Addendum

Powerful FE technology for specialist applications

Addendum

Version 13.6�

LUSAS Forge House, 66 High Street, Kingston upon Thames,

Surrey, KT1 1HN, United Kingdom

Tel: +44 (0)20 8541 1999 Fax +44 (0)20 8549 9399 Email: [email protected] http://www.lusas.com/

Distributors Worldwide

Summary of Major Improvements

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��Overview of Improvements 1

Summary of Major Improvements .......................................................................................1 New Model Startup ............................................................................................................1 Crash Recovery .................................................................................................................1 Material Properties ............................................................................................................1 Section Properties.............................................................................................................1 Model attribute and results report....................................................................................2

IMDPlus (Interactive Modal Dynamics).....................................................................2 Multiple Tendon Prestress Wizard............................................................................2 Beam Stress Resultants Output from Beams and Shells........................................2

Faster Solutions ................................................................................................................3 Improvements for Processing Large Models ..................................................................3 Improved Model Manipulation..........................................................................................3 Improved Results Display.................................................................................................4 General Display/Interface Improvements.........................................................................5 Improved Speed of Response ..........................................................................................5 Improvements to Scriptable Dialogs................................................................................6 Improvements to Contact Analysis ..................................................................................6 New Elements ....................................................................................................................6 New Material Models .........................................................................................................7 New Loading Types ...........................................................................................................7 Configuration Settings......................................................................................................7 Network Licencing.............................................................................................................7

Customised Product Improvements ...................................................................................7 LUSAS Bridge ....................................................................................................................7 LUSAS Composite .............................................................................................................9 LUSAS Analyst...................................................................................................................9

General Improvements.........................................................................................................9 Interfacing...........................................................................................................................10

Major Improvements in Detail 11 LUSAS Modeller Startup Wizard .......................................................................................11

New Model Startup ..........................................................................................................11 Crash Recovery ..................................................................................................................12 Material Library...................................................................................................................13 Section Library ...................................................................................................................14

Library Locations.............................................................................................................15 Standard Section Property Calculator ..............................................................................15 Arbitrary Section Proprty Calculator .................................................................................15 Precast Beam Section Generator ......................................................................................17 User Defined Sections .......................................................................................................18 Report Wizard.....................................................................................................................18

IMDPlus (Interactive Modal Dynamics.......................................................................20 Seismic Analyses ............................................................................................................21 Moving Load Analyses ....................................................................................................24 Setup Modal Information ................................................................................................28 Run Moving Load ............................................................................................................29

Beam Stress Resultants Output From Beams and Shells .......................................32 Customised Product Improvements 35

Overview of Improvements

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The Bridge Menu ............................................................................................................... 36 The Civil Menu ................................................................................................................... 36 Grillage Wizard .................................................................................................................. 37 Bridge Loading .................................................................................................................. 38

Gravity ............................................................................................................................. 38 Surfacing......................................................................................................................... 39 Eurocode Vehicle Loading............................................................................................. 40 Finland Vehicle Loading ................................................................................................ 40 Israel Vehicle Loading.................................................................................................... 41 Korean Vehicle Loading................................................................................................. 41 Norway Vehicle Loading ................................................................................................ 42 Swedish Vehicle Loading............................................................................................... 42 United Kingdom Vehicle Loading.................................................................................. 43 Unites States of America Vehicle Loading.................................................................... 46 Moving Loads ................................................................................................................. 47

Loading Combinations...................................................................................................... 47 BD37/88 Combinations................................................................................................... 48 BRO94 Combinations..................................................................................................... 49 Korean Highway Code Combinations ........................................................................... 50

Run Influence Analysis ..................................................................................................... 50 Vehicle Load Optimisation................................................................................................ 51 Single Tendon Prestress Wizard...................................................................................... 52

Prestress for Beams....................................................................................................... 54 Prestress for Plane Stress ............................................................................................. 55

Multiple Tendon Prestress Wizard............................................................................ 55 RC Slab/Wall Design ......................................................................................................... 62 Beam Stress Check ........................................................................................................... 63 The Analyst Menu .............................................................................................................. 64 Adaptive Meshing.............................................................................................................. 64 Design Factors................................................................................................................... 67 The Composite Menu ........................................................................................................ 67 Composite Material Library............................................................................................... 68 Define Failure Strength ..................................................................................................... 69 Configuration Settings...................................................................................................... 70

Network Licencing 71 What it is and how it works .............................................................................................. 71 Installing the License Manager......................................................................................... 71


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��

�� Full details of all new facilities can be found in the on-line documentation which is available from the LUSAS Start menu or from within Modeller. This document briefly describes all new features added to the software since the initial 13.0 release.

��

A new model startup dialog eases the definition of basic model information such as the model title and units. The units specified are carried through to the material and section library selection to reduce the possibility of the introduction of errors due to incorrect units.

��

Crash recovery is now automatically invoked if a hardware or software error causes a sudden termination of a modelling session. On reopening the model file Modeller will now detect such an untimely exit and provide an option to return to the modelling stage immediately prior to the system failure.

��

A material library has been incorporated to enable the material properties of the more common structural materials to be defined.

��

The section library has been updated to enable access to multiple libraries and sections are now available for UK, US, EU and Korea. Local or network section libraries may also be added as required.

Standard section property calculators have been incorporated to compute the section properties of standard shapes. The standard shapes included are solid and hollow rectangular sections, solid and hollow circular sections, angle, channel, tee and ‘I’ sections. The computed section properties may be added to the user section library for future use.


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An arbitrary section property calculator has been added which enables the section properties to be computed for any open or closed section. The section shape is defined within Modeller using surfaces. The section properties including the torsion constant and shear area are then computed and may be stored in the local or network section library for future use.

A precast beam section generator has been introduced to work in conjunction with the arbitrary section calculator. A library of cross sections for widely available precast concrete beams is available and the option for including the slab contribution is also provided so that the section properties required in a grillage model can be obtained.

�� A report wizard is now available for writing model attribute and results details to a Word file. This has been extended to accommodate thick shell elements The facility now supports BEAM, GRIL, BMS3, TTS3, QTS4, TTS6 and QTS8 elements for attribute reporting and BEAM, GRIL and BMS3 elements for results processing.

�� !�A interactive modal dynamic capability has been added to enable dynamics to be carried out in the time domain using modal superposition. Modal superposition is significantly faster than step by step dynamics as the analysis is carried out in the modal domain. The IMDPlus facility enables

�� true earthquake time histories to be applied for 2D and 3D seismic problems.

�� the application of constant intensity moving loads

�� the application of multiple trainsets or axle configurations for constant wheel separation.

��"� �� #�$��A multiple tendon prestress wizard is now available for the post tensioning of multiple tendons in stage construction problems. Prestress forces are computed as defined in BS5400 and applied to structural models constructed from beam elements. The interaction between multiple tendons is accounted for in the elastic shortening calculation.

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��The beam stress resultant output wizard enables equivalent beam stress resultants to be computed through a detailed shell and/or beam model at a number of sections along a user defined path. By resolving beam and shell forces and making the assumption that plane sections remain plane the resultant forces are computed. The equivalent beam stress resultants may then be output on the section neutral axis or at the path intersection. The width of the section may be defined using an effective width if desired.


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&�� LUSAS now incorporates a Multi-Frontal Direct Solver and a Multi-Frontal Block Lanczos Solver for speeding up the processing of large problems. These solvers are available as an option. Trials have shown that both the Multi-Frontal Direct and Block Lanczos solver significantly speed up analyses whilst at the same time reducing disk usage.

A METIS equation reordering algorithm has been introduced which significantly improves the performance of the Multi-Frontal Direct Solver, especially for large solid models.

The I/O performance of the eigensolver and linear equation solver has been improved. Two separate changes have been made. The first reduces the number of memory-to-memory transfers in the portable i/o system. The second allows the eigensolver to take advantage of additional memory to reduce I/O traffic.

Improvements have been made to the robustness of the eigensolver which has new diagnostic capabilities to detect potential errors that may arise in the mass matrix (B/M) in vibration analysis, or the stiffness matrix (A/K) in a buckling analysis. If either the matrices are extremely ill-conditioned or exactly singular the eigensolver will now stop with warnings before errors occur. Improvements to error handling for singular matrices in the linear equation solver have also been carried out including more detailed diagnostic capabilities.

The iterative solver has also been enhanced to be more robust and provide faster solutions. For well conditioned 3D solid problems with a single loadcase the iterative solver can, in some cases, provide faster solutions than the direct solvers in LUSAS.

Complex eigenvalue solutions can also be carried out in LUSAS Solver. Details of this facility can be found in the on-line help.

The work carried out on the solvers has involved a restructuring of some of the data storage to take advantage of the additional memory that is available on the average system. These changes have typically provided a speed up of 20% for the existing frontal solvers.

