow (Comp)

• Solid Wall (Comp)

• Volumetric Heat

• Total Heat Load

Type Sets are ultimately associated with either nodes (Nodal) or elements. With elements, they can be associated with the element itself or the element’s nodes (Element Uniform or Element Variable).

Analysis Type The analysis type is Thermal. The form changes if an alternative analysis type is selected.

Current Load Case The set will be assigned to this Current Load Case named “Default.” To change, select this box and make a new selection in the form that appears. Time-dependent sets require a time-dependent Load Case.

Existing Sets The names of all sets of the type selected are displayed here. Selecting one retrieves it from the database.






Note: Note: The new set is not created until Apply is selected.


32

Input LBCs Set Data (Static Load Case)

Data used to define a static loads and boundary conditions set is input on this form. Although the basic methodology remains the same, the parameters displayed change depending on both the type of analysis selected, the LBCs set type (e.g., Pressure), LBCs type (e.g., nodal, element uniform), and the target element type, if applicable. Inputs for all options are presented in Loads and Boundary Conditions Application (Ch. 2). Fields can be used as inputs. Sets which include vector quantities may be associated with a coordinate frame.


• Patran ABAQUS

• Patran ANSYS

• Patran LS-DYNA

• Patran MSC.Marc



• Patran PAMCRASH

• Patran SAMCEF

• Patran P2NF

• Patran FEA

• Patran Thermal


34

Input LBCs Set Data (Time Dependent Load Case)

Data used to define a dynamic loads and boundary conditions set is input in this form. Although the basic methodology remains the same, the parameters displayed change depending on both the type of analysis selected and the type of set (e.g., Pressure). Fields can be used as inputs. Sets, which include vector quantities, may be associated with a coordinate frame.

Load/BCs Set Scale Factor

All loads and boundary conditions data variables are multiplied by this Scale Factor. The default value is 1.0.

Translations

Rotations

Spatial Fields

All parameters appropriate to the Analysis Type and Loads/BCs type selected appear as input databoxes. The following rules apply to data entry in these databoxes:

1. Commas or spaces may be used as delimiter (e. g., “<1 0 1>”).

2. “< >” above the input databoxes indicates that this variable is a vector quantity.

A blank (no entry) is considered a null, or no input, which is the same as zero, except for displacement (including initial displacements) type sets. A zero value for a displacement means that the displacement component in that direction is constrained. A null value indicates that the nodes are free to move. Null values can be indicated by “,,” (e.g., “10 ,, 4”).

3. Data values can be constants, scalar fields, or vector fields. If a vector field is input in a databox, the vector components are used in sequence as the parameters in the box.Note: If a field is entered, a vector field must be used to define vector quantities and a scalar field must be used to define scalar quantities.

4. To use a field, first select the databox, and then a field. name here. The name is echoed in the databox.

FEM Dependent Data...

This button will display a Discrete FEM Fields input form to allow field creation and modification within the loads/bcs application. Available only when focus is set in a databox which can have a DFEM field reference. See Spatial Discrete FEM Field Access by Other Applications, 262.


This is the default coordinate frame specified in Preferences. Select this databox if a different one is applicable to this set.

Note: For displacements this must be set to the nodal analysis coordinate frame. If there is a conflict between loads and boundary conditions analysis coordinate frame and nodal analysis coordinate frames the nodal analysis will be modified to the LBCs analysis coordinate frame.


Important: The resulting data values are calculated as Loads/BCs Set Scale Factor multiplied by both Spatial Dependence and Time Dependence.


36

Load/BCs Set Scale Factor

All data in this set are multiplied by this Scale Factor. The default value is 1.0.

Note: Note: If the set is constant in space, input one (1.0) as Load/BCs Set Scale Factor.

Spatial Dependenc Time Dependence

Time dependence must be defined as a field. First, select an input box and then a field name from the list below.


Change Current Load Case

This form allows the current load case to be changed from within the Loads/BCs Application. Any new set created will automatically reside in the Current Load Case and in no other load case, unless specifically added to that load case in the Load Cases Application.

Translations

Rotations

All parameters appropriate to the Analysis Type and Loads/BCs type selected appear as input databoxes.

Note: Commas or spaces may be used as delimiters. Blanks (no entry) are considered a null, or no input, which is the same as zero, except for displacement sets.

Spatial Fields/Time/Freq. Dependent Fields

Time dependence must be defined as a field. First, select an input box and then a field name from the list below.

FEM Dependent Data...

Displays a Discrete FEM Fields input form to allow field creation and modification within the loads/bcs application. Available only when focus is set in a databox which can have a DFEM field reference. See Spatial Discrete FEM Field Access by Other Applications, 262.


This is the default coordinate frame specified in Preferences. Select this databox if a different one is applicable to this set.


38

LBCs Select Application Region

This form is used to select the entities to which the loads and boundary conditions sets will be applied. The select databox can be used to graphically select the Application Region. Entities may also be selectively removed from the Application Region.

Filter If the user has multiple load cases, the filter feature can be used to list only those Load Cases which match the text shown in the databox to its left.

Note: An (*) is considered a wild card.

Existing Load Cases Select the Load Case which is to be the Current Load Case. The change will be reflected in the main form on exit.


40

Modify LBCs SetsThis form permits a selected set to be modified in a general manner. Any property or parameter may be changed. The selected set is effectively deleted and replaced with a modified copy.

Geometry/FEM Loads and boundary conditions sets can be associated either directly with FEM entities or with geometric entities.

Note: It is not permissible to mix geometric and FEM entities in a single application region.

Sets applied to geometry can be displayed on the associated FEM model by turning on the “Display on FEM Only” toggle on the Display/Functional Assignments form (see Display>LBC/Element Property Attributes (p. 393) in the Patran Reference Manual) and executing either the Plot Markers or Plot Contours action.

Select Geometric Entities

Focus is automatically set to this databox. In the instances where more than one type entity is valid, a separate selection icon menu appears indicating the type of entity to be selected (e.g., curve or surface). Use standard selection tools to select the desired entity or group of entities. The entity types and IDs of selected items appear in this databox.

Remove Removes selected entities (those appearing in the Select Nodes databox) from the Application Region.

Application Region When the selected entities are correct, select the Add button. The selected entities appear in the Application Region listbox.


42

Delete LBCs SetsThis action permits any loads and boundary conditions set to be deleted from the database. Multiple sets can be deleted at once. If a set is deleted in error, it can be reinstated prior to taking further actions.

Action Select Modify.

Current Load Case The set will be assigned to this Current Load Case. To change, select this button and make a new selection in the form that appears. The set will also remain in the original load case. Time dependent sets require a time-dependent load case.

Select Set to Modify Select the set to be modified.

Rename Set As Rename the set here.

Target Element Type For element associated sets, the element type (1D, 2D, or 3D) associativity can be changed. If this is done, however, remove the old types from the application region and add the new types.

Modify Data Select this box to bring up the Input Data form. Make changes to the set data as required.

Modify Application Region

Select this box to bring up a form for changing the entities to which this set applies. Standard selection methods are used.

Note: The set is not modified until Apply is selected.


Action Select Delete.

O bject Select the type of the loads and boundary conditions set that is to be deleted. The list of options depends on the analysis type selected.

Analysis Type Select the Analysis Type. The options available are a function of analysis code.


44

Show LBCs Sets Tabular FormatThis form permits the contents of a selected loads and boundary conditions set to be displayed in a table format. For graphical display of set data, use the Plot Contours or Plot Markers Actions.

Existing Displacement Sets

All sets of the type selected will appear in this databox. Select those to be deleted. Selected sets appear in the listbox below.

Load/BCs to be deleted Selected sets appear in this databox. They can be removed from this delete list by selecting them.

Note: Nothing is deleted until Apply is selected. Wait for the deleted sets to be removed from the Existing Sets listbox. Deleted sets may be reinstated by selecting the erasure icon in the main menu.


Action Select Show Tabular.

O bject Select the type of the loads and boundary conditions set that is to be displayed

Analysis Type Select the Analysis Type. The options available are a function of analysis code.

Current Load Case To change the Current Load Case, select this databox and make a new selection in the listbox that appears. The set will also remain in the original Load Case.

Existing Load/BCs Sets All sets of the type selected will appear in this databox. Select the one to be shown.

Note: Selecting Apply brings up the display table. The table is removed from the screen by leaving the Show Action.


46

Loads/BCs Set Show Tabular

This table lists all the entities in the set and shows their associated parameters and data values.

Plot Contours of LBCs Set DataThis form is used to display loads and boundary conditions set data on the model. The method used is to create a fringe contour plot of the selected variable. It is useful for visual verification of complex loading conditions. Once created, the plot can be changed using any of the graphics tools located in the display menu (e.g., change spectrum, shading, etc.).

Entity Type Column1 is the entity type, its ID number and its Sub ID. All entities are the same type in a set.

Scale Factor This Scale Factor multiplies all data values in this row.

Load/BCs Table Show

Entity Type Coordinate Frame Scale Factor Force

Node 78 1

Node 79 1

1

1

1

Force F1

Node 80

Node 81

Node 82

0

0

0

0

0

100 .

100.

100.

100.

100.

100.

100.

100.

100.

100.

Note: In many cases, the table is much larger than can be displayed on the screen. Use scroll bars to view the entire table.


48

Plot LBCs Set MarkersLoads and boundary conditions markers (e.g., arrows or circles) appear on the screen when sets are created. This form is used to control their display. The display may be limited to the groups in the current viewport or may include all groups. Marker display is also controlled from the “Display” form in the main form. (See Display>LBC/Element Property Attributes (p. 393) in the Patran Reference Manual.)

Action Select Plot Contours.

Object Select the type of the loads and boundary conditions set that is to be displayed.

Analysis Type Verify that this is the Analysis Type being performed.

Current Load Case This is the Current Load Case. To change, select this box and make a new selection in the submenu that appears.

Existing Sets All sets in the Current Load Case appear in this listbox. Contours for all Loads/BCs sets in the Current Load Case with the selected data variable are plotted.

Select Data Variable Select the variable data to display on the model.

Component If the data is a vector, either the magnitude of the resultant or a component may be selected with this menu.

Time If the Current Load Case is Time Dependent then you may specify the time at which the loads and boundary conditions set contours will be evaluated.

Select Groups This area of the form permits contour display control by groups. Selecting All Groups causes contours to be displayed in all groups. Selecting Current Viewport provides contour display only on those groups in the Select Groups listbox. At least one group must be selected.

Fringe Attributes See Display Attributes (p. 6) in the Results Postprocessing.

Reset Graphics Select this databox to remove the contour plot and restore the original model display.


50

This is the default form that is displayed when the Modify Vector Display toggle is on. This allows the current vector Load/BCs display to be displayed in a coordinate frame that is different than one used when the Load/BC set was created. This feature doesn’t cause the Load/BCs set to be altered. Only the display is temporarily altered.

Action The action will be either to remove (or reinstate) load and boundary conditions markers from the display.

Modify Vector Display This toggle allows vector Loads/BCs quantities currently displayed to be displayed in a different coordinate system.

Current Load Case This is the Current Load Case. To change the current load case, select this box and make a new selection in the listbox that appears.

Assigned Load/BCs Sets

These load and boundary conditions sets are assigned to the Current Load Case. Select the ones you wish to act on. They will be highlighted. Click a second time to deselect. Only Load/BCs in the Current Load Case can be displayed with this form.

Group Filter This area of the form permits marker display control by groups. Selecting All Groups provides a filter list of all groups available in the model. Selecting Current Viewport provides a filter list of only those groups in the current viewport.


Modify Vector Display The Loads/BCs vector display will be restored to its original orientation whenever: (1) a new Loads/BCs set is created, (2) a Load/BCs set is modified, (3) a Loads/BCs set is deleted or (4) the database is closed.

Use Existing Selecting the Use Existing switch will allow the user to select an existing coordinate frame in the Select Coord Frame selectdatabox. This is the coordinate frame in which selected vectors will be displayed.

Entities Selecting the Entities switch allows the user to select geometric and/or FEM entities on which the vector display is to be modified. Selecting the Vector Load/BCs Sets allows the user to display all the currently displayed Load/BCs set vectors in the selected coordinate frame.

Note: The display of displacements and other Load/BCs set types which use an implied local coordinate system (e.g., Pressure, Distributed Load) will not be altered. When the apply button is selected, the Vector coloring method on the Vector Attributes form is set to component.


52

Selecting the Define Local switch will allow the user to define a local coordinate frame. The local coordinate system definition is similar to defining a beam cross section orientation. This is the coordinate frame in which selected vectors will be displayed.

Note: In many cases, the table is much larger than can be displayed on the screen. Use scroll bars to view the entire table.


Define Local The Define Local option allows the user to modify vector display on nodes.

Nodes The Nodes selectdatabox allows the user to select the nodes on which the vector display will be modified. These nodes are also the used as the origin of the coordinate system.


54

Nodes on 1-Axis Nodes on the 1-Axis define the orientation of the 1-axis. If this list is empty the nodes Nodes list are paired sequentially to define the 1-Axis. The last node in the Nodes list is used for orientation only. If this list is not empty then the nodes in this list are paired with the nodes in the Nodes list. If there are more nodes in the Nodes list than in this list, the last node in the Nodes on 1-Axis is paired with the remaining Nodes list nodes.

Vector(s) in 1-2 Plane Vectors in 1-2 plane define the orientation of the 1-2 plane. One or more vectors can be used to define the 1-2 plane. If there are more nodes in Nodes list than in this list then the last vector will be used for the remaining nodes. If there are more vectors that nodes then the remaining vectors in this list are ignored.

Note: When the apply button is selected, the Vector coloring method on the Vector Attributes form is set to “Same For All”

55Ch. 2: Loads and Boundary Conditions ApplicationLoads and Boundary Conditions Global Display Parameters

2.4 Loads and Boundary Conditions Global Display ParametersThis section includes display parameters which affect the Loads/BCs application. All of these parameters are found under the top menu pick “Display.” For more help see Display>LBC/Element Property Attributes (p. 393) in the Patran Reference Manual.

Form Effect

Display/Functional Assignments • Global control of Functional Assignment marker display. Allows user to change the colors and turn the display on/off of set types.

Display/Entity Type • When the graphic preference is set to “entity mode,” the Display FA Vectors affect whether any Functional Assignments markers are displayed.Note: This can be used to quickly refresh the graphical display, but once this toggle is off, no markers will be displayed until it is turned on again.

Display/Group • When the graphics preference is set to “group mode,” the Display FA Vectors affect whether any Functional Assignments are displayed.

Display/Properties/Vector • Allows user to control whether graphical “vectors” (i.e., arrows) are displayed with a constant length or are scaled relative to their magnitude.

Display/Properties/Geometric • The number of visualization lines parameter affects where the Loads/BCs markers are displayed on geometric entities. If this number is greater than 10, markers will only be calculated at locations corresponding to 10 visualization lines.

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56

Ch. 3: Element Properties ApplicationPatran Reference Manual

3 Element Properties Application

Overview of the Element Properties Application 58

Rules for Creating/Modifying/Applying Element Properties 61

Element Properties Forms 63

Patran Reference ManualOverview of the Element Properties Application

58

3.1 Overview of the Element Properties Application

PurposeThe Element Properties application provides the ability to: (1) define sets of analysis code specific element properties, and (2) apply, or associate these sets with selected finite elements. Element properties are created in named groups that are referred to as sets. The general use of Fields in defining sets is supported. Element Property sets also reference material properties created in the Materials top menu selection. Element Property sets remain in the database unless specifically deleted and thus provide an archival record. The ability to display individual properties, both in tabular form or visually on the model, is also provided.

Definitions

Element Property Set:

A group of properties (e.g., thickness, mass, density, material name), that when taken together, provide all necessary information to define a specific element type as required by the selected analysis code. Sets have an associated name and number. Names are supplied by the user, and numbers are assigned in sequence by Patran. The only place you will see numbers displayed is in the Show/Marker Plot option. This is because text information cannot currently be displayed as marker annotation.

Analysis Code:

Each Element Property set is associated with a specific element type of a specific analysis code.

Fields:

A Field is a scalar or vector quantity that is a function of up to three independent variables. It can be defined by tables or PCL expressions, and can be applied to both the definition of material properties and element properties. Examples would be a thickness distribution of a shell, or the stress-strain behavior in a material. Fields are defined in the Fields application switch. In Element Properties, names that are prefixed by f: are field names.

Markers:

These are the graphic symbols that appear on the screen and provide visual feedback of the location, magnitude and direction of displayed element properties. They appear as the result of a Show/Marker Plot action. To remove them from the screen, turn off the “General Marker” display in the Display/Functional Assignments menu or click on the clear display icon (broom).

Scalar Plot:

Virtually all element properties can be displayed as fringe plots on the model. Select the Show/Scalar Plot option and then the property to be displayed. To remove the plot from the screen, select the Display/Entity Types menu and change the Render Style to Wireframe or click on the clear display icon (broom).

59Ch. 3: Element Properties ApplicationOverview of the Element Properties Application

Tabular Plot:

A table which lists all elements with the selected property in the current viewport or all viewports in sequence along with the associated Set Name(s), Property Type, and Value.

Property:

A property is any information required to define FEM element properties as required by an analysis code. These include thickness, spring constants, areas, degrees-of-freedom, offsets, directions, masses, etc. Each property has a name and is of a specific type.

Property Type:

Each property has an associated property type. There are nine different property types: Integer, Real Scalar, Real Scalar List, Vector, Material Name, Character String, Node, Coordinate Frame, and Nodal Field Name. Every Property is classified as one of these types.

CapabilitiesThe Element Properties application has the capability of creating, modifying, deleting and showing sets of element properties. Element properties associated with all of the analysis codes listed under Preferences/Analysis are supported.

The Element Property sets that can be created also depend on the type of analysis being performed. Three different types are currently supported: Structural, Thermal, and Fluid Dynamic (CFD). Several analysis codes support both structural and thermal analyses.

Element properties are created and stored in the database as sets. Each set has a unique name and is associated with one analysis type (e.g., structural), one analysis code (e.g., MSC Nastran), and one element type (e.g., QUAD4). If the analysis code or analysis type preference is changed, the existing element property sets are modified to use the closest matching element type in the new preference environment. All applicable property data is automatically transferred.

Existing sets can be identified by selection within the respective Existing Sets listboxes, manual entry (modify and delete) of the set name, or visually selecting associated entities from the screen. If more than one unique property set results from a screen selection, all unique property set names associated with the screen-picked entities will be displayed alphabetically in a Selection Listbox to allow the final selection of a single existing property set. The delete operation has a slightly different behavior where all of the screen-picked property set names will be echoed in a To Be Deleted listbox.

Sets can be visually displayed on the screen by markers which show the location, type, magnitude, and direction of the selected property. Sets can also be displayed as tables.

A powerful capability is the display of any set scalar data directly on the model as a fringe plot. For display purposes, data is treated as “results,” with full user control over the spectrum, method, shading, etc. Data display is scalar, of course, but the data can be any nonvector element property.

Patran Reference ManualOverview of the Element Properties Application

60

The use of PCL commands in defining properties is supported indirectly. First, use the PCL option in the Fields function to create the desired input data distribution. The field can be used in the Element Properties function by simply selecting it from a listbox display.

Summary of Key Features

FEM and Geometric Associativity

The Element Properties function provides a straightforward, convenient means for taking property data, whether from fields or direct input, and associating it directly with FEM entities or indirectly through Geometric entities. Data is grouped as uniquely named sets. These sets can be created, deleted, modified or displayed.

Archival Records Provides archival records in the model database of all previous property sets unless specifically deleted.

Set Manipulation Combines Material Properties and other property data into sets and associates these sets with FEM entities (e.g., QUAD4s). Provides a means of creating new sets that are modifications of existing sets.

Set Creation Provides for creating, deleting, modifying and showing sets. Visual display of sets includes showing the type, location, magnitude, and direction of properties. Entities and their associated properties can also be shown in a table format.

Set Selection Provides for selection of existing property sets by selecting associated entities from the screen.

Fields Support Fully supports the use of Fields in defining data input. This permits access to PCL commands in defining spatially varying property distributions.

Multiple Analysis Types Provides support for structural, thermal, and fluid dynamic (CFD) analysis types.

Scalar Data Display Scalar data (e.g., thickness) can be displayed as fringe plots on the model. The data is treated as “results,” with full control over the display (e.g., spectrum, shading, type, etc.).

61Ch. 3: Element Properties ApplicationRules for Creating/Modifying/Applying Element Properties

3.2 Rules for Creating/Modifying/Applying Element PropertiesAll Element Property sets created are associated with an analysis preference. This preference is selected in the Preferences/Analysis menu. Make the appropriate selection before proceeding. Be aware that if the analysis preference is changed during a session, Patran will attempt to convert existing element property sets to the new preference environment. Converting back to the original preference will not necessarily restore the element property definitions to their original state. To run the same problem on different codes, while maintaining the original state of the element property definitions, copy the database, change the analysis preference, and make the appropriate changes to element properties, materials, loads, etc.

Element Property sets can be created, modified, deleted, and displayed. Set Modification is completely general in that this action essentially deletes the original set and replaces it with the modified set.

The Create option may also be used to Modify a set. The only difference is that you will be prompted with a message warning that the set already exists, and asking whether it should be overwritten.

Creating a new set that is a modification of an existing set is accomplished by creating a renamed set using the Create action.

The region of application on the model of the defined set is established using the standard selection tools. The ID of selected items is displayed in the Select Members databox. These members can be added or removed from the Application Region by pushing the appropriate button on the form. The Application Region listbox can also be edited directly. The Element Property set is applied to the members in the Application Region box, not the Select Members box.

The Option(s) portion of the form will vary with element type, as will the menu brought up by selecting Input Properties. The typical Input Properties menu has boxes for providing data values as well as specifying material and field names. To avoid confusion field names are prefixed by f: and material names by m:. Also, property inputs that are enclosed in [brackets] are optional, and need not be input if the defaults are applicable.

Element Property sets are associated with specific finite element types. See the preference guide or the user manual for discussions of the large number of specific element types and properties supported. Elements may be associated to only one element property set. Property sets that are associated directly to elements take precedence over property sets associated to elements through geometry.

The use of fields to define complex spatial data distributions, such as thickness distributions, is encouraged. Fields are created in the separate Fields application. The use of Discrete FEM Fields can be very helpful for properties that vary in value for many elements but can not be defined using a function. In general, Element Discrete FEM Fields should be used. There are cases where a Nodal Discrete FEM Field is more convenient. One such case is for a thickness which varies across the element. Care must be taken when using Nodal Discrete FEM Fields for property values that may not vary within a given element. In this case, the Field evaluator will average the values for each of the element nodes. This may result in unwanted values.

Material properties are created separately in the Materials application. Material properties must be defined prior to creating element property sets. Their existence is required to complete definition of the

Patran Reference ManualRules for Creating/Modifying/Applying Element Properties

62

property set. If you don’t have the material properties yet, input a dummy material name in any required material property databox, and a blank material will automatically be created.

The PATRAN 2.5 Neutral File uses material numbers rather than material names. If a PATRAN 2.5 Neutral File is created under File/Export or Analysis translation, the material names supplied by the user will appear in the Neutral File as material numbers assigned in sequence by Patran. If a material number is significant to an analysis code using the Neutral File (e.g., a pointer to a materials library), the user should use an explicit material number instead of a name. For example, the material name “m:18” or “MATRL.18” will be passed to the Neutral File as material “18,” even if it is the only material in the database.

Important: Do not mix material names and material numbers in the same database.

