20_ANSYS_WB_hints_gift_ expertfea_com.pdf

150 ANSYS Workbench Mechanical tips and tricks

by Claudiu D.

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© Oct. 2014, expertfea.com


- dedicated to God -

ISBN 978-973-0-16372-8

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CONTENT:

A) Index of topics.....................................................................page 7 B) Foreword............................................................................ page 13 C) 150 Hints............................................................................ page 15 D) Afterword.......................................................................... page 348

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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 7


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. 8


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 9


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 10


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 11


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 12


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

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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!

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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.

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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.

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This is the result.

Click Symmetry from Model toolbar.

Right click Symmetry, Insert, Cyclic Region. 19


ANSYS already found the cylindrical coordinate system we just created.

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

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After the solving is finished, the FEA will show the full cylinder, comprised of several slices, depending on their angle.

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

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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. 43


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.

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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. 45


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.

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This is the solved FEA.

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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. 55


Change Offset Type: Top.

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

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Change Offset Type: Bottom.

This is the mesh for Bottom side. No interference!

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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.

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Manipulation gives also the rotation angle.

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

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Having chosen Set, this is the result; the lower jaw is displaced downwards, compared to the initial configuration.

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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.

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If you are satisfied with the result, click Set.

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

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

Tools, Options.

Appearance, scroll down and check Beta Options.

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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.

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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.

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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/visualizingnodal-connectors-in-mechanical 255 © Oct. 2014, expertfea.com

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. 270


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.

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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.

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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.

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This is the resulting Path.

Right click any Solution item, Duplicate Without Results.

Scoping Method = Path, Path = Path (the Construction Geometry we created). 299


Right click, Evaluate All Results.

This is the resulting stress along the path we created.

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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.

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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.

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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). 310


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. 311


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. 312


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

Clicking on Fracture, Crack you should obtain this shape.

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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.

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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.

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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. 331


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

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Hint 144. Activate more options for Mesh Sizing.

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

This is how Body Sizing appears.

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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.

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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.

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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. 344


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!

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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_6WLVV_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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20_ANSYS_WB_hints_gift_ expertfea_com.pdf

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