�� '�(��'��Processing of the results plot file (*.mys) in Solver has been made more efficient in terms of computer memory usage and time taken to write results. Much less memory is now required when writing the plot file.

The model (*.mdl), results (*.mys) and restart (*.rst) files are now stored in a compressed format. This can reduce the sze of these files substantially.

The solution capabilities of Solver have been improved so that it is now possible to solve a model size of 500,000 HX8 elements on a 32 bit PC.

�� Group definition and manipulation has been improved to enable groups to be created directly from the advanced selection filter. In addition, groups may now be created from geometric and material assignments in results processing.


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When assigning loadcase dependent attributes, the option is now available to set the loadcase to which the attribute is to be assigned as active. By default this option is selected and causes the attribute that has just been assigned to be displayed on the screen.

Meshing can be interrupted by pressing the Ctrl-Break keys when the message ’To abort meshing, press Ctrl-Break” is shown in the status bar. This is particularly useful when accidentally assigning a finer mesh than was intended. The interruption of meshing will leave the model unmeshed, with all mesh definitions and assignments still in place, so that Modeller will continue to attempt to remesh the model with each user activity. To prevent this, the mesh lock can be activated until such time as the model is again ready to be meshed. Once meshing has been completed successfully without interruption, normal operation will return.

��The results display has been upgraded. New features include:

Improved graphing which enables the graph attributes to be edited and new graph data to be added. .

The following improvements have also been made

�� A graph can now be generated along a selected line which may or may not form part of the model or along an annotation line.

�� All dataset names are appended with a dataset number.

�� Dataset names of results have the loadcase number and title appended.

�� The distance dataset names include the coordinates of the first and last intersects and the line number if utilised.

�� The model title can be added to the graph display above the graph title.

�� The model filename, date, system of units and version of Modeller being used are written to the borders of the graph display.

Improved animation which enables animations to be resized and saved as avi files for display in other windows applications.

Improved results display which allows results values to be displayed on selected nodes or elements, providing fine control over the display of values, by ensuring values are only displayed at the required locations on the model. In addition the number of significant figures, font and orientation of values may be defined.

Improved contour annotation which enables the contour key title to be changed, the number of significant figures in the contour key to be defined and the size of the contour key to be adjusted.

Improved visualisation of the Wood & Armer safety factor for assessment so that a value less than one represents safety and a factor greater than one failure.


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The Spectral Response facility has been improved to allow excitation to be defined in 3 directions. This enables seismic analyses to be carried out on 3D structures in which the horizontal excitation differs from the vertical excitation.

SMART Combinations now allow Wood Armer moments to be used to evaluate the permanent and variable factors to be applied.

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Modeller can be interrupted when refreshing the screen by pressing Control + Break keys which causes a return to interactive mode. The screen will be left exactly as it was at the moment the break is requested. The availability of this facility is indicated by the message ’To abort the refresh, press Ctrl-Break to interrupt refresh’ in the status bar at the bottom of Modeller.

The ’freeze redraw’ facility has been enhanced and renamed ’manual refresh’. Switching on manual refresh does not clear the screen so that it is then possible to select items on the screen in the normal way. As no automatic refreshes are performed interaction is much faster. A certain amount of screen ’debris’ is to be expected after prolonged use and the screen can be refreshed at any time by pressing F5 on the keyboard. The resulting refresh may be interrupted by pressing ctrl-break as described above.

It is now possible to instruct Modeller to automatically save an additional copy of the model file. This feature can be used to save the model to both local and network locations or to provide protection against a corrupt model. The extra model file can be saved in either binary (mdl) or command (cmd) file format. Access to this new feature is via a new button on the Model Properties or SaveAs dialog.

Selection of items on the screen has been speeded up. Deselection of most items in most circumstances is also much quicker, although in some cases (in particular hidden line and solid plots) no improvement is possible without losing the integrity of the image. If faster deselection of these items is required, manual refreshing can be invoked as described above.

Expressions can now be entered in edit boxes on forms and evaluated accordingly.

The model axes are now annotated x,y,z.

Spring support values are displayed with a minimum length so that relatively low stiffnesses are not scaled to zero.

�� Significant improvements in the speed of response of Modeller have been made particularly in the following areas:

�� Meshing, especially for large solid meshes.

�� Opening Model files.

�� Display of attributes, especially when loading in models with large numbers of loadcases.


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�� Creation of Autoloader defined loading.

�� '��Script dialogs have been reduced in size to fit within the graphic area so that the graphics window is no longer automatically maximised. The dialog boxes are also no longer repositioned when invoked.

The minimum screen resolution has been changed from 8000x600 to 1024x768 to enable scriptable dialogs to be larger. It is recommended that Modeller is run in a full size window so that scroll bars are not required to move around scriptable dialogs.

A facility has been introduced which allows dialog boxes to be created directly in Modeller. Dialogs may consist of combo, list and check boxes etc. and visual basic scripting commands can be added to the code for these dialogs to perform model/results manipulation. This facility is aimed at the advanced user and further details can be obtained from the Customer Support Department.

�� + ��Significant improvements have been made to the contact capability. New features include:

Consistent tangent for 3D contact which provides faster convergence of contact problems with or without friction.

Separate contact iterative loops which enable the equilibrium contact conditions to be established before material nonlinearities are computed.

Contact Cushioning which improves the convergence characteristics of difficult contact problems.

Improved slideline results processing which includes slide results in values, contours and vectors layers and enables graphs of the contact parameters to be created either as a time history or as a variation on the contact surface.

Rigid body contact enables contact between bodies with a large variation in stiffness to be carried out without the need to model the deformation in the stiffer body.

Curved contact allows the curvature on contact surfaces to be accounted for when modelling contact with low order elements.

For details of these new features see the Slidelines section in the Modeller User Manual.

��,�� The family of interface elements has been extended to include axisymmetric interface elements, low order interface elements for plane strain analysis and a range of triangular interface elements in 3D.

Non-structural mass elements have been added to allow line and surface masses to be modelled.


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��A non-associated Mohr Coulomb model which includes dilation effects has been implemented.

Convergence properties of the modified von-Mises and Hoffman material models have been improved.

A multi surface cracking concrete with crushing material model has been included.

A concrete creep and shrinkage material model complying with CEB-FIP Model Code 1990 has been introduced.

Viscous damping joint properties have been implemented which are suitable for modelling seismic isolation systems. Viscous dampers may be defined at discrete points in a structure to introduce a dynamic damping force that varies nonlinearly with velocity.

A generic polymer model has been introduced for materials where viscoelastic and viscoplastic behaviour dominate the material response.

��(�� '�"��Internal beam loads (ELDS) have been extended to include a distributed moment Mx. An option to define projected distributed loading has also been added.

�� '�� '��

An interactive utility has been written to assist with the defining of Configuration settings. This utility provides a means of displaying a variety of system information (e.g. available memory and disks) and prompts for the modification of various LUSAS settings and options if required. See section on Configuration Settings in Product Customisation.

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An optional network (floating) licence capability has been introduced to enable a LUSAS licence to be used on any selected computer in a network. The licence may be locked to specific computers in the network or allowed to run on any computer in the network.

��

(.�+��%��'��The facilities within LUSAS Bridge have been extended to incorporate the following:

�� An upgrade to the grillage wizard extends the range of standard grillages to include orthogonal, skewed and curved grillages. Options for defining a spaced beam with slab deck and cracked section are also included.

�� A prestress definition facility enables the forces equivalent to a prestress tendon to be automatically computed and applied to a beam in any orientation. Losses due to wobble,


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creep, shrinkage, relaxation and anchorage slip are accounted for. The wizard can accommodate curved beams and to optionally output a report detailing the input parameters and calculated losses. An additional option available in version 13.4 is the import of user specified/computed tendon forces via an Excel spreadsheet.

�� Comprehensive code dependent vehicle loading with an abnormal indivisible load generator to accommodate special heavy vehicles is included.

�� A moving load generator is provided to enable vehicle loads to be moved along predefined lines. In 13.4 it has been modified to orientate vehicles on inclined lines and arcs and recognised search areas.

�� SMART Combinations enable combinations to be formed which automatically choose the load factor based on the results quantity being combined. In bridge analysis it is often necessary to choose which of two factors to use when combining loadcases to establish the worst loading effects. One factor represents a relieving effect the other an adverse affect. The criteria on which factor to use is defined in the codes of practice which vary around the world. The load factors can however be viewed as a permanent effect (the lower factor) and a variable effect (the difference between the lower and higher factor). The permanent factor is always applied whereas the variable factor is only applied if the overall effect is adverse as defined by the code in use. With the use of permanent and variable factors, combinations may be assembled which automatically adopt the correct factor for adverse or relieving effects. This enables the number of combinations and envelopes required to model a bridge to be substantially reduced. Combinations may be carried out with reference to a single results quantity such that all associated values represent the coincident effects.