63Ch. 3: Element Properties ApplicationElement Properties Forms

3.3 Element Properties FormsThe functions of the Element Properties menu are listed and described below in the order in which they appear on the menu.

Menu Pick Action

Create ... Input analysis code specific finite element property data and associate that data with selected FEM or geometric entities.

Modify ... Make any modification desired to Existing Property Sets.

Delete ... Remove element property sets from the database.

Show ... Display tables listing FEM or geometric entities and their associated properties. Create scalar, vector, and marker plots of selected properties.

Patran Reference ManualElement Properties Forms

64

Create Element Property SetsThis form is used to both define element property data and associate that data with selected entities. Property data is intrinsically code specific, so be sure that the desired analysis code has been selected (see the Preferences/Analysis menu). Property sets have both an associated name and number.


Dimension The element types are 2-Dimensional. The options are:

• 0D (e.g., mass)

• 1D (e.g., beam)

• 2D (e.g., shell)

• 3D (solid)

Type The options for the types of elements are analysis code specific. Refer to the Preference Guide or the analysis code User’s Guide for help.

Existing Property Sets The names of previously defined property sets are listed in this databox. Select one if you want to use it as the template for the new set.

Property Set Name Select this databox and give the set a new unique name (31 characters maximum). This databox will also allow existing property sets to be selected from the existing properties listbox or by selecting entities from the screen. If more than one unique property name results from a screen-pick, a Selection Listbox will appear, allowing the selection of a single property set name.

Options The options selection databoxes that appear in this portion of the form are analysis code specific. Refer to the code users manual for help in making the desired selections.

Input Properties... Select this databox to bring up the form used to input properties relevant to the type and option selected.

Select Members Select this databox and enter the entity IDs which you want to add or remove from the Application Region. Type in directly or use the selection tools. These can either be FEM, ASM, or SGM entities.

Add

Remove

These buttons are used to either Add or Remove the contents of the Select Members databox to/from the Application Region.

Application Region These are the entities to which the property set will apply. You can add or remove members either by editing the contents directly, or by selecting members in the select box and pushing the Add or Remove buttons.


• Patran ABAQUS

• Patran ANSYS

• Patran Marc


• Patran SAMCEF

• Patran FEA

• Patran Thermal


66

Typical Element Properties Input Menu

There are different Input Properties menus for virtually all element types used in all analysis codes and their different analysis types. The menu below is the one for the homogeneous shell element in ABAQUS. It is typical of many of the different menus.

Defining Vectors

When the “Value Type” for any data box in the Input Properties form is “Vector” a vector definition is expected. The general syntax for vectors is defined in The List Processor (p. 43) in the Patran Reference Manual. Element Properties extends this to allow an alternate coordinate system to be specified for interpreting the vector. This syntax is:

“vector_specification coordinate_frame”

A simple example is “<0 1 0> Coord 3”. The vector <0 1 0> is interpreted as being in coordinate system 3. If the vector needs to be in any other system, the appropriate transformation is done by Patran.

Any valid vector specification that can be generated by using the Select Menus or entered by hand may be followed by a coordinate frame. The coordinate frame is stored with the vector and is used whenever the vector is referenced for any purpose (eg. Display or analysis code translators).

When the Value Type for any data box is Vector and the data box is selected the following select box appears on the screen.

Material Name Specific input items are listed in this column. Items in brackets are optional.

Value Input the desired values in these databoxes. When names are selected for the listbox below, they will include a type prefix: “m”: for material name and “f”: for a field name.

Value Type Each property has a value type. These are listed in this column for reference and indicating what the analysis code is expecting. Some properties may be one of several value types. In this case an option-menu containing the valid value types will appear. Properties enclosed in [ ] are optional.

Field Definitions This listbox will appear when Material Property Sets or Field Definitions may be used in the selected Value databox. Selecting a field or material will cause the name to appear in the Value databox. Read Section 3.2 Rules for Creating/Modifying/Applying Element Properties for use of Discrete FEM Fields.


• Patran ABAQUS

• Patran ANSYS

• Patran MSC.Marc


• Patran SAMCEF

• Patran FEA

• Patran Thermal

68

After a vector has been defined it may be verified by selecting the Show Action, the Property Name, and Display Method Vector Plot. The vectors defining the property will be shown on the model.

Users should be aware of possible difference between the Patran and analysis code definitions for vector properties. For example, in Patran the beam orientation is completely independent of the analysis coordinate system at the beam nodes. In MSC Nastran, the orientation vector is assumed to be defined in the same system as the analysis system at the first node of the beam. In PatranNastran it is perfectly permissible to define the orientation in a different coordinate system from that analysis system. When the MSC Nastran input file is generated, the necessary transformation of this vector to the analysis system at node 1 will be performed.

These select tools provide different options for defining vectors. They are discussed in more detail in Select Menu (p. 35) in the Patran Reference Manual.

These three tools define the vector as the 1 (x), 2(y), or 3(z) axis of a selected coordinate system. This is a convenient way to specify the vector when it is aligned with one of the three axes of a rectangular coordinate system. When the system is not rectangular (e.g. cylindrical) these tools may not provide the desired definition because the defined vector does not change direction at different points in space— these tools just provide an alternate way to define a global vector.

This tool may be used to define a general vector with respect to an alternate coordinate system. When this icon is picked, the select menu changes to the one on the right.

These tools provide different ways to define vectors. In addition, the user is requested to select a coordinate system in which this vector is defined. The simplest list processor syntax that appears in the databox for a vector in an alternate coordinate system is <x_component, y_component, z_component> coord cord_id (e.g. <1, 0, 0> coord 3). In many cases it is easy to simply type a definition in this form into the databox.


Modify Element Property SetsModifying an Element Property Set is functionally equivalent to creating new set using an old set as a template and then deleting the old set. This enables a complete generality in the type and scope of modifications that can be made.


70

Dimension The dimensionality of the set can be changed. The options are:0D (e.g., mass)

• 0D (e.g., mass)

• 1D (e.g., beam)

• 2D (e.g., shell)

• 3D (solid)

Type The options for the types of elements can be changed. These are analysis code specific. Refer to the Preference Guide or the analysis code user manual for help.

Select Prop. Set to Modify

The names of previously defined property sets are listed in this databox. Select one you want to modify.

New Property Set Name

Give the set a new name (31 characters maximum). This databox allows existing Property Sets to be selected from the existing properties listbox or by selecting entities from the screen. Existing property set names can also be manually entered.

Options The options selection databoxes that appear in this portion of the form are analysis code specific. Refer to the code users manual for help in making desired modifications.

Select Members Select this databox and input the entity IDs which you want to add or remove from the Application Region. Type in directly or use the selection tools.

Add

Remove

These buttons are used to either Add or Remove the contents of the Select Members databox to/from the Application Region.

Application Region These are the entities to which the property set will apply. You can add or remove members either by editing the contents directly, or by selecting members in the select box and pushing the Add or Remove buttons.

Note: The set is not modified until Apply is selected. Wait for the green heartbeat before proceeding.


Delete Element Property SetsDeleted Element Property Sets are removed from the database. They can only be restored if the “undo” icon is selected as the next subsequent action.


72

Prop. Sets By Name The names of existing property sets appear in this listbox. As each one is selected, its name is echoed in the delete listbox below.

This toggle enables Property Set Name databox. If this toggle is off, the databox will not be displayed.

Filter Use the filter button to filter the Property set list.

Screen Picked Property Set

This databox allows existing Property Sets to be selected by selecting entities from the screen. All unique property sets associated with the screen-picked entities will be highlighted in the existing properties listbox above and echoed in the delete listbox below. Existing property set names can also be manually entered.

Auto Add/Remove If On, properties selected in the top listbox are immediately removed and added to the bottom listbox, and properties selected in the bottom listbox are immediately removed and added to the top listbox.

If Off, the Add and Remove buttons perform the same function manually.

Selected Property Sets This databox lists the names of sets that will be deleted when Apply is selected. If you decide you do not want to delete a listed set, remove it from the list by selecting it.

Clear Removes all properties from the listbox above and adds them to the top listbox.

Note: The sets are not deleted until Apply is selected. Wait for the green heartbeat before proceeding.


Show Element Property Sets “Show” in this form does not apply to showing the contents of an Element Property Set. Use the Create or Modify actions for that purpose. This form permits display of selected properties assigned to entities in the current viewport or in all groups. Property display can be either by table, by placing annotated markers or vectors on viewport displayed entities, or by creating a contour plot of the selected property on the model.


74

Existing Properties This is a list of all of the types of properties that have been defined, regardless of set association, that are available to be shown. Select one. Note that names are displayed as their associated integer value in the graphical display. For example, property sets are given an integer ID in the order of their creation.

Type The type of the selected property appears here (e.g., integer, real scalar).

Display Method Select the desired method of display. The available options are Table, Plot Marker, and Plot Scalar.

Table: Displays a table listing each element that has the selected property, the set name, data type, and data value.

Marker Plot: Marker symbols are plotted at the center of each element or geometric entity along with the data value (e.g., set ID number).

Vector Plot: Vectors are plotted at the center of each element or geometric entity.

Scalar Plot: Makes a color contour plot of the data values on the model and displays a value spectrum bar. The default plot type is “Fringe-Flat.” This can be changed in the Display/Entity Types menu.

Note: To display properties assigned to geometric entities on their associated elements, select the “Display on FEM only” toggle in the Display/functional assignments menu pick. See Display>LBC/Element Property Attributes (p. 393) in the Patran Reference Manual for more information.


Show Element Properties in Tabular Format

Entitiy Column The first column is a list of the entities that have the selected property (e.g., have a specified thickness).

Property Set Name Column

The second column lists the names of the Element Property Sets associated with the column 1 entity.

Data Type Column The third column lists the type of data (e.g., integer, real scalar, field at nodes, etc.).

Value Column The fourth column lists the data value. Fields are not evaluated. Use the Scalar Plot option to show field defined values.

Elementprops Table Show

Entity Data Type

Element 1

Element 2

Element 3

Element 4

Element 5

Element 6

Element 7

Element 8

tank_flange

tank_flange

tank_shell

tank_flange

tank_flange

tank_flange

tank_flange

tank_shell

Real Scalar

Field at Nodes

Real Scalar

Real Scalar

Real Scalar

Real Scalar

Real Scalar

Field at Nodes

0

f

0

0

0

0

0

f

Property Set Name


76

Show Element Properties as a Scalar, Vector, or Marker Plot


Existing Properties Select the type of property to be displayed. The type of the property appears immediately below as shown.

Display Method Select the Marker Plot, Vector Plot, or Scalar Plot option.

Marker Plot: Marker symbols are plotted at the center of each element along with the data value (e.g., set ID number).

Scalar Plot: Makes a color contour plot of the data values on the model and displays a value spectrum bar. The default plot type is “Fringe-Flat.” This can be changed in the Display/Entity Types menu.

Vector Plot: Vectors are plotted at the center of each element or geometric entity.

Select Groups Property display can be restricted to just those elements in selected groups in the current viewport, or can include all elements in all groups that have the selected property. Note: At least one group must be selected.

Fringe Attributes See Display Attributes (p. 6) in the Results Postprocessing.

Note: After completing the show action, the display will remain on the model. Scalar plots can be erased by changing their type to “Wireframe” in the Display/Entity Types menu. Markers are removed by turning off the “General Marker” display in the Display/Functional Assignments menu. The display can also be reset by pressing the “clear display” icon (broom).


78

Expand Element Properties

The Expand form will expand one element property assigned to many elements into many element properties assigned to one element each.


Prop. Sets By Name List the properties by Name, ID, or Suffix. Then select the properties to expand.


Property Name Options

Prop Name.Elem ID is the original name of the property to be expanded. Elem ID is the ID of the element which the new property will be associated with.

Use the Prefix or Suffix options to add a specific (maximum of 8 characters) Prefix or Suffix to the name of the new property.

Delete Original Property Sets

If checked, Patran will automatically delete the original (now empty) property set.


80

Compress Element Properties

You can use the Compress Element Properties form to select Property Sets to be compared against each other. Any duplicate sets are merged to the one with the first alphanumeric name..


Action Choose the object dimension or any object dimension.

Object Select the type or any to be compressed.

Type Choose the method by which the property sets will be sorted.

Prop. Sets By Name The names of existing property sets appear in this listbox. As each one is selected, its name is echoed in the Selected Property Sets listbox below.


Screen Picked Property Set

Allows picking a property by picking an entity that references that property.

Auto Add/Remove If On, properties selected in the top listbox are immediately removed and added to the bottom listbox, and properties selected in the bottom listbox are immediately removed and added to the top listbox.

If Off, the Add and Remove buttons perform the same function manually.

Selected Property Sets This databox lists the names of sets that will be compressed when Apply is selected. If you decide you do not want to compress a listed set, remove it from the list by selecting it.

Apply This button causes all of the sets in the Selected Property Sets listbox to be compared against each other. Any duplicate sets are merged to the one with the first alphanumeric name. The Significant Digits value can be changed based on the precision desired (Default = 3). The sets that are merged are deleted. Compression information is written to the file "compress.prop.rpt" in your current directory unless a preference is set false with the following command:

pref_env_set_logical( "property_compress_file_write", FALSE )


82

Ch. 4: Materials ApplicationPatran Reference Manual

4 Materials Application

Overview of the Materials Application 84

Rules for Creating/Modifying Materials 86

Materials Forms 87

Composite Materials Construction 112

Theory - Composite Materials 138

84Ch. 4: Materials ApplicationOverview of the Materials Application

4.1 Overview of the Materials Application

PurposeThe Materials application provides the ability to define groups of analysis code specific material properties. Materials or “material models” are created as named groups of individual properties. Each group is intended to provide only the information necessary to define a material for use with a specific analysis code, analysis type, and possibly a specific element type. There is no intent to provide a complete material specification or database “undo.”

A single Material may, however, have multiple Constitutive Models associated with it. Thus, a material might have an elastic representation and an inelastic one under the same name. The specific representation of a given material used for an analysis is controlled via the Material Status. Patran will attempt to use all Active Constitutive Models when an analysis is submitted. To use a simple elastic model for check runs, set all other Constitutive Models Inactive. To use a more complex model for detailed studies, set the simpler Constitutive Models Inactive.

Material property data may be obtained directly from the Patran Mvision material databases through the Patran Materials, as well as input directly. There is also the capability to define and assign materials in name only. This permits property data to be included in run files external to Patran.

Material Property Fields can be created which define distributions of any property with respect to any combination of temperature, strain, or strain rate. Materials remain in the database unless specifically deleted and thus provide an archival record. The ability to display properties versus temperature, strain, and strain rate is provided in either tabular form or as XY plots. Resultant stiffness and compliance matrices can also be displayed.

Material Names: The material name may be assigned as a character string or an integer (e.g.,18, m:18 or MATRL.18). Use a number if the material number is significant to the analysis code, such as a pointer to a materials library.

DefinitionsMaterial Property: A material property is any information used to create a material model that is required by a specific analysis code. These include items such as density, specific heat, elastic modulus, Poisson’s ratio, etc.

Note: If a PATRAN 2.5 Neutral File is exported from Patran, materials that were assigned a character name will appear in the Neutral File as a material ID number in the sequence in which they were created.

Important: Do not mix material names and numbers in the same database.

85Ch. 4: Materials ApplicationOverview of the Materials Application

Material: Also called a Material Model. A group of material properties that, when combined, provide all necessary information to define a material as required by the selected analysis code. Materials have an associated name and description. These are supplied by the user.

Material Property Fields: A Material Property Field is a distribution of a material property with respect to temperature, strain, strain rate, time or frequency. It is defined by tables that are input in the Fields top menu selection. An example would be the dependence of an elastic modulus on temperature.

XY Plot: Virtually all material properties can be displayed as XY Plots with the X-axis being temperature, strain, or strain rate. For bivariate properties, additional curves can be plotted at different values of the third variable. See Overview of the XY Plot Application (Ch. 1) in the Patran User’s Guide for more information.

CapabilitiesThe Materials application has the capability of creating, deleting, modifying, and showing materials.

Materials are created and stored in the database as named groups of property data. Each group has a unique name and is associated with one analysis type (e.g., structural), one analysis code (e.g., MSC Nastran), and in some cases one element type. Multiple models involving different Constituent Models can be created under the same Material name. The particular model used for an analysis is controlled by the Constituent Model Status.

Materials can be visually displayed as XY Plots of a selected property plotted as a function(s) of temperature, strain, or strain rate. Multiple curves can be created and included in the same plot, permitting comparisons to be made between materials. Properties can also be displayed as tables. Both stiffness and compliance matrices which result from the input values can be displayed.

Summary of Key FeaturesThe Materials function provides a straightforward and convenient means for taking property data, whether from fields or direct input, and grouping it in specific formats for code dependent element property definition. These data are grouped as a named Material. Materials can be created, deleted, modified or shown. Key features of the Materials function are:

• Provides archival records in the model database of all previous Material property data unless specifically deleted.

• Fully supports the use of Material Property Fields in defining data input. These Fields can provide property variation with respect to temperature, strain, strain rate, time or frequency, as well as various combinations of these.

• Provides support for structural, thermal, and fluid dynamic (CFD) analysis types.

• Provides for creating, deleting, modifying, and showing sets. Visual display of sets includes creating XY plots of selected properties. Tabular display includes showing resultant stiffness and/or compliance matrices resulting from the input properties.

86Ch. 4: Materials ApplicationRules for Creating/Modifying Materials

4.2 Rules for Creating/Modifying MaterialsAll Material Properties created are associated with an Analysis Preference. This preference is selected in the Preferences/Analysis menu. Make the appropriate selection before proceeding. Be aware that if the analysis preference is changed during a session, Patran will attempt to convert existing material properties to the new preference requirements. No record of the properties entered with the original preference active is retained, so converting back to the original preference may not completely restore the material property sets.

Materials can be created, deleted, modified, and shown. Modification is completely general in that this action essentially deletes the original set and replaces it with the modified set.

The Create option may also be used to Modify a material. The only difference is the user will be prompted with a message warning that the set already exists and asking whether it can be overwritten.

Creating a new material that is a modification of an existing material is accomplished by creating a renamed set using the Create action.

Every Material has a unique, user-defined name from 1 to 31 characters long. A sequential ID number is also automatically assigned for internal use, and may be supplied to certain analysis codes during translation.

Each material has an associated user provided description (1 to 256 characters). By default, this descriptor contains the date and time of the start of the Patran session during which the material was created.

Material properties may be associated with specific finite element types. See the Translator Documentation for discussions of large numbers of specific element types and properties supported.

The use of fields to define complex temperature, strain, strain rate, time or frequency dependencies is encouraged. These material property fields are created in the Fields application. Multiple material fields can be used in the definition of a single material.

87Ch. 4: Materials ApplicationMaterials Forms

4.3 Materials FormsThis section provides help for the forms that are used to create, delete, modify and show material properties and materials. Only those forms that are of general use are included here. A reference is provided in the appropriate chapter of the translator documents which describes each material form as it applies to the preferred analysis code and the type of finite element model.

Create MaterialsThis is the basic form used to create all homogeneous material models. Materials are defined with reference to a specific analysis code. Be sure the proper code and type have been selected before proceeding (Preferences/Analysis menu).

Option Description

Create Materials • Manual Input

• Constitutive Model Status

• Materials Selector

• Externally Defined

• Create Composites

Show Materials • Tabular

• Show Composites

Modify Materials • Isotropic

• 2d Orthotropic

• 3d Orthotropic

• 2d Ansiotropic

• 3d Ansiotropic

• Modify Composites

Delete Materials


Material property inputs depend on:

• Analysis Code Selection (e.g., ABAQUS)

Object Select the material category to be created. All materials which belong to that category are listed in the Existing Materials box. (Provide additional filtering if the list is lengthy.)

Method Select the Method to be used to create the Material. The three available Methods are:

Manual Input of the properties from an auxiliary form.

Material Selector - Utilize P3/Materials Selector Database to obtain material properties.

Externally Defined - Create and assign material names only, with properties supplied externally.

Existing Materials Selecting a material in the Existing Materials box causes it to be transferred to the Material Name databox.

Material Name Each material must have a unique name (1 to 31 characters). It will also be assigned a sequential Material ID number automatically.

Description User-supplied descriptions of a selected material are displayed here for reference (2500 characters maximum).

Code: / Type: The Analysis Preference and Type are displayed for reference. Check for correctness.

Input Properties Input Properties brings up forms for data entry.


• Patran ABAQUS

• Patran ANSYS

• Patran LS-DYNA3D

• Patran MSC.Marc



• Patran PAMCRASH

• Patran SAMCEF

• Patran P2NF

• Patran FEA

• Patran Thermal



• Analysis Type Selection (e.g., Structural)

• Specific Constitutive Equations (e.g., Isotropic, 2D Orthotropic)

• General Behavior Model (e.g., Elastic or Viscoelastic)

• Specific Behavior Model Inputs (e.g., Damping Constant, Exponents)

• Failure Theory and Related Model Inputs (e.g., von Mises, maximum stress)

There is a very large number of options available, and the information for creating them all is not resident in this help section. It is available, however, in related sections located in the specific preference documentation.

Manual Input

This is one of literally hundreds of Input properties forms that can appear depending on the analysis code, type, material model, or option selected. Most forms are similar to this one. There is a Constitutive Model plus other option selections followed by places for input of specific property parameters. When a property input location is selected where the use of fields is appropriate, a list of Material Property Fields available for use appears as shown.


Constitutive Model First select the Constitutive Model for the material. A single material may have multiple constitutive models.

Property Name/Value Input the values necessary to define the material model.


Constitutive Model Status

A single material may contain multiple Constitutive Models. The Constitutive Model used is determined by the Constitutive Model Status. Patran will use all Constitutive Models active when the analysis is submitted. Redundant or unneeded Constitutive Models should be rendered inactive.

Existing constitutive models of an existing material will appear in either of the listboxes, depending on their active/inactive status. Selection of a model from one listbox will add it to the other one.

Temperature Dependent Fields

When an input databox is selected which allows a field definition, this listbox will appear with a list of available Material Property Fields. Selecting a Field enters its name into the input property databox.

Current Constitutive Models

The existing constitutive models and their respective options as well as their status (i.e., active or inactive) will appear here. A newly created set will appear as an active model, after Apply is selected.


• Patran ABAQUS

• Patran ANSYS

• Patran LS-DYNA3D

• Patran MSC.Marc



• Patran PAMCRASH

• Patran SAMCEF

• Patran P2NF

• Patran FEA

• Patran Thermal



Materials Selector

This form is used to invoke the Patran Materials product which can access Patran Mvision databases to define properties for the selected material.


Materials Selector Database

This form is used to select and access the Patran Mvision Materials Selector Databases that contain the needed materials data.

Object Select the material category to be created.

Method Selecting Materials Selector, as the method, changes the form to the one shown here and displays the Database Selection menu. See Materials Selector Database, 94.

• MSC.Mvision Materials Selector Databases

More Help:


Externally Defined

The Externally Defined method is used when a material name is necessary for creation of Element Properties, but the actual material properties will be supplied by the user external to Patran.

Directories First, select a directory or enter the path to the directory where the database resides. Use the Filter button to search the selected directory for applicable databases.

Databases Available databases in the selected directory appear here. Select the one desired. Its name appears in the box below.

Apply Selecting Apply opens the database.

Materials Selector Databases

/smith/.. /smith/.fminit2.0 /smith/Exercises /smith/Mail /smith/Part_2_basic_functions /smith/Part_4_FEM

/smith/.

Directories Databases

/okinawa/users/smith/*.mdb

Filter

Existing P3Materials Selector Database

-Apply- Filter Cancel


Create Composites

This is the basic form used to create all composite materials.

