Stress analysis INVENTOR

We perform a structural static analysis withthe goal of minimizing model weight.Objectives ■ Create a simulation for modal analysis ■ Override the model material with a different materia

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Chapter 1 Part Modal and Stress Analysis 1

Simulation 1: About this tutorial 1

Open the Model for Modal Analysis 3

Enter the Stress Analysis Environment 3

Assign Material 4

Add Constraints 4

Preview Mesh 6

Run Simulation 7

View the Results 7

Summar y 11

Simulation 2: About this tutorial 12

Copy Simulation 13

Create Parametric Geometry 14

Include Optimization Criteria 16

Add Loads 16

Set Convergence 17

Run Simulation 18

View the Results 19

Summar y 21

Chapter 2 Assembly Stress Analysis 23

About this tutorial 23

Get Started 25

i

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Stress Analysis Environment 25

Excluding Components 26

Assign Materials 27

Add Constraints and Loads 28

Stress Analysis Settings 31

Contact Conditions 32

Generate Meshes 33

Run the Simulation 34

View and Interpret the Results 35

Summar y 37

Chapter 3 Contacts and Mesh Refinement 39

Open the Model 40

Stress Analysis Environment 41

Create a Simulation 41

Exclude Components 42

Assign Materials 42

Add Constraints and Loads 43

Define Contact Conditions 46

Specify and Preview Meshes 50

Copy and Modify Simulation 54

Specify Local Mesh Controls 54

Run the Simulation Again 56

View and Interpret the Results Again 57

Summar y 59

Chapter 4 Assembly Modal Analysis 61

Open the Assembly 64

Create a Simulation Study 65

Exclude Components 66

Assign Materials 67

Add Constraints 67

Create Manual Contacts 68

Specify Mesh Options 70

Preview Mesh and Run Simulation 70

View and Interpret Results 71

Summar y 73

Chapter 5 FEA Assembly Optimization 75

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Define the Simulation 77

Assign Materials 78

Adding Constraints 78

Adding Loads 79

Modify the Mesh 80

Preview the Mesh 81

Create Parametric Geometry 82

Optimization Criteria 84

View and animate 3D plots 87

View XY Plots 88

Summar y 90

Chapter 6 Stress Analysis Contacts 93

Overview 94

How a Caulk Gun Works 96

Assembly Simulation 99

Contact Types 100

Bonded Contact 102

Separation Contact 103

Sliding and No Separation Contact 104

Separation and No Sliding Contact 107

Shrink Fit and No Sliding Contact 108

Spring Contact 110

Loads and Constraints 111

Simulation Results 112

Summary 114

Chapter 7 Frame Analysis 117

Frame Analysis Environment 119

Frame Analysis Settings 122

Assign Materials 122

Change Beam Properties 124

Change Direction of Gravity 124

Add Constraints 125

Add Constraints to the Next Beam 128

Add Loads 129

View and Interpret Results 132

Contents | iii

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Summary 133

Chapter 8 Frame Analysis Results 135

Get Started 136

Display Maximum and Minimum Values 140

View Beam Detail 141

Display and Edit Diagrams 142

Adjust Displacement Display 144

Animate the Results 146

Generate Report 147

Summary 148

Chapter 9 Frame Analysis Connections 149

Connections Overview 150

Change Direction of Gravity 154

Add Custom Nodes 154

Add Custom Nodes 157

Change Color of Custom Nodes 159

Assign Rigid Links 160

Add Constraints 164

View the Results 166

Assign a Release 167

Run the Simulation Again 169

View the Updated Results 170

Summary 171

Chapter 10 Modal Type of Frame Analysis 173

Create a Simulation Study 175

View the Results 177

Animate the Results 178

Summary 179

Chapter 11 Dynamic Simulation - Part 1 181

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Degrees of Freedom 183

Automatic Constraint Conversion 184

Assembly Constraints 187

Add a Rolling Joint 189

Building a 2D Contact 190

Add Spring, Damper, and Jack Joint 193

Define Gravity 195

Impose Motion on a Joint 196

Run a Simulation 197

Using the Output Grapher 198

Simulation Player 199

Summary 202

Chapter 12 Dynamic Simulation - Part 2 205

Work in the Simulation Environment 206

Construct the Operating Conditions 208

Add Friction 210

Add a Sliding Joint 212

