SN Time Fatigue

Create an SN Time fatigue loadcase.


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:
  • Create SN Time Fatigue loadcase.
  • Import channels and create events.
  • Solve and review results.

Model Description

The following model files are needed for this tutorial:
  • SNTime.ssp
  • Channel1.csv

Figure 1.
The project (.ssp) file has the following specifications:
  • Material is set to Steel for all parts.
  • Linear static subcase with results is included.

Open Project

Open the SimSolid project file.

  1. Start a new SimSolid session.
  2. Click the (Open Project) icon.

    Figure 2.
  3. In the Open project file dialog, choose SNTime.ssp
  4. Click OK.

Review Model

Review the model and load case.

  1. In the Project Tree, expand the Structural 1 Analysis Workbench.
  2. Expand the Loads&Constraints branch and review the loads.

    Figure 3.
  3. Click (Results plot) and choose the desired plot to review regions of high stress.

Add Fatigue Material Properties

Edit material to include fatigue properties.

If an SN curve has already been assigned, skip this step. Check the assigned material properties by right-clicking Assembly in the Project Tree and selecting Show > Materials.

  1. In the main menu, click Settings > Material database.

    Figure 4.
  2. In the dialog, click Edit current.

    Figure 5.
  3. In the Generic Materials group, right-click Steel and select Copy from the context menu.
  4. Edit the copied material.
    1. Select Steel1 - Copy_0.
    2. Click Edit material.
  5. Add fatigue curves.
    1. In the editing field of the dialog, expand the Fatigue properties branch and click Add stress-life (SN) curve....
    2. Verify the Curve definition method is set to Estimate from UTS.
  6. Click Apply.
  7. Click Save.

Create SN Time Analysis

Create SN Time Fatigue Loadcase.

  1. On the main window toolbar, click (Fatigue analysis).
  2. In the drop-down menu, select SN Time.

    Figure 6.
    The new analysis will appear in the Project Tree. The SN Time Workbench items are listed.

    Figure 7.

Import Channels

Import channels using a .csv file.

  1. On the workbench toolbar, click (Import channels).
  2. In the file explorer, choose Channel1.csv.
  3. Click Open.
    The imported channel appears in the Project Tree.

    Figure 8.
    You can import multiple channels for each loadcases, and more than one channels can be included in the same file.
  4. In the Project Tree, double-click on Channel 1.
    The Channel group dialog opens and lists the channels available in the load history file, along with their plots and coordinates. You can cycle between them to view the plots.
    Note: You cannot edit channels from this dialog.

    Figure 9.
  5. Optional: You can sort the plot table by Time or Amplification Factor by clicking on the column headers.
  6. Click Cancel to close the window.
    Note: Figure 10 shows the header format for the .csv file. The first column is Time and the rest of the columns are channel names.

    Figure 10.

Create Events

Create an events consisting of channels and loadcases.

  1. On the workbench toolbar, click (Create event).
  2. In the Event setup window, verify that Channel group is set to Channel1.

    Figure 11.
  3. Create a channel-loadcase map.
    1. Click Add row.
    2. Under Channel, choose C1 from the drop-down menu.
    3. Under Load case, choose Structural 1 in the drop-down menu.
    4. For Channel scale, enter 5.
      This indicates stresses are amplified by 5 for Structrual 1.
    5. For Event repeats, accept the default of 1.
  4. Click OK.
    The events appear in the Project Tree.

Run Analysis

Solve the analysis.

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

Review Results

Plot fatigue damage and pick info for the fatigue subcase.

  1. In the Project Tree, Select the Fatigue SN Time 1 subcase.
  2. On the Analysis Workbench, select > Fatigue damage.
    The Legend widow will open and display the contour plot.

    Figure 12.
    Note: If there are multiple events in the load case, you can plot damage for each event or you can plot cumulative damage.
  3. Pick info.
    1. On the Results Workbench toolbar, click (Pick info).
    2. In the modeling window, select points of interest.
    3. In the Pick info dialog, for Event, select Total from the drop-down menu to view cumulative damage, or select the individual Event of interest.

      Figure 13.