�� Improvements to combinations and envelopes include the ability to tabulate combination and envelope data in a table where it can be viewed, modified or copied and pasted into other Windows packages. Combinations and envelopes may now be made up from any loadcase, combination or envelope data.

�� Improved vehicle wizards include updates to BD37/88, the definition of an offset for knife edge loads and the ability to enable overhanging abnormal vehicles to be automatically applied to the nearest wheel load within the structure.

�� New vehicles libraries have been added to support Eurocode, AASHTO, Israel, Finland and Norway and the UK and Swedish vehicle libraries have been extended.

�� Train loads have been added to support Eurocode, UK and USA.

�� Predefined bridge load combinations to BD37/88, BRO94 and the Korean Highway Code automate the definition of combinations for bridges. Support for other codes is being continuously added.

�� A vehicle load optimisation wizard simplifies the use of Autoloader. New dialogs prompt for the bridge code specific input and carriageway definition to enable the influence surfaces to be visualised and the final optimised loadcases to be generated in accordance with the chosen code. Codes currently available are AASHTO (USA), BD21/97, BD37/88, BD21/01, BD37/01, BRO94 (Sweden), Korean, HK (Hong Kong), Finland and Norway.


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�� An RC slab/wall design facility has been incorporated to compute the reinforcement required from a plate or shell analysis. Crack width checking can also be carried out in accordance with BS5400, BS8110 and BS8007.

�� The improved beam stress check includes the ability to modify beam section properties.

�� Upgraded plate elements enable the plate element orientation to be computed independent of the surface definition.

�� Joint meshing with stiffness /unit length or area enables line and surface supports to be defined to accommodate foundation supports.

(.�+��The facilities within LUSAS Composite have been extended to incorporate the following:

�� A new composite material library has been added which includes a variety of materials used to model composites.

�� Improvements to the composite failure criteria have been included so that failure strengths can be modified from the treeview.

�� An option to define symmetric composite laminates to reduce the data input required.

�� Improved composite brick elements to enable through thickness effects to be computed more accurately.

�� New thermal composite elements which are compatible with the structural composite brick elements enable thermal structural coupled problems to be solved.

�� Improved results processing to enable principal stress vectors to be displayed on composite layers.

(.�+��+ ��

�� A facility to carry out adaptive analysis for 2D continuum elements has been introduced. This facility enables an analysis to be automatically run several times to provide results that fall within a user defined global error.

�� Design factors have been included to enable a number of standard design criteria to be chosen when accessing structural integrity. Analysis results can now be checked against these criteria to determine the reserve strength or factor of safety of the material.

)� �� As well as the improvements listed above over 600 general improvements have been made to LUSAS. A few of the more significant of these changes include:

�� Viscous control has been added to loadcase control


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�� An interface to LUSAS system variables from within Modeller

�� Definition of initial velocity loading

�� Tabulation of a deformed model with specified factor

�� Transfer of mass participation factors to Modeller

�� Attribute visualisation for thermal problems

�� V13 Modeller support for V12 Solver

�� Predefined isometric, di-metric and tri-metric views

�� '�� The PATRAN Interfaces, PATLUS and LUSPAT, and the FAM/FEMVIEW interface

FVLUSAS are now available on the 95/98/NT/2000/XP platforms. See the CAD Toolkit Manual for details.

�� The MMI (material model interface) which enables users to compile their own material models into LUSAS Solver is now available on the PC. See LUSAS Solver Reference Manual for details.

Major Improvements in Detail

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��

(.�+��#�$�� An improved LUSAS Modeller Startup Wizard has been implemented that allows the creation of new models and has the ability to browse and open recently used files. The file list reports the status of each file i.e. whether it is in use, indicates the presence of associated results or if model crash recovery is possible. The option to load an associated result file on top of the selected model is also given if any are present.

��The new model startup dialog appears whenever a new model is created.

The job number and title are appended to the model and will be used during the analysis and annotated to the plot border. To subsequently change the title specified use the File> Model Properties menu.

The working folder defines where the model will be saved on the computer.

Units are used to annotate the LUSAS output and preset the units on many of the units dependent dialogs. LUSAS Solver is units independent so the user must ensure all input units are consistent. To subsequently change the units specified use the File> Model Properties menu.

The consistent units available within Modeller are:

�� N m kg C s - newtons, metres, kilogrames, Centigrade, seconds

�� kN m t C s - kilonewtons, metres, tonnes, Centigrade, seconds

�� MN m kt C s - meganewtons, metres, kilotonnes, Centigrade, seconds

�� N mm t C s - newtons, millimetres, tonnes, Centigrade, seconds


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�� kN mm kt C s - kilonewtons, millimetres, kilotonnes, Centigrade, seconds

�� Dyne cm g C s - dynes, centimetres, grams, Centigrade, seconds

�� pdl ft lb C s - poundals, feet, pounds, Centigrade, seconds

�� tf m tg C s – tonnes force, metres, tonnes gravity, Centigrade, seconds

�� lbf ft slug C s – pounds force, feet, slugs, Centigrade, seconds

�� kips ft kslug C s – kips, feet, kilopounds, Centigrade, seconds

�� lbf ft slug F s – pounds force, feet, slugs, Fahrenheit, seconds

�� kips ft kslug F s - kips, feet, kiloslugs, Fahrenheit, seconds

�� pdl ft lb F s – poundals, feet, pounds, Fahrenheit, seconds

�� kpdl ft klb F s - kilopoundals, feet, kilopounds, Fahrenheit, seconds

�� lbf in slinch F s – pounds force, inches, slinches, Fahrenheit, seconds

�� kips in kslinch F s - kips, inches, kiloslinch, Fahrenheit, seconds

A selection of startup templates are provided which contain useful attributes for a number of analysis types. These may be selected from the drop down list as required.

Startup templates may be added to by creating vbs/cmd files and adding these file names to the file startupfiles.csv located in the \lusas13\programs\scripts\treeview directory.

��Should a system failure occur the session file named <model name>.ses is used to enable Modeller to replay the session to a point just before the failure occurred. The session file now only contains information to rebuild the model from the last save operation and is initialised on each successful model save. If a list of the commands used during part or all of a modelling session is required this may be created using sub session files invoked from the Files>Command Files>Open Recording menu entry.


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��(��The more commonly used structural material properties are defined in the material library which is located under the Attributes> Material> Material Library menu.

The units will default to those selected on model startup but may be changed if desired. Select the material required from the drop down list and click OK or Apply to add the material properties to the Treeview. The material properties may then be assigned to the model in the usual way.


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�� (��Within LUSAS Modeller the section library is available from the Attributes> Geometric> Section Library menu entry.

Standard section libraries available are:

�� UK Sections

�� EN Sections

�� AISC Sections

�� Korean Sections

�� User local (see note below)

�� User server (see note below)

The user should select the analysis type in the Usage section in order to set the local axes. The section may be rotated by specifying a beta angle. Shear deformation may be neglected by selecting the Exclude Shear Deformation option. This multiplies the shear area by 10E3. Once selected the user should add the chosen section properties to the Treeview using the OK or Apply button. The section is then available for assigning to the appropriate line members.


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Note: If no local or server sections have been defined as described below then these options will not appear in the section libraries list.

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The location of the section and material libraries may be defined from the Utilities> Library Management> Library Locations menu entry. The local section library is always located in the current working (project) directory while the server library may be located anywhere on the computer network.

�� The properties for a number of standard section shapes may be computed using the standard section property calculator. The dimensions of the shape are input and the properties computed and added to the local or server section libraries. To use the section properties in a model select the appropriate library from the section library dialog.

+�� The arbitrary section property calculator computes the section properties of any open or closed section. Sections are created within LUSAS Modeller either as a single regular or irregular surface, or as a group of surfaces. The LUSAS Model must be defined in the XY plane.

Holes in a section must be defined as separate surfaces which must be assigned to a group named Holes. Any number of holes can be included in a cross section.


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The section property calculator will compute the area, moments of inertia and torsion constant required by the LUSAS beam elements. The torsion constant is computed using the soap bubble analogy which involves running a field analysis using the LUSAS Solver. This process is carried out automatically.

If the computed properties are to be used in a LUSAS model they should be added to either the local or server section library by selecting the appropriate check box when the properties are computed.

To use the computed section properties in a model the properties are selected from the appropriate library using the section library dialog which is accessed from the Attributes> Geometric> Section Library menu entry.

The mesh used to compute the section properties determines the accuracy of the section properties but also affects the computation time. It has been found that a reasonable result is achieved if at least 2 elements are used through thin sections of the model. If a finer mesh is required it is recommended that the problem is initially set up using the default mesh and then the Automatic Meshing option is deselected to allow the mesh to be adjusted.