Object Select the material category to be created. All materials which belong to that category are listed in the Existing Materials box. Provide additional filtering if the list is lengthy.

Method The material properties will be defined external to Patran, which will associate the input material name (and ID) with selected elements.

Existing Materials Selecting a material in the Existing Materials box causes it to be transferred to the Material Name box.

Material Name Each Material must have a unique name (1 to 31 characters). It will also be assigned a sequential Material ID number automatically.


Preference/Type The Analysis Preference and Type are displayed for reference. Check for correctness.

Input Properties Input Properties button is “grayed out” indicating it is not available for the selected External Definition Method.


Show MaterialsThis form is used to display both tables of the material stiffness and compliance matrices as well as XY plots of selected properties as functions of temperature, stress, or strain rate.

Method Select the type of composite material to be created. Laminate is the default. The Rule-of-Mixtures model, five Halpin-Tsai models, and two Short Fiber Composite models are also available.See Composite Materials Construction, 112 for more help.

Existing Materials Selecting materials in the Existing Materials listbox causes them to be written to the form containing composite model-specific definition data to be used as constituent materials. For example, if the “Laminate” Method is displayed, then selecting materials in the Existing Materials listbox causes them to be written in the Material Name column of the spreadsheet on the Laminated Composite form and treated as ply materials.

Laminated Composites Contains the existing materials that have been created using the material model indicated by the Method selection. Selecting materials in this listbox causes their names to be written to the Material Name databox and their definition data to be written to the model-specific form immediately to the left of this form.

Material Name Each material must have a unique name (1 to 31 characters). It will also be assigned a sequential Material ID number.

Material Descriptions User-supplied descriptions of materials (up to 2500 characters) are entered here.

Apply Selecting Apply causes the composite material definition on this form and on the model-specific form to be used to create a new composite material.

Reset Restores all composite material Create form inputs (including those on the model-specific form) to the values present at the last time Apply was selected.


Object Select the material category to be created. All materials which belong to this category are listed in the Existing Materials box. Provide additional filtering if the list is lengthy.

Existing Materials Selecting a material in the Existing Materials box causes it to be transferred to Material Name box.


Show Properties, Tabular

This form permits review of the input property values. They cannot be modified here. It also provides for display of the stiffness and compliance matrices that result from those properties.

Material Name Each material has a unique name (1 to 31 characters) and a unique Material ID. The Material ID is automatically assigned when the material is created.


Preference/Type The Analysis Preference and Type are displayed for reference. Check for correctness.


Constitutive Model Select the desired constitutive model for the material being shown. One material can have multiple constitutive models.

Property Name/Value This section of the form presents a reprise of the Create form, so it (or Modify) can also be used to review inputs.


Show Material Stiffness/ Compliance Matrix

This is the Material stiffness matrix that results from the constitutive model and input properties. Material directions follow the analysis code definitions. The matrix size is appropriate to the material type displayed. Compliance matrices can also be displayed.

Show Composites

This is the basic form used to show all composite materials.

Current Constitutive Models

Existing constitutive models of the material are listed here. The analysis options of models and their active/inactive status are also shown.

Show Material Stiffness

Show Material Compliance

These buttons show the selected matrix in a separate form, as shown on page 103.


Method Select the type of composite material to be shown. Laminate is the default. The Rule-of-Mixtures model, five Halpin-Tsai models, and two Short Fiber Composite models are also available.

Existing Material All existing materials are displayed in the Existing Materials listbox.


Modify MaterialsModifying a Material is a completely general operation in that the modified material overwrites itself in the database. Thus anything can be changed.

Laminated Composites Contains the existing materials that have been created using the material model indicated by the Method selection. Selecting materials in this listbox causes their names to be written to the Material Name databox and their definition data to be written to the model-specific form immediately to the left of this form.

Material Name Each material must have a unique name (1 to 31 characters).

Material Description User-supplied descriptions of materials (up to 2500 characters) are displayed here.


Modify Composites

This is the basic form used to modify composite materials.

Method The material category to be edited is selected here. Only existing materials that match the category will appear in the Material name listbox. See figure below for other categories.

Constitutive Model The material constitutive to be edited is selected here. Only existing materials that match the constitutive model will appear in the Material name listbox. When the selected category is Composite, this option menu changes to a label indicating that Laminates are the only Composites that may be modified in this form.

Material Sets By... Options to sort material set names by name, .ID or suffix.

Material Set Names Material set names to modify. Any number may be selected.

Filter Material Names Databox for entering a filter to use for displaying material set names. A "CR" with focus in this databox causes the current filter to be applied.

Filter Filter button to cause the material set names to be filtered by the current filter in the filter databox.

Material Values to Change All of the allowable property values common to the selected material sets. Multiple values may be selected.

Action The modify action to be applied. "Set Equal To" replaces the current value. "Delete" removes the property value. "Add", "Subtract", "Multiply" and "Divide" apply the operation of the new value to the current.

Always Update Values This toggle specifies whether a given material set should be given the property value even if the property value does not already exist. The default is Off or False.

Current Value The current value of the selected property value. If the property value does not exist for all of the selected material sets, the word "Undefined" will appear. If the property value does not exist for some of the selected material sets, or if the property value varies between material sets, the word "Varies" will appear.

New Value The new value to be assigned to operate on the current value.

Temperature Dep/Model Variable

If the property value and selected value type can be defined using a field, this listbox will contain those items which are available.


Method When selected category is Composite, only Laminates can be modified.


Delete MaterialsDeleted Materials are removed from the database. They can only be restored if the “undo” icon is selected immediately.

Mat. Value(s) to Change [ID] The only laminate value that may be modified is the offset.

Action Deleting the laminate offset value sets it to the default, which is half the thickness.


Object Select the material category to be deleted. All materials which belong to this category are listed in the Existing Materials listbox. Provide additional filtering if the list is lengthy.

Existing Material

Selected Materials

Selecting materials in the Existing Materials listbox causes them to be transferred to the Delete Materials list. Similarly, selecting a material in the Delete Materials listbox restores it to the Existing Materials list.

Description User-supplied descriptions of selected materials are displayed here for reference.

Compress Duplicate Data

This button causes all of the sets in the Selected Materials listbox to be compared against each other. Any duplicate materials are merged to the one with the first alphanumeric name. The Significant Digits value can be changed based on the precision desired (Default = 3). The materials that are merged are deleted. Compression information is written to the file "compress.mat.rpt" in your current directory unless a preference is set false with the following command:

pref_env_set_logical( "material_compress_file_write", FALSE )

Reset Reset restores all Materials in the Delete Materials listbox and thus to the Existing Materials listbox, if it is selected prior to selecting the Apply button.

112Ch. 4: Materials ApplicationComposite Materials Construction

4.4 Composite Materials ConstructionThe Method menu for Composite materials contains the nine composite material models shown below.

Laminated CompositeThe Laminated Composite option is used to compute the material properties of a laminate having, for each ply, an arbitrary constituent material, constant thickness, constant orientation and an optional global ply id for optimization. A laminate offset may also be specified. This is generally done when the neutral surface does not coincide with the middle surface. The offset is defined as the coordinate of the bottom of the stack relative to the neutral surface, which, by default, is the negative of half the laminate thickness.

Five Stacking Sequence Conventions are available for defining the layers. If there is no plane of symmetry, or global ply ids will be defined, then select the “Total” convention and define the attributes of all “n” layers of an n-ply stack. If the stack is symmetric or anti-symmetric with an even number of plies, select the appropriate convention and define the attributes of just the first n/2 layers. A (30,60,60,30) stack may be defined by selecting “Symmetric” and entering the angles “30 60" while a (30,60,-60,-30) stack may be defined by selecting “Anti-Symmetric” and entering the angles “30 60.” If the plane of symmetry passes through the center of a ply, use one of the “Mid-Ply” conventions and define the attributes of the first (n+1)/2 layers. A (45,90,45) stack may be defined by selecting “Symmetric/Mid-Ply” and entering the angles “45 90" while a (45,90,-45) stack may be defined by selecting “Anti-Symmetric/Mid-Ply” and entering the angles “45 90.” This last convention may be used with middle plies of arbitrary orientation to create laminates that are not truly anti-symmetric.

Global ply ids may only be entered when the Stacking Sequence Convention is “Total”. Attempts to enter them for other Stacking Sequence Conventions is not allowed.

Classical lamination theory is used to compute shell force-deformation properties. Other properties, including the elasticity matrix and the thermal expansion coefficients, are calculated using volume-weighted averaging. For more information on material property calculation, see Theory - Composite Materials, 138.

Option Method

Composite • Laminated Composite

• Rule-of-Mixtures Composite

• Halpin-Tsai Continuous Fiber Composite

• Halpin-Tsai Discontinuous Fiber Composite

• Halpin-Tsai Continuous Ribbon Composite

• Halpin-Tsai Discontinuous Ribbon Composite

• Halpin-Tsai Particulate Composite

• Short Fiber Composite (1D)

• Short Fiber Composite (2D)


Laminated Composite Form

This form contains a spreadsheet on which the composite ply material stacking sequence is defined. The spreadsheet can be loaded either by selecting ply materials from the Existing Materials listbox contained on the Materials application form or by entering a list of ply material names, thicknesses, orientation angles or global ply ids in the textbox on this form and selecting the Load Text Into Spreadsheet button, or by specifying the thickness for all layers of a given material in the lower databox. The user-selected cell determines where text is loaded into the spreadsheet. If in Overwrite mode, then the selected column is overwritten, starting with the selected cell, until the entries in the textbox are exhausted. If the entries exceed available space in the spreadsheet column, then a prompt will ask if additional rows are to be created. If in Insert mode, then new rows will be created just below the selected cell to accommodate the data in the textbox. If (as in the case at start-up) no rows exist, Insert mode is the default mode and entries in the textbox are loaded into the column specified by the switch on this form, starting at the first row.


Stacking Sequence Convention

Select the convention that matches your laminate. Select “Total” if there is no symmetry plane, or if you will be assigning Global Ply IDs, in which case all layers must be defined in the spreadsheet. Symmetric and Anti-Symmetric laminates require only the bottom half of the stack. The “Mid-Ply” options are similar, except that the last specified layer in the spreadsheet is not assumed to be repeated (ie., “0 45” defines a 0/45/0 stack).

If the convention is changed from “Total” and any non-blank Global Ply IDs exist, a warning will be issued and the option to clear all Global Ply IDs will be given. If declined, the convention will remain “Total”.


Offset Specify the laminate offset, which is the coordinate of the bottom of the stack relative to the neutral surface. If no offset is specified, Patran assumes that the middle surface is the neutral surface.

Stacking Sequence Definition

Select a cell to set the insertion or overwrite starting point. Select a method of entry: Overwrite or Insert mode. To delete a row of cells, select a group of cells in a column and select the Delete Selected Rows button.

If the Stacking Sequence Convention is not “Total”, cells in the Global Ply ID column may not be selected. Attempts to do so will fail and an informational message will be given.

Insert Material Names The textbox and its associated button, option menu and switch are strongly coupled to the spreadsheet. Enter strings of ply material names, thicknesses, orientation angles (in degrees) or global ply ids into the textbox. Then select the Load Text into Spreadsheet button to load the textbox contents into the spreadsheet. Entry starts at the selected cell (if in Overwrite mode) or just after it (if in Insert mode). The textbox title is determined by the settings of the associated option menu and buttons.

This textbox accept shorthand. For example

“-60,0,-60,0,-60,0” or “3(-60,0)” could both be used to enter the thicknesses shown above. To clear global ply ids cells enter “0” for the cell value. To clear a number of global ply ids enter “n(0)” where n is the number of rows to clear.

Delete Selected Rows Deletes the rows corresponding to any selected cells.

Thickness for All Layers

Enter a value and hit <Return or Enter> to load that value into the spreadsheet Thickness column for all rows where the Material Name matches the one given over this databox. To change the name of this material (in order to assign thicknesses to a different material), select a spreadsheet cell containing the name of the desired material. This databox is not displayed until a ply material name is entered into the spreadsheet.

Load Text Into Spreadsheet

Loads the contents of the textbox into the spreadsheet.

Show Laminate Properties

Displays the Composite Material Properties form showing all stored properties of the material specified in the Material Name databox contained in the Materials Application form.


Rule-of-Mixtures CompositeThe Rule-of-Mixtures model is used to describe three-dimensional solids having an arbitrary number of material phases with arbitrary orientations and volume fractions. Orientations are defined for each phase

using a triad of space-fixed rotation angles in a 3-2-1 sequence. These angles rotate the composite material frame into the phase frame. The orientation of each phase is defined by starting with

the phase frame aligned with the composite frame, and rotating the phase material frame degrees about

the 3-axis of the composite material frame, then rotating the phase frame degrees about the 2-axis of

the composite frame, and finally rotating the phase frame degrees about the 1-axis of the composite frame.

Rule-of-Mixtures materials are, in general, fully anisotropic. All properties are calculated using volume-weighted averaging. The algorithms are described in Rule-of-Mixtures Composite Materials, 143.

Text Entry Mode Determines whether textbox data are to be loaded into the Material Name, Thickness, Orientation or Global Ply ID columns. If any spreadsheet rows exist, a new cell will be highlighted in the appropriate column to indicate where data from the textbox are to be loaded. Global Ply IDs becomes inactive if the Stacking Sequence Convention is not “Total”.

Clear Text and Data Boxes

Clears the textbox and the two databoxes. The spreadsheet is unaffected.


Rule-of-Mixtures Composites Form


Halpin-Tsai Continuous Fiber CompositeThe Halpin-Tsai Continuous Fiber model is used to describe 2-phase composites in which the matrix phase is isotropic and the fibers are uniform, continuous, cylindrical, and transversely isotropic. The resulting composite is therefore transversely isotropic. The Halpin-Tsai relations are used to calculate

, from which the remaining elastic constants can be determined. Some

earlier versions of Patran calculated instead of , so this option is provided for compatibility.

Only the names of the material constituents and their respective volume fractions are required input. The volume fractions provide default empirical factors for the Halpin-Tsai equations. If Halpin-Tsai relations are not desired the Override Default Equations toggle may be selected and empirical factor may be entered for each of the five elastic constants. See the Halpin-Tsai material model discussion in Halpin-Tsai Composite Materials, 146 for the implementation of these constants in the Halpin-Tsai equations.

Phase Material Name List

Select phase materials by selecting their names in the Existing Materials listbox contained in the Materials application form. If the cursor is set in the Phase Material Name List textbox, then selecting a material in the Existing Materials listbox will cause that material name to be inserted at the cursor. Phase materials must have 3-D material properties.

Phase Volume Fraction Specify the phase volume fractions corresponding to the phase materials specified in the Phase Material Name List textbox. The number of entries should be the same in both textboxes, but the last volume fraction may be omitted, in which case it will be assumed to be that value which would make the sum of all volume fractions unity. If the last volume fraction is not omitted, then the sum of the volume fractions must be unity.

Phase Orientations Specify the phase orientations corresponding to the phase materials specified in the Phase Material Name List textbox. Phase orientations are

defined using a triad of space-fixed rotation angles in a 3-2-1 sequence. These angles (in degrees) rotate the composite material frame into the phase frame. The number of angles entered in the Phase Orientations textbox must therefore be three times the number of materials in the Phase Material Name List textbox. The first three angles are the first triad, the second three angles are the second triad, and so on. It is not necessary to group the angles with brackets or parentheses; simply input the sequence of angles separated by spaces.

Show Material Properties

Displays the Composite Material Properties form showing all stored properties of the material specified in the Material Name databox contained in the Materials application form. 2-D material properties, such as the shell force-deformation matrices [A], [B], and [D], which are not consistent with this 3-D material option, always have displayed values of zero.

Clear Clears all information from the three textboxes on this form.

EL ET LT GLT and GTT

TT GTT


The Halpin-Tsai Continuous Fiber model expects a transversely isotropic fiber material and an isotropic matrix material. Warning messages will occur if this is not the case. Patran will ignore any additional properties that those materials may have and use the minimum number required to create a transversely isotropic composite material. It is, therefore, possible to use fully anisotropic fiber and matrix materials to create a transversely isotropic material. Physically, this makes no sense, so be careful if the warning message should appear.


Continuous Fiber Composite Form

Material Constituents Select the fiber and matrix materials by clicking on their names in the Existing Materials listbox contained in the Materials application form. The switch, which you can set, determines whether the selected material goes into the Fiber listbox or the Matrix listbox.

Fiber Volume Fraction Use either the slide bars or the databoxes to set the Fiber Volume Fraction and the Matrix Volume Fraction. The two parameters are coupled so that their sum cannot exceed one. Sums less than one are permitted (but not recommended) for modeling voids.


Halpin-Tsai Discontinuous Fiber CompositeThe Halpin-Tsai Discontinuous Fiber model is used to describe 2-phase composites in which the matrix phase is isotropic and the fibers are uniform, discontinuous, cylindrical, and transversely isotropic. The resulting composite is therefore transversely isotropic. The Halpin-Tsai relations are used to calculate

, from which the remaining elastic constants can be determined. Only the

names of the material constituents, their respective volume fractions, and the fiber aspect ratio are required input. The volume fractions and fiber aspect ratio provide default empirical factors for the Halpin-Tsai equations. If the default Halpin-Tsai relations are not desired the Override Default Equations toggle may be selected and empirical factor may be entered for each of the five elastic constants, in which case, the fiber aspect ratio is no longer required. See the Halpin-Tsai material model discussion in Halpin-Tsai Composite Materials, 146 for the implementation of these constants in the Halpin-Tsai equations.

The Halpin-Tsai Discontinuous Fiber model expects a transversely isotropic fiber material and an isotropic matrix material. Warning messages will occur if this is not the case. Patran will ignore any additional properties that those materials may have and use the minimum number required to create a transversely isotropic composite material. It is, therefore, possible to use fully anisotropic fiber and matrix materials to create a transversely isotropic material. Physically, this makes no sense, so be careful if the warning message should appear.

Override Default Equations

Enable the five Empirical Factors databoxes.

Empirical Factors If enabled, enter five Empirical Factors used to calculate the corresponding composite elastic constants. The implementation of these constants is described in Halpin-Tsai Composite Materials, 146.


Displays the Composite Material Properties form showing all stored properties of the material specified in the Material Name databox contained in the Materials application form. 2-D material properties such as the shell force-deformation matrices [A], [B], and [D], which are not consistent with this 3-D material option, always have displayed values of zero.

Clear Clears all information from the two Material Constituent databoxes and the five Empirical Factors databoxes.

EL ET LT GLT and GTT


Halpin-Tsai Discontinuous Fiber Composite Form


Halpin-Tsai Continuous Ribbon CompositeThe Halpin-Tsai Continuous Ribbon model is used to describe 2-phase composites in which the matrix phase is isotropic and the fibers (or ribbons) are uniform, continuous, orthotropic, and have rectangular cross sections. The resulting composite is therefore orthotropic. The Halpin-Tsai relations are used to calculate from which the remaining elastic constants are determined. Only

the names of the material constituents, their respective volume fractions, and the fiber (or ribbon) aspect ratio are required input. The volume fractions and fiber aspect ratio provide default empirical factors for the Halpin-Tsai equations. If the default Halpin-Tsai relations are not desired, the Override Default Equations toggle may be selected and empirical factor may be entered for each of the six elastic constants, in which case the fiber aspect ratio is no longer required. See the Halpin-Tsai material model discussion in Halpin-Tsai Composite Materials, 146 for the implementation of these constants in the Halpin-Tsai equations.

The Halpin-Tsai Continuous Ribbon model expects an orthotropic fiber (or ribbon) material and an isotropic matrix material. Warning messages will occur if this is not the case. Patran will ignore any additional properties that those materials may have and use the minimum number required to create an orthotropic composite material. It is, therefore, possible to use fully anisotropic fiber and matrix materials to create an orthotropic material. Physically, this makes no sense, so be careful if the warning message should appear.

Material Constituents Select the fiber and matrix materials by selecting their names in the Existing Materials listbox contained in the Materials application form. The switch, which you can set, determines whether the selected material goes into the Fiber listbox or the Matrix listbox.




Empirical Factors If enabled, enter five Empirical Factors used to calculate the corresponding composite elastic constants. The implementation of these constants is discussed in Halpin-Tsai Composite Materials, 146.



Clear Clears all information from the two Material Constituent databoxes, the Fiber Aspect Ratio databox, and the five Empirical Factors databoxes.

E11 E22 E33 12 G12 and G23


Halpin-Tsai Continuous Ribbon Composite Form


Halpin-Tsai Discontinuous Ribbon CompositeThe Halpin-Tsai Discontinuous Ribbon model is used to describe 2-phase composites in which the matrix phase is isotropic and the fibers (or ribbons) are uniform, discontinuous, orthotropic, and have rectangular cross sections. The resulting composite is therefore orthotropic. The Halpin-Tsai relations are used to calculate , from which the remaining elastic constants are

determined. Only the names of the material constituents, their respective volume fractions, and the fiber (or ribbon) aspect ratios are required input. The volume fractions and fiber aspect ratios provide default empirical factors for the Halpin-Tsai equations. If the default Halpin-Tsai relations are not desired the Override Default Equations toggle may be selected and empirical factor may be entered for each of the five elastic constants, in which case the fiber aspect ratios are no longer required. See the Halpin-Tsai material model discussion in Halpin-Tsai Composite Materials, 146 for the implementation of these constants in the Halpin-Tsai equations.

The Halpin-Tsai Discontinuous Ribbon model expects an orthotropic fiber (or ribbon) material and an isotropic matrix material. Warning messages will occur if this is not the case. Patran will ignore any additional properties that those materials may have and use the minimum number required to create an orthotropic composite material. It is, therefore, possible to use fully anisotropic fiber and matrix materials

Material Constituents Select the fiber (or ribbon) and matrix materials by selecting their names in the Existing Materials listbox contained in the Materials application form. The switch, which you can set, determines whether the selected material goes into the Fiber listbox or the Matrix listbox.

Fiber Volume Fraction Use either the slide bars or the databoxes to set the Fiber (or ribbon) Volume Fraction and the Matrix Volume Fraction. The two parameters are coupled so that their sum cannot exceed one. Sums less than one are permitted (but not recommended) for modeling voids.



Empirical Factors If enabled, enter six Empirical Factors used to calculate the corresponding composite elastic constants. The implementation of these constants is discussed in Halpin-Tsai Composite Materials, 146.


Select to display the Composite Material Properties form showing all stored properties of the material specified in the Material Name databox contained in the Materials application form. 2-D material properties, such as the shell force-deformation matrices [A], [B], and [D], which are not consistent with this 3-D material option, always have displayed values of zero.

Clear Select this button to clear all information from the two Material Constituent databoxes, the Fiber Aspect Ratio databox, and the six Empirical Factors databoxes.

E11 E22 E33 12 G12 and G23


to create an orthotropic material. Physically, this makes no sense, so be careful if the warning message should appear.


Halpin-Tsai Discontinuous Ribbon Composite Form


Halpin-Tsai Particulate CompositeThe Halpin-Tsai Particulate model is used to describe 2-phase composites in which both the particulate and the matrix phase are isotropic. The resulting composite is, therefore, isotropic. Common applications of the Particulate model include materials used in civil engineering applications, such as concrete. The Halpin-Tsai relations are used to calculate E and G, from which the remaining elastic constants can be determined. Only the names of the material constituents and their respective volume fractions are required input. The volume fractions provide default empirical factors for the Halpin-Tsai equations. If the default Halpin-Tsai relations are not desired, the Override Default Equations toggle may be selected and empirical factor may be entered for each of the six elastic constants. See the Halpin-Tsai material model discussion in Halpin-Tsai Composite Materials, 146 for the implementation of these constants in the Halpin-Tsai equations.