Use the Input Grapher 213

Use the Output Grapher 217

Export to FEA 219

Publish Output in Inventor Studio 223

Summary 225

Chapter 13 Assembly Motion and Loads 227

Open Assembly 229

Activate Dynamic Simulation 231

Automatic Joint Creation 231

Define Gravity 232

Insert a Spring 232

Define the Spring Properties 235

Insert a Contact Joint 237

Edit the Joint Properties 239

Add Imposed Motion 241

View the Simulation Results 241

View the Simulation Results (continued) 242

Export the Data 243

Summary 244

Contents | v

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Chapter 14 FEA using Motion Loads 245

Open Assembly File 247

Run a Simulation 249

Generate Time Steps 249

Export to Stress Analysis 249

Use the Motion Loads in Stress Analysis 253

Generate a report 256

Summary 257

Index 259

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Part Modal and Stress

Analysis

Simulation 1: About this tutorial

Modal analysis

Simulation Category

20 minutes

Time Required

1

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The second simulation is a parametric study on the same model Parametricstudies vary the design parameters to update geometry and evaluate variousconfigurations for a design case We perform a structural static analysis withthe goal of minimizing model weight.

Objectives

■ Create a simulation for modal analysis

■ Override the model material with a different material

■ Specify constraints

■ Run the simulation

■ View and interpret the results

Prerequisites

■ Familiarity with the ribbon user interface and Quick Access Toolbar

■ Familiarity with the use of the model browser and context menus

■ See the Help topic “Getting Started” for further information

Navigation Tips

■ Use Show in the upper-left corner to display the table of contents for this

tutorial with navigation links to each page

■ Use Forward in the upper-right corner to advance to the next page.

Next (page 3)

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Open the Model for Modal Analysis

Let’s get started on the Modal Analysis simulation first

1 On the Quick Access Toolbar, click the Open command.

2 Set your project file to Tutorial_Files.ipj if not already set.

3 Select the part model named PivotBracket.ipt.

4 Click Open.

Previous (page 1) | Next (page 3)

Enter the Stress Analysis Environment

The stress analysis environment is one of a handful of Inventor environmentsthat enable specialized activity relative to the model In this case, it

incorporates commands for doing part and assembly stress analysis

To enter the stress analysis environment and start a simulation:

1 Click the Environments tab in the ribbon bar The list of available

environments is presented

2 Click the Stress Analysis environment command

3 Click Create Simulation

4 The Create New Simulation dialog box displays Specify the name Modal Analysis.

5 In the Simulation Type tab, select Modal Analysis.

6 Leave the remaining settings in their current state and click OK A new

simulation is started and the browser is populated with stressanalysis-related folders

Open the Model for Modal Analysis | 3

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Assign Material

For any component that you want to analyze, check the material to make surethat it is defined Some Inventor materials do not have “simulation-ready”properties and need modification before using them in simulations If youuse an inadequately defined material, a message displays Modify the material

or select another material

You can use different materials in different simulations and compare theresults in a report To assign a different material:

1 In the ribbon bar, in the Material panel, click Assign Materials.

2 Click in the Override Material column to activate the drop-down list.

3 Select Aluminum-6061.

4 Click OK.

NOTE Use the Styles and Standards Editor to modify materials if they are not

completely defined You can access the editor from the lower left corner of theAssign Materials dialog box

Add Constraints

Next, we add the boundary conditions, a single constraint on the interiorcylindrical face

To add the constraint:

