150 ANSYS Workbench Mechanical - expertfea.com expertfea_co… · 1 © Oct. 2014, expert fea.com...

1 © Oct. 2014, expertfea.com

150 ANSYS Workbench

Mechanical

tips and tricks

© Oct. 2014, expertfea.com

by Claudiu D.


- dedicated to God -

ISBN 978-973-0-16372-8


CONTENT:

A) Index of topics.....................................................................page 7

B) Foreword............................................................................ page 13

C) 150 Hints............................................................................ page 15

D) Afterword.......................................................................... page 348


A) Index of topics:

2D FEA setup - Hint 4

3D curve from a TXT coordinate file in DesignModeler - Hint 150

Advanced Size Function - Hint 109

Analysis Settings - Hint 104

Animations - Hint 105

ANSYS Customization Tools - Hint 65

APDL commands - Hint 69

Axes orientation - Hint 86

Axes re-orientation in Joints - Hint 3

Backup - Hint 68

Beta options - Hint 57

Body Views - Hint 43

Body Views - Hint 92

Bolt Pretension - Hint 51

Breaking of contacts in Explicit Dynamics - Hint 123

Carry Over Time in solving - Hint 63

Circular Pattern in DesignModeler - Hint 121

Composite materials - Hint 81

Construction Surfaces - Hint 140

Contacts and Joints details and properties - Hint 137

Contact Sizing - Hint 38

Contact Tool as Initial Contact Result - Hint 16

Contact Tool as Solution - Hint 17


Contact Tool Worksheet - Hint 21

Contacts between same face - Hint 76

Contacts in shell elements - Hint 88

Contacts in small size assemblies - Hint 127

Contour results - Hint 79

Convergence check - Hint 119

Convergence tool - Hint 110

Coordinate systems for rotational loads - Hint 78

Coordinate systems in nodes - Hint 61

Crack modelling - Hint 132

Cross sections library - Hint 95

Cyclic Symmetry - Hint 2

Default Solid Materials - Hint 84

Deformation and Stress in Modal FEA - Hint 147

Design Points - Hint 90

Display Solution items in nodes - Hint 13

Duplicate connections tool - Hint 73

Element Midside nodes - Hint 59

Element types query - Hint 117

Element types query - Hint 135

Enclosure of geometry - Hint 62

Energy Conservation and Energy Symmary plots in Explicit Dynamics -

Hint 115.

Energy Error in Explicit Dynamics - Hint 113.