The Halpin-Tsai Particulate model expects an isotropic particulate material and an isotropic matrix material. Warning messages will occur if this is not the case. Patran will ignore any additional properties that those materials may have and use the minimum number required to create an isotropic composite material. It is, therefore, possible to use fully anisotropic particulate and matrix materials to create an isotropic material. Physically, this makes no sense, so be careful if the warning message should appear.

Material Constituents Select the fiber and matrix materials by selecting their names in the Existing Materials listbox contained in the Materials application form. The switch, which can be set, determines whether the selected material goes into the Fiber listbox or the Matrix listbox.



Enables the six Empirical Factors databoxes.

Empirical Factors If enabled, enter six Empirical Factors used to calculate the corresponding composite elastic constants. The implementation of these constants is discussed in Halpin-Tsai Composite Materials, 146.



Clear Clears all information from the two Material Constituent databoxes, the two Fiber Aspect Ratio databoxes, and the six Empirical Factors databoxes.


Halpin-Tsai Particulate Composite Form

Material Constituents Select the particulate and matrix materials by selecting their names in the Existing Materials listbox contained in the Materials application form. The switch, which you can set, determines whether the selected material goes into the Particulate listbox or the Matrix listbox.

Fiber Volume Fraction Use either the slide bars or the databoxes to set the Particulate Volume Fraction and the Matrix Volume Fraction. The two parameters are coupled so that their sum cannot exceed one. Sums less than one are permitted (but not recommended) for modeling voids.


Short Fiber Composite (1D)The 1D Short Fiber Composite model is used to compute the material properties of short fiber composites whose fiber orientation distributions can be described by a Gaussian curve. The user specifies a mean fiber orientation and a standard deviation to define the Gaussian (or normal) distribution.

A Monte Carlo integration scheme is used to sum the contributions of normally distributed “fibers” of a unidirectional material which should usually be a Halpin-Tsai Discontinuous Fiber material or a Halpin-Tsai Discontinuous Ribbon material. In other words, the geometrically appropriate Halpin-Tsai model is used to synthesize the properties of a unidirectional material having the same fiber material, matrix material, and fiber and matrix volume fractions as those of the short fiber composite to be created. The Short Fiber Composite model is then used to “distribute” the properties of the unidirectional Halpin-Tsai material within the specified Gaussian function. The material properties for each iterate are summed using the volume-weighted averaging methods used for Rule-of-Mixtures Composites. The default number of iterations is 1000, but it may be overridden to any positive integer. Scalar quantities, such as density, are simply assigned the same values as those of the constituent unidirectional material.

For more information on the algorithm, see Short Fiber Composite Materials, 153.


Enables the two Empirical Factors databoxes.

Empirical Factors If enabled, enter two Empirical Factors used to calculate the corresponding composite elastic constants. The implementation of these constants is discussed in Halpin-Tsai Composite Materials, 146.


Displays the Composite Material Properties form showing all stored properties of the material specified in the Material Name databox contained in the Materials application form. 2-D material properties such as the shell force-deformation matrices [A], [B], and [D], which are not consistent with this 3-D material option, always have displayed values of zero.

Clear Clears all information from the two Material Constituent databoxes and the two Empirical Factors databoxes.


Short Fiber Composite (1D) Form

Unidirectional Material Constituents

Specify the Unidirectional Material Constituent by selecting its name in the Existing Materials listbox contained in the Materials application form. Constituent materials may have 2-D or 3-D material properties.

Mean Orientation (degrees)

Specify the mean orientation of the fibers in polar coordinates. A mean orientation of 0 degrees means that the preferred fiber direction is toward the material frame 1-axis, while a 90-degree mean tends to align the fibers with the 2-axis.

Standard Deviation (degrees)

Specify the standard deviation of the fiber distribution. It must be positive.

Number of Monte Carlo Iterations

Select the number of Monte Carlo iterations used for the numerical integration of the unidirectional material properties. The default of 1000 is usually adequate, but any positive integer is acceptable. Avoid excessively large values which will only tie up the computer CPU needlessly.


Short Fiber Composite (2D)The 2D Short Fiber Composite model is used to compute the material properties of short fiber composites whose fiber orientations can be described by a Gaussian surface. The user specifies mean fiber orientations and standard deviations, as well as a correlation coefficient, to define the Gaussian (or normal) distribution.

A Monte Carlo integration scheme is used to sum the contributions of normally distributed “fibers” of a unidirectional material which should usually be a Halpin-Tsai Discontinuous Fiber material or a Halpin-Tsai Discontinuous Ribbon material. In other words, the geometrically appropriate Halpin-Tsai model is used to synthesize the properties of a unidirectional material having the same fiber material, matrix material, and fiber and matrix volume fractions as those of the short fiber composite to be created. The Short Fiber Composite model is then used to “distribute” the properties of the unidirectional Halpin-Tsai material within the specified Gaussian function. The material properties for each iterate are summed using the volume-weighted averaging methods used for Rule-of-Mixtures Composites. The default number of iterations is 1000, but it may be overridden to any positive integer. Scalar quantities, such as density, are simply assigned the same values as those of the constituent unidirectional material.

The Unidirectional Material Constituent must have 3D properties defined. For more information on the algorithm, see Short Fiber Composite Materials, 153.


Displays the Composite Material Properties form showing all stored properties of the material specified in the Material Name databox contained in the Materials application form. Material properties such as the shell force-deformation matrices [A], [B], and [D], which are not consistent with this material option, always have displayed values of zero.

Clear Clears the Unidirectional Material Constituent databox.


Short Fiber Composite (2D) Form


Composite Material PropertiesThe Composite Material Properties form is displayed when the “Display” button on a Composite option-specific form is selected.

Unidirectional Material Constituents

Select the Unidirectional Material Constituent by selecting its name in the Existing Materials listbox contained in the Materials application form. Constituent materials must have 3-D material properties.

First Dimension: Theta (degrees)

Select the mean orientation and the standard deviation corresponding to the

azimuthal angle . See Short Fiber Composite Materials, 153 for a

description of the spherical frame in which is defined. Use either the slide bar or the databox to specify the standard deviation. The standard deviation must be positive and cannot exceed 30.0.

Second Dimension: Phi (degrees)

Select the mean orientation and the standard deviation corresponding to the

polar angle . See Short Fiber Composite Materials, 153 for a description

of the spherical frame in which is defined. Use either the slide bar or the databox to specify the standard deviation. The standard deviation must be positive and cannot exceed 30.0.

Correlation Coefficient Use either the slide bar or the databox to define the Correlation Coefficient. The default value of zero is usually adequate. The Correlation Coefficient must be a nonnegative number less than one.

Number of Monte Carlo Iterations

Select the number of Monte Carlo iterations used for the numerical integration of the unidirectional material properties. The default of 1000 is usually adequate, but any positive integer is acceptable. Avoid excessively large values which will only tie up the computer CPU needlessly.



Clear Clears the Unidirectional Material Constituent databox.


Composite Material Properties

3D Elasticity Matrix

3D Flexibility Matrix

E’s,NU’s,G’s, and Qij's

Thermal

CTE’s,C

Composite Property Display Options

Cancel

Membrane, Bending, and Coupling Matrices

High Precision Value

6.782E+06

A, B, and D Matrices

Bend

1.581E+05

0.000E+00

7.193E_01

0.000E+00

-1.526E-05

0.000E+00

7.193

-9.86

2.279

0.000

2.56

-1.52 Membrane

0.000E+00

0.000E+00

-1.526E-05

1.886E-04

5.395E+03

6.782E+06

-1.526E-05

0.000E+00

2.563E-03

-2.958E-01

6.782E+06

5.395E+03

0.000E+00

-7.629E-06

0.000E+00

2.163E+03

-2.958E-01

1.886E-04

Bending

Membrane

u

uu uuuu

uu uu


High Precision Value Selecting any of the displayed values in the 6x6 spreadsheet causes that value to be displayed in greater precision in the databox.

Composite Property Display Options

A, B, and D Matrices. The displayed 6 x 6 matrix relates the in-plane force and moment vector {N1,N2,N12,M1,M2,M12} to the vector of midsurface

strains and curvatures in the expression

where A, B, and D are symmetric 3x3 matrices.

3D Elasticity Matrix. The 3D Elasticity matrix relates the stresses to

the strains in the expression:

The Thermal and Moisture Expansion Coefficient vectors are displayed with the Density, Structural Damping Coefficient, Specific Heat, and Reference Temperature.

3D Flexibility Matrix. The 3D Flexibility matrix relates the strains to

the stresses in the expression:

E’s, NU’s, G’s, and Qij’s

Triads of E’s, ’s, and G’s are presented, along with the plane stress

Stiffness matrix [Q] relating the stresses to the strains

in the expression:

Thermal: Kij, Ni, and Mi. The 3 x 3 Conductivity matrix Kij is shown with the Resultant Thermal Force and Moment vectors, Ni and Mi, respectively.

CTE’s, CME’s and Others. The Thermal and Moisture Expansion Coefficient vectors are displayed with the Density, Structural Damping Coefficient, Specific Heat, and Reference Temperature.

1 2 12 1 2 12

NM

A B

B D

=

S =

1 2 12

1 2 12

Q =

Patran Reference ManualTheory - Composite Materials

138

4.5 Theory - Composite MaterialsThe Create Composite options in Patran synthesize material properties for four classes of composite construction techniques.

Two of these construction methods can be implemented in more than one way. There are five Halpin-Tsai options and two Short Fiber composite options.

Laminated Composite Materials The Laminate model is used to describe laminated solids and shells. In this construction, adjacent layers (or laminae or plies) are arranged as shown in Figure 4-1, and the orientation of each layer is defined by a single constant angle . Each layer may be a unique material and have a unique constant thickness. The Laminate model uses Classical Lamination Theory (CLT) to calculate the membrane, bending, and membrane-bending coupling stiffness matrices for a laminated shell.

Table 4-1 Patran Composite Material Construction Techniques

Construction Method Algorithm Intended Application

Laminate Classical Lamination Theory. Laminated shells and solids.

Rule of Mixtures Volume-Weighted Averaging. 3D composites with multiple phases, arbitrary orientations, and arbitrary volume fractions.

Halpin-Tsai Halpin-Tsai Equations. 2-Phase Composites.

Short Fiber Monte-Carlo integration combined with volume-weighted averaging.

Short fiber composites whose orientation distribution can be described by a Gaussian curve or surface.

139Ch. 4: Materials ApplicationTheory - Composite Materials

Figure 4-1 Laminate Definition Conventions

Classical Lamination Theory

The two fundamental assumptions of CLT are: (1) that surface normals remain normal when the laminate deforms:

(4-1)

where is the strain, is the midsurface strain, is the curvature, and z is the distance from the

neutral surface; and (2) that each layer is in a state of plane stress, implying that the transverse stresses are all zero:

(4-2)

The constitutive equation for an orthotropic ply in a state of plane stress is given by:

(4-3)

where:

45

0

90

-45

0

7

6

5

4

3

2

1

Z Y

X

i i0

zi+= i 11 22 33 =

i i0 i

33 23 31 0= = =

1

2

12

Q11 Q12 0

Q12 Q22 0

0 0 Q33

1

2

12

=


140

(4-4)

(4-5)

(4-6)

(4-7)

The constitutive matrix for a layer in the laminate frame is given by:

(4-8)

with:

(4-9)

where is the matrix transforming the laminate frame strain into the ply frame and is the angle

from the laminate frame to the ply frame shown in Figure 4-1. Combining the expression for the kinematic assumption, (4-1), with the constitutive equation for the kth ply

(4-10)

yields:

(4-11)

Substituting (4-11) into the integral expressions for force per unit length and moment per unit

length :

(4-12)

leads to:

Q11

E11

1 1221– -----------------------------=

Q22E22

1 1221– -----------------------------=

Q12

21E11

1 1221– -----------------------------

12E22

1 1221– -----------------------------= =

Q33 G12=

Q

Q T1–

Q TT

=

T

cos2 sin2 2 sincos

sin2 cos2 2 sincos–

sincos– sincos cos2 sin2–

=

T

k Q k k=

k Q k0 z Q k

+=

N M

N dz= and M zdz=


(4-13)

(4-14)

The midsurface strains and curvatures are not a function of z, and is constant wi

thin each ply, so the above expressions may be simplified to:

(4-15)

(4-16)

where is the coordinate of the top of the kth ply (or higher z coordinate of the kth ply, see Figure 4-1.

The shell constitutive equations relating the midsurface strains and curvatures to the in-

plane forces and moments are documented in (4-15) and (4-16). From these two expressions

the stiffness matrices for membrane behavior , bending behavior , and membrane-bending

coupling behavior can be extracted:

(4-17)

(4-18)

(4-19)

If no laminate offset is specified, then Patran assumes that the middle surface is the neutral surface, and the above expressions for shell stiffness are used. The Patran offset is not the distance from the middle surface to the neutral surface, but rather the coordinate of the bottom of the stack (or lowest z coordinate, see Figure 4-1) relative to the neutral surface, which, by default is the negative of half the laminate thickness. If a non-default offset is specified, implying that the neutral surface does not coincide with the

N Q k0 dz Q k

z dz+=

M Q kz 0 dz Q k

z2 dz+=

0 Q k

N 0 Q khk hk 1–– 1

2--- Q k

hk2

hk 1–2

–

k 1=

n

+

k 1=

n

=

M 12--- 0 Q k

hk2

hk 1–2

– 13--- Q k

hk3

hk 1–3

–

k 1=

n

+

k 1=

n

=

hk

0 F M

A D

B

A Q khk hk 1––

k 1=

n

=

D13--- Q k

hk3

hk 1–3

–

k 1=

n

=

B12--- Q k

hk2

hk 1–2

–

k 1=

n

=


142

middle surface, then the following corrections must be made to the bending matrix and the

membrane-bending coupling matrix :

(4-20)

(4-21)

where d is the coordinate of the neutral surface relative to the middle surface and is related to the user-input offset as:

d = offset + (laminate thickness)/2 (4-22)

Thus, if a laminate having three layers of thickness .02 is specified without an offset, the default offset is taken to be -.03, since d = 0. If, however, the neutral surface is taken to be, for example, the interface between the first and second ply, corresponding to d = -.01, then the user-input offset should be -.04, yielding the corrected bending and coupling matrices:

(4-23)

(4-24)

Patran also calculates the resultant in-plane forces and moments corresponding to a

uniform temperature increase of one degree:

(4-25)

(4-26)

where is the vector of thermal expansion coefficients in the laminate frame for the kth layer.

All other laminated composite material properties are calculated using the same algorithms as those implemented by the Rule-of-Mixtures option, whose description starts on the next page.

D

B

D' D 2d B d2 A+ +=

B' B d A+=

D' D 0.02 B– 0.0001 A+=

B' B 0.01 A–=

N t M t

N t Q k kdz Q k

k hk hk 1––

k 1=

n

= =

M t Q k kzdz

12--- Q k

k hk2

hk 1–2

–

k 1=

n

= =

k


Rule-of-Mixtures Composite MaterialsThe Rule-of-Mixtures model is used to describe three-dimensional solids having an arbitrary number of material phases with arbitrary orientations and volume fractions. Orientations are defined for each phase

using a triad of space-fixed rotation angles in a 3-2-1 sequence. These angles rotate the composite material frame to the phase frame. The orientation of each phase is defined by starting with

the phase frame aligned with the composite frame and rotating the phase material frame degrees about

the 3-axis of the composite material frame, then rotating the phase frame degrees about the 2-axis of

the composite frame, and finally rotating the phase frame degrees about the 1-axis of the composite frame. Rule-of-Mixtures composites are, in general, fully anisotropic.

Material Property Derivation

Scalar quantities, such as density, are calculated using a simple volume-weighted averaging method, as in

(4-27)

where is the density of the kth phase, is the volume fraction of the kth phase, and n is the number

of phases. The composite structural damping coefficient is also calculated in this way. For vector and matrix quantities, however, it is necessary to transform the phase properties into the composite material coordinate frame before performing volume-weighted averaging. Thus, the expression for the composite elasticity matrix is given by

Caution: The elasticity matrix [C] calculated for laminated composites using the Rule-of-Mixtures equations is based on a volume weighted averaging scheme and is insensitive to the order of plies in a lay-up. In other words, for plies of the same material and thickness, a 90-0-90 degree stack will yield the same elasticity matrix as a 90-90-0 degree stack. Thus the elasticity matrix should be used for laminate problems with membrane behavior only (no bending and no coupling behavior). Additional simplifications, which may or may not be warranted for the user’s application, are made when the nine engineering constants (elastic moduli, Poisson’s ratios, and shear moduli) are evaluated from the elasticity matrix. In order to calculate nine unique engineering constants, Patran assumes that the 12 terms of the elasticity matrix that correspond to normal-shear coupling and shear-shear coupling behavior are zero. This reduces an elasticity matrix that is, in general, anisotropic, to orthotropy, on the premise that the engineering constants can only be meaningful if the laminated composite is effectively orthotropic. The resulting engineering constants can only be used, therefore, for laminate problems in which the response is characterized by membrane behavior only, when the laminate is effectively orthotropic.

kvk

k 1=

n

=

k vk


144

(4-28)

with

(4-29)

where is the elasticity matrix for the kth phase in the phase frame, is the matrix that

transforms the strains in the kth phase from the laminate frame to the phase frame, and the dij are the

terms of the matrix of direction cosines

(4-30)

from the composite frame to the phase frame in terms of the rotation angles, , , and , for the kth

phase. Similarly, the composite thermal conductivity matrix is calculated using the expression

(4-31)

where is the thermal conductivity matrix of the kth phase in the phase frame. The composite

thermal and moisture expansion coefficient vectors are given by

(4-32)

(4-33)

C DD k

TC k DD k

vk

k 1=

n

=

DD k

d11d11 d21d21 d31d31 d11d21 d21d31 d11d31

d12d12 d22d22 d32d32 d12d22 d22d32 d12d32

d13d13 d23d23 d33d33 d13d23 d23d33 d13d33

2d11d12 2d21d22 2d31d32 d11d22 d12+ d21 d21d32 d31+ d22 d11d32 d31+ d12



=

C k DD k

kcos kcos ksin– kcos ksin

ksin k kcos ksin ksin+cos kcos k ksin ksin ksin–cos kcos– ksin

ksin k kcos ksin kcos–sin kcos k ksin ksin kcos+sin kcos kcos

k k k

D k

T k D k

vk

k 1=

n

=

k

S DD k

TC k

kvk

k 1=

n

=

S DD k

TC k

kvk

k 1=

n

=


where is the composite flexibility matrix, is the thermal expansion coefficient

vector for the kth phase, and is the moisture expansion coefficient vector for the kth phase. The

nine engineering constants (elastic moduli, Poisson ratios, and shear moduli) are calculated from the composite flexibility matrix as follows:

(4-34)

(4-35)

(4-36)

Note that only nine of the 21 Sij’s are used to calculate the nine engineering constants. The potential anisotropy of the composite material is partially ignored: it is assumed to be at most orthotropic. Thus, these nine constants should be used in subsequent analyses only if the composite is known to be

orthotropic. Patran also calculates the 2D plane stress constitutive matrix from the 3D composite

elasticity matrix :

(4-37)

(4-38)

(4-39)

The user must be sure that the composite material is appropriate for a 2D plane stress analysis before

using the matrix. The composite specific heat, or heat capacity per unit mass, is calculated using a

mass weighted averaging scheme:

(4-40)

S C1–

= k

k

Ei1

Sii------= i 1 2 3 =

ij S– ijEi= ij 12 23 31 =

Gij1

S i 3+ i 3+ ---------------------------= ij 12 23 31 =

Q

C

Qij CijC3iC3j

C33----------------–= ij 11 12 22 =

Q3j C4j

C34C3j

C33-----------------–= j 1 2=

Q33 C44

C34C34

C33-----------------–=

Q

CP CPkmk

k 1=

n

1--- CPkkvk

k 1=

n

= =


146

where is the specific heat for the kth phase, is the mass fraction for the kth phase, and is the

density of the composite material. Finally, the reference temperature for the composite material is taken to be the reference temperature for the first phase material specified by the user.

Halpin-Tsai Composite MaterialsThe Halpin-Tsai models are used to describe 2-phase composites in which the matrix phase is isotropic. Halpin-Tsai materials may be transversely isotropic, orthotropic, or isotropic, depending on the geometry of the material reinforcing the matrix. The composite material frame corresponds with the fiber (or non-matrix) phase frame. Five different Halpin-Tsai material models exist in Patran: continuous fiber, discontinuous fiber, continuous ribbon, discontinuous ribbon, and particulate. These provide empirical relations for the engineering constants using, generally, Rule-of-Mixtures equations having the form

(4-41)

and Halpin-Tsai equations of the form:

(4-42)

where is the composite elastic property (which may be an elastic modulus, a Poisson ratio, or a shear

modulus), and are the corresponding properties for the fiber and matrix material, respectively,

and are the volume fractions for the fiber and matrix phase, respectively, and is a user-

specified empirical constant. Each Halpin-Tsai model specifies a set of equations for the engineering

constants and each equation in the set has a default value for which may be overridden by the user. These models are summarized below from J.C. Halpin’s text, Revised Primer on Composite Materials: Analysis, Technomic Publishing Co., Lancaster, PA, 1984, pp. 123-142.

Uniform Continuous Fiber

This model assumes the 2-phase geometry shown in Figure 4-2. The fibers are uniform, continuous, cylindrical, and transversely isotropic. The resulting composite is therefore transversely isotropic. This is the only Halpin-Tsai model supported by some earlier versions of Patran.

CPk mk

PC Pfvf Pmvm+ =

PC Pm

1 vf+ 1 vf–

-------------------------- with Pf Pm–

Pf Pm+ --------------------------==

PC

Pf Pm

vf vm


Figure 4-2 Halpin-Tsai Continuous Fiber Material Coordinates

Rule-of-Mixtures equations are used to determine for the composite, with the default

value for the empirical constant being 1.0 in both cases. (The default value of for any Rule-of-Mixtures equation in the five Halpin-Tsai models is always 1.0.) Halpin-Tsai equations are used to

determine , so that the expression for , for example, is given by:

(4-43)

in which ETm is the transverse matrix modulus and ETf is the transverse fiber modulus. The default

empirical constants for are given by:

(4-44)

(4-45)

T

L

ELand LT

ET GLT and GTT ET

ET ETm

1 vf+ 1 vf–

-------------------------- where ETf ETm–

ETf ETm+ ---------------------------------==

ET GLT and GTT

ET2 40vf

10+=

GLT1 40vf

10+=


148

(4-46)

where is the Poisson ratio for the isotropic matrix material and the ugly expression is a

correction term for composites with high fiber volume fractions. (Remember, these are empirical relations. They were not derived for the sole purpose of looking elegant and sophisticated.) The

composite transverse Poisson ratio is then determined from the known transverse isotropy:

(4-47)

Some earlier versions of Patran used a Halpin-Tsai equation to calculate instead of GTT, and then

used relations for transverse isotropy to calculate GTT. Although Halpin’s text does not specify a default

value for , Patran provides the value:

(4-48)

which should be selected with some caution. GTT is then calculated using the expression:

(4-49)

Uniform Discontinuous Fiber

This model assumes the fibers are uniform, discontinuous, cylindrical, and transversely isotropic. The resulting composite is therefore transversely isotropic.