1 In the ribbon bar, in the Constraints panel, click the Fixed Constraint

command The docked dialog box displays

2 Select the face as shown.

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Preview Mesh

Before starting the simulation, we can view the mesh

1 In the ribbon bar, Prepare panel, click Mesh View.

The command is a toggle between model view and mesh view

2 To return to the model, click Mesh View again.

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Run Simulation

Now, to run the simulation

1 In the Solve panel, click the Simulate command to display the Simulate

dialog box

2 Check the More section of the dialog box for messages Click Run to

display the simulation progress Wait for the simulation to finish

View the Results

After the simulation finishes, the Results folder populates with the various

results types The graphics region displays the first mode shaded plot

In the browser under the Results node and then the Modal Frequency

node, notice the first mode shape (F1) has a check mark by it, indicating it isbeing displayed There are nodes for the mode shapes corresponding to eachnatural frequency The color chart shows relative displacement values Theunits are not applicable since the mode shapes values are relative (They have

no actual physical value at this point.)

Now you can perform post-processing tasks using the Display commandslocated on the ribbon bar The commands are described in Help

Run Simulation | 7

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For post-processing of structural frequency simulation studies, the browserlist shows the natural frequencies Double-click any of these nodes to showthe corresponding Mode Shape 3D plot.

1 Animate the results using the Animate Results command in the Result

panel on the ribbon bar

2 While the animation is playing, click Orbit in the navigation tools on

the side of the graphics window As you orbit the graphics, the animationcontinues to play

NOTE The following image depicts a frame from the animation of mode F3.

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3 Click OK.

4 In the Results browser list of natural frequencies, double-click the results

for mode F3 to display that mode.

View the Results | 9

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NOTE If you plan to complete the second part of this tutorial, keep this model file

open Otherwise, save your model file to a different name before you close it

Summary

In this first tutorial for Part Stress Analysis, you learned how to:

■ Create a simulation for modal analysis

■ Override the model material with a different material

■ Specify constraints

■ Run the simulation

■ View and interpret the results

What Next? Continue with “Simulation 2 - Parametric Static Analysis”

Summary | 11

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Simulation 2: About this tutorial

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Parametric static analysis.

Level 3 special interest Skill Level

is to minimize the weight of the model

Objectives

■ Copy a simulation

■ Use analysis parameters to evaluate how to refine the weight of the model

■ Generate configurations of the parametric dimension geometry

■ Modify design constraints and view results based on those changes

Prerequisites

■ Completed Simulation 1 (Modal Analysis), the first part of this tutorial set

Navigation Tips

■ Use Show in the upper-left corner to display the table of contents for this

tutorial with navigation links to each page

■ Use Forward in the upper-right corner to advance to the next page.

Copy Simulation

We will create a copy of the first simulation, and edit it to define the secondanalysis

1 In the browser, right-click the Simulation (Modal Analysis) node

and click Copy Simulation A copy of this simulation is added to the

browser and becomes the active simulation

Copy Simulation | 13

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We will edit the simulation properties to define a parametric dimensionstudy.

2 Right-click the newly created Simulation node, and click Edit Simulation Properties.

3 Change the name to Parametric.

4 Change the Design Objective to Parametric Dimension using the

drop-down list

5 Set the simulation type to Static Analysis.

6 Click OK.

Create Parametric Geometry

We will produce a range of geometric configurations involving the thickness

of the model to facilitate weight optimization Adding parameters to theparametric table is required

Add parameters to the parametric table

1 In the Manage panel, click Parametric Table.

2 In the browser, right-click the part node just below the Simulation (Parametric) node, and click Show Parameters.

3 In the Select Parameters dialog box, check the box to the left of the

parameter named d2, 12 mm.

4 Click OK.

After identifying the parameter we want to use, we must define a range forthe parameter and generate the corresponding geometric configurations

Define parameter range

1 In the Values cell for Extrusion1 d2, enter the range 6-12 The values

must be in ascending order

2 Press Enter to accept the values When you click inside the Value field,

the value now says 6-12:3 This indicates that there are now three values

in the range These are equally divided between the first and last number,

hence that values are 6, 9, and 12.

