Tutorial: Running a Baseline Analysis

Tutorial Level: Beginner Run a baseline static analysis, then review and animate the results.

In this lesson you will learn how to:
  • Open a model and display the Model Browser
  • Run a baseline static analysis
  • View results for the factor of safety
  • View results for displacement
  • View results for von Mises stress
  • View results for tension and compression
  • Play an animation


Overview

In this tutorial, you will run a baseline static analysis of a part in a steady state and review the results.

In mechanics, when the loading on a system is balanced, we achieve equilibrium, or a steady state. Analysis performed at this state is also called static analysis. When solving a static analysis, the solvers will solve the equation Kx = f where:
  • K: is the global stiffness matrix
  • x: is the displacement vector response to be determined
  • f: is the external forces vector applied to the structure

The following tutorial demonstrates how to run a baseline analysis in order to better understand what a static analysis is.

Open the Baseline Analysis Model

Before you begin, copy the file(s) used in this tutorial to your working directory.
  1. Double-click the Baseline Analysis.stmod file to load it in the modeling window.


  2. If not already visible, press F2 to open the Model Browser.


  3. Make sure the display units in the Unit System Selector are set to MPA (mm t N s).

Run a Baseline Static Analysis

  1. On the Structure ribbon, click the Run Analysis button in the Analyze tool group to open the Run Analysis window.
  2. Run the analysis using the following settings:
    1. Select OptiStruct as the solver.
    2. Change the Element Size to 3.0 mm.
    3. Set Speed to More Accurate.
    4. Click Load Cases and verify that both the Jump and the Rock load cases are selected.
    5. Click Run to perform the analysis.
  3. When the run is complete, select it in the Run Status window and click View Now to see the results.
    Tip: You can also double-click the Results icon in the Model Browser to view results for a load case.

    The results are displayed in the Analysis Explorer.


View the Factor of Safety Results

  1. In the Analysis Explorer, click Show Selected Load Case and select Hide all Loads and Supports .


  2. In the Analysis Explorer under Load Case, select Jump.
  3. In the Analysis Explorer under Result Types, select Factor of Safety. The Factor of Safety result type for the Rock load case is shown in the modeling window.
    By default, areas that are approaching a minimum safety factor of 1.0 are shown in red to indicate where the part is most likely to fail. The areas shown in pink indicate where the model is under stress.


  4. In the Analysis Explorer under Factor of Safety, click and drag the slider on the legend until just before the contours disappear.
    This masks all areas on the model with a factor of safety higher than the selected value on the slider.


  5. The factor of safety is around 1.7. Since this is greater than 1.0, the model is not predicted to fail for this load case.

View the Displacements Results

  1. In the Analysis Explorer under Result Types, select Displacement.


  2. Turn on the Min/Max callout and note that the maximum displacement for the model is approximately .396 mm as shown in the legend.




  3. Click Show/Hide Deformed State to show the deformed state of the model. Click again to hide it.


  4. Click the button on the animation toolbar to visualize the displacement. Click the button to pause the animation.
  5. Optional: Click the icon to change the animation settings.
    Tip: Inspire automatically scales the displacement animation to make it easier to see. Deselect the Auto checkbox and enter a Scale By value to change the scale of the animation.

View the von Mises Stress Results

  1. With the Jump load case still selected, select von Mises Stress under Result Types.


  2. By default, the peak stress for the load case is shown. Click next to the legend in the Analysis Explorer and select Aluminum (7075) Yield Stress.


  3. The majority of the rocker arm is blue, but the pin is red. However, the pin is made of titanium, not aluminum.


  4. Click next to the legend in the Analysis Explorer and select Titanium (Ti -6211 Yield Stress).


    Now the pin is blue as well. It's looking good!
    Tip: If you want to change the legend colors used for this or any other result type, click Legend Options next to the legend and select Rainbow Legend colors. Alternatively, you can use Preferences > Inspire > Run Options > Analysis Legend Colors to change the default legend colors for each result type.

View the Tension and Compression Results

  1. Select Tension/Compression under Result Types.
    Areas on the model shown in orange are subject to tension, and areas shown in green are subject to compression.


  2. Click Show/hide initial shape to show and hide the initial shape as a reference.
  3. Click Show/hide contours to show and hide the contours. Use Show/Hide Options to turn off Blended contours and Interpolate during animation.
  4. Optional: If you want to change the maximum value in the legend, double-click the label for the maximum value and type a new value. Analysis results are updated after you press Enter.
  5. Optional: If you want to change the legend colors used for this or any other result type, click Legend Options next to the legend and select Rainbow Legend colors. Alternatively, you can use Preferences > Inspire > Run Options > Analysis Legend Colors to change the default legend colors for each result type.
  6. When finished, close the Analysis Explorer.

Refine Mesh for Improved Results (Optional)

  1. From the Setup menu, select Mesh Control.
    For more information, see Mesh Controls.
  2. Select the highlighted surfaces and define the mesh size on these surfaces as 1.0 mm. This will seed the underlying solid mesh with a smaller element size than the global value of 3.0 mm.
    Note: Hold down Ctrl to select multiple faces.
  3. On the Structure ribbon, click the Run Analysis button in the Analyze tool group to open the Run Analysis window.
  4. Rerun the analysis using the following settings:
    1. Change the Element Size to 3.0 mm.
    2. Select OptiStruct as the solver.
    3. Set Speed to More Accurate.
    4. Click Load Cases and verify that both the Jump and the Rock load cases are selected.
    5. Click Run to perform the analysis.
  5. When the run is complete, select it in the Run Status window and click View Now to see the results.
    Tip: You can also double-click the Results icon in the Model Browser to view results for a load case.

  6. Select Show/Hide Elements in the View Controls to show the mesh.
    Note the mesh refinement on the selected fillets and the smoother transition of stress results.