Sections constructed for two or more materials can also be accommodated. This is achieved using a modular ratio approach. Firstly the material to be used in the main analysis is selected and an isotropic field material property attribute is created with both the thermal conductivity and the specific heat set to unity. This attribute should be assigned to surfaces made from the selected material. Further material property attributes should then be defined for each


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additional material with the thermal conductivity set to G1/G2 and the specific heat set to E1/E2.

Where:

G1 is the shear module of the material to be used in the main analysis G2 is the shear modules of the material in use E1 is the Young’s Modulus of the material to be used in the main analysis E2 is the Young’s Modulus of the material in use.

These material attributes should be assigned to the appropriate surfaces before running the arbitrary section property calculator.

The use of the arbitrary section property calculator is described further in the example Section Properties of a Box Section.

��%�� )� ��The Precast Beam Section Generator produces 2D cross sectional models of widely available precast concrete beams. The library of sections catered for comprises Y, YE, TY, TYE, SY, M, UM and U beam types. The option for including the contribution from a slab is provided so that the section properties required in a grillage model can be obtained. The Arbitrary Section Property Calculator is used to compute the section properties.

The generator is invoked from the Utilities> Section Property Calculator> Precast Section… menu option:


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.�� User defined sections may be added and removed from the local and server libraries from the Utilities> Library Management> Section Library menu option.

��#�$��The Report Wizard allows the user to create a Word Report that contains details of the model properties and analysis results. When processing the model properties the following output options are available:

�� Element details

�� Geometric properties

�� Material properties

�� Support conditions

�� Loadcase details

�� Load attribute details

�� Local coordinates


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�� Model geometry

�� Model plots

�� Combinations

�� Envelopes

When processing analysis results the following output options exist:

�� Element forces

�� Displacements

�� Reactions

The wizard is invoked via the Utilities> Report Wizard… menu entry. This facility will only currently process model attributes for BEAM, GRIL, BMS3, TTS3, QTS4, TTS6 and QTS8 element types while for model results only BEAM, GRIL and BMS3 elements are catered for.


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�� The IMDPlus module allows the user to analyse seismic and moving load analyses using modal superposition techniques in the time domain. For moving load analyses, models must be three-dimensional but may be two- or three-dimensional for seismic analyses. In order to use IMDPlus, consistent dynamic units should be used, for example – SI Units: Force = N, Mass = kg, Length = m, Time = sec.


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��+ ��In order to perform a seismic analysis in IMDPlus, a mass normalised eigenvalue analysis should have been performed to describe the frequency behaviour of the structure. Once completed, the response of the structure associated with up to seven earthquake acceleration time histories can be calculated and nodal / element results interrogated.

Run Seismic Analysis button provides control of the main input options for IMDPlus along with the output control

The IMDPlus seismic analysis module allows the user to analyse the time domain response of a two- or three-dimensional structure to earthquake acceleration record input to the supports. The input consists of the earthquake information, solution control and output control.

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For two-dimensional models, earthquake acceleration time history records can be applied in the global X- and Y-directions of the model. For three-dimensional models, an additional


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earthquake acceleration component in the global Z-direction of the model can be input. The input format for these acceleration records is space delimited, TAB delimited or Comma Separated Variable (CSV).

For all formats, the time step of the acceleration records must be identical in all files. IMDPlus supports the solution of up to seven earthquakes at a time with enveloping / averaging of the Secondary Response Spectra (SRS). For space or TAB delimited files the number of time steps in each directional record for multiple record files must be identical across each of the earthquakes. For Comma Separated Variable files, the number of time steps in each directional record can vary but the number of time steps in individual earthquakes must be identical. If more than one earthquake is present in the record files, the number of valid combinations will be analysed.

Direction factors can be used to scale the input acceleration time histories. If no scaling is required these factors should be set to unity.

��*�� '��

This allows the control of the modes of vibration to be included in the analysis and damping of the structure.

The Modify button for the included modes allows the user to use all modes of vibration or selected modes. If a significant proportion of participating mass is missing based on the selected modes of vibration the user will be warned. Omission of modes of vibration with significant mass contributions that can be excited by the input acceleration time histories will lead to unreliable solutions. Ideally, total mass participation up to 90% should be used unless it is guaranteed that the modes of vibration associated with any missing mass are at frequencies that cannot be excited.

The Default damping option allows the user to force all modes of vibration included in the analysis to have the default damping. This default damping is set via the Modify button. If default damping is not selected (the default when accessing the window for the first time), viscous damping must have been included in the eigenvalue analysis in order to calculate the damping for each mode of vibration.

If viscous damping is present in the eigenvalue analysis, additional options for the inclusion of over-damped modes of vibration in the IMDPlus analysis become available.

&��/��

The frequency interpolation options provide control over the interpretation of the earthquake acceleration time histories in IMDPlus. These are

�� All frequencies included All modes of vibration are included in the analysis even if their frequencies are greater than the maximum frequency that may be reliably resolved based on the record time step (the Nyquist frequency)

�� Limit frequencies to Nyquist frequency All modes of vibration up to and including the Nyquist frequency are included in the analysis. Modes of vibration with frequencies in excess of this value are discarded


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�� Linear interpolation of records Allows the linear interpolation of the records. Required time step is specified by the user for the analysis

�� Cubic spline interpolation of records Allows the cubic spline interpolation of the records. Required time step is specified by the user for the analysis

For rapidly varying input acceleration time histories, such as real acceleration records measured on site which can have large reversals in acceleration over one or two time steps, this form of interpolation should generally not be used. For synthetic acceleration time history records, the use of cubic splines is usually valid since the Fourier series used to generate the synthetic record tend to produce smoother responses. It is however up to the user to ensure that the method if interpolation used is suitable for the analysis being carried out.

�� !�

The user can select displacement, velocity and acceleration results at the nodes or force/stress or strain results at the elements. If both nodes and elements are in the current selection, the radio boxes select which entity type is required for processing.


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The check boxes allow detailed control of the output and are as follows

�� Response time history outputs displacement / velocity / acceleration time histories for nodes or outputs force / stress / strain time histories for elements

�� Peak response summary outputs maxima / minima / absolute peak responses and times to text file of displacements / velocities / accelerations for nodes and forces / stresses / strains for elements

�� Generate SRS generates Secondary Response Spectra based on the acceleration response of the selected nodes (not available for elements). Control of the damping range and resolution for the SRS information is accessed via the Modify button

�� Modal combination/factor history outputs modal factors for the response of the structure at each time step of the analysis. Output takes the form of a command file which can be imported into Modeller to define Modal Combinations of the modes of vibration. These combinations can then be used to visualise the deformations and produce contour plots of entities other than velocities and accelerations. Load Curves which can be pasted into a Solver datafile along with CSV table formats are also available

�� Generate graphs in Modeller automatically generates graphs of the response of the selected node or element in Modeller

�� Generate textfile output allows the results to be output to disk for hardcopy output or import into other graphing packages

�� '�(��+ ��In order to perform a moving load analysis in IMDPlus, the path of the load needs to be defined in addition to the frequency behaviour of the structure. Once the mass normalised eigenvalue solution has been obtained, the procedure indicated by the order of the buttons should be followed.

�� Setup Moving Load Path button allows the user to specify the configuration and path of the moving load

�� Setup Modal Information button performs the computation of the modal force based on the user defined path

�� Run Moving Load Analysis button provides control of the main input options for IMDPlus along with the output control

�� '�(��)� ��

The moving load generator is used to mimic the path of a load across a structure by automatically setting up a number of static load cases at prescribed locations along a single line/arc or a collection of lines/arcs which define a single continuous path. These loadcases can then be used to calculate the modal forces equivalent to the applied loading for import into IMDPlus.


25

Before entering the moving load generator, ensure that a discrete load group representing the load configuration to be moved across the structure has been defined in the Treeview and at least one line representing the vehicle path across the structure has been defined and selected. The line representing the vehicle path should not be one of the lines forming the model.

�� Specify the moving load ID for the configuration to be moved across the structure.

�� If the structure has multiple depths, ensure that a search area has been defined and assigned to ensure that the loading is applied to the required location. If no search area has been defined, all surfaces in the model will be used for projection of the load configuration onto the model.

�� Adjust treatment of load outside the search area using the Advanced button if required. Load factor and discretisation of patch loads can also be adjusted via the Advanced button.

�� Define the incremental distance for the movement of the load across the structure.


26

�� Select whether the load moves in the forward or backward sense. For a single line, the forward direction is defined by the local direction of the line. For a selection of lines, the forward direction is defined by the selection order. The coordinates of the interpreted start and finish locations for the path are displayed on the dialog.

�� Select the number of load cases per analysis for the subdivision of the Solver solution for the path. Typically this should be between 100 and 1000.

�� If only the dynamic effects of the load configuration are required, the Datacheck option should set active to speed up the solution process and if IMDPlus is being run interactively via Modeller the Run analyses option should also be set active (These are the defaults).