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NOTE The number after the colon specifies the additional configurations

desired, excluding the base configuration The base is 12 mm, and the two additional configurations are 6 mm and 9 mm.

Once the parameter range is specified, we can generate the various

configurations based on the range values

Generate configurations

1 Right-click the table parameter row, and select Generate All

Configurations The model generation process is started.

2 After the model regeneration is completed, move the slider to see the

different shapes created

Create Parametric Geometry | 15

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We are not finished with the Parametric Table yet, so do not close it.

Include Optimization Criteria

Remember that our goal for this simulation is to minimize weight We optimizethe simulation using a range of geometric configurations generated previouslywhile utilizing the Yield Strength failure criteria

Add Design Constraints

1 In the Design Constraints section, pause the cursor over the empty

row, right-click, and click Add Design Constraint.

2 In the Select Design Constraint dialog box, click Mass, and click OK.

3 Repeat step 1.

4 In the Select Design Constraint dialog box, Select Von Mises Stress.

Ensure that Geometry Selections is All Geometry.

5 Click OK.

Enter Limit values and safety factor

1 In the Von Mises Stress row, click in the Constraint type cell, and

select Upper Limit from the drop-down list.

2 Enter 20 for Limit.

3 Enter 1.5 for Safety Factor

Add Loads

Next, add the structural load

1 Click the Force Load command The dialog box displays.

2 Select the face as shown.

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3 Enter 200 N for the Magnitude.

P refinement increases the polynomial degree of the selected elements in thehigh stress areas to improve the accuracy of the results

1 In the Prepare panel, click Convergence Settings.

2 For Maximum Number of h Refinements, enter 1.

3 Click OK.

Set Convergence | 17

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Run Simulation

Now we will run the simulation To start the Simulation, use the Simulate

command in the ribbon bar or through the simulation node context menu

1 Click the Simulate command to display the Simulate dialog box.

2 Click Run The Simulation progress displays Wait for the simulation

to finish

When the simulation is complete, the Von Mises Stress plot displays bydefault

3 In the Display panel, click Adjust Displacement Display ,

drop-down list, and select Actual.

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View the Results

After the simulation finishes, the graphics region displays a 3D color plot, and

you can see that the Result folder is populated Now we can evaluate the

results through the parametric table and the 3D and XY plots available forpost processing

Optimize model

First, we optimize the mass using the parametric table populated in previoussteps Then we look at 3D and XY plots to understand the behavior of themodel under the defined boundary conditions

The goal is to minimize the mass of the model taking into account parametricdimensions and stress constraints

1 If you previously closed the Parametric table, reopen it by clicking the Parametric Table command.

2 For the Mass Design Constraint, click in the Constraint Type cell,

and select Minimize from the drop-down list.

The parametric values change to show the configuration with the least massthat meets the given constraints In this case, the original thickness value was

12 mm and the optimized value is 9 mm which in turn reduces the mass of

the model

Note the design constraint Result Value for Max Von Mises Stress The

value has a green circle preceding it It indicates that the design constraintvalue is within the safety factor range

Slide the Extrusion1 parameter value to 6 When the table updates, you will see that the design constraint Result Value is now outside the safety factor.

The value is preceded by a red square indicating the design constraint valuehas been exceeded the safety factor Slide the parameter value back to 9

View and animate 3D plots

Now you can perform post-processing tasks using the Display panel commandsfor smooth shading, contour plots, etc These commands are described inHelp

1 In the Result panel, click Animate Results.

2 In the Animate dialog box, click the Play command The VonMises Stress plot colors change to reflect the application of the load To

View the Results | 19

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view the deformation changes, stop the animation, select Adjusted x1 from the Adjust Displacement Display , drop-down list andrestart the animation.