A Rule-of-Mixtures equation is used to determine for the composite, with the default value for the

empirical constant being 1.0. Halpin-Tsai equations are used to determine EL, ET, GLT, and GTT, so

that the expression for EL, for example, is given by:

(4-50)

in which ELm is the longitudinal matrix modulus and ELf is the longitudinal fiber modulus. The default

empirical constants for EL, ET, GLT, and GTT are given by:

(4-51)

GTT

14 3m–

------------------------=

m 40vf10

TT

TTET

2GTT------------- 1–=

TT

TT

TT2 40vf

10+=

GTTET

2 1 TT+ --------------------------=

LT

EL ELm

1 vf+ 1 vf–

-------------------------- where ELf ELm–

ELf ELm+ ---------------------------------==

EL2

ld--- 40vf

10+=


(4-52)

(4-53)

(4-54)

where is the fiber length-to-diameter ratio. As with the Uniform Continuous Fiber model, the

transverse Poisson ratio is determined from (4-47).

Uniform Continuous Ribbon

This model assumes the fibers are uniform, continuous, and orthotropic, with a rectangular cross section. The resulting composite is orthotropic.

Rule-of-Mixtures equations are used to determine for the composite, with the default value

for the empirical constant being 1.0 in both cases. Halpin-Tsai equations are used to determine

, so that the expression for E2, for example, is given by:

(4-55)

in which E2m is the transverse matrix modulus, and E2f is the transverse fiber modulus. The default

empirical constants for E2, E3, G12, and G23 are given by:

(4-56)

(4-57)

(4-58)

(4-59)

ET2 40vf

10+=

GLT1 40vf

10+=

GTT

14 3m–

------------------------=

ld---

TT

E1and 12

E2 E3 G12 and G23

E2 E2m

1 vf+ 1 vf–

-------------------------- where E2f E2m–

E2f E2m+ -------------------------------==

E22

wt---- 40vf

10+=

E32 40vf

10+=

G12

wt---- 1.73

40vf10

+=

G232 40vf

10+=


150

where is the ribbon width-to-thickness ratio.

The transverse Poisson ratio is calculated from the expression:

(4-60)

where is the transverse Poisson ratio for the fiber material and is the matrix Poisson ratio. The

remaining two engineering constants, , are not provided for in the theory, but are

calculated in Patran by making the approximation that , from which:

(4-61)

Uniform Discontinuous Ribbon

This model assumes the fibers are uniform, discontinuous, and orthotropic, with a rectangular cross section. The resulting composite is orthotropic.

A Rule-of-Mixtures equation is used to determine for the composite with the default value for the

empirical constant being 1.0. Halpin-Tsai equations are used to determine E1, E2, E3, G12, and G23, so

that the expression for E3, for example, is given by:

(4-62)

in which E3m is the cross-ply matrix modulus and E3f is the cross-ply fiber modulus. The default

empirical constants for E1, E2, E3, G12, and G23 are given by:

(4-63)

(4-64)

(4-65)

wt----

23

231

vf

23f---------

1 vf– m

------------------+ ----------------------------------------=

23f m

G13and 31

G13 G12 and 13 12==

31 13

E3

E1------=

12

E3 E3m

1 vf+ 1 vf–

-------------------------- where E3f E3m–

E3f E3m+ -------------------------------==

E12

lt- 40vf

10+=

E22

wt---- 40vf

10+=

E32 40vf

10+=


(4-66)

(4-67)

where is the ribbon length-to-thickness ratio and is the ribbon width-to-thickness ratio.

As with the Uniform Continuous Ribbon model, the transverse Poisson ratio is calculated from

(4-60), and the remaining two engineering constants, G13 and , are calculated by making the

approximation that , yielding by (4-61).

Particulate Composite

This model assumes an isotropic particulate reinforcement of the matrix. The resulting composite is therefore isotropic.

Halpin-Tsai equations are used to determine both E and G, so that the expression for E, for example, is given by

(4-68)

in which Em is the matrix elastic modulus, and Ef is the fiber elastic modulus. The default empirical

constants for E and G are given by

(4-69)

(4-70)

The isotropy of the particulate composite uniquely defines the Poisson ratio .

Elasticity and Flexibility Matrices

The elasticity matrix can be expressed in terms of the orthotropic engineering constants as

(4-71)

G12

l w+ 2t

-----------------1.73

40vf10

+=

G232 40vf

10+=

lt- w

t----

23

31

G13 G12 and 13 12== 31

E Em

1 vf+ 1 vf–

-------------------------- where Ef Em–

Ef Em+ ---------------------------==

E 2 40vf10

+=

G 1 40vf10

+=

Cii

1 jkkj– D

----------------------------Ei= ijk 123 231 312 =


152

(4-72)

(4-73)

body

(4-74)

If the composite material symmetry is more general than that of an orthotropic material, i.e., if the material is isotropic or transversely isotropic, then the above equations can be simplified. The flexibility matrix is calculated by inverting the elasticity matrix.

Halpin-Tsai Thermal and Moisture Expansion Coefficients

The exact Levin solution for 2-phase composites (V.M. Levin, “Thermal Expansion Coefficients of Heterogeneous Materials,” Mekhanika Tverdogo Tela, Vol. 2, No. 1, pp. 88-94, 1967) is used to determine both thermal and moisture expansion coefficients for all Halpin-Tsai models. The composite thermal expansion coefficient vector is calculated using the expression

(4-75)

and the composite moisture expansion vector is given by the analogous expression

(4-76)

(4-77)

(4-78)

(4-79)

(4-80)

(4-81)

(4-82)

Cij

ji jkki+ D

-------------------------------Ei= ijk 123 132 231 =

C i 3+ i 3+ Gij= ij 12 23 31 =

D 1 1221–= 1331– 2332– 2122331–

C S DIF

1–S C S–

T

DIF+=

C S DIF

1–S C S–

T

DIF+=

vf f vm m+=

vf f vm m+=

S vf S fvm S m

+=

DIF f m–=

DIF f m–=

S DIF S f S m–=


and is the composite flexibility matrix.

Other Material Properties

All other material properties are calculated using the methods described for Rule-of-Mixtures materials (which are described immediately preceding this Halpin-Tsai discussion), but the calculations are generally simpler for Halpin-Tsai materials because both phase frames coincide with the composite frame. Thus, it is not necessary to transform phase properties to the composite frame before summing their contribution to the composite properties.

Short Fiber Composite MaterialsThe Short Fiber Composite model is used to compute the material properties of short fiber composites whose fiber orientations can be described by a normal (Gaussian) distribution. The orientations may vary in a single plane, in which case a Gaussian curve

(4-83)

describes the fiber orientations. Here is the mean orientation and is the standard deviation of

the distribution. The fiber orientations may also vary in two dimensions, however, in which case the fiber distribution is described by a Gaussian surface

where and are the mean orientations, and are the corresponding standard deviations,

and is the correlation coefficient. Figure 4-3 illustrates the spherical coordinates used to define a 2D

Gaussian distribution in Patran. Here the e1-e2 plane defines the “equator” and is the azimuthal angle

defining, effectively, a “longitude,” while a positive angle defines a “latitude” in the southern hemisphere.

S C

F 1

2-----------------exp

12--- av–

----------------- –

=

av

F 1

2 1 2–---------------------------------------exp

12 1 2– -----------------------

av–

-----------------

22

av–

----------------- av–

----------------- –

av–

-----------------

2+–

=

av av


154

Figure 4-3 Spherical Coordinates for 2D Gaussian Distributions of Short Fiber Composites

A Monte Carlo integration scheme is used to sum the contributions of normally distributed “fibers” of a unidirectional material which should usually be a Halpin-Tsai Discontinuous Fiber material or a Halpin-Tsai Discontinuous Ribbon material. In other words, the geometrically appropriate Halpin-Tsai model is used to synthesize the properties of a unidirectional material having the same fiber material, matrix material, and fiber and matrix volume fractions as those of the short fiber composite to be created. The Short Fiber Composite model is then used to “distribute” the properties of the unidirectional Halpin-Tsai material within the specified Gaussian function. The integration is simplified by the approximation that

all fibers lie within a range of the mean orientation, where is a standard deviation. The default number of iterations is 1000, but it may be overridden to any positive integer. The material properties for each iterate are summed using the Rule-of-Mixtures methods described earlier in this section. Scalar quantities, such as density, are simply assigned the same values as those of the constituent unidirectional material.

Short Fiber Composites are usually, to a first approximation, transversely isotropic or orthotropic, but because of the randomness of the Monte Carlo integration scheme, small shear coupling terms are introduced which tend to make these materials fully anisotropic. Larger iteration counts reduce this effect somewhat, but it cannot be eliminated. Nonetheless, it should not be cause for undue concern: the purpose of this model is to provide material properties with good first-order accuracy. The more complex Eshelby equivalent inclusion (and related) methods, which provide for fiber-matrix and fiber-boundary interaction effects, have been eschewed in favor of this simpler method. This Monte Carlo/Rule-of-Mixtures approach yields good first-order results accounting for the most significant factor in composite

e2

e3

e1

3


stiffness (the fiber orientations) and allows the materials designer to gain an understanding of the relative effects of varying fiber orientation parameters.


156

Ch. 5: Load Cases ApplicationPatran Reference Manual

5 Load Cases Application

Overview of the Load Cases Application 158

Rules for Creating/Modifying Load Cases 161

Load Cases Forms 162

Patran Reference ManualOverview of the Load Cases Application

158

5.1 Overview of the Load Cases Application

PurposeThe Load Cases application provides the ability to group multiple loads and boundary conditions (LBCs) sets, see Loads and Boundary Conditions Form, 23, into single load cases for application to the model. Load cases remain in the database unless deleted.

159Ch. 5: Load Cases ApplicationOverview of the Load Cases Application

Definitions

CapabilitiesThe Load Cases function provides the ability to combine a large number of individual loads and boundary conditions sets into a single coherent case for application to the model. If supported by the analysis preference, the use of load case LBC scale factors can reduce the number of individual loads and boundary conditions required. Unless deleted, load cases remain in the database and provide a permanent record of the analysis loading conditions.

The Load Cases function provides the capability of creating, deleting, modifying, and showing load cases.

Load Cases Group of selected loads and boundary conditions sets. Each load case has a unique user-selected descriptive name as well as an associated descriptive statement.

Loads and BCs Sets These are named groups of node and/or element loads that are created in the Loads and BCs Application. Fields created in the Fields Application may or may not have been used in their creation.

Static Load Cases Load cases in which none of the constituent loads or boundary conditions sets has a time varying component.

Time Dependent Load Cases

Load cases in which one or more of the constituent loads or boundary conditions sets has a time varying component. These are also referred to as dynamic load cases.

Priority In the event that a conflict arises between loads and boundary conditions set types (e.g., Displacement) with the same loads and boundary conditions type (e.g., Nodal, Element Uniform) that belong to the same load case, the priority will specify which loads and boundary conditions set will take precedence. Priorities may be set so that values are added together when a conflict arises or priorities may be set so that one load and boundary conditions set overwrites other sets with which it conflicts. Priorities are currently not supported by the MSC Nastran analysis preference.

Load Case

Scale Factor

A scale factor which is applied to the entire load case. Each load case has a load case scale factor. The default value is 1.0. Some analysis preferences may not allow a scale factor other than 1.0.

Load Case LBC

Scale Factor

Scale factor applied to a LoadsBC set by the load case. Some analysis preferences may not allow a scale factor other than 1.0.

Patran Reference ManualOverview of the Load Cases Application

160

Summary of Key FeaturesThe Load Cases function provides straightforward, intuitive means for combining separate loads and boundary conditions sets to form load cases. Key features of the Load Cases function are:

• Provides archival load case data within the database.

• Provides a means of creating new load cases by retrieving, modifying, and renaming existing load cases.

• Provides for creating, deleting, modifying, and showing load cases. When deleting load cases, provides the option of also deleting the constituent Loads/BCs sets. If load and boundary conditions sets to be deleted belong to more than one load case, they will not be deleted.

• Provides a means of re-use of Loads/BCs sets by use of load case LBC scale factors. This can reduce the number of individual Loads/BCs required.

161Ch. 5: Load Cases ApplicationRules for Creating/Modifying Load Cases

5.2 Rules for Creating/Modifying Load CasesThere is always a current load case. This will be the “default” load case unless changed by the user. Any loads and boundary conditions sets created are added to the current load case.

The current load case can be changed in three ways:

• When a new load case is created using the Load Cases Create option, the new load case becomes the current load case if the Make Current toggle is on.

• When a load case is modified using the Load Cases Modify option, the modified load case becomes the current load case if the Make Current toggle is on.

• The current load case can also be changed from the Loads/BCs application.

The current load case affects which loads and boundary conditions sets markers will be displayed. Only those loads and boundary conditions in the current load case can be graphically displayed.

The default load case is static. In order to create time-dependent loads and/or boundary conditions sets, the load case type must be defined as time dependent in the Load Cases application.

If a static loads and boundary conditions set is assigned to a time dependent or dynamic load case, the loads and boundary conditions set will be assumed to be constant with time.

Load case information is permanently stored in the database (unless deleted) and can be modified at any time.

For simple analyses, the Load Cases application need not be used. All loads and boundary conditions sets will automatically be included in the default load case and applied to the model.

Patran Reference ManualLoad Cases Forms

162

5.3 Load Cases FormsThe functions on the Load Cases menu are listed and described below in the order in which they appear on the menu.

Create Load CasesThis form permits you to create new load cases, either from scratch or by modification of existing load cases. The new case is given a unique name, type (static or time dependent), description, and assigned a complement of loads and boundary conditions sets. The new load case can also be made the current load case if desired.

Menu Pick Action

Create • Create new load cases either from scratch or by modifying existing load cases.

Modify • Modify existing load cases. Change name, type, description, LoadsBCs sets. Change current load case.

Delete • Delete load cases from the database, including associated Loads/BCs sets if desired.

Show • Show all load cases in the database. Review names, types, descriptions, and constituent Loads/BCs sets. Show current load case.

Assign/Prioritize Loads/BCs • Assign Loads/BC sets to the load case. Resolve potential conflicts for a given load case within specific Loads/BCs set types. Assign scale factors to the load case and Loads/BC sets in the load case.

• Combine load cases.

163Ch. 5: Load Cases ApplicationLoad Cases Forms


164

Action Create action brings up this form.

Existing Load Cases All load cases in the database appear in this table. Select a case to be modified into a new case if this approach is desired. When an existing load case is selected, the load case scale factor databox below updates and the Assign/Prioritize form is displayed.

Load Case Name The name of a selected case (if any) will appear here. Change the name or input a new unique name. (31 characters maximum.)

Make Current Toggle this button ON if you want this to be made the current load case. Note: A combination loadcase may be the current loadcase, just like any other loadcase. If the current loadcase is a combination loadcase, and LBC markers are plotted for LBCs therein, then the marker values will be scaled based on the accumulated scale of the LBC across all loadcases in the combination. However, LBCs cannot be assigned directly to a combination loadcase. So if the current loadcase is a combination loadcase, the Loads/BCs Create operation will fail.

Load Case Type Select the load case type (static, time dependent, or combination).

Description Input a load case description (Up to 256 characters). It is important to do it now to have a listing later.

Input Data Assigns Load/BCs sets to the Load Case. Modifies the default priority. The default priority is “add” (i.e., if a conflict arises then add Load/BCs values together). Sets the scale factors for the assigned Load/BCs sets. Combine Load/BCs sets from existing load cases.

Load Case Scale Factor Sets the Load Case Scale Factor for the load case being created. The default is 1.0. This is disabled if not supported by the current analysis preference.


Modify Load CasesThis form permits you to change the name, type, description, and composition of load cases in the database. The current load case can also be changed.


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Action Modify action brings up this form.


Select Load Case to Modify

All load cases in the database appear in this table. Select the case to be modified. When a load case is selected, the load case scale factor databox below updates and the Assign/Prioritize form is displayed.

Rename Load Case As The name of the selected case will appear here. Change the name if desired.

Make Current Toggle this button on if you want this to be made the current load case.

Load Case Type The load case type of the selected load case (static or dynamic) is shown here.

Description The load case description provided by the user will appear here. Make any changes that are desired.

Assign/Prioritize Load/BCs

Assigns Loads/BCs sets to the Load Case. Modifies the default priority. The default priority is “add” (i.e., if a conflict arises then add Load/BCs values together). Sets the scale factors for the assigned Load/BCs sets. Combine Load/BCs sets from existing load cases.

Load Case Scale Factor Sets the Load Case Scale Factor for the load case being modified. This is disabled if not supported by the current analysis preference.

Note: A combination loadcase may be the current loadcase, just like any other loadcase. If the current loadcase is a combination loadcase, and LBC markers are plotted for LBCs therein, then the marker values will be scaled based on the accumulated scale of the LBC across all loadcases in the combination. However, LBCs cannot be assigned directly to a combination loadcase. So if the current loadcase is a combination loadcase, the Loads/BCs Create operation will fail. See section 3 Loads/BCs Forms below for more information.


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Delete Load Cases

Action Select the Delete action here to bring up this form.


Existing Load Cases All load cases in the database appear in this table. When a load case is selected, the Show Assigned Loads/BCs form will appear, listing the loads and boundary conditions which comprise the selected load case. Load cases only be deleted one at a time.

Load Case Type The load cases type of the selected load cases is shown here (static, time dependent, or combination).

Description The load case description provided by the user is shown here. Verify that this is the case to be deleted.

Delete Load/BCs Sets Toggle this button ON if you want the constituent loads and boundary conditions sets to be deleted also (default is OFF).


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Show Load Cases

Action Show action brings up this form.


Show Assigned Loads/BCsThis form displays the loads and boundary conditions currently assigned to the load case selected from the Show or Delete form. This form is automatically displayed when the load case selection is made.

Existing Load Cases All load cases in the database appear in this table. When a load case is selected, the load case scale factor databox below updates and the Show Assigned Loads/BCs, 171 form will appear, listing the loads and boundary conditions which comprise the selected load case. Load cases may only be selected one at a time.

Load Case Type The load case type of the selected load case is shown here (static, time dependent or combination).

Description The case description provided by the user is shown here (256 characters maximum).

Load Case Scale Factor Shows the Load Case Scale Factor for the selected load case. This is disabled if not supported by the current analysis preference.


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Show Assigned Load Cases

When a combination load case is selected from the Show Load Cases form, the Show Assigned Load Cases form will appear. This form lists the different load cases that are part of the combination load case. To view the collective assigned LBCs and their combined scales, select the “Show Assigned Loads/BCs” button on the form. This displays a spreadsheet of LBCs and their priorities/scales. It traverses all of the loadcases within the combination and retrieves all of their LBCs, accumulating their scales along the way. The net affect is showing a “flattened” version of the combination loadcase.


Prioritize Loads/BCs Within Load CasesLoad case contents are completely defined in this form. From this form the following actions may be performed:

• Assign (add or remove) Loads/BCs sets to the Load Case

• Modify the default priority.

• Set the Load Case Scale Factor

• Set the Load Case LBC Scale Factors

• Combine load cases

Potential conflicts for a given load case within specific Loads/BCs set types may be resolved. For example, if there are two displacement sets in the same load case, which specify a constraint on the same node, the priority will determine what the resulting constraint at that node will be. If default priority of “Add” is not changed, then the constraints will be added together at that node. If the constraint in one displacement set is to supersede the other, then an overwrite priority must be set for the Loads/BCs set which will take precedence.


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Assign/Prioritize Loads/BCs

The Assign/Prioritize Loads/BCs form can be used to group, scale and prioritize loads and boundary conditions as well as load cases. Creation of new load cases can be done by using either existing load cases or individual loads & boundary conditions. Optionally, independent scale factors can be assigned to each Load & Boundary condition or Load Case.

There are two views to the Assign/Prioritize Loads/BCs form. The default view of the form is shown below. This selection allows simple “grouping” and prioritization of loads and boundary conditions. By default, load cases & loads and boundary conditions selected are automatically added as individual rows to the Assigned Loads/BCs spreadsheet. If the load or boundary condition already exists as an entry in the spreadsheet, nothing will be added. Individual scale factors maybe assigned to each load and boundary condition directly via the spreadsheet “Scale Factor” column.

The other view of the form is enabled by selecting the “Additional Loads/BCs Controls...” button. This selection allows explicit load case and load & boundary condition scaling as well as controls for combining/overwriting loads and boundary conditions.


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Select Individual Load/BCs

Select Individual Loads/BCs - Lists all existing loads & boundary conditions in the database. Selected items are inserted into the Assigned Loads/BCs spreadsheet where individual load scaling can be defined if desired. The default scale factor of 1.0 is applied to all selected loads & boundary conditions. Multiple items may be selected from the listbox. If additional load & boundary condition scaling is required, you can select the “Additional LoadsBCs Controls...” button.


Select Loads/BCs from Existing Load Cases

Select LoadBCs from Existing Load Cases - Lists all existing load cases in the database. When selected, the loads & boundary conditions associated with the selected load case is inserted into the Assigned Loads/BCs spreadsheet where individual load scaling can be defined if desired. The scale factor for selected load cases is the existing scale factor times the load case scale factor. If additional load case scaling is required, you can select the “Additional LoadsBCs Controls...” button.

Additional Load/BCs Controls...

Additional LoadsBCs Controls - allows user to toggle between “simple” grouping of load and boundary conditions and “explicit scaling and combining” of loads, boundary conditions and load cases. The default view of the form allows simple grouping of loads and boundary conditions. By toggling this button, the form will change and the additional user scale controls will be displayed. Additionally, user control of whether loads and boundary conditions are combined or overwritten is also provided.


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Select Individual Load/BCs

Lists all existing load cases in the database. When selected, the loads & boundary conditions associated with the selected load case is inserted into the Loads/BCs Scaling spreadsheet where additional scaling can be defined if desired. The Existing Load Case Scale Factor databox is updated with the scale factor of the selected load case. Only one load case may be selected at a time.

Select Loads/BCs from Existing Load Cases

Lists all existing loads & boundary conditions in the database. Selected items are inserted into the Loads/BCs Scaling spreadsheet where additional scaling can be defined if desired. Multiple items may be selected. The Existing Load Case Scale Factor databox is disabled when items are selected from here because it is not applicable.


Input Scale Factor Entry into the Loads/BCs Scaling spreadsheet. Not visible if scaling is not supported by the current analysis preference.

Existing Load Case Scale Factor

Scale factor of selected load case. Enabled only if scaling is supported by the current analysis preference and if a selection is made from the Select Load/BCs from Existing Load Cases listbox.

Additional Scale Factor Factor for additional scaling, i.e. for combining (superposition) load cases.

Overwrite/Combine Computes the cumulative scale factors for the respective items in the Loads/BCs Scaling spreadsheet and inserts these items into the Assigned Loads/BCs spreadsheet. Should any of these items already exist in the Assigned Loads/BCs spreadsheet, Overwrite replaces the existing scale factors with the newly computed factor while Combine adds the two together.


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Load/BC Type This databox allows data entry into the Assigned Loads/BCs spreadsheet. The label and expected data type for this databox changes in accordance to which column is active. If this databox is not visible, then either multiple columns have been selected or the current analysis preference does not support the data related to the active column. The Load/BC Type column provides read-only data.

Add

Value

Sort By Priority

These buttons are visible if & only if the current analysis preference supports loads & boundary condition prioritization. In such cases, if the Priority column is active, the Input Priority databox does not become visible unless Value is picked or a range of rows where first row in the range has a numerical priority is selected. The Sort By Priority button re-sequences the spreadsheet in numerically ascending order of priorities. While “Add” priorities are listed first after such a sort, numerical priorities take precedence over “Add” with respect to loads or boundary conditions of the same type. The order of precedence for numerical priorities with respect to loads or boundary conditions of the same type is such that a lower priority value indicates a higher priority status.


