# Non-Linear Separating Contact and Bolt Pretensioning - Hanger Beam

Perform nonlinear spearating contact analysis and setup bolt/nut tightening loads.

## Purpose

SimSolid performs meshless structural analysis that works on full featured parts and assemblies, is tolerant of geometric imperfections, and runs in seconds to minutes. In this tutorial, you will do the following:
• Perform assembly analysis
• Perform nonlinear separating contact analysis
• Use SimSolid bolt tensioning functions
• Compare SimSolid results with those obtained in traditional FEA.

## Model Description

The hanger beam model in this tutorial has 70 parts, 16 bolts/nuts, and 32 washers.

The following files are needed in this tutorial:
• Hanger beam.x_t (CAD source file)
• Hanger Beam.ssp (SimSolid project files with the first load case solved. This is where you will start the tutorial.)
• Hanger Beam SOLVED.ssp (SimSolid project file with all load cases solved. Provided as a reference.)
Important: The introductory steps of this tutorial provide information on how the first analysis was created. If you wish to skip this, go straight to Open Project.

## Import Geometry

Import model geometry into SimSolid.

1. Open a new SimSolid session.
2. Click the (Import from file) icon.
3. In the Open geometry files dialog, choose Hanger Beam.x_t.
4. Click Open.
The assembly will load in the modeling window. The Automatic connections dialog will open.

## Create Connections

Specify gap and penetration tolerances to create automatic connections.

1. In the Project Tree, click on the Connections branch.
2. In the Connections workbench toolbar, click (Automatic connections).
3. Specify Gap and Penetration tolerances as 2.
4. Set Connection resolution level to Increased.
5. Click OK.
Note:
• SimSolid will create connections even in areas with overlapping geometry.
• SimSolid will automatically identify bolts, nuts and washers.
• Sliding contact will be applied automatically in bolt shanks, bonded otherwise.

## Create Structural Linear Analysis

Create a structural linear analysis with immovable constraints and a handlebar load.

1. On the main window toolbar, click (Structural analysis).
2. Choose Structural linear.
The new analysis will appear in the Project Tree under Design study 1 and the Analysis Workbench will open.

## Create Immovable Supports

Create immovable supports

1. In the Analysis Workbench, click (Immovable support).
2. In the dialog, verify the Faces radio button is selected.
3. In the modeling window, select the faces on the end of the Lowerbeams (Face 2, Lowerbeam, Face 26, Lowerbeam, Face 29, Lowerbeam, Face 1, Lowerbeam).
4. Click OK.
The new constraint, Immovable 1, will appear in the Project Tree. A visual representation of the straint will appear on the model.

## Create Force

Create the hanger beam load.

1. In the Analysis Workbench, click (Force/Displacement).
2. In the dialog, ensure the Faces radio button is selected.
3. In the modeling window select Face 18, Hangerbeam and Face 2, Hangerbeam.
4. Specify a Z direction force of -1000 N.
5. Click OK.
The new force, Load/Displ. 1, will appear in the Project Tree. Vectors representing the load will appear on the model.

## Change Max Number of Adaptive Solutions

Define the number of solution passes.

1. In the Project Tree, double-click on Solution settings.
2. In the dialog, set the objective to Custom and increase the number of adaptive solutions to 4.
3. Activate the Adapt to features checkbox.
4. Click OK.

## Assign Materials

Apply materials to all parts in the assembly.

1. In the Project Tree, click on the Assembly branch.
2. In the Assembly workbench, click (Apply materials).
3. Pick Steel from the Generic materials list.
4. Click Apply to all parts.
5. Click Close.
In the Assembly branch of the Project Tree, material properties are identified for each part.

## Run Analysis

Solve the analysis.

1. In the Project Tree, open the Analysis Workbench.
2. Click (Solve).

## Open Project

Open the SimSolid project file.

1. Start a new SimSolid session.
2. Click the (Open Project) icon.
3. In the Open project file dialog, choose Hanger Beam.ssp
4. Click OK.