�� Click the OK button to form the loadcases representing the load configuration moving across the structure.

�� '�(��+��

Options for Processing Loads Outside Search Area

For patch loads the load outside the search area can be moved into the search area along the paths defined by the local x and y axes of the loading patch. The patch load is transferred into the path along the projected directions and added to the first loading positions found inside the patch in the projected direction. Options are:

�� Exclude All Load (default)

�� Include Local X Projected Load

�� Include Local Y Projected Load

�� Include Local X and Y Projected Loads

�� Include Non-Projected Load

�� Include Full Local X Load

�� Include Full Local Y Load

�� Include Full Load

The load cannot be moved if the entire patch load lies outside the search area. Loads inside the search area are not moved. See Processing Loads Outside the Search Area or click on the list above for explanations of each option.

For point loads the load outside the search area can be moved into the nearest valid projection on any edge in the search area. If no such valid projection exists then the load is moved to the nearest node in the search area. Options are:

�� Exclude All Load (default)

�� Include Full Load


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The load can be moved even if all the point loads lie outside the search area. Loads inside the search area are not moved.

Number of Divisions in Local X and Y Direction specifies the numbers of divisions in the local x and y directions of the patch being assigned. The divisions are used to split the applied patch into individual component loads before they are in turn used to calculate equivalent nodal loads on the model. By default, 10 divisions are used in the local x direction and the aspect ratio of the patch is used to calculate the divisions in the y direction. At least one division should be used per element division. The more individual loads a patch is split into, the more accurate the solution obtained. Equivalent weighting values are used to calculate the portion of each discrete load that is applied to each corner of the element that it lies within. The load is then applied as Concentrated Loads. These weighting values are based on element shape functions and may vary with element type.Note. Discrete patch loads are not work equivalent as the discrete points are simply lumped at the nearest node.

Load Factor specifies a factor by which the loading is multiplied before the equivalent nodal loads are calculated.


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�� The modal force calculator computes the equivalent modal force associated with all of the load configuration positions set up in the moving load generator.

These modal forces are output in the format required for IMDPlus.

�� Select the first results file containing the eigenvalue results. If multiple eigenvalue results files are being used then this will be indicated in the total number reported.

�� Select the first static / datacheck results file containing the moving load solutions.

�� Enter the basename for the modal force output. By default this will be set to the same basename as the original model (.mdl removed).

�� Select the start and end load case numbers for the moving load path. If a subset of the original path is required then these can be set values other than the default first and last load cases created by the moving load generator. The resolution of the path can be


29

modified through the load case increment or the path can be reversed by choosing Backwards or setting the start load case to a value greater than the end load case (will automatically change the direction radiobuttons).

�� Click the OK button to perform the calculations

�� '�(��The IMDPlus moving load analysis module allows the user to analyse the time domain response of a three-dimensional structure to passage of a load across the structure. The input consists of the loading information, solution control and output control.

�� '�(��

The filename of the modal forces computed for the passage of the load across the structure should by default be present in the input. If for any reason this is not the case or if a different modal force file is required, enter the name or search for it by clicking on the Browse button.


30

IMDPlus provides two methods for the definition of load configurations, the complete definition or the composite axle definition. For loads where the lateral configuration of the discrete load components remain constant in terms of both their offsets and relative magnitudes, the composite axle definition method can be used to define the complete loading configuration from a single unit axle. This method is generally only applicable to certain vehicles such as trains, hence the name. To use this method, the moving load defined previously for the definition of the path should have an overall load equal to unity. If this is the case, the load configuration can be defined through a separate file entered into the associated entry. This axle definition takes the form of a text file that contains the positions of the axles (in a negative sense from the front of the vehicle) and the total weights of the axles, one axle per line of the file. The format of this file can be space delimited, TAB delimited or CSV formats.

Using the composite axle definition method, multiple load configurations can be analysed without needing to recalculate the modal forces via the moving load generator and modal force calculator, thereby speeding up the analysis process significantly. This method is particularly useful for solution of bridges where multiple train / vehicle configurations need to be analysed.

��*�� '��

Allows the control of the modes of vibration to be included in the analysis and damping of the structure.

The Modify button for the included modes allows the user to use all modes of vibration or selected modes. If a significant proportion of participating mass is missing based on the selected modes of vibration the user will be warned. Omission of modes of vibration with significant mass contributions that can be excited by the input acceleration time histories will lead to unreliable solutions. Ideally, total mass participations up to 90% should be used unless it is guaranteed that the modes of vibration associated with any missing mass are at frequencies that cannot be excited.

The Default damping option allows the user to force all modes of vibration included in the analysis to have the default damping. This default damping is set via the Modify button. If default damping is not selected (the default when accessing the window for the first time), viscous damping must have been included in the eigenvalue analysis in order to calculate the damping for each mode of vibration.

If viscous damping is present in the eigenvalue analysis, additional options for the inclusion of over-damped modes of vibration in the IMDPlus analysis become available.

��

The solution control defines the range of speeds to analyse for the passage of the moving load along with quiet time and time step controls.

�� Enter the minimum speed in m/s.

�� Enter the maximum speed in m/s. If the maximum speed is identical to the minimum speed then a single speed will be analysed.

�� Enter the speed increment in m/s. If the speed increment is zero then a single speed equivalent to the minimum speed will be analysed.


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�� Enter the quiet time after the passage of the load in seconds. If zero is entered, the IMDPlus analysis will finish immediately after the load has reached the end of the path. If a quiet time greater than zero is entered, this time will be added to the solution to allow the decay of the structural response to be analysed and visualised.

�� Select whether IMDPlus will determine the time step of the analysis based on the Nyquist time step (Maximum time step required to capture the response of the highest frequency of vibration included in the analysis) or to specify the time step. If specifying the time step, this should be sufficient to capture the response of the structure.

�� '�(��!�

The user can select displacement, velocity and acceleration results at the nodes or force/stress or strain results at the elements. If both nodes and elements are in the current selection, the radio boxes select which entity type is required for processing. The check boxes allow detailed control of the output and are as follows

�� Response time history outputs displacement / velocity / acceleration time histories for nodes or outputs force / stress / strain time histories for elements

�� Peak response summary outputs maxima / minima / absolute peak responses and times to text file of displacements / velocities / accelerations for nodes and forces / stresses / strains for elements. If more than one speed is analysed, these summaries are presented versus speed.

�� Generate SRS generates Secondary Response Spectra based on the acceleration response of the selected nodes (not available for elements). Control of the damping range and resolution for the SRS information is accessed via the Modify button

�� Modal combination/factor history outputs modal factors for the response of the structure at each time step of the analysis. Output takes the form of a command file which can be imported into Modeller to define Modal Combinations of the modes of vibration. These combinations can then be used to visualise the deformations and produce contour plots of entities other than velocities and accelerations. Load Curves which can be pasted into a Solver datafile along with CSV table formats are also available

�� Generate graphs in Modeller automatically generates graphs of the response of the selected node or element in Modeller. For moving load analyses this includes graphing of the peak response summaries.

�� Generate textfile output allows the results to be output to disk for hardcopy output or import into other graphing packages


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�%�� &��%�� The slice resultants from beams and shells option allows the computation of the equivalent beam stress resultants for flat or curved thin and thick shell models. This allows the conversion of the results of a complex shell model into an equivalent beam analogy for use in design codes of practice. The slice resultants are computed using valid visible 3D beam and shell elements. Invisible elements are ignored.

��

The slice locations are defined using a path which can consist of straight lines and arcs or combined lines that contain straight lines and arcs in the selection. The path must be continuous without any branching characteristics. The slice path orientation is defined by either the order of selection when more than one line/arc is selected or the orientation of the line/arc if only a single line/arc has been selected. The locations for the slices along the path can be defined using three methods:


33

1. From points or nodes in the selection If nodes or points are selected, these are projected onto the path perpendicular to the appropriate path segment tangent to obtain the slicing locations

2. Incremental distances from start of path Incremental distances can be entered to define the distances along the path for the slicing. Distances can be both positive and negative but the running total distance should remain within the length of the path. For example, 1@0;1@10;1@-5 will cut slices at distances of 0, 10 and 5 along the path

3. Absolute distances from start of path Absolute distances can be entered to define the distances along the path for the slicing. Distances must be positive and within the length of the path. For example, 0;5;10 will cut slices at distances of 0, 5 and 10 along the path

The Distance from reference origin to start of path (chainage) can be also be entered. If this value is non-zero, the value is added to the distances along the path.

The orientation of the slice local axes is defined from both the tangent of the path at the location of the slice and the direction that the model is viewed from. If the slicing path is in the plane of the screen the positive slice local z axis will be defined by the tangent of the path and the positive slice local y axis will be orientated in the out of screen sense. If slicing path is not in the plane of the screen, the positive slice local y axis will be defined perpendicular to the path tangent in the path tangent/out of screen plane. The positive slice local x axis will be defined perpendicular to both the slice local y and z axes.