Combination Load Cases

When the Type is set to “Combination” and the Input Data button is selected, the Assign Load Cases form is presented. This form is also displayed if a combination load case is selected from the Load Case Create or Modify form, with the load case assignments/scales of the combination load case displayed.

Static loadcases are selected from the “Existing Static Load Cases” listbox to add them to the combination load case definition. As they are selected, they are added to the list of loadcase/scale factor pairs (spreadsheet), where the scale factors may be modified (default 1.).

Assigned Load/BCs To change values in the Priority column, first select the rows to be changed in this column. You can select all rows by selecting the column header. “Add” inserts the string “Add” into the Priority column of the selected rows. Value assigns sequentially increasing priorities to the selected rows and makes the Input Priority databox visible. Numerical priorities values may be manually changed via this databox. Only integer values are permitted for numerical priorities.


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Select Static Loadcases As existing Static Load Cases are selected, they are added to the spreadsheet below, with a default scale factor of 1.0

Filter The listed loadcases may be filtered using wildcard characters (*). Once the filter value is set, select the “Filter” button to re-build the Static Load Cases list based on that filter.

Scale The scale associated with the loadcases may be modified by selecting that loadcase in the spreadsheet, then setting the value in the databox above. The value will be updated after hitting the Enter key.

Remove Selected Rows The Remove Selected Row and remove All Rows buttons are used to remove loadcases from the spreadsheet.


Simple Load and Boundary Condition Grouping

Procedure for Simple Load Case Grouping

1. First, clear the Assigned Loads/BCs spreadsheet.

2. Select the desired load and boundary condition or load case from either the “Select Individual LoadBCs” or the “Select Loads/BCs from Existing Load Cases” listbox. The corresponding loads and boundary conditions will be automatically added to the “Assigned Loads/BCs” spreadsheet

3. Specify any additional scale factor to be applied to the overall definition of the individual loads and boundary conditions listed in the spreadsheet.

Repeat steps 2 through 3 until the proper definition of the Load Case is defined.


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Combining Load Cases

The Assign/Prioritize form is designed to accommodate the combining (superposition) of existing load cases. See Procedure for Combining Load Cases, 185.


Procedure for Combining Load Cases

1. First, clear the Assigned Loads/BCs spreadsheet.

2. Select the desired load case from the Select Loads/BCs from the Existing Load Cases listbox.


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3. Specify the scaling factor to be applied to the overall definition of the selected load case.

4. The Combine button will insert the loads and boundary conditions associated to the selected load case into the Assigned Loads/BCs spreadsheet. The cumulative scale factor for each of these items is the product of the individual Loads/BCs scale factor, the original load case scale factor, and the additional scale factor.

Repeat steps 2 through 4 for all load cases to be combined.

Ch. 6: Fields ApplicationPatran Reference Manual

6 Fields Application

Overview of The Fields Function 188

Procedures for Using Fields 191

Fields Forms 206

Fields Example 297

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6.1 Overview of The Fields Function

PurposeThe Fields Function enables the creation and maintenance of a library of complex data sets in a simple and straightforward manner. Fields are used to define loads and boundary conditions as a function of one, two, or three variables; material properties as functions of temperature, strain, strain rate, time and frequency. Data Fields are used in the material properties, loads and boundary conditions, and element properties applications. Fields can be either scalar or vector in nature. Complex scalar fields are also permitted if you are using the MSC Nastran Analysis Preference.

An important purpose of the Fields functionality is to provide a means of interpolating, or applying the results of one finite element analysis onto the same or different geometry or FEM model. Real scalar, complex scalar, and real vector results can be interpolated. This powerful capability is useful for multidisciplinary analyses, for example, a thermal analyst creates a model from a resident geometry model and does an analysis. A structural analyst then creates a separate model using the same geometry, reads in the thermal analysis results, and automatically interpolates them onto the structural model.

DefinitionsField: A field is a set of data defined by relationships between one or more independent variables. The fields available in Patran support up to three dimensions and are divided into three types: spatial, material property, and non-spatial fields. Fields can be created either from tabular input, mathematical relationships expressed in PCL or as scalar or vector results on a collection of finite elements. These are described in detail below:

General Field: All three of the above field types may be created using the “General Field” method in addition to the Tabular or PCL methods. A General Field is defined by creating a function expression in PCL to describe the data variation. The terms of the function expression may consist of independent variables, constants and PCL functions related by mathematical operators. The PCL function terms can

Spatial Fields Describes a data set which varies over real or parametric coordinate space. It may exist over one, two or three dimensions. In real space, the field will vary over the coordinates of the selected rectangular, cylindrical, or spherical coordinate system. For parametric space, the field will vary over the c1, c2 or c3 coordinates of the single geometrical entity specified in the Create or Modify forms. Spatial fields can be either scalar or vector in nature.

Material Property Fields

Defines a material property as a function of temperature, strain, strain rate, time or frequency (the material state variable), or combination of any two or all three of these variables.

Non-Spatial Fields Defines a scalar field as a function of time, frequency, temperature, displacement, velocity, or a user-defined variable for dynamic analysis applications.

189Ch. 6: Fields ApplicationOverview of The Fields Function

include user written PCL functions which utilize custom forms for data input. The General Fields implementation for this release is limited; it supports only scalar fields and will primarily be useful for the incorporation of custom PCL functions and forms. It will be expanded upon in future releases.

Continuous FEM Field: A special type of Spatial Field which is created from a finite element mesh and associated results values. By utilizing the connectivity of the mesh, a Continuous FEM Field can be evaluated (via interpolation) at any point within its space. A Continuous FEM Field is created from the graphical display of values on a mesh contained in a group. The field remains valid as long as the mesh and group are defined. Interpolation occurs automatically whenever the Continuous FEM Field is applied.

Discrete FEM Field: A Spatial Field consisting of values defined at elements or nodes. A Discrete FEM Field is created by the importation of Loads or Boundary Conditions via a Patran Neutral file, or with the Fields User Interface. As there is no mesh associated with this field, it is only defined at discrete points. No interpolation is available. The Discrete FEM Field was formerly known as the LBC Field.

CapabilitiesThe fields function is used to create and maintain a library of data fields; they are not applied here. Fields that have been created in this area of Patran are then selected and applied in other functional areas such as: material properties, loads and boundary conditions, and element properties.

Spatial fields are commonly used to control application of pressures and temperatures in the Loads/BCs application, although they can also be applied to displacements and other generalized loads. Spatial fields can be scalar or vector in nature and can be applied in either real or parametric space. Input is either tabular, via PCL function, external PCL routine or through the General Field. Multiple spatial fields can be simultaneously applied.

Material property fields are applied to individual properties (modulus, CTE, etc.) in the Materials Application. These fields can be one-, two-, or three-dimensional in nature with the independent variables being temperature, strain, strain rate, time and frequency (singly or in combination).

Non-Spatial Fields are principally used to specify time and frequency varying data. Time and frequency dependent loads and boundary conditions, and frequency-dependent material properties are all defined via Non-Spatial Fields. Non-Spatial functions of temperature, displacement, velocity, and user-defined variables can also be created. In addition, complex scalar functions of frequency can be created when the MSC Nastran Analysis Preference is selected.

The default size of all tabular fields is 30 entries in each dimension, although it can be increased to up to 1000 in the Options forms. Also, alternative methods of extrapolation can be selected if field table ranges are exceeded.

Summary of Key FeaturesFlexibility: The structure of fields is flexible and generalized. While each type of field has intrinsic characteristics and uses (time or frequency dependence, material property or spatial dependence), the format of each is unspecified. Fields may be entered with tabular input, a PCL function, a General Field

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190

function or a FEM field; data may be vector or real scalar or complex scalar and up to three dimensions. All fields spreadsheet input forms, allow import and export of comma separated value (CSV) files. This provides compatibility with popular spreadsheet programs such as Microsoft Excel.

Ease of Use: Complicated data fields may be modeled using intuitive forms which lead the user through the entire field generation process. Descriptive names are allowed for every field. The fields function provides a convenient location for all data fields where they may be created, shown and modified before application to the model.

Archival Record: All fields created remain in the database unless deleted. This represents a history of all fields used in previous analyses. Also, it permits old fields to be retained, modified, and reapplied.

Field Creation from Analysis Results: Spatial Fields can be created from an imported finite element mesh and associated results or loads. This so called Continuous FEM Field will automatically interpolate result values for any points within its defined space. This capability is useful for mapping one set of analysis results onto another finite element model.

191Ch. 6: Fields ApplicationProcedures for Using Fields

6.2 Procedures for Using FieldsFields can be created, modified, deleted, and shown using the procedures outlined in the following sections. The hierarchy of this presentation reflects the Patran Fields form structure.

Create

To create a new field, select the Patran Fields application button to display the fields form. Select the Create action (the default setting), then select the Object to be created, a Spatial, Material Property or Non-Spatial data field. Before continuing, a choice may be made between creating an all new field, or creating one like an existing field. Upon selection of the object, Patran will display any existing fields of the same object type in the Existing Fields box.

To create a new field like an existing field, select one of the displayed existing field names. All options in the appropriate fields forms will then automatically be set to those of the selected existing field, as well as the tabular data or PCL functions if applicable. After modifying the data and renaming the field as desired, select the Apply button. This will result in the creation of a new field without changing the original.

Instructions for creating a completely new field of any object type are given on the following pages.

• Spatial Fields, 192

• Data Tables, 194

• General Fields, 197

• FEM Fields, 198

Caution: If using degree-based trigonometric functions in your PCL expression, and the angular input is to be derived from a nodal or element position, Patran will internally return such angles in radians. Therefore, you will need to include a radians-to-degrees conversion factor in your expression, i.e. instead of sind( ‘T ), you will need to use sind( ‘T * 180/3.14159 ). You can also use radian-based trigonometric functions.

Caution: When creating Fields in Cylindrical and Spherical Coordinate Frames be aware of problems associated with discontinuities present in function and angle definition. These

usually occur at degrees. For example, defining a Field from 0 to 360 degrees, and applying it where the internally defined angle abruptly changes from +180 degrees to -180 during the application.

180

Caution: Tabular theta values must fall between and . Values outside of this range are not valid. (This restriction does not apply to complex field phase values.)

– +

Patran Reference ManualProcedures for Using Fields

192

Spatial Fields

Upon selecting the object “Spatial Field,” the method of data input must be selected. The options are PCL Function or Tabular Input. A description of these methods follows:


PCL Function A unique name for the field should be entered by selecting the Field Name box. The Field Type (scalar or vector) is now selected, followed by the Coordinate System Type (real or parametric). The appropriate coordinate system for the field is chosen and indicated in the Coordinate System box. For parametric, this is the parametric coordinate system of the single geometrical entity specified. Fields using parametric coordinate systems are evaluated in the parametric coordinate system of the single geometrical entity specified. The PCL function(s) defining the field is (are) now input into the scalar or vector field function box(es). Any valid PCL expression may be used to define the field values. Valid independent variables for the functions are (c1, c2, c3) for parametric fields, and (X, Y, Z), (R, T, Z) and (R, P, T) for rectangular, cylindrical and spherical real fields, respectively.

Tabular Input A unique name for the field should be entered by selecting the Field Name box. The Field Type (scalar or vector) is not active for tabular input, as only scalar fields are permitted. The Coordinate System Type buttons (real or parametric) actually provide three types of fields: real tabular input, parametric tabular input, and endpoints only parametric tabular input. These three types are described below:

• Real Tabular Input. This option permits the creation of one-, two- or three-dimensional scalar fields from tabular input. These fields are defined over the real space defined by the selected coordinate system. The dimensionality is determined by the Active Independent Variables selected. Independent variables are entered in the first row and column as well as an additional databox depending on the dimensionality of the table. The options button opens a form to specify the maximum number of entries into the table. (The default value is 30.) The operation of the data table forms is described in more detail in Data Tables, 194.

• Parametric Tabular Input. This option is very similar to Real Tabular Input described above, except that the space is determined by the parametric directions of the single geometrical entity specified. The dimensionality of the field defines the geometric entity required (i.e., a two-dimensional field is applied to a patch). This option is available only when the Endpoints Only button at the bottom of the fields form is not selected.

• Endpoints Only Parametric Tabular Input. This is the default spatial parametric field type. This field supplies a linear variation between values applied to the points c = 0 and c = 1 of the single geometrical entity specified. The dimensionality of the field defines the geometric entity required (i.e., a two-dimensional field is applied to a patch).


194

Data Tables

Once the dimensionality of the field is determined by the number of Active Independent Variables selected, the data table form of appropriate dimension is opened with the Input Data button. The Options button allows the user to set the number of independent variables and the extrapolation procedure to be used for the field. Below are general rules for using the data table forms throughout the Fields function. Rules are given for each table dimensionality. Valid independent variables for all Spatial tables are (c1, c2, c3) for parametric fields, and (X, Y, Z), (R, T, Z), and (R, T, P) for rectangular, cylindrical and spherical real fields respectively.

General Field See General Fields, 197 for detailed description.

FEM There are two types.

1. Continuous FEM Fields can be evaluated on any point in space over which they are defined.

2. Discrete FEM Fields can only be evaluated at defined points in space.

A unique name for the field should be entered by selecting the Field Name box.

• For a Continuous FEM field, select the “Continuous” FEM Field Definition switch. The Field Type (scalar or vector) is now selected. Select the group containing the mesh which defines the field. Note that the desired result (scalar or vector) must be displayed on the mesh. A vector field is created from vector markers plotted on the mesh, while a scalar field is created from a fringe plot of the scalar value. The “Options” form allows definition of the extrapolation option (used when the field is evaluated at a point outside the mesh region), and the 2D to 3D extrapolation feature. 2D to 3D extrapolation will set the value of the field constant along a given axis.

• For a Discrete FEM Field, select the “Discrete” FEM Field Definition switch. The Field Type (scalar or vector) is now selected. Select the “Entity Type” (Node or Element) next and the “Input Data” button. The spreadsheet widget requires the creation of a table of node or element ids and values. Nodes or elements may be selected or typed in, and may not be combined in a single field. The values must be typed in, and will be automatically formatted to scalar or vector form.

Material Property Fields: Upon selecting the object Material Property, the material property create form will be displayed. Any existing material property fields will be displayed in the Existing Fields box. The Method box will contain a choice of Tabular Input or General, set the method to Tabular Input. A descriptive name may be entered in the Field Name box. The appropriate Active Independent Variables for the field must now be chosen. A tabular material property field may be a function of one, two or three of the independent variables temperature, strain, or strain rate. It may also be a single variable function of either time or frequency. The Options button allows the user to set the number of independent variables and the extrapolation procedure to be used for the field. The rules for data entry into material property fields are specified above in Data Tables. The OK button must be selected after entering data to create and store the field defined.

Non-Spatial Fields: Upon selecting the object Non-Spatial, the non-spatial create form will be displayed. Any existing non-spatial fields will be displayed in the Existing Fields box. The Method box will contain a choice of Tabular Input, General or Discrete FEM(SAMCEF only).

1D Table The left-hand column of the table contains the independent variable. It is labeled with its parametric or real spatial axis. Data is entered by selecting the desired cell, which automatically activates the Input databox. Data typed into the box is stored in the cell when return is pressed, and the cell below is then automatically selected. Any other cell may be selected with the mouse. Numbers larger than the cell display will be entered in exponential format.

2D Table The left-hand column of the table contains the first independent variable, while the top row contains the second. Both are labeled with the corresponding parametric or real spatial axis. The top left cell naturally accepts no input. Data is entered by selecting the desired cell, which automatically activates the Input databox. Data typed into the box is stored in a cell when <return> is pressed, and the cell below is then automatically selected. Any other cell may be selected with the mouse. Numbers larger than the cell display will be entered in exponential format.

3D Table The left-hand column of the table contains the first independent variable, while the top row contains the second. The third independent variable is shown and controlled via the databox below the table; it defines the layers of tabular data. The row, column and databox are all labeled with the corresponding parametric or real spatial axis. As in the 2D case, the top left cells accept no input. The first two independent variables are entered by selecting the desired cell, which automatically activates the Input databox. Data typed into the box is stored in a cell when return is pressed, and the cell below is then automatically selected. Any other cell may be selected with the mouse. Numbers larger than the cell display will be entered in exponential format. The third independent variable is entered by selecting the databox at the bottom of the form. Different values may be entered for each layer of data. Layers are controlled by the two arrow buttons.


196

Tabular Input

A unique descriptive name for the field should be entered by selecting the Field Name box. The Active Independent Variable for the field must now be chosen. A tabular non-spatial real-valued field may be a function of time, frequency, temperature, displacement, velocity, or a user-defined variable. A tabular non-spatial complex-valued field must be a function of frequency.

Selecting the Input Data button displays the tabular input data form. The data entry rules for real-valued non-spatial fields are similar to those for the 1D case explained above in Data Tables, except that a PCL function may also be used to fill the data table. If PCL function input is desired, select the Map Function to Table button and the PCL function form will open. Any valid PCL function may be entered into the PCL Expression box. Note that the independent variable (“t “, “f “, “T”, “u”, “v”, or “UD”) in this expression must always be preceded by a “' “. Filling in the Start, End and Number of Points boxes will define points uniformly spaced with respect to the independent variable. Selecting the Use Existing...Points button will cause the function to be evaluated at all points previously entered in the table. Selecting Apply in the Map Function to Table form causes the function values to be mapped to the table. The data entry rules for complex-valued non-spatial fields differ from those of real-valued non-spatial fields in the following respects: first, you have the option to select the complex data format. It may be Real-Imaginary, Magnitude-Phase (degrees), or Magnitude-Phase (radians). Second, you (obviously) need to define two ordinate values instead of one. Spreadsheet data entry via the input databox works as it does for real-valued fields, but you also have the option (if cells from both complex component columns have been selected) to enter two values, or a complex expression, so that both columns may be loaded simultaneously. Finally, the Map Function To Table form that is displayed for complex fields is used to load one ordinate spreadsheet column at a time because PCL does not recognize complex expressions.

The Options button allows the user to set the number of independent variables and the extrapolation procedure to be used for the field. The Apply button in the Fields form must be selected after entering data to create and store the field defined.


General Fields

The General Field can be used to create a field of any object type. The data are described by a mathematical function composed in PCL. The function expression is composed of terms which can be PCL Functions, Constants or Independent Variables, related by mathematical operators. The expression is composed in a text box by selecting terms from option menus, or by simply typing a PCL expression. Unlike other fields methods which strictly limit the available independent variables, the General Field allows access to nearly any independent variable for any field. It is up to the user to create functions with appropriate arguments for the intended application.

The General Field for this release will be of limited utility. It is restricted to scalar fields of up to three variables, is not defined in parametric space, and analysis code translators will not evaluate general field functions for material properties. The primary use of General Fields in this release will be for accessing custom PCL functions and forms.

To create a General Field, select the “General” method for any field object. This will display the General Field Create form. Any existing fields of the current object will be displayed in the Existing Fields box. A descriptive name may be entered in the Field Name box. Selecting the Input Data button displays the General Fields Input Data form. This form, identical for all field objects, is used to compose function terms and to display the function expression.

The Input Data form presents two option menus, enabling the user to select the next term “type” and “subtype.” The types currently available are “Patran Functions” and “Independent Variables.” By default, there are no subtypes available under “Patran Functions” except with the Patran Thermal analysis preference. Any custom functions added will allow the user to specify a subtype. There are no subtypes for independent variables. Upon specifying a term type (and subtype), the listbox will fill with available selections for the next term. If an independent variable is selected, it will be appended to the function

Discrete FEM (SAMCEF Only)

A unique descriptive name for the field should be entered by selecting the Field Name box. Select the “Entity Type” (Node or Element). Select the “Active Dynamic Variable” of “Time(t)” or “Frequency(f)”.

Select the “Input Data” button to enter the field data into the spreadsheet. The spreadsheet widget requires the creation of a table of node or element ids and values. Nodes, elements, element faces, element edges or element vertices may be selected or typed in. Nodes and elements may not be combined in a single field. The values must be typed in. Presently, only scalar values are allowed.

The spreadsheet data is entered by layers. Each layer represents a different time or frequency value. Time or frequency must increase or stay the same with increasing layer numbers before the “Apply” button is selected on the main Fields form. If layer data is entered out of order, the “Sort Layers in Ascending Order” button may be used before selecting “Apply”.

Layers or rows may be added or deleted by using the other button options on the spreadsheet form.


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expression. If a function is selected, another form will be displayed to accept the function input arguments.

Function input arguments may be specified in a custom PCL form created for the custom function, or in a simple “Generic Input” form which is part of General Fields. The use of a custom input form will be helpful for complicated or specialized functions. The incorporation of a custom form into General Fields is a simple step beyond custom PCL form programming. See Adding Custom General Field Functions (p. 567) in the PCL and Customization. The Generic form will be displayed if no custom form is created. The Generic form displays only the function name, a data box for each argument, and a label indicating the data type expected for that argument. Because of the limited information presented on the Generic form, it is best used only for simple functions. When entering data or expressions into the argument databoxes, proper PCL syntax must be maintained, and any independent variables in the expression must be preceded by a “' “. Upon selecting “OK” in the function input form, the argument data will be stored, and the function name, complete with integer prefix and independent variable list, will be appended to the function expression text box. (The prefix is an ID used to associate the function’s argument data with the particular term of the function expression.)

FEM Fields

A FEM Field is a field which is associated to a finite element model. There are two kinds of FEM Field, Continuous and Discrete. Both are created with the Fields, Spatial User Interface, using the “FEM” method. The Continuous FEM Field is created from data associated to a finite element mesh. The connectivity provided by this mesh allows interpolation of data to any point within the space defined. This field is most often used to map data from one analysis to another.

The Discrete FEM Field (formerly known as the LBC Field) is simply a table of data associated to a list of nodes or elements. This field cannot be interpolated, as no connectivity is defined.

Creating a Continuous FEM Field

Perform the following steps to create a Continuous FEM field. A finite element mesh and associated results must be imported. It is recommended that a new viewport with a new current group be used. This segregates the results model from the current model, permitting easy manipulation.

1. Import analysis results (and the associated model if not in the current database).

Important: While the function expression may be entered into the textbox, or edited via the keyboard, editing of a PCL function term will result in an error. A PCL function term (a term with an integer prefix) has argument data associated with it. Because of this, the modification of a function term must be done with the Modify Highlighted Function button. To modify a PCL function term, first highlight the desired term (double clicking the term will do). Selecting the Modify Highlighted Function button will display the corresponding form and any current data. Modifications will be stored when “OK” is selected.


2. Display the desired results or loads on the mesh. If they are scalar, display them as a fringe plot. If they are vector use any available vector display method. The plot must be displayed while creating the FEM field to ensure the correct data is used. See Fields Create (Spatial, Continuous FEM), 264.

3. Create the field with the user interface.

Once created, a Continuous FEM field can be used like any other spatial field and will be evaluated on any point in space over which it is defined. The evaluation process automatically invokes an interpolator.

Creating a Discrete FEM Field

One way to create a Discrete FEM field is to import a PATRAN 2.5 Neutral File finite element mesh with loads on it. Another way is to utilize the user interface in the Fields application or from within client applications (i.e. Element Properties or Loads/BCs) to explicitly define values associated with existing FEM entities. Note that a Discrete FEM field is defined only at the FEM entities listed. No interpolation is available.