## Create Non-linear Separating Contact Analysis

Copy Structural 1 and edit to create non-linear separating contact analysis.

1. In the Project Tree, right-click Structural 1 and choose Copy.
The copy will appear as Structural 2 in the Project Tree.
2. Under Structural 2, right-click on Setup and choose Edit.
3. In the dialog, activate the Separating contact checkbox.
4. Click OK.

## Edit Contact Conditions

Change contact conditions for selected connections.

1. In the Bookmark browser, click Bookmark 5.
The modeling window will update with the saved view.
2. In the modeling window, right-click on the Hanger beam (shown in orange) and select Review part contact conditions.
3. In the dialog, hold down Control and click to select Connection 125 and Connection 126.
4. Click the Edit contact conditions button.
5. In the Contact conditions dialog, select Structural 2.
6. Activate the Separating radio button.
7. For the Friction coefficient, specify 0.1.
8. Click Close.

## Run Analysis

Solve the analysis.

1. In the Project Tree, open the Analysis Workbench.
2. Click (Solve).

## Compare Results

Observe the difference in results between structural linear analysis and non-linear separating contact.

1. In the Project Tree, select the Structural 1 branch.
2. In the Bookmark browser, choose Bookmark 3.
This bookmark shows the deformation detail.
3. In the Project Tree, select the Structural 3 branch.
The modeling window will update to show deformation detail for Structural 2.
4. Optional: Switch back and forth between Analysis branches to highlight the differences in the results.
5. Repeat steps 1 through 4 for Bookmark 4 (stress detail).

## View Separation and Contact Forces

View the separation and contact forces at the separating surface.

These forces are represented as colored values at each connection point (not a true contour). You used increased resolution when creating connections to get a denser array of points to plot.

1. In the Project Tree, select the Results branch under Structural 2.
2. On the Analysis Workbench, select (Contact Response).
3. In the Response at connections dialog, hold down Control and click to select Connection 125 and Connection 126.
4. Select the response type you wish to view.
5. Use the slider to increase or decrease the size of the colored points.
6. Click Close.

## Setup Bolt/Nut Tightening

Copy analysis and edit to include bolt/nut tightening.

1. In the Project Tree, right-click on Structural 2 and select Copy.
The copy will appear as Structural 3 in the Project Tree.
2. In the Bookmark browser, select Bookmark 5 (Bolted joint).
3. Verify Structural 3 is selected in the Project Tree.
4. In the Analysis Workbench toolbar, click (Nut tightening).
5. In the modeling window, select the 4 nuts attached to the hanger beam as shown in orange in Figure 16.
6. For Thread pitch, enter 1 mm.
7. Activate the Target axial load radio button and enter 5000 N in the text box.
8. Click OK.

## Run Analysis

Solve the analysis.

1. In the Project Tree, open the Analysis Workbench.
2. Click (Solve).

## Compare Results

Observe the difference in results between structural linear analysis and non-linear separating contact.

1. In the Project Tree, select the Structural 1 branch.
2. In the Bookmark browser, choose Bookmark 3.
This bookmark shows the deformation detail.
3. In the Project Tree, select the Structural 3 branch.
The modeling window will update to show deformation detail for Structural 2.
4. Optional: Switch back and forth between Analysis branches to highlight the differences in the results.
5. Repeat steps 1 through 4 for Bookmark 4 (stress detail).

## Compare with Traditional FEA

Run the same analysis using your existing traditional FEA application.

1. Use the model files to run this same analysis with your traditional FEA application.
Important:
• Do not merge or simplify geometry, use bonded and sliding contact same as SimSolid.
• Check for part overlaps
• Make sure elemetn density is acceptable for smaller parts
2. Compare the following between the two programs:
• Solution quality
• Number of workflow steps required
• Time required to mesh
• Time required to solve
• Time required to examine results
• Time required to refine and rerun model