For post-processing of results, double-click the result in the browser to displaythe result in the graphics region Then, select the Display command you want

to use

View XY graphs

XY Charts show a result component over the range of a parameter

To view an XY plot, right-click over the parameter row in the Parametric Table

and choose XY Plot.

In this case, the above XY plot displays Stress results versus parametricconfigurations

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In this last tutorial for Part Stress Analysis, you learned how to:

■ Copy a simulation

■ Modify the simulation properties to change the type of simulation

■ Generate configurations of the parametric dimension geometry

■ Use analysis parameters to evaluate how to refine the weight of the model

■ Modify design constraints and view results based on those changes

What Next? As a next step, consider doing the Assembly FEA tutorials If

you have already completed them, why not acquaint yourself with theDynamic Simulation tutorials?

Experiment with what you have seen and used Explore how you can use thisdesign tool to help you complete your digital prototype with confidence inits performance

Previous (page 19)

Summary | 21

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Assembly Stress Analysis

About this tutorial

Simulate the structural static behavior of an assembly for analysis

Simulation Category

35 minutes

Time Required

2

23

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Tutorial File Used

NOTE Click and read the required Tutorial Files Installation Instructions at tp://www.autodesk.com/inventor-tutorial-data-sets Then download the tutorialdata sets and the required Tutorial Files Installation Instructions, and install thedatasets as instructed

ht-The stress analysis environment is a special environment within assembly,part, sheet metal, and weldment documents The environment has commandsunique to its purpose

We analyze a subset of an assembly using the “exclude from simulation”functionality in Stress Analysis Contact types are changed as required by thephysical behavior of the model Meshing settings are adjusted to capture thegeometry of the model more accurately

Objectives

■ Create a simulation

■ Evaluate and assign materials as needed

■ Add loads and constraints

■ Identify contact conditions

■ Know how to navigate the model space with the various view tools

■ Know how to specify and edit project files

Navigation Tips

■ Use Next or Previous at the bottom-left to advance to the next page orreturn to the previous one

Next (page 25)

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Get Started

To begin with, we will open the assembly to analyze With Autodesk Inventor

up and running, but with no model open, do the following:

1 Click the Open command on the Quick Access toolbar

2 Set the Project File to Tutorial_Files.ipj

3 Select Assembly FEA 1 ➤ analyze-2.iam.

4 Click Open.

5 Save the file with a different name, such as: analyze-2_tutorial.iam

Stress Analysis Environment

We are ready to enter the stress analysis environment

1 On the ribbon, click Environments tab ➤ Begin panel ➤ Stress Analysis

2 On the Manage panel, click the Create Simulation command.The Create New Simulation dialog box displays

The settings provide opportunity to tailor the simulation by specifying

a unique name, single point or parametric dimension design objective,and other parameters

NOTE On the Model State tab, you specify the Design View, Positional, and Level of Detail to use for the simulation The settings

can be different for each simulation

3 Click OK to accept the default settings for this simulation.

The browser populates with a hierarchical structure of the assembly andanalysis-related folders

Most of the commands in the ribbon panels are now enabled for use Disabledcommands enable as their use criteria is satisfied

Get Started | 25

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To exclude these components:

1 Expand the analyze-2_tutorial.iam browser node.

2 Right-click Handle, and click Exclude From Simulation.

3 Repeat the command for both the Screw and SHCS_10-32x6

components

The default display setting for excluded components is partially transparent

as seen in the following image:

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Assign Materials

The next step is to look at the component materials and make adjustments.For this simulation, we will make a minor material change using materialsthat are fully defined

Before you begin doing simulations, we recommend that you ensure yourmaterial definitions are complete for those materials being analyzed When

a material is not completely defined, the material list displays a symbolnext to the material name If you try to use the material, you receive a warningmessage

If you attempt to edit a material during this tutorial, you may not be able to

if the project setting Use Styles Library is set to No To edit this setting,

you cannot be working in the model To change the setting requires exiting

Assign Materials | 27

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the tutorial For purposes of this tutorial, use a material that is already fullydefined You can modify the other materials at a later time.