Errors in Project Schematic - Hint 66

Face Delete in DesignModeler - Hint 143

Face splitting using Projection command in DesignModeler - Hint 145

Fatigue Tool - Hint 50

Files exchange and backup - Hint 36

Files inspection and repairing - Hint 6

Filling hollow geometry - Hint 108

Geometry and Mesh filters - Hint 130

Geometry details and properties - Hint 138

Geometry update - Hint 53

Geometry items search - Hint 120

HEX Mesh - Hint 29

Hydrostatic Fluid Element HSFLD 24x - Hint 7

Hyperelastic materials - Hint 56

Identifiers' usage for custom results - Hint 99

Images and Figures - Hint 102

Increase data requests in solution items - Hint 67

Inflation in meshing - Hint 55

Joints usage and setup for faster FEA - Hint 41

Labels and Probes - Hint 97

Legend accurate view- Hint 34

Legend visibility- Hint 87

Manage Views - Hint 15

Materials refreshing - Hint 10


Merged bodies behavior - Hint 83

Mesh metrics - Hint 72

Mesh Sizing options - Hint 144

Messages - Hint 74

Midsurface command in DesignModeler - Hint 141

Minimum Time Step in Explicit Dynamics advises for geometry

defeaturing - Hint 148

Modal analysis - Hint 111

Multiple cores and GPU acceleration - Hint 35

Multizone in Meshing - Hint 58

Named Selection - Hint 85

Named Selection from promoted tree feature - Hint 128

Neoprene Rubber properties - Hint 8

Nodal connectors - Hint 101

Nodal Coordinate Systems - Hint 139

Nodal loads - Hint 27

Node numbers display - Hint 134

Nonlinear Controls activation when the FEA is not converging - Hint

124

Nonlinear materials - Hint 45

Object Generator tool for duplicating features - Hint 136

Orientation of views shortcuts in Mechanical window - Hint 146

Parameterization of Geometry, Mesh, Loads etc. - Hint 60

Part location in Geometry branch - Hint 129


Parts manipulation in Joints - Hint 24

Pinch usage in meshing - Hint 47

Plots of multiple Solution items - Hint 23

Points coordinates - Hint 98

Press-fit/ shrink-fit contact - Hint 18

Probes deleting - Hint 131

Project Schematic customization - Hint 75

Random Colors usage - Hint 49

Reactions check in FEA - Hint 82

Redundancy Analysis - Hint 42

Remote loads and supports - Hint 94

Report publishing and customization - Hint 28

Response Spectrum results - Hint 77

Restarting failed FEA - Hint 142

Restore accidentally closed windows or toolbars - Hint 25

Results on Path - Hint 125

Rotate bodies in DesignModeler - Hint 133

Revolute Joint between parts with holes - Hint 26

Scale of solution - Hint 14

Section Planes and Coordinate Systems - Hint 64

Section Plane from Coordinate System - Hint 126

Section Planes configuration for quarter views - Hint 31

Section Planes editing - Hint 32

Section Planes usage - Hint 19


Selection of overimposed geometry features - Hint 106

Selection type change - Hint 39

Sever restart - Hint 103

Shear diagrams for beam problems - Hint 5

Shell elements orientation - Hint 11

Shell extraction - Hint 12

Sketch copy and re-usage - Hint 100

Solution on different local Coordinate Systems - Hint 93

Solution Output plots, optimal view - Hint 30

Solve faster - Hint 33

Solve FEA with progressing contact statuses - Hint 40

Solving interruption - Hint 46

SpaceClaim usage in 3D modeling - Hint 9

Sphere of Influence in Meshing- Hint 20

Stiffness behavior - Hint 70

Stress Error tool - Hint 91

Surface body creation - Hint 54

Surface selections propagation - Hint 37

Sweepable Bodies and Mappable Faces - Hint 22

Temporary FEA Files - Hint 1

Thermal effects in Structural FEA - Hint 149

Time Increment plot - Hint 112

Toolbars activation - Hint 44

Transient vs. Static FEA comparison - Hint 80


Units Systems - Hint 107

User Defined Results - Hint 89

Viewports - Hint 48

Virtual Topology - Hint 96

Visibility of Solution - Hint 71

Welding Points - Hint 52


B) Foreword

This is a unique book, coming from lots of years of working in ANSYS

Workbench, a compilation of hints on how to improve, ease, and quicken your

FEA practice.

We recommend reading and browsing it entirely, because even if some

ideas may seem familiar to you, we are sure that you will be pleasantly

surprised of hints that you didn't know them until now.

After having finished reading it, keep it close to you, because you will

surely need it.

Even though a few tutorials are used to illustrate some examples, it is not

a tutorial manual. We have already posted many tutorials on

expertfea.com/tutorials.html and we will post more.

We tried to bring only original content, and we succeeded in 99%, but it is

possible that a few paragraphs are inspired from Internet and we acknowledged

that by thanking to our colleagues in the Afterword section of the book.

Because ANSYS Inc. continuously improves their software, we will update

this book, and release new enriched editions very often.

Thank you for your purchase and happy reading!


C) Hints

Hint 1. If you have problems with HDD space, move the solving folder to where

you have enough space.

From the main window, go to Tools, Options...

Project Management, File Locations and Folder for Temporary Files.


Hint 2. When having revolute parts and cyclically symmetrical BC's and Loads,

consider using Cyclic Symmetry from DesignModeler or Mechanical Window.

Browse for wedge.x_t. Right click Coordinate System, Insert, Coordinate System.

Type = Cylindrical; Geometry, select the outer cylindrical face, Apply.


This is the result.

Click Symmetry from Model toolbar.

Right click Symmetry, Insert, Cyclic Region.


ANSYS already found the cylindrical coordinate system we just created.

This is the successful result, marked with a green check sign.


After the solving is finished, the FEA will show the full cylinder, comprised of

several slices, depending on their angle.


Hint 4. When performing 2D analysis, change this property before entering

Model or Setup.


Hint 8. When using the default Neoprene Rubber, insert Density and Poisson

Coefficient .

These are the default properties for the Neoprene Rubber in ANSYS.

Brwose for wedge.x_t. Assign the material to a part to perform a simple FEA.