Modify a FieldTo modify an existing field, select the Modify action in the fields form. Then select the object to be modified, a Spatial, Material Property or Non-Spatial field. The “Select Fields to Modify” box will then display the names of all existing fields of the specified object type. Upon selecting one of the displayed names, all settings in the form will automatically be changed to reflect the parameters of the selected field, and filled data tables or PCL functions (as appropriate) will also be displayed. After changing any of the parameters or data as desired, selecting the Apply button will result in the creation of a modified field.

Discrete FEM Fields can also be modified from within client applications (i.e. Element Properties or Loads/BCs) by using the Access DFEM Fields button usually located on the input data form. The action of the client application must also be set to Modify. For more information see Input LBCs Set Data (Static Load Case), 32 or Typical Element Properties Input Menu, 66.

Note: See fields_create (p. 1344) in the PCL Reference Manual for more information.

Important: The FEM field group/results should not be deleted before evaluation has taken place, as the field has no means of interpolation without the mesh.

Important: The original field will be deleted in all cases. To create a new field without deleting the old, refer to Create, 191.


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Common Spreadsheet FunctionalityAll Fields spreadsheet input forms have the following common functionality. All Fields spreadsheet input forms have an "Import/Export..." button in the upper right.


Input Data Databox

The Input Data databox is used to enter data into the spreadsheet. First one or more cells must be selected, and then data is entered into the databox. The keyboard “Enter” key causes the data to be copied into the cells. When a single cell is selected, the contents of the cell are copied to the databox. By default, if more than one cell is selected, the databox is cleared. Users who prefer that the upper leftmost selected cell contents be copied to the databox may do so by adding the following to their settings.pcl file:

pref_env_set_logical("fields_spreadsheet_multicell", TRUE )

Auto Highlight Toggle

This toggle controls the behavior of the Input Data databox when a spreadsheet cell is selected. It is off by default. When a cell is selected, the contents of the cell are placed into the Input Data databox. If the toggle is off, it is not highlighted (selected) in the databox. If the toggle is on, it is. Users who prefer to default the toggle on may do so by adding the following to their settings.pcl file:

pref_env_set_logical( "fields_spreadsheet_auto_highlight", TRUE )


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Selecting it gives you a file form and the option to Import or Export CSV (comma separated value) files.

An options menu allows you to set the separator (comma is default) and whether to read the first line for Import or write column headings for Export.

Import/Export Button

Allows import and export of comma separated value (CSV) files. This provides compatibility with popular spreadsheet programs such as Microsoft Excel. See below for details.

Undo Button This button will undo the last change made to the spreadsheet. There is no limit to the number of undo-s that can be done. Closing the form, selecting an existing field from the main form or using Import cannot be undone and reset the undo level to zero.


Import completely replaces what is in the current spreadsheet. Export writes everything in the current spreadsheet.

Some Fields spreadsheets require the spreadsheet to be fully populated. This means there must be a dependent value specified for every combination of independent variables. The Options form from the Fields/Create and Modify forms has a frame for specifying an “Incomplete Data Action”. This tells Patran what you want it to do if there are missing values in an imported CSV file. “Abort” is the default. If it is set, and a CSV file is imported with any missing values, the import will abort with a warning message. “Set to Zero” and “Set to User Specified Value” can also be chosen. If they are, and a CSV file is imported with any missing values, they will be set to the value specified.


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For example, if your CSV file looks like this:

X,Y,Value 1.0000000E+000, 1.0000000E+001, 9.1000000E+001 1.0000000E+000, 2.0000000E+001, 9.4000000E+001 2.0000000E+000, 1.0000000E+001, 9.2000000E+001 2.0000000E+000, 2.0000000E+001, 9.5000000E+001 3.0000000E+000, 1.0000000E+001, 9.3000000E+001 3.0000000E+000, 2.0000000E+001, 9.6000000E+001 3.0000000E+000, 4.0000000E+001, 9.8000000E+001

the value for x = 1, y = 40 and x = 2 and y = 40 are missing. They will be set to the value specified on import.

Delete a FieldDeletion of an existing field is accomplished by selecting the Delete action, and the Object to be deleted (Spatial, Material Property or Non-Spatial). When the desired object type has been selected, the Existing Fields box will display all fields of that type. All fields selected for deletion will be displayed in the Fields To Be Deleted box. Selecting the Apply button will cause the fields to be deleted.


After selecting Apply in the Delete form, wait for the name(s) of the field(s) selected to be removed from the Existing Fields listbox. Verify the correct Fields were deleted. If an error is made, select the Undo icon.

Show a FieldThe data in any field may be reviewed by selecting the Show action. The Show form contains a scroll box which displays all existing fields. Upon selecting a field to show, the corresponding independent variables will be displayed in the Select Independent Variable box directly below. Any one independent variable at a time may be selected for display. Data is displayed in both graphical and tabular format. For one dimensional data, a single curve over the range will be displayed. multidimensional data will be displayed as a family of curves, each curve at some fixed value of the other independent variable(s). Selecting the Specify Range button enables a precise definition of the range over which the variable will be displayed, and also allows control of the fixed variable values.

If a Discrete FEM field is selected, the data is displayed only in Tabular format.

Note: Currently, Show is not enabled for the General Field.

Patran Reference ManualFields Forms

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6.3 Fields FormsThe functions on the Fields menu are listed and described below in the order in which they appear on the menu.

207Ch. 6: Fields ApplicationFields Forms

Action Object Options

Create... • Spatial Field • PCL Function

• Tabular Input

• 1D Tabular Input

• 1D Linear Parametric Tabular Input

• 1D Tabular Input Options







• General Field

• FEM Fields

• Discrete Input Data

• Continuous Options

• Material Property • 1D Data Input Table

• 2D Data Input Table


• General Fields

• Non-Spatial Field • Tabular Input

• Active Independent Variable, Input Data

• Input Data, Map Function

• T2D Data Input Table


• Complex Scalar Field Data Input Table

• Discrete FEM (SAMCEF Only)

• General Fields


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Fields Create (Spatial, PCL Function)This form is used to create scalar or vector spatial fields in real or parametric space using a PCL expression or externally defined PCL function.

Show... • 1D Table Display

• 2D Table Display

• 3D Table Display

• 1D Specify Range



• Discrete Table Display

Modify... • Spatial Field • PCL Function

• Tabular Input

• General Fields

• Discrete FEM Field

• Continuous FEM Field

• Material Property • Tabular Input

• General Fields

• Non-Spatial Field • Tabular Input

• Discrete FEM (SAMCEF Only)

• General Fields

Delete...

Action Object Options


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Action Select Create as the action.

Object The new field will be Spatial in either real (X,Y,Z) or parametric (C1,C2,C3) space. It may be either scalar or vector in nature depending on the selections made below.

Method The new field will be defined using an input PCL expression or externally defined PCL function.

Existing Fields Existing fields are displayed here. Select one if the new field is to be a modification of an existing field. The selected field name will appear in the box below.

Field Name Alternatively, enter a unique field name here.

Field Type Select Scalar or Vector as the field type. The form changes depending on the pick.

Coordinate System Type

For type Real, input or select the desired coordinate frame if the default is inappropriate. For type Parametric, select the single geometrical entity whose parametric coordinates and space will be used for all evaluations of this field.

Coordinate System Input or select the desired coordinate frame if the default is inappropriate.

Scalar Function ('X,'Y,'Z)

Input a PCL command defining the field or the name of the external PCL function file.

Note: `X,`Y,`Z changes to `C1,`C2,`C3 when Parametric is selected. The apostrophes identify independent variables. If the coordinate system is cylindrical or spherical, the independent variables are `R, `T, `Z or `R, `T, `P. `T and `P in a PCL function are automatically converted into radians when the function is evaluated.

Note: For more help, see Field Type (Vector Option), 211.


Field Type (Vector Option)

Field Type Select Scalar or Vector as the field type. The form changes depending on the pick.


For type Real, input or select the desired coordinate frame if the default is inappropriate. For type Parametric, select the single geometrical entity whose parametric coordinates and space will be used for all evaluations of this field.

Coordinate System Enter or select the desired coordinate frame if the default is inappropriate.


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Fields Create (Spatial, Tabular Input)This form is used to create scalar or vector spatial fields in real or parametric space with user supplied tabular data. The fields may be one-, two-, or three-dimensional in nature and may be either in real or parametric space.

Vector Function `X,`Y,`Z changes to `C1,`C2,`C3 when Parametric is selected. The apostrophes identify independent variables.

First Component

Second Component

Third Component

Input a PCL command defining the vector field components or the names of external PCL function files.

The First, Second and Third Components are defined as the components in the frame in which the field is evaluated. The frame is specified in the application using the field. Applied in an LBC defined in a rectangular frame for instance, the components would be in the X, Y, and Z directions.


Action A new field will be created.

Object The new field will be Spatial in either real (X,Y,Z) or parametric (C1,C2,C3) space. It may be either scalar or vector in nature, depending on the selections made below.

Method The new field will be defined using data tables input by the user.

Existing Fields Existing fields are displayed here. S

Field Name Enter a unique field name here. Or, to create a new field using attributes of an existing field, highlight the existing field and type the new name here.


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Select Real if the field is in X,Y,Z space. Select Parametric if it is in C1, C2, C3 space. The form changes to the one shown on the next page if Parametric is selected.

Coordinate System Enter or select the desired coordinate frame if the default is inappropriate.

Active Independent Variables

Select the independent variables to use. The number selected determines whether a one-, two-, or three- dimensional table input form will be displayed. At least one variable must be selected. Select Real if the field is in X,Y,Z space, Parametric if it is in C1, C2, C3 space.

Note: For more help, see Coordinate System Type (Parametric), 215.


Coordinate System Type (Parametric)

Spatial Field 1D Tabular Input

This form is used to enter tabular data into a one-dimensional table. The default maximum table length


Select Real if the field is in X,Y,Z space. Select Parametric if it is in C1, C2, C3 space. The form changes to the one shown on the next page if Parametric is selected.

Geometric Entity A spatial parametric field must be associated with a geometric entity. This single geometrical entity’s parametric coordinates and space will be used for all evaluations of this field. Select this box and either input directly or select from the viewport using the selection tools.


Determines whether a one-, two-, or three- dimensional table input form will be displayed. At least one variable must be selected. The labels change to 1D, 2D, and 3D when the Endpoints Only option is selected.

Input Data... Selecting this box brings up the appropriately sized and labeled input table form.

Options... Allows you to modify the maximum table size (default is 30 x 30 x 10). Also, the treatment of points which lie outside of the table range may be specified. Inactive when Enpoints Only is ON.

Endpoints Only This invokes a procedure where field values are defined only at the end points of each parametric direction. The program performs a linear interpolation in parametric space between these points. This can also be done using the regular table forms. Making this selection causes specialized input forms to be used along with visual identification of selected points.


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is 30. This can be changed in the Options submenu in the main fields application menu. The first column heading changes depending on the independent parameter being input.

Spatial Field 1D Linear Parametric Tabular Input

This form is used to input tabular data into a one-dimensional table using the Endpoints Only option available when using parametric coordinates. Only two values are input; the field values at the beginning and end of the curve. Intermediate values are obtained by linear interpolation in the parametric direction


.

Endpoint Values (0) Select this box and type in the desired data value(s) to be used at the beginning (0) and end (1) of the selected curve.

Endpoints Only (1) Select this box and type in the data value(s) at the end of the selected curve(s). Linear interpolation in parametric space will be used for intermediate points.

Linear Parametric Table

(C1) Value

(0)

(1)

Endpoint Values

OK Cancel

Note: As each box is selected a circle will appear around the associated point in the viewport. The parametric directions can also be displayed by turning on the “Parametric Direction” button located on the Display/Geometric form. See Display>Geometry (p. 385) in the Patran Reference Manual for more information.


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Spatial Field 1D Tabular Input Options

This form permits the maximum number of rows of one-dimensional field tables to be increased over the default value of 30. The method used to handle field data if a parameter exceeds the table range can also be selected from among three different options.


Maximum Number of X

Select this box and increase the default maximum table size to equal or exceed the desired table size. It is not necessary to reduce this number if smaller tables are used.


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This form is used to input tabular data into a two-dimensional table. The default maximum table size is 30 in both dimensions. This can be changed in the Options submenu in the main Fields Application form.

Extrapolation Option Click on this selection box to change the method used to handle values that may exceed the range of the table. The options are:

1. Use Closest Table Value (default)

2. Linear Extrapolation

3. Set Value to Zero

Incomplete Data Action

Click on this selection box to change the way incomplete CSV file imports are handled. The options are:

1. Abort

The import is immediately aborted.

2. Set to Zero

All missing values are set to Zero.

3. Set to User Specified Value

All missing values are set to the value in the databox below.



This form is used to input tabular data into a two-dimensional table using the Endpoints Only option available when using parametric coordinates. Four values are input; the field values at the corners of the surface. Intermediate values are obtained by linear interpolation in both parametric directions.


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Enpoint Values Select each of these boxes individually and input field values at the parametric corners of the surface(s).


(C1,C2) Value

(0,0 )

(0,1 )

(1,0 )

(1,1 )

Endpoint values

OK Cancel

Note: As each box is selected, a circle will appear around the associated point in the viewport. The parametric directions can also be displayed by turning on the “Parametric Direction” button located on the Display Properties/Geometric form. See Display>Geometry (p. 385) in the Patran Reference Manual for more information.



This form permits the maximum number of rows and columns of two-dimensional field tables to be increased over the default value of 30. The method used to handle field data if a parameter exceeds the table range can also be selected from among three different options.


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Maximum Number of X

Maximum Number of Y

Select these boxes and increase the default maximum table size to equal or exceed the desired table size. It is not necessary to reduce this number if smaller tables are used. Values do not need to be the same.



This form is used to input tabular data into a three-dimensional table. The default maximum table size is 30 by 30 by 10 in X, Y, and Z (or C1, C2, and C3) respectively. This can be changed in the Options submenu in the main Fields Application form.

Extrapolation Option Determines the method used to handle values that may exceed the range of the table. The options are:




Incomplete Data Action Click on this selection box to change the way incomplete CSV file imports are handled. The options are:

1. Abort


2. Set to Zero





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This form is used to input tabular data into a three-dimensional table using the Endpoints Only option available when using parametric coordinates. Eight values are input: the field values at the corners of the solid(s). Intermediate values are obtained by linear interpolation in the parametric directions.


Enpoint Values Select each of these boxes individually and input field values at the parametric corners of the solid(s).


(C1,C2,C3) Value

(0,0,0 )

(0,0,1 )

(0,1,0 )

(0,1,1 )

(1,0,0 )

(1,0,1 )

(1,1,0 )

(1,1,1 )

Endpoint values

OK Cancel

Note: As each box is selected a circle will appear around the associated point in the viewport. The parametric directions can also be displayed by turning on the “Parametric Direction” button located on the Display Properties/Geometric form. See Display>Geometry (p. 385) in the Patran Reference Manual for more information.


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This form permits the maximum number of rows, columns, and layers of three-dimensional field tables to be increased over the default values. The method used to handle field data if a parameter exceeds the table range can also be selected from among three different options.


Maximum Number of X

Maximum Number of Y

Maximum Number of Z

Select these boxes and increase the default maximum table size to equal or exceed the desired table size. It is not necessary to reduce this number if smaller tables are used.


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Time Spatial Fields Create (Patran Thermal only)This form is used to create time dependent spatial field distributions. The functionality is available only while under the Patran Thermal preference. These fields can be referenced from heating and convective thermal Loads/BC. The time independent variable (t) will appear as an additional active independent variable that can be selected from the main form. The Fields/Create form is shown below.

Extrapolation Option Determines the method used to handle values that may exceed the range of the table. The options are:




Incomplete Data Action Click on this selection box to change the way incomplete CSV file imports are handled. The options are:

1. Abort


2. Set to Zero





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The capability is available for Tabular Input only. Both Real and Parametric coordinate system types are supported. In the case Real, the coordinate system can reference a rectangular or cylindrical system.

The Input Data form provides a spreadsheet entry for the Time/Spatial independent variables and the Value. The number of columns depend on the active independent variables selected on the Fields create form. The table must be structured; that is, values at the same X,Y,Z spatial locations must be provided for each of the time point.

Click in a blank cell and press Enter to clear form.

Object

Method

When the Object is Spatial and Method is Tabular Input and the Analysis preference is PThermal, widgets to select a dynamic variable will be shown. Either time or frequency or neither may be selected.


Select X, Y, and/or Z as spatial independent variables.

Active Dynamic Variables

Enable time-dependency.


An Import utility is available on the Input Data form for comma separated value (CSV) files. These can be saved from popular spreadsheet programs such as Excel. The value separations supported are Comma, Semi-colon, Tab and Space.


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Fields Create (Material Property, Tabular Input)This form is used to create material property tabular fields. Currently temperature, strain, strain rate, time or frequency can be selected as the independent variable in a material property field. This form is also used to create new fields which are modifications of existing fields.

Note: CSV files can be saved from Excel or created with a text editor.


Action Select the Create action.

Object Select Material Property as the type of field to be created.

Method Select the Tabular Input Method.


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Material Field 1D Data Input Table

This form is used to input tabular data into a one-dimensional Material Data table. The default maximum table length is 30. This can be changed in the Options submenu in the main fields application menu. The first column heading changes from temperature (T) to strain (e), strain rate (er), time (t), or frequency (f) depending on the independent parameter used.

Existing Fields Any existing Material Property fields are displayed here. Select one if the new field is to be a modification of an existing one.

Field Name Enter a unique field name here, or change the name of the existing field selected.


Select the appropriate independent variable or variables. The number selected determines whether a one-, two- or three-dimensional table input form will be displayed. Select up to three variables from Temperature,

Strain or Strain Rate. Only one of the variables, Time or Frequency may be

selected.

Input Data... Selecting this box brings up the appropriate one-, two-, or three-dimensional input table form.

Options... Selecting the Options menu permits changing the maximum table size. Also, the treatment of points which lie outside of the table range may be specified.



This form is used to input tabular material property data into a two-dimensional table. The default maximum table size is 30 in both dimensions. This can be changed in the Options submenu in the main Fields Application form.


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This form is used to input tabular data into a three-dimensional table. The default maximum table size is 30 by 30 by 10 in T, e, and er respectively. This can be changed in the Options submenu in the main Fields Application form.


Fields Create (Non-Spatial, Tabular Input)This form is used to create Non-Spatial time and frequency-dependent fields. It is also used to create new fields which are modifications of existing fields.


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Object Select Non-Spatial as the type of field to be created.

Method Select the Tabular Input Method.

Existing Fields Existing Non-Spatial fields are displayed here.

Field Name Enter a unique field name here. Or, to create a new field using attributes of an existing field, highlight the existing field and type the new name here.

Scalar Field Type Select the desired Scalar Field Type. This switch is available only for the MSC Nastran Analysis Preference. For all other Analysis Preferences, all Non-Spatial Tabular fields are real valued scalar fields.


Fields Create (Active Independent Variable, Input Data)

Use this form to input tabular data into a one-dimensional data table. The default maximum table length is 30. This can be changed in the Options submenu in the main fields application form. The first column will show the Active Independent Variable (Time, Frequency, Temperature, Displacement, or Velocity), and the second is the associated field value.


Select the desired independent variable. Up to three variables may be selected for real-valued fields, but you cannot select both time and frequency. For complex fields, the independent variable must be frequency.

Input Data... Displays the table input form.

Options... Allows you to change the maximum table size (default is 30). Also, the treatment of points which lie outside of the table range may be specified.


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Fields Create (Input Data, Map Function)

This form permits a dependent field to be defined by a PCL expression or function. The PCL expression is evaluated either at Independent variable points specified in the input table or at equally spaced intervals as defined in this form.

Map Function To Table

Select this option if you want to use a PCL expression or function to define the data points. The Independent variable points used can either be those input in the above table, or be equally spaced values as defined in the Map Function submenu.


Non-Spatial Field 2D Data Input TableThis form is used to input tabular non-spatial property data into a two-dimensional table. The default maximum table size is 30 in both dimensions. This can be changed in the Options submenu in the main Fields Application form.

PCL Expression f(t) Input the PCL expression you want to use to define the time dependence. Use ‘t for the time variable.

Use Existing Time Points

Select this option if you want to use the points specified in the input table. The expression will be evaluated at those points. The Start Time, End Time, and Number of Points databoxes will be grayed out if you select this option.

Start Time

End Time

Number of Points

To evaluate the expression at equally spaced time points, input the starting time, ending time and number of points here. The number of points is one plus the number of intervals.


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Non Spatial Field 3D Data Input TableThis form is used to input tabular data into a three-dimensional table. The default maximum table size is 30 by 30 by 10 in the first, second, and third independent variables, respectively. This can be changed in the Options submenu in the main Fields Application form. The independent variables can be any three of Time (t), Frequency (f), Temperature (T), Displacement (u), Velocity (v), and User-Defined (UD), except that Time and Frequency cannot be selected simultaneously.


Non-Spatial Complex Scalar Field Data Input Table

This form is used to input tabular complex non-spatial property data into a one-dimensional table. The default maximum table size is 30. This can be changed in the Options submenu in the main Fields Application form.


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Complex Data Format Select the format in which you would like to enter your complex data

Input Data Select this box and type in the desired value. Pushing the Return key puts this value in the selected cell. If you have selected cells from the 2 right-hand columns, then you may enter complex pairs. Both columns will then be loaded simultaneously. Complex pairs may be entered as space-delimited constants. Real-imaginary pairs may, in addition, be entered in the form of expressions like “1+2i”, “-3i-5”, “-i”, or”-3.14159”.


Fields Create (Input Complex Data, Map Function)

This form permits the components of a complex field to be defined by a PCL expression or function. The PCL expression is evaluated either at Independent variable points specified in the input table or at equally spaced intervals as defined in this form.

Data Select a cell you wish to input a value for or a cell you wish to modify. The selected cell frame is highlighted. If you select cells from the 2 right-hand columns simultaneously, then you may enter complex pairs.

Map Function To Table

Select this option if you want to use a PCL expression or function to define the data points. The Independent variable points used can either be those input in the above table, or be equally spaced values as defined in the Map Function submenu.


248

Complex Component Select the complex component that your PCL expression will represent. The component choices are consistent with the Complex Data Format selected on the parent form, “Non Spatial Complex Scalar Table Data”.

PCL Expression f(‘f) Input the PCL expression you want to use to define the frequency dependence. Use ‘f for the frequency variable.

Use Existing Frequency Pts

Select this option if you want to use the frequency points specified in the input table. The expression will be evaluated at those points. The Starting Frequency, Ending Frequency, and Number of Points databoxes will be grayed out if you select this option.

Map Function to Table

Complex Component

Real

Imaginary

PCL Expression f('f)

Use Existing Frequency Pts.

Starting Frequency

Ending Frequency

Number of Points

Apply Cancel


Fields Create (Non-Spatial, Discrete FEM) (SAMCEF Only)This form is used to create a discrete FEM Field (formerly known as an LBC Field).

Starting Frequency

Ending Frequency

Number of Points

To evaluate the expression at equally spaced frequency points, input the starting frequency, ending frequency and number of points here. The number of points is one plus the number of intervals.

Apply When you hit Apply, the parent form spreadsheet column corresponding to the selected complex component is updated. If the “Use Existing Frequency Pts.” toggle is not selected, then the abscissa column is also updated. Finally, the alternate Complex Component switch item is automatically selected in preparation for defining the remaining complex component.


250


Object Select Non-Spatial.

Fields

Create Action:

Non Spatial Object:

Discrete FEM Method:

field_3 field_2 field_1

Existing Fields

Field Name

Time (t) Frequency (f)

Active Dynamic Variable

-Apply-

Input Data ...