Options are available for the calculation of the moments about either the Neutral axis or the Path intersection with the slice plane.

Note: For the calculation of beam stress resultants it has to be assumed that plane sections remain plane under the action of the loading. The strain distribution over the whole section also is assumed to remain linear. The location of the neutral axis can therefore be calculated directly from the areas and stiffness of the contributing materials in the composite cross-section (see Gere & Timoshenko, Mechanics of Materials, 3rd SI Ed., pg 301-). For the calculation of the neutral axis location, the Transformed-Section Method is used which incorporates Modular Ratio techniques.

��

Additional options are available for the control of the slicing. These include:

�� Effective width If the effective width option is selected, the width of visible elements to include in the calculations can be specified. This effective width is centred on the slicing path in the screen plane at a perpendicular to the path. If the effective width is not used, all valid visible elements will be included in this direction. For both options, the slice is infinitely deep in the slice local y axis

�� Include whole elements only If the effective width option is selected, the option to include whole elements only is available. If selected, partial elements intersected by the current slice will be ignored in the calculations


34

�� Smooth corners on path If the smooth corners on path option is selected, the average tangent of the path at a connection between two lines/arcs will be used for the slicing if the distance along the slice path exactly matches this path connection. If the smooth corners on path option is not selected, two slices will be taken at the connection using the tangents for both of the lines/arcs connecting at this location

�� Slicename prefix Allows user to input a user defined prefix for the slice names.

Notes

�� The assumption that plane sections remain plane which is required for the calculation

�� Linear variation of stress is assumed for the approach and therefore low order flat shells are supported (3 or 4 noded thin and thick shells) and high order flat shells are calculated ignoring the mid-side nodes if they are coplanar with collinear edges. For curved high order shells the element is subdivided into constituent pseudo elements and each pseudo element interrogated using linear interpolation

�� The slicing path must be defined using straight lines, arcs or combined lines containing only these two line types. Splines and annotation lines cannot be used

�� Slice forces can only be computed relative to the intersection of the slicing path with the slice plane or the neutral axis based on the sliced section. No facilities are available for the transformation of slices without defining a separate path and recalculating the slices

�� Taking slices at the free end of a structure can lead to overestimation of the forces and moments on the section. This occurs due to the stresses in the section not returning to zero at a free and unloaded end

�� Taking slices at a supported end of a structure can lead to discrepancies in the forces and moments when compared to a beam model due to the end effects taken into account by the full 3D shell modelling

�� Where a slice passes through a node in the structure, results are presented for the contributions of the elements on both sides of the slice. This is presented as results for the negative and positive local Z sides of the slice

�� Engineering thick beam elements are supported (BMS3 and BTS3) along with thin beam (BS3, BS4, BSL3 and BSL4) elements

�� Option 380 must be used for BTS3 elements when using eccentricitices

�� When using 3 or 4-noded shell elements the mesh density should be sufficiently fine to capture the behaviour of the structure.

Customised Product Improvements

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�� After running LUSAS Modeller, a product specific menu entry will added to the menu bar according to the product that is in use.

The following menu bar entries will be added for each product as defined below:

�� Civil - for LUSAS Civil & Structural

�� Bridge - for LUSAS Bridge

�� Analyst - for LUSAS Analyst

�� Composite - for LUSAS Composite


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"��%��'�� The LUSAS Bridge menu options will appear as shown:

"�� The LUSAS Civil menu will appear as shown


37

)��'��#�$��The grillage wizard enables orthogonal, skewed and curved grillages to be generated. Both slab deck and spaced beam with slab deck constructions are supported and cracked section may be included. The dialogs allow straightforward input of the data required. The wizard accounts for multiple spans and applies support conditions. Groups are also created to enable geometric and material properties to be easily assigned.


38

%��'��(�� '�A number of options have been added to simplify the input of bridge loading in accordance with a number of codes of practice. The ranges of codes supported is being continually extended.

Apart from the gravity loading, all bridge loads are defined using discrete loads. These are assigned to a point (which need not form part of the model) at the chosen load origin by dragging the load definition from the Treeview onto the graphics display.

)��

By selecting the Gravity option a load dataset is added to the Treeview defining gravitation acceleration in the vertical axis direction. The units selected in the startup dialog are accounted for in the definition. The vertical axis is set by the chosen startup template and can be modified from the Utilities>Vertical Axis menu selection.


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�� ' The surfacing option enables the surface loading to be defined for each lane. The loading should be defined in t/m3. This will be converted to the units selected on the startup dialog if required.


40

,��0��(�� '�These dialogs provide a means of defining vehicle and train loads in accordance with Eurocode ENV 1991-3: 1995.

&� �� 0��(�� '�The Finland vehicle loading facility provides a means of defining Finnish vehicle loads to the Finnish loading design code.


41

��0��(�� '�The Israel vehicle loading facility provides a means of defining Israeli vehicle loads to the Israeli loading design code.

1�� 0��(�� '�Dialogs have been added to simplify the input for standard Korean vehicle loads.


42

��0��(�� '�These dialogs provide a means of defining Norwegian vehicle loads to the Norwegian loading design code

��0��(�� ' A number of dialogs have been added to simplify the input of vehicle loading in accordance with the Swedish bridge code BRO94 and BRO2002 Classification loads.


43

. ��1� '��0��(�� '�A number of dialogs have been added to simplify the input of vehicle loading in accordance with the UK bridge codes BS5400, BD37/88 and BD37/01, BD21/97, BD21/01 and train loading The wizard generates lane and knife edge loads according to these codes.


44

The train load generator can produce loading types RU, SW/0, SW/2, RL, RA1, RT, Class 67 and Class 91.


45

An Abnormal load generator is provided to input the special heavy vehicle loading types that can be required on heavy load routes.


46

. ��+��0��(�� '�To simplify the input of vehicle and train loading in accordance with the Standard Specifications for Highway Bridges (LFD and LFRD) AASHTO.


47

�� '�(��The moving load generator enables a series of loadcases to be automatically generated to represent a vehicle moving across the bridge deck. The path of the vehicle is defined by selecting a line which must not form part of the model. The vehicle direction can be specified.

The generator splits the chosen line into a number of segments and creates a loadcase for the vehicle in each load position.

(�� '�� Loading combinations can be defined to BD 37/88, BRO 94 or the Korean Highway Code. The combination generators should only be used in conjunction with the predefined load templates. These templates are initiated from the startup dialog and predefine the possible characteristic loadcases. Loads are assigned to these characteristic loadcases and the combination generator then combines these in accordance with the chosen code.

If a model exists which has not been created from the appropriate startup template all loading should be removed and the loadcases should be defined using the vbs file <Code>Loadcases.vbs which is located in the \lusas13\programs\scripts\treeview directory.


48

The use of bridge load combinations is described in the example BRO94 Slab Analysis.

%�23*44�� A wizard is provided to automatically compute the load combinations required by BD37/88. The combination requires the user to have used the BD37/88 bridge load template on model startup to define the characteristic loadcases.


49

%��56�� A wizard is provided to automatically compute the load combinations required by BRO94. The combination requires the user to have used the BRO94 bridge load template on model startup to define the characteristic loadcases.


50

1�� 7�'�� A wizard is provided to automatically compute the load combinations required by the Korean Highway Code. The combination requires the user to have used the Korean (Bridge) template on model startup to define the characteristic loadcases.

�� + ��The Run Influence Analysis option automates the running of an influence analysis for beam, plates or shells. LUSAS Solver is invoked for each set of influence parameters and the influence line/surface is loaded into the Treeview. By activating each results loadcase the influence shape can be visualised.


51

0��(�� The vehicle load optimisation wizard simplifies the use of AutoLoader for the generation of the most adverse loading for each influence surface. Finnish and Norwegian design codes have been added to the list of options available.

The use of Autoloader is described fully in the Autoloader User Manual.

The use of the load optimisation facility is described in examples Grillage Load Optimisation and Slab Load Optimisation.

Vehicle Load Optimisation (Autoloader)

In certain loading situations an upward load may be applied by Autoloader. This can be a result of a HB loading overhanging a lane where HA loading is applied. The upward load is applied to cancel the excess of HA loading. The loading standard BD 37/88 "Loads for Highway Bridges", clause 6.4 deals with this loading situation in more detail.

Using grillages with Vehicle Load Optimisation (Autoloader)

When using a grillage with the Vehicle Load Optimisation facility each of the lines representing a section of the deck must be meshed with one element only i.e. each bay of the grillage must have one element assigned. In addition, only lower order elements can be used. Quadratic elements with mid-side nodes are not permitted.