Apply a Pressure on the top face and a Fixed Support on the bottom face. Assign

some Solution items, such as Stress and Deformation. We observe question

marks signaling a problem.

For a proper orientation of the Coordinate System, select it and at origin; Define

By, Geometry Selection; Geometry, select the outer cylindrical face, Apply.


This is the result; right click Solution, Solve.

At the bottom we get these messages, showing that Neoprene Rubber is missing

some data. Go to Engineering Data.

Having Neoprene Rubber selected, double click Density from Toolbox and insert

950 as value.


Having Neoprene Rubber selected, double click Isotropic Elasticity from

Toolbox, Linear Elastic and insert 0.08 MPa and 0.499 as seen.

Refresh Project, Return to Project.

Now the question marks have disappeared and we can successfully re-run the

FEA.


This is the solved FEA.


Hint 11. When meshing with shell elements, check element direction (Top,

Middle or Bottom), to avoid interferences or gap, if the mesh protrudes more or

less than desired.

Browse for carbody.x_t. We have this geometry of thickness 10 mm that needs

to be meshed with shell elements; the default side/ direction of meshing is

Offset Type: Middle.

This is the mesh for Middle side. Observe the interference.


Change Offset Type: Top.

This is the mesh for Top side. Observe the interference.


Change Offset Type: Bottom.

This is the mesh for Bottom side. No interference!


Hint 24. Reposition parts in Mechanical window.

Browse for gripper.x_t. Select the needed joint, than on the Joint Configure

toolbar, click Configure.

This triad appears allowing manipulation (translation and rotation about each

axis); the only degree of freedom is highlighted in green, so drag the green

curved line to rotate the joint.


Manipulation gives also the rotation angle.

When you are satisfied with the result, click Set, or Revert to the initial position.


Having chosen Set, this is the result; the lower jaw is displaced downwards,

compared to the initial configuration.


Hint 42. Check the model for redundant connections.

Right click Connections, Redundancy Analysis.

This table appears in the lower right corner; click Analyze.

This is the analysis result; after an engineering evaluation, if you are sure, click

Convert redundant to free.


If you are satisfied with the result, click Set.

You can export the mechanism analysis table as TXT or XLS file.


Hint 57. Activate Beta options to access lots of extra features in ANSYS.

Tools, Options.

Appearance, scroll down and check Beta Options.


Hint 83. When you are not interested in the contacts between some parts and

you want them to behave as a whole body, you can fix them with a rigid joint.

In this case, we want these 2 parts to act as being the same body; Connections,

Body-Body, Fixed.

For Reference, select a surface from the jaw, green here, Apply.


For Mobile, select a surface from the link, Apply.

This is the resulting rigid joint between the 2 bodies; they will act as one body.


Hint 101. You can visualize nodal connectors: Force or Remote Displacements

and all Supports, weak springs, MPCs.

For this scenario, we have inserted these boundary conditions (Contacts, Joints

and a force),we solved and obtain this stress plot.

Click on Solution, Graphics lower right tab, to obtain this plot.

More related info, here: http://www.padtinc.com/blog/the-focus/visualizing-

nodal-connectors-in-mechanical


Hint 109. For a quality mesh, use with care Advanced Size Function.

Off, gives 71.931 nodes and 40.816 elem.

Proximity and Curvature gives 262.727 nodes and 169.492 elem.


Hint 115. How to find out when the behavior is erroneous in Explicit Dynamics,

meaning that no impact appears.

Click Solution Information, Solution Output and choose to show these plots. This

behavior is normal, impact occured.


In Energy Conservation or Energy Summary plots, if the lines are flat and do not

vary, then the boundary conditions are wrong and no impact occurs. Check your

loads, displacements etc., to see if their applied directions or their timings are

correct.


Hint 125. How to check results on a line direction.

With selection filter on Vertex/ Node, select 2 points, then press Construction

Geometry when you are in Model (C4) branch.

Right click Construction Geometry, Insert, Path.


This is the resulting Path.

Right click any Solution item, Duplicate Without Results.

Scoping Method = Path, Path = Path (the Construction Geometry we created).


Right click, Evaluate All Results.

This is the resulting stress along the path we created.


Hint 126. How to make a Coordinate System's plane as a Section Plane.

Right click the needede Coordinate System, Create Section Plane will make a

section on its XY plane.