1 In the Material panel, click the Assign command The dialogbox displays the list of components, their material assignments, anoverride material, and a column showing how the material safety factor

is defined

2 In the Override Material column, click the first component

(Upper_Plate:1) cell to expose the material list.

3 In the list, click Steel.

4 Repeat the process for the all instances of the Upper and Lower plates.

Notice that when a components material is changed, all instances ofthat component inherit the change

5 Click OK to exit the Assign Materials dialog box.

The browser Material folder receives a Steel folder added with all the

components referencing that material listed within that folder If you deleteindividual components from the folder, their material reverts to the assemblyassigned material

Add Constraints and Loads

Next we define the boundary conditions by adding structural constraints andloads We start with constraints first

1 In the Constraints panel, click Fixed The dialog box displayswith the Location selector active

2 Select the two holes through which the screw passed They are the holes

that are left after excluding the screw from the simulation

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3 Click OK The two faces are axially constrained, as if the screw were

there

Add Constraints and Loads | 29

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Now, we assign loads on the components.

1 In the Loads panel, click Force The dialog box displays with

the Location selector active.

2 Select the face on the ch_09-Upper_Grip component as shown.

3 In the dialog box, enter 100 for the Magnitude value, and click OK.

4 Repeat the previous steps for the ch_09-Lower_Grip component.

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5 Click OK to exit the Force dialog box.

Stress Analysis Settings

Stress Analysis settings apply to all new simulations It is where you definethe default settings that you saw in the Simulation Properties at the beginning

of this process

Stress Analysis Settings | 31

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In the Settings dialog box, you can specify:

such as Separation, Sliding / No Separation, and so on.

For this simulation, we automatically compute inferred contacts and thenchange some of those to another type

1 In the Contacts panel, click Automatic It detects the contacts

within the default tolerance and populates the Contacts folder.

2 Expand the Contacts folder You can see that all contacts were created

as Bonded contacts (default setting) and placed in a folder Expand the

Bonded folder.

3 We must change the contacts listed in the following list To make

changes, use multi-select Select one contact, hold down the Ctrl key,and multi-select the remaining contacts in this list

■ Bonded:1 (Upper Plate:1, Lower Plate:1)

■ Bonded:6 (Upper Plate:1, Pin A:3)

■ Bonded:10 (Upper Plate:1, Pivot Threaded:1)

■ Bonded:12 (Upper Plate:2, Lower Plate:2)

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■ Bonded:26 (Lower Plate:1, Pivot Lower:1)

■ Bonded:32 Lower Plate:2, Pivot Lower:1)

4 Right-click a selected contact, and click Edit Contact.

5 Change the type to Sliding / No Separation, and click OK.

Generate Meshes

Before running the simulation, view the mesh to make sure that any areasneeding a different mesh setting from the default are cared for First, we willspecify the mesh settings

1 In the Prepare panel, click Mesh Settings Alternatively,

right-click the Mesh folder and click Mesh Settings.

2 Set Maximum Turn Angle = 30 to capture round areas of the

geometry

3 Check Create Curved Mesh Elements.

4 If not already checked, check Use part based measure for assembly mesh.

This option uses the part size as mesh criteria, as opposed to a single sizefor all parts

5 Click OK.

6 Having specified the mesh settings, you preview the mesh by clicking

the Mesh View command The results are a mesh overlay onevery part participating in the simulation

Generate Meshes | 33

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NOTE If areas of the model need a finer or more coarse mesh, add local mesh

controls Local mesh controls are covered in another tutorial

Run the Simulation

We are now ready to run the simulation

1 In the Solve panel, click Simulate The Simulate dialog boxdisplays

The dialog box more command >> exposes the messages section If there

are process steps to do, such as add constraints, the message is reportedhere

2 Click Run The simulation processes and returns results.

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