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© Oct. 2014, expert
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150 ANSYS Workbench
Mechanical
tips and tricks
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- dedicated to God -
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CONTENT: A) Index of topics...page 7 B) Foreword... page 13 C) 150 Hints... page 15 D) Afterword... page 3487
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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
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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.
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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
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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
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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
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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
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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.
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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...
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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.
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This is the result.
Click Symmetry from Model toolbar.
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ANSYS already found the cylindrical coordinate system we just created.
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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.
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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.
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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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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.
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Change Offset Type: Top.
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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.
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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.
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Hint 57. Activate Beta options to access lots of extra features in ANSYS.
Tools, 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.
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For Mobile, select a surface from the link, Apply.
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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/visualizing-nodal-connectors-in-mechanical
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Hint 109. For a quality mesh, use with care Advanced Size Function.
Off, gives 71.931 nodes and 40.816 elem.
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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.
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This is the resulting Path.
Right click any Solution item, Duplicate Without Results.
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Right click, Evaluate All Results.
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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).
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With selection on Geometry (right of x,y,z button), select the whole body, Scope, geometry, Apply.
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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.
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Rotate the Coordinate System, until X is normal to the round.
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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.
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Hint 144. Activate more options for Mesh Sizing.
Initially, keep Mesh, Sizing, Use Advanced Function = Off.
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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.
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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.
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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)
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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_6-WLVV_ZCS77xKES2DdQ, https://www.youtube.com/user/NeaMitica2011) for being a true friend, and the best engineering mentor.