Further on, you can temper with Coordinate System's axes if you would like to

change the orientation of the XY plane, thus change you section orientation.


Hint 127. How to deal with contacts in small size assemblies.

When having parts at the size of 1mm and lower, ANSYS Workbench will put by

default many contacts, because the parts are too crowded and they reach the

contact limits imposed in the software. With Body Views activated, carefully

check and delete the unneeded contacts.


Hint 132. How to perform basic crack modeling.

Selecting Model (A4), you have access to Fracture module.

Here is a fast draft creation method. Right click Fracture, Insert, Crack.

With selection mode on Mesh (right of x,y,z button), click a node in the middle

of the fillet (round), Create Coordinate System (observe the green point).


With selection on Geometry (right of x,y,z button), select the whole body,

Scope, geometry, Apply.

Change Definition, Global Coordinate System to Coordinate System.


Insert these values for the Major, Minor and Largest Contour Radius. An intial

crack contour is shown. We need to align the X axis to be normal to the fillet.

Select Coordinate System, Principal Axis, Axis X, Define By Hit Point Normal.


Rotate the Coordinate System, until X is normal to the round.

Clicking on Fracture, Crack you should obtain this shape.


If you right click Fracture, generate All Crack Meshes, you obtain this final mesh.

Further on, after the loads and restraints are applied as needed, you can ask for

results in the crack region: Solution, Tools, Fracture Tool.

Right click Fracture Tool and insert crack specific results: SIFS, J-Integral, VCCT.

Solve the FEA and investigate the results. Read ANSYS' Help for more details.


Hint 135. How to find out the element types present in the mesh.

In the most upper toolbar, press the Information button, near the Worksheet

button; in the toolbar underneath, Select Mesh instead of Select Geometry.

Click on any element to see its properties in the left side Selection information

table. Also works for shell or line elements.


Hint 143. How to simplify a model by deleting unnecessary faces in Geometry

Modeler

Open in DesignModeler 2014_sept_25_iPhone6_bending7.x_t. Select the faces

needed to disappear: here are 2 holes and 1 fillet/ round. Go to Create, Delete,

Face Delete; Apply.

Right click FDelete1, Generate.


This is the resulting shape: without the holes and the fillet.


Hint 144. Activate more options for Mesh Sizing.

Initially, keep Mesh, Sizing, Use Advanced Function = Off.

This is how Body Sizing appears.


Make Mesh, Sizing, Use Advanced Function = On: proximity and Curvature.

Body Sizing feature will reveal extra options: Curvature Normal Angle, Growth

rate, Local Min Size.


Hint 149. How to apply thermal effects in Structural FEA.

Open 2014_oct_05_torsion_test2.x_t in Static Structural. Suppress the end

caps.

Fix one end of the rod.

Go to Environment, Loads, Thermal Condition.


Select the rod, Apply. Insert the ramped values for the temperature, as seen

here.

Insert a Directional Deformation about the Y axis, as seen here. Solve.

As expected, the maximum deformation of 0.532 mm is at the free end. Let us

see what Coefficient of Thermal Expansion Structural Steel has. File, Close

Mechanical.


Double clicking Engineering Data cell we will find out that α = 1.2e-5/ °C

We know that the formula for displacement is: ΔL = α*L*ΔT

where L = rod's length and ΔT = (Tfinal-Tinitial),

so ΔL = (1.2e-5/ °C)*(110 mm)*(422°C -22°C) = 1.2e-5*110*400 mm

ΔL = 1.2e-2*11*4 mm = 0.528 mm (ANALYTICAL)

ΔL = 0.531 mm (FEA) => FEA aproximates very well the hand calculation!


D) Afterword

Our thanks go to:

o God

o ansys.com

o simutechgroup.com

o padtinc.com

o ozeninc.com

o epsilonfea.com

o https://www.leapaust.com.au

o Mr. John Chawner (President and Co-Founder of Pointwise,

pointwise.com), for sharing with us the funny memes;

o Mr. Daniel Balint (https://sites.google.com/site/qturbo3d/), for being a

true friend, always available for support in FEA and more;

o Mr. Dumitru Mihai (https://www.youtube.com/channel/UCI_6-

WLVV_ZCS77xKES2DdQ, https://www.youtube.com/user/NeaMitica2011)

for being a true friend, and the best engineering mentor.

ISBN 978-973-0-16372-8

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