52

�� '��"� �� #�$��The Single Tendon Prestress Wizard allows engineers to determine the stresses in the post tensioned concrete structures. It is accessed through the Bridge or Civil menus via the Bridge> Prestress Wizard> Single Tendon… menu selection.

Computation of tendon forces due to post tensioning is available in accordance with BS5400 or AASHTO-LRFD. Direct import of tendon forces may also be defined via an Excel spreadsheet.

Selection of the BS5400 option from the Bridge> Prestress Wizard> Single Tendon> BS5400 menu invokes the dialog that follows:

Selection of the AASHTO-LRFD option from the Bridge> Prestress Wizard> Single Tendon> AASHTO-LRFD menu invokes the dialog that follows:


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The concrete beam may either be modelled as a series of beam elements or a mesh of plane stress elements. In both cases the location of each tendon or group of tendons is defined by a set of Points that are connected by a spline.

The tendon (and in the case of prestress for beams, the lines representing the beam) must be selected prior to starting the single tendon prestress wizard.

The prestress wizard computes the equivalent forces due to the prestress cable in accordance with the chosen code. The prestress forces are assigned to the current active loadcase of the beam or plane stress elements automatically. After load assignment the forces may be visualised if required.

When the prestress definition is computed two graph datasets are created to enable the tendon losses to be visualised against the tendon length. In addition, a Microsoft Word report may be generated. This option requires the template Modeller.dot (located in the \lusas13\programs\scripts folder) to be relocated to the Microsoft Word templates folder.

Using this simplified force approach, the effects of prestress can be defined in a separate linear loadcase which can be combined with the other loadcases to compute the overall structural behaviour.


54

The use of the prestress facility is described in example ‘Linear Analysis of a Post Tensioned Bridge’.

Tendon forces can also be computed directly by the user and imported from a spreadsheet. If this option is selected in the Prestress Wizard the following dialog appears.

The tendon (and in the case of prestress for beams, the lines representing the beam) must be selected prior to selecting the prestress wizard.

A filename for the spreadsheet is entered and when the OK button is clicked the tendon geometry is written to the spreadsheet. When this has been done the spreadsheet is displayed and the tendon forces can be added by manually editing the spreadsheet. The forces are then read into Modeller and the procedure follows that described above for the codes.

��%��The line defining the tendon should be defined as a spline passing through a set of user-defined points, ensuring sufficient points are defined on the cable to adequately model the loading. Use the command Geometry> Line> Spline> From Points to do this.


55

To compute the loading for one tendon:

2. Select all Linesrepresenting the beam

1. Select the Spline representing the tendon

3. Select the Prestress Wizard

1. Select the line defining the tendon

2. Select all of lines that define the concrete beam

3. Select the prestress definition entry.

The wizard will compute the prestress loading and apply it to the beam. The line must be meshed with the appropriate engineering beam elements (BEAM, GRIL or BMS3). Geometric and concrete properties should be assigned and support conditions added in the normal way.

Note. This sequence must be completed for each tendon in the model.

�� The line defining the tendon should be defined as a spline passing through a set of user-defined points, ensuring sufficient points are defined on the cable to adequately model the loading. Use the command Geometry>Line> Spline> From Points to do this.

To compute the loading for one tendon:

1. Select the line defining the tendon

2. Select the prestress definition entry

The wizard will compute the prestress loading and apply it to the plane stress elements which should be assigned appropriate geometric and material properties.

��"� �� #�$��This wizard simplifies the computation of forces for post tensioned tendons in accordance with various design codes, automatically accounting for short and long term losses.


56

The line features representing beams may be straight or curved and may consist of multiple lines defining each span. Before load assignments can be undertaken the lines must be meshed with beam elements.

This first page of the wizard allows the design code to be chosen and the elastic shortening effects to be entered.

Selecting Based on design code enables the Set losses… button. This allows the average overall tendon force loss to be entered as a percentage. This percentage loss is applied to all loading that is assigned to the model.

Selecting the User defined option enables the Set losses… button. This allows the percentage of applied load remaining after attaching subsequent tendons to be specified.

The wizard analyses the assignments in order to correctly determine how to apply elastic shortening. When using elastic shortening several loads may be created for each tendon as the load intensity depends on previous tendon assignments.

When BS5400 is chosen from the design code option part IV clause 6.7.2.3 of BS5400 details what is required for elastic shortening.


57

Selecting Ignore effects will not apply any elastic shortening effects to the tendons.

If previous prestress data has been stored in the model, the Reset previous prestress input option causes the prestress wizard to ignore previous input and allow new data to be entered. If the wizard is cancelled at any time, the previous data saved in the model file will not be lost. Data will only be overwritten when the finish button is chosen on the final dialog.

Notes: The wizard expects the input units to be the same as the current model unless otherwise stated on the dialogs. When the prestress loads are calculated the prestress forces are converted into the current model units. The current model units can be found on the status bar of LUSAS Modeller.

"� ��

This page of the wizard allows the tendon profiles to be specified or edited. Tendon profiles are stored and viewed in the Utilities treeview. Like other utilities they are not directly assignable to geometry and can be only edited from this wizard.

To create tendon profiles enter a dataset title and select the Create button. Coordinate data can then be entered for this new profile in the blank grid.


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Profile coordinates can be entered a single column with a space or a comma separating the x, y and z coordinates or by selecting the 3 Columns option to obtain a 3 column grid. Note that selecting the top left row / column box this will allow you to copy and paste data from a spreadsheet using Ctrl + C and Ctrl + V keyboard shortcuts.

As the coordinates are entered they can be visualised in the adjacent graph. The profile coordinates can be entered in either local or global coordinates. Entering in local coordinates will transform the profile to global coordinates when assigned to lines. Note that if the assigning line is an arc and the tendon profile is generated with a straight local x-axis this will be “wrapped” to follow the path of the assigned arc, therefore there is no need to arc the tendon profile. In this situation it may be better to specify the profile as an arc in global coordinates.

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This page of the wizard allows tendon properties to be entered. These cover long and short term losses.

To create tendon property enter a dataset title and select the Create button. Tendon property data can then be entered.


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If required specify any Long term losses. Relaxation loss is a percentage of the prestress force. Stress at transfer is defined as the compressive stress at the centroidal axis due to prestress.

Notes: The prestress definition dialog expects input units to be the same as the current model unless otherwise stated on the dialogs. When the prestress loads are calculated the prestress forces are converted into the current model units. The current model units can be found on the status bar of LUSAS Modeller

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This page of the wizard allows a tendon load to be defined from the previously entered profiles and properties.

The tendon force must be defined in addition to the anchorage losses that are defined as slippage from either or both ends and the angle of the jacks.

To create tendon load enter a dataset title and select the Create button. Tendon load data can then be entered.


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This page of the wizard allows the assignment of the tendon loads that have been defined in the previous dialog. These can be assigned to single or multiple loadcases using the checklist box. Selecting a loadcase will automatically select all subsequent loadcases. To switch the subsequent loadcases off select the loadcase following the chosen loadcase and this will toggle the activation of the subsequent loadcases.

New loadcases for tendon assignment can be created by entering a number and selecting the Create button. These will not be generated in the model until the tendon calculation is complete.

The selection of lines to be used in the assignment can either be entered in the line numbers box directly, or by selecting the lines from the model and clicking Copy from selection. These lines may be straight or curved and may consist of multiple lines defining each span. Before the tendon assignment can be undertaken the lines must be meshed with beam elements.

Checks are made on saving that the lines selected for assignment from a single continuous open-ended path. Thus unconnected lines, multiple paths, branching and/or a closed loop are reported as an error.


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Line numbering and line direction determines the tendon profile direction for the superimposed tendon. Line direction must be consistent along the selected lines representing the beam assignments. Any inconsistencies in line direction will cause an error.Use the Offset from End 1 to allow the selected tendon profile to be displaced along the starting point of tendon jacking.

If the Compute loading option is checked the loading calculation and assignments will be undertaken on finishing the wizard. If the option is not checked no calculations will take place. However, the data entered, as long as it is valid, will be stored to the model. This is useful if it is required to exit the wizard during the process of entering data. The Next> button can be clicked to get to this final page enter a single assignment and then exit the wizard assured that the current entered data will be stored to the model.

Check the Generate graph datasets box if a graph visualisation of the tendons is required. When the prestress definition is computed graph datasets will be created to enable the tendon losses to be visualised against the tendon length.

Check the Generate report box if a HTML report is required. If selected, a HTML document will be created in the current working folder (or the specified directory) and automatically displayed in the default web browser at the end on the calculation.

This report gives a table of contents of all the tendon calculations. Summaries for the tendon properties and profile are given followed by the prestress losses and the prestress load components as used in the LUSAS loading datasets. This report is useful for QA purposes.

Clicking the Finish button will save all of the entered data to the model and, if selected, compute the tendon forces and assign them to the relevant loadcases.