[Options...]


Non-Spatial Discrete FEM Field Tabular Input (SAMCEF Only)

This form is used to input Discrete FEM Tabular data. The default table length is 30. This can be changed by adding and deleting rows. The default number of layers is 10. This can be changed by adding and deleting layers. The Input Data Box changes depending on whether entities or values are selected and what is selected on the main form.

Method Select the Discrete FEM Method.

Existing Fields Existing fields are displayed here. Select one if the new field is to be a modification of an existing field. The field name will appear in the box below.


Entity Type Select Node for nodal entities or Element for element entities (for element select menu options, see FEM Select Icons (p. 41) in the Patran Reference Manual).


Select the dynamic variable.


Options... The Options Menu allows you to change the treatment of points that lie outside the dynamic variable range.


252

Discrete Space/Time Field Table Data

Select Entities (Nodes)

Delete selected row(s) Clear Selected Cells

Number to Insert (from selected)

3

5

4

2

1

7

9

8

6

Entity Values

InsertAction: 1

Number of Layers to Delete (from current) 1 Delete

Layer: 10 Time Value:


Fields Create (General Field)This form is used to create fields for any Fields object. It is also used to create new fields which are modifications of existing General Fields.

Select Entity Nodes The select databoxes allow you to pick either nodes or elements off the viewport or enter them manually. The main form determines whether you are using Nodes or Elements and they cannot be mixed. The entities will be highlighted in the viewport.

If more than one entity is in the select databox, the spreadsheet will be filled out starting at the first selected cell.

The databox allows you to enter Scalar values.

Entity

Values

select a cell. If an Entity cell is chosen a select databox will appear and if a Value cell is chosen a databox will appear.

Time Value Select the layer and set the time or frequency value here.

Number to Insert Define the number of rows or layers to be inserted or appended. Defaults to 1.


254


Object Select one of the three objects (Spatial, Material Property, Non Spatial) as the type of field to be created.

Method Select the General Method.

Existing Fields Any existing fields are displayed here. Select one if the new field is to be a modification of an existing one. The selected field name will appear in the box below.

Field Name Alternatively, enter a unique field name here, or change the name of the existing field selected.



Select Real, if the field is in X,Y,Z space. Parametric space is not enabled for the General Field.


Fields Create (General Field, Input Data)

This form is used to compose the function defining a General field. The terms of the function may be constants, independent variables or functions and appear in the textbox at the bottom of the form. The function expression is composed using the widgets in the “Select Function Term” and “Arithmetic Operator” frames.




256

Function Term Type This menu allows choice of term type, function or independent variable.

Term Sub-Type This menu allows choice of term subtypes. For function terms, this is user defined.

Select Function Term The term choices are listed here. Selecting a function displays its argument input form; selecting an independent variable appends it to the expression.

Select Arithmetic Operator

Selecting an operator appends it to the expression.


Fields Create (General Field, Generic Function)

This form lists the input arguments (and data types) for a General Field Function. It is displayed when there is no custom PCL form supplied for a General Field Function. Because it provides the user little information about the argument requirements, it is best used with functions having self-evident argument requirements.

Function Expression The Function Expression is displayed here. Typing the expression into this form in PCL syntax is acceptable for all but function terms. Function terms must be composed via the menus to maintain the integrity of the argument input data.

Modify Highlighted Function

Select this button to modify the argument data for an existing term which is a function. Highlight the desired function (double clicking will do) and select “Modify Highlighted Function.” This will display the function’s input form, and all its current data. This button works only for terms which are functions (terms preceded by an integer prefix). Attempting to modify terms which are functions in the textbox via the keyboard will result in an error.


258

Fields Create (Spatial, Discrete FEM)This form is used to create a discrete FEM Field (formerly known as an LBC Field).

Function Name This line displays the name of the function.

Allowable Independent Variables

This is the list of allowable independent variables for this function. Note temperature is not allowed for Spatial fields, and Theta is not allowed for Material Property fields.

Function Argument List

This is the list of arguments for the functions; one databox per argument. The expected datatype is given to the left. Inputs to the databoxes must be valid PCL syntax, all independent variables must be preceded with a “ ' “. This example is a function requiring three integer arguments.

OK Select the “OK” button when you are satisfied with the arguments. This will store the argument data and append the function name (and list of its independent variables) to the Function Expression textbox in the General Field Input Data form.

General Field Generic Function

Function Name: some_test()

'X 'Y 'Z 'e 'er 't 'f 'RAD

Allowable Independent Variables:

Integer

Integer

Integer

Function Argument List:

OK Cancel



Object Select Spatial.


260

Spatial Discrete FEM Field Tabular Input

This form is used to input Discrete FEM Tabular data. The default table length is 30. This can be changed by adding and deleting rows. The Input Data Box changes depending on whether entities or values are selected and what is selected on the main form.

Method The new field will be a FEM field.



FEM Field Definition Select Discrete for a discrete field.

Field Type Select Scalar or Vector as the Field Type.




262

Spatial Discrete FEM Field Access by Other Applications

This form is used to input Discrete FEM Tabular data from within other applications such as Loads/BCs. The form characteristics are similar to the Fields DFEM Fields Input Data form (p. 260) except as noted here.

Select a Node The select databoxes allow you to pick either nodes or elements off the viewport or enter them manually. The main form determines whether you are using Nodes or Elements and they cannot be mixed. The entities will be highlighted in the viewport.

The databox allows you to enter either Scalar or Vector values (as set on the main form). Scalar and vector values cannot be mixed.

Entity

Values

Select a cell. If an Entity cell is chosen a select databox will appear and if a Value cell is chosen a databox will appear.

Number of Rows to Insert

Define the number of rows to be added. Defaults to 1.

Insert Rows... Adds rows to the spreadsheet after the cell selected or at the end if no cell is selected.

If more than one entity is in the select databox, the spreadsheet will be filled out starting at the first cell selected.

Field Action Field Action is determined by the action of the Client Application at the time this form is displayed.

Field Name If a field referenced prior to displaying this form, its name will be inserted here. Otherwise, a field name (maximum 31 characters) must be entered before the field can be Created/Modified.

-OK- Reset

Elem 25.2.1 20.0

Elem 26.3 1.0

< .5,1, 1.5 >

< 10, 20, 30 >

Field Name

< 1, 1, 1 >

Input Vector

Clear selected cell(s)

Insert row(s)Number of rows to insert

Cancel

DFem Field Access for Loads/BCs

Delete selected row(s)

Entity ScaleFactor Values

1

2

Field Action: Create

Discrete FEM Field Information (Loads/BCs)

Field Type: Vector Field Entity: Node

Normalize selected vector(s)

Load 3D Field Elements into Application Region

1

Edge FaceRetain Element Sub-Entities:

Sort selected row(s) Descending Ascending u uu


264

Fields Create (Spatial, Continuous FEM) This form is used to create a Continuous FEM Spatial Field.

Field Entity The field entity and data types are determined by entity & data required by the client application.

Load 3D Field Elements into Application Region

Enabled if the field entities are to be loaded into the application region of the client after clicking OK.

Input Vector Sorts the active cells in ascending or descending order.

Entity

Scalar Factor

Values

The Scale Factor is used to scale the data in the Values column upon apply. If a referenced field already exists when this form is displayed, the data corresponding to this field will be also be displayed. If values were inputted previously with a scale factor, the scaled data will be displayed in the Values column with an associated scale factor of 1.0.

OKResetCancel

OK creates/modifies the field. Reset clears the Values column and sets the scale factor column cells to 1.0--existing entities will remain. Cancel exits this form.


Action Select Create and Spatial as the action and field type respectively.


Method The new field will be a FEM field.



FEM Field Definition Select Continuous for a Continuous FEM field.

Field Type Select Scalar or Vector as the field type.



266

Spatial Continuous FEM Field Options

This form is used to change options when creating/modifying a FEM field.

Mesh/Results Group Filter

This filter permits control of group selection. A group with a contour (scalar) or vector marker (vector) plot must be selected. The field data is defined by the graphical display.

Only groups with contour or vector plots are displayed. The plots must therefore be created before field creation. Selecting all groups causes the listbox to display all groups (with plots) in the database. If Current Viewport is selected, only those groups (with plots) in the current viewport are shown in the listbox. A group must be chosen.

Options... This button displays the form to modify the Extrapolation Option and Interpolation Method.


Extrapolation Option Extrapolation method - Choose from “Use Closest Table Value,” “Linear Extrapolation,” or “Set to Zero.” Defaults to “Use Closest Table Value.”

2D to 3D Interpolation This feature enables the Interpolator to map a 2D field into 3D space. This is accomplished by setting the field values constant in the direction normal to the 2D plane.

Coordinate System Select Coordinate Frame to define interpolation.

Specify Constant Axis Toggle to enable 2D to 3D Interpolation.

Axis Normal to Interp. Plane

Switch enabled when the toggle above is set. Select one axis.


268

Fields ShowThis form contains the commands necessary to display fields, both tabular and PCL defined. The display can either be in the form of a table, or in the form of an XY plot of the table data.

Note: 2D to 3D interpolation can only be used under a limited set of conditions. As stated above, the interpolation is accomplished by keeping the field values constant in the direction normal to the plane specified. For this reason, to obtain a correct 3D evaluation, the coordinate frame axis specified must be exactly normal to the 2D field plane. For rectangular coordinate frames, any axis may be chosen as the constant. For cylindrical and spherical coordinate frames the radial axis (axis 1) is not valid.


Action Select Show.

Select Field to Show All fields are listed in this databox. Select the one to be displayed. If a FEM Discrete Field is selected, the switches, buttons and toggles on the form are hidden and the Field is displayed in tabular format without having to press Apply.


270

Additional widgets are displayed depending on the type of field selected. If a vector field is selected, then a switch listing the vector components is displayed. You would then select the vector component that you want shown. If a complex field is selected, then a switch listing the output complex formats is displayed. This gives you the option to display the field as 1) real and imaginary components, 2) magnitude and phase (degrees), 3) magnitude and phase (radians), or 4) a Bode plot, which displays the magnitude in db and the phase in degrees. If a Non-Spatial Discrete FEM field is selected, a select databox will appear allowing you to select one or more nodes or elements as the FEM location for the XY Plot and tabular results. If you select elements, you must select a face or edge entered in the spreadsheet.

Show Field (1D Table Display)

This table appears after selecting Apply in the Field Show form when the selected field is one-dimensional. It contains the tabular data as specified in the Specify Range submenu. The points displayed are the values that are plotted in the XY Plot if this option was selected.

Select Independent Variables

Switches for each field variable are displayed here. Select the independent variable, or the horizontal axis of the XY plot.

Specify Range Select this submenu to specify the range of the independent variable, or set the number of points to be used in the display. This is required for PCL defined fields.

Post XY Plot If toggled ON, a window containing an XY plot of the field dependent variables versus the selected independent variable will appear. If the field is complex, then each complex component will appear in its own XY plot window. To remove a plot from the screen, iconify it or unpost it from the XY Plot Application form.

Unpost Current XY Window

Removes the current XY plot window from the display. The plot window may be deleted using the XY Plot application.



This table appears after selecting Apply in the Field Show form when the selected field is two-dimensional. It contains the tabular data as specified in the Specify Range submenu. The points displayed are the values that are plotted in the XY Plot if this option was selected.

X These are the values of the independent variable that were either input or computed based on parameters input in the Specify Range menu.

Value These are the values of the field corresponding to the independent variable values.

Plotted Curves

Cancel

X Value


272


This table appears after selecting Apply in the Field Show form when the selected field is three-dimensional. It contains the tabular data as specified in the Specify Range submenu. The points displayed are the values that are plotted in the XY Plot if this option was selected.

X These are the values of the independent variable that were either input or computed based on parameters input in the Specify Range form.


Curve

Y

This is the XY plot curve number and its associated dependent variable value.

Plotted CurvesPlotted Curves

Cancel

1Curve 0.Y

X Value


Show Field (Complex 1D Table Display)

This table appears after selecting Apply in the Field Show form when the selected field is one-dimensional. It contains the tabular data as specified in the Specify Range submenu using the complex format specified on the Ordinate Display Type switch. The points displayed are the values that are plotted in the XY Plot if this option was selected.

X These are the values of the independent variable that were either input or computed based on parameters input in the Specify Range form.


Curve

Y, Z

This is the XY plot curve number and its associated Y and Z variable values.

Plotted CurvesPlotted Curves

Cancel

1Curve 0., 0.Y, Z

X Value


274

Show Field (1D Specify Range)

This submenu is used to define the range of the independent variable to be used in creating the XY plot. For fields created using PCL, the number of points used to display the function must be specified.

Frequency These are the values of the independent variable (Frequency) that were either input directly or computed from parameters input in the Specify Range menu.

Magnitude These are the values of the first complex component of the field corresponding to the independent variable values.

Phase (degrees) These are the values of the second complex component of the field corresponding to the independent variable values.

Plotted Complex Curves

Cancel

Magnitude Phase (degrees)Frequency




Use Existing Points If toggled ON, the plot will contain all existing points in a tabular field.

MinimumMaximum

The minimum and maximum value of the independent plot variable (horizontal axis) can be specified by changing the values in these boxes.

No. of Points The number of points used in the display is set in this box. This value must be input for display of PCL defined fields.


276




Independent Variable Range

Minimum/Maximum



Fixed Independent Variable Range

Minimum/Maximum

The minimum and maximum values of the other variable is displayed.

No. of Sets This is the number of sets (curves) of the second variable. A value must be input for PCL defined fields.

Specify Range


X 0

Minimum

20

Maximum

12

No. of Points


Y 0

Minimum

1000

Maximum

4

No. of Sets

OK

Use Existing Points


Show Field (Discrete FEM Table Display)

This read-only table appears when a Discrete FEM Field is selected in the listbox. It contains a list of entities and associated values in the field.



Minimum/Maximum




Minimum/Maximum

The minimum and maximum values of the other variable is displayed.

No. of Sets This is the number of sets (curves) of the second variable. A value must be input for PCL defined fields.

Specify Range


X 0

Minimum

20

Maximum

12

No. of Points


Y 0

Minimum

1000

Maximum

4

No. of Sets

Z 0 2 3

OK

Use Existing Points


278

Fields Modify (Spatial, PCL Function)This form permits modification of any existing spatial PCL defined field in the database. The modified field replaces the original field.

Entities These are the nodes or elements in the field.

Values These are the Scalar or Vector values of the field that correspond to the entities.

Discrete FEM Field Table Data

OK

3

5

4

2

1

7

9

8

6

Entities Values




Method Select PCL Function as the method used to define the field.


280

Fields Modify (Spatial, Tabular Input)This form permits modification of any existing tabular spatial field in the database. The modified field replaces the original field.

Select Field to Modify Existing Spatial fields are displayed here. Select the one you need to modify.

Rename Field As The name of the selected field appears here. Change it if desired.

Field Type The type of the existing field is indicated here. This form is used for Scalar fields. If you change the type to Vector, the form changes to the one shown on the next page.


The Coordinate System Type of the selected field is indicated here. Change it if desired.

Coordinate System The reference coordinate frame of the selected field is indicated here. Change it if desired.

Scalar Field Function The PCL command defining the field or the name of the external PCL function file is displayed here. Change it as desired. Note that ’X,’Y,’Z changes to ’C1,’C2,’C3 when Parametric is selected.

Options... This button displays the form to modify the Extrapolation Option and Interpolation Method.




Method Select Tabular Input as the method used to define the field.


282

Fields Modify (Material Property)This form permits modification of any existing material property field in the database. The modified field replaces the original field.


Rename Field As The name of the selected field appears here. Change it if desired.

Field Type The type of the existing field is indicated here. This form is used for Scalar fields. If you change the type to Vector, the form changes to the one shown on the next page.


The Coordinate System Type of the selected field is indicated here. Change it if desired.

Coordinate System The reference coordinate frame of the selected field is indicated here. Change it if desired.

Active Ind. Variables Select the independent variable(s) you want to use. The number selected determines whether a one-, two-, or three-dimensional table input form will be displayed. At least one variable must be selected.

Input Data... Selecting this box brings up the appropriate input table form.

Options... Selecting the Options menu permits changing the maximum table size (default is 30 x 30 x 10). Also, the treatment of points which lie outside of the table range may be specified.



Object Select Material Property.

Method Select Tabular Input.


284

Fields Modify (Non-Spatial)This form permits modification of any existing Non-Spatial Tabular field in the database. The modified field replaces the original field.

Existing Fields Any existing Material Property fields are displayed here. Select the one to be modified.

Rename Field As The selected field name appears here. Change it if desired.


Select the appropriate independent variable or variables. The number selected determines whether a one-, two- or three-dimensional table input form will be displayed. Select up to three variables from Temperature, Strain or Strain Rate. Only one of the variables, Time or Frequency may be selected at once.

Input Data... To change data in the table, select this box to bring up the table input form.

Options... Selecting the Options menu permits changing the maximum table size (default is 30 x 30 x 10). Also, the treatment of points which lie outside of the table range may be specified.




Method Select Tabular Input.


286

Fields Modify (Non-Spatial, Discrete FEM) (SAMCEF Only)This form permits modification of any existing Non-Spatial Discrete FEM field in the database. The modified field replaces the original field.

Select Field to Modify Any existing Non-Spatial fields are displayed here. Select one to be modified.


Scalar Field Type The selected scalar field type appears here if you are using the MSC

Nastran Analysis Preference. Change it if desired.


Select the desired independent variable. Only one variable may be

selected.

Input Data... To change data in the table, select this box to bring up the table input form.

Options... Selecting the Options menu permits changing the maximum table size (default is 30). Also, the treatment of points which lie outside of the table range may be specified.




Fields

Modify Action:

Non Spatial Object:

Discrete FEM Method:

field_3 field_2 field_1

Select Field to Modify

Rename Field as

Node Element

Entity Type

Time (t) Frequency (f)


-Apply-

Input Data ...

[Options...]


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Fields Modify (General Field)This form is used to create fields for any Fields object. It is also used to create new fields which are modifications of existing General Fields.

Method Select Discrete FEM.

Select Field to Modify Any existing Non-Spatial fields are displayed here. Select one to be modified.


Field Type Select Node for nodal entities or Element for element entities (for element select menu options, see FEM Select Icons (p. 41) in the Patran Reference Manual).


Select the dynamic variable.

Input Data... This button displays the Input Data form as shown in the Create section.

Options... The Options Menu allows you to change the treatment of points that lie outside the dynamic variable range.



Object Select one of the three objects as the type of field to be modified.


290

Fields Modify (Spatial, Discrete FEM)

This form permits modification of any existing Discrete FEM Spatial Field in the database. The modified Field replaces the original Field.

Method Select General.




Select Real, if the field is in X,Y,Z space. Parametric General Fields are not enabled in this release.


Input Data... Selecting this box brings up the General Field Input form.



Object Select Spatial

Method Select FEM.


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Fields Modify (Spatial, Continuous FEM)

This form permits modification of any existing Spatial FEM Continuous Field in the database. The modified Field replaces the original Field.

Select Field to Modify Any existing fields are displayed here. Select the field to be modified. The selected field name will appear in the box below.


FEM Field Definition The field definition of the existing field is indicated here. This form is used for Discrete FEM Fields.

Field Type The type of the existing field is indicated here. This setting affects the input form.

Entity Type Entity type of the existing field is indicated here. This setting affects the input form.



Object Select Spatial

Method Select FEM.


294

Fields DeleteThis action permits any field to be deleted from the database.



FEM Field Definition The field definition of the existing field is indicated here. This form is used for Continuous FEM Fields.

Field Type The type of the existing field is indicated here.

Group Name of the group results apply to.

Options... The extrapolation option and interpolation direction can be changed by displaying the Options form. The form reflects the current field settings.


Action Select Delete.

Object Select the type of field to be deleted.


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Existing Fields All fields of the type selected will appear in this databox. Select those to be deleted.

Fields to be Deleted Selected fields appear in this databox. They can be removed from this list by selecting them.

297Ch. 6: Fields ApplicationFields Example

6.4 Fields Example

Spatial PCL FunctionAn analyst is required to determine the stress on a dam near its capacity. The analyst decides to neglect all but the water pressure loads on the dam. As pressure is a function of depth, it is easily defined using a spatial field. Since the pressure distribution can be represented by a simple formula, the PCL Function method should be used. The configuration to be analyzed is shown below:

Due to certain modeling considerations, the analyst decides to put the origin of his model at the base of the dam. The analyst must now determine a formula which defines the pressure on the back of the dam

in terms of his spatial coordinate system. Since , it is clear that

.

As the density of water is 62.4 lb/ft3, and the maximum depth is 190 feet, the following PCL expression is entered in the “Scalar Function” databox:

(62.4 * 190) - (62.4 * ‘Y)

When selected as an edge load in the Loads/BCs create pressure form, this field will generate a pressure ranging from 0 psf at the surface to 11,856 psf at 190 feet. It is important to realize that this field is only meaningful for Y coordinates from 0 to 190. Care must be taken not to apply this field to entities greater in Y than 190 to prevent nonsensical negative pressures.

190 Feet

X

Y

pressure depth=

pressuredam depthtotal Y –=

Patran Reference ManualFields Example

298

MSC.Mvision Builder and Evaluator 2002 Installation Guide

I n d e xFunctional Assignments

I n d e xI n d e x

Index

Numerics1D short fiber composite, 1352D short fiber composite, 137

Aanalysis code, 62analysis preference, 90

Cchange current load case, 41composite materials

theory, 142continuous FEM field, 202create

fluid dynamics LBCs, 33load cases, 166structural LBCs, 27thermal LBCs, 30

Ddelete

LBCs sets, 46load cases, 172

discrete FEM field, 203display parameters, 59dynamic load cases, 163dynamic loads/BCs sets, 12

Eelement properties

analysis code, 62fields, 62markers, 62property, 62property type, 63scalar plot, 62tabular plot, 62

element property set, 62

element uniform, 12element variable, 12

FFEM fields, 202field definitions

continuous FEM field, 193discrete FEM field, 193field, 192general field, 192material property fields, 192non-spatial fields, 192spatial fields, 192

field typesmaterial property fields, 199non-spatial fields, 199spatial fields, 196

fields, 62fields create, 257fields forms, 210fluid dynamics LBCs, 33functional assignments

naming conventions, 10

Ggeneral fields, 201

HHalpin-Tsai

continuous fiber, 123continuous ribbon, 128discontinuous fiber, 126discontinuous ribbon, 130models, 150particulate model, 133

Llaminated composite, 116


300

LBCsdisplay parameters, 59markers, 52plot contours, 50select application region, 42show tabular, 50

load case lbc scale factor, 163load case scale factor, 163load cases, 12, 163, 166, 169, 172, 174

change, 41loads/BCs sets, 12, 163

Mmarkers, 13, 17, 52, 62material model, 89material property, 88material property fields, 89, 199modify

LBCs sets, 44load cases, 169

Nnaming conventions, 10nodal, 12non-spatial fields, 199

Pplot contours, 50priority, 163, 177property, 62property type, 63

Rrule-of-mixtures composite, 121

Sscalar plot, 62show

assigned loads/bcs, 175load cases, 174

show tabular, 50spatial fields, 196static load cases, 36, 163structural LBCs, 27

Ttabular plot, 62target element type, 12theory

composite materials, 142thermal LBCs, 30time dependent load cases, 38, 163

Patran 2010 Reference Manual Part 4: Functional Assignments

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Transcript of Patran 2010 Reference Manual Part 4: Functional Assignments