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��*#��' �The RC Design menu entry enables the reinforcement required in slabs and walls to be computed in accordance with BS 8110. Calculation of crack widths can be carried out in accordance with BS5400, BS8110 and BS8007.

This wizard uses the Wood and Armer moments to compute the steel area required. If regular bar spacing is specified the appropriate bar sizes can be computed and contoured.

To use the RC Slab/Wall wizard prepare the slab analysis in the usual way and run the analysis. If using Shell elements ensure that all the elements are orientated with the surface normal pointing upwards (towards the top of the slab).

With the results loaded select the RC Design>Slab/Wall entry from the Bridge or Civil menu. Ensure the concrete cube strength and steel characteristic strength are correct and set the appropriate top and bottom bar sizes, cover and skew angle. Click OK to display contours of the K factor, reinforcement area or bar sizes required.

To enable the effective depth to be computed the top and bottom cover and top and bottom bar size are input. The effective depth is used to establish if compressive reinforcement is required

using the equation K M b d f cu� / . .2 If K is greater than Kmax a warning message is

issued. The area of reinforcement is computed in mm2/m width using the equation

A M fy zs � / . .� where z is the lever arm and � the Gamma factor which has a default

value of 0.95.


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The crack checking facility provides a contour plot of crack widths in a particular direction and level, i.e. Mx(B), My(T) etc. Crack checking can follow on from a slab analysis or it can be carried out as a singular process.

To carry out crack checking a proportioned value of Young’s modulus for the long and short term loading effects is required. An option exists to examine the model and extract Wood-Armer moment results at nodes for each of the specified loadcases; a proportioned value of Young’s modulus is then computed using these moments. Alternatively, percentages of short and long term loading for an active Loadcase can be specified.

Two options are available for the contours of crack width. A contour can be plotted over the entire structure based on calculated nodal values or a plot of allowable crack widths can be displayed. This option will compare the calculated value with a user specified value and plot contours of pass or fail i.e. blue for pass and red for fail. The default value for the allowable crack width is 0.25mm.

If a prior slab design has been carried out, and crack checking reveals non compliance, the back button provides the option to return to the slab designer to repeat the operation.

When visualisation of slab design results has been completed RC Design> Off should be selected from the bridge menu to reset the results options.

The use of the RC Design facility is described in example Simple Slab Design.

%��-�Beam stress recovery has been made available using the user definable results utility.

To use this facility the results file must be loaded on top of the model file. The user is required to input the beam section modulus of each member type. These are assigned to the appropriate line elements from which the beam stresses are computed. As well as the section modulii the yield stress may be input to enable the utilisation factor to be computed.


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Results may be printed or displayed using the standard facilities. A typical set of output results is shown.

"��+ �� The LUSAS Analyst menu options will appear as shown:

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+�� '�An adaptive meshing wizard has been added for the 2D continuum element. The Adaptive Meshing entry under the Analyst menu automatically runs the adaptive process on the current model with specified parameters until results within a specified error are achieved or until the maximum number of iterations is exceeded. Problems with varying thickness or material should not be run adaptively.

Having created a model, an irregular surface mesh must be applied. The default element size must be used by leaving the element size as zero.


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The adaptive process is only applicable to the following element types:

Plane Strain

TPN3 QPN4 TPN6 QPN8 QPN4M

Plane Stress

TPM3 QPM4 TPM6 QPM8 QPM4M

Axisymmetric

TAX3 QAX4 TAX6 QAX8 QAX4M

The model must first be saved. The adaptive process will not overwrite the original model it will append “_0” to the model name and use this for all files used in the adaptive process.

The Adaptive Meshing command initially brings up the dialog:


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with the following parameters to be supplied by the user

�� Maximum and Minimum element spacing sets the minimum and maximum allowable element size in model units. Setting either value to zero will ensure the default is used.

�� Maximum % change sets the maximum allowable percentage change in element size.

�� Global relative % error sets the target error. The mesh will be successively remeshed until the global relative % error falls below this value.

�� Error norm factor sets an artificial factor that scales the errors to ensure mesh refinement.

�� Maximum number of iterations sets the maximum number of remeshes allowed.

�� Cancel facility if selected then the user is prompted as to whether they want to continue the adaptive process after each remesh.

�� Use default background grid and spacing if selected then a default background grid and point mesh are generated and applied to the initial model. All other background grids and point meshes present in the model are deleted.

The adaptive process continues as follows:

�� The adaptivity parameters are set according to the values from the dialog. These values override those set under Model Properties.

�� If a default background grid has been selected, this is generated and applied.

�� The initial model is solved.

�� An adaptive loop is executed which consists of remeshing the model, solving the model and checking the global % error. The loop is repeated until the user chooses to cancel (if the cancel facility has been selected), the maximum number of iterations has been reached


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or the global error is within the required tolerance. A graph of error against iteration number is drawn after each iteration.

Once the adaptive process has finished the results may be viewed on the mesh in exactly the same way as a normal mesh. The adaptivity error results are stored in the Eadp column of the Stress results entity. The target value for Eadp is 1. This indicates the error matches the target value. Areas of the model with a value of Eadp greater than 1 require more elements whereas areas of the model with a value of Eadp less than 1 require less elements. Contours of Eadp may be viewed to observe where mesh refinement is required.

If problems in attaining a converged solution are experienced it may be because a point load or support is creating a singularity. If this is the case a very fine mesh will be generated in the problem area. Points can be removed from the adaptive process using the Geometry>Point>Adaptivity>Exclude menu entry. Points at which singularities occur should be excluded using this command before the adaptive process begins.

��' �&��Design factors provide a means of assessing the reserve strength capacity of a materials. The material strength data is defined and assigned to the model so the factor of safety or reserve strength can be visualised using a number of different criteria.

"�� The LUSAS Composite menu options appear as shown:


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��(��The more commonly used structural composite properties are defined in the material library which is located under the Attributes>Material>Composite Library menu.

The units will default to those selected on model startup but may be changed if desired. Select the composite material required from the drop down list and click OK or Apply to add the properties to the Treeview. The composite material properties may then be assigned to the model in the usual way.


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Composite failure recovery has been made available using the user definable results utility.

To use this facility the user must have the results file loaded on top of the model file or the results file must be opened in write mode. Composite strength data is entered and assigned to the appropriate surface elements.

The composite failure criteria available are:

�� Tsai Hill

�� Hoffman

�� Tsai Wu

�� Hashin Fibre

�� Hashin Matrix

A failure criteria greater than 1 indicates failure. Results may be printed or displayed using the standard facilities or printed from the composite menu using the print options provided.


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�� '�� '��The configuration utility simplifies the configuration of the LUSAS product by allowing various LUSAS settings and options to be modified interactively. Default configuration values are set-up automatically during installation of LUSAS. To make subsequent changes, on the Windows toolbar select Start> Programs> LUSAS 13.6 for Windows> Tools> Configuration Utility

A tabbed dialog allows access to separate configuration settings for license key information, temporary file information and memory usage.

Network Licencing

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An optional network (floating) licence capability has been introduced to enable a LUSAS licence to be used on any selected computer in a network. The licence may be locked to specific computers in the network or allowed to run on any computer in the network.

Network licensing is controlled by SentinelLM licence management software, a third party product used by many other software suppliers.

#�� -��SentinelLM is a software toolkit and collection of software that protects each of the licensed LUSAS applications.

When LUSAS is started it first makes a check with SentinelLM to verify that use is permitted by the licence agreement. If use is authorised, then SentinelLM gives the software permission to run. If permission is granted, this process is invisible. If permission is denied, then LUSAS will exit and a suitable error message will be issued. Permission may be denied because other users are already using the available licences, the licence has expired, or no licence has been installed.

On a successful completion or controlled exit the licence is returned to the licence server so that another user may obtain it and run the software. If the computer crashes, or some other event prevents LUSAS from exiting normally and clearing itself up, the licence will remain active for 5 minutes after the failure after which the licence will be returned as normal.

�� '��(�� '��The CDROM contains a License\Server\Setup folder containing setup.exe, which has to be run to install SentinelLM on the machine designated as the license server. Once the license server has been installed it will be running and waiting for licence information. If SentinelLM has been installed for license control of other software products it will only be necessary to enter LUSAS license information into the license server.

For information on installing network licences refer to the V13.6 Installation Note supplied with the CDROM or consult the readme.txt file on the CDROM.

Note that for network licenses the file FEA.KEY, which is set up automatically during installation, contains only the following two lines.

[SENTINELLM]

Network Licencing

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-1 Backup license servers can be setup in the same way as the main license server and SentinelLM provides a mechanism to allow the backup license servers to take over if the main license server is down. Separate license keys are required for each backup server. For more details see the Online System Administrators Guide, using the shortcut in the LUSAS Start menu folder. The guide provides useful information on installing and monitoring licenses.

Addendum

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Transcript of Addendum