Frequency Response Analysis

Create frequency response analysis in SimSolid for a vertical wind turbine assembly.

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:
  • Use modal analysis results to create a frequency response analysis.

Model Description



Figure 1. Wind turbine model
The following model file is needed for this tutorial:
  • Frequency.ssp
This file has the following specifications:
  • Material is set to Steel for all parts.
  • Regular connections - 3mm gap and penetration tolerance.
  • SimSolid automatically creates bonded contact conditions.

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 Frequency.ssp
  4. Click OK.

Create Modal Analysis

  1. On the main window toolbar, click the (Modal analysis) icon.


    Figure 3.
  2. In the popup Number of modes window, specify the number of modes as 9.
  3. Click OK.
    The new modal analysis will appear in the Project Tree.

Create Immovable Support

Create immovable support.

  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 Face 36, Part4 <1>.
    Figure 4.
  4. Click OK.
    The new constraint, Immovable 1, will appear in the Project Tree. A visual representation of the constraint will appear on the model.

Run Analysis

Solve the analysis.

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

Review Modes

Plot the Displacement Magnitude contour and review the modes.

  1. On the Analysis workbench toolbar, click the (Results plot) icon.
  2. Select Displacement Magnitude.
    The Legend window will display, along with the Frequency (Hz) window with a list of modes.


    Figure 5.
  3. Review the modes.
    1. Select a mode in the Frequency (Hz) window.
    2. In the Legend click to view the mode animation.
    3. Cycle between the different modes and view the mode shapes.

Create Frequency Response Analysis

Use modal results to create frequency response analysis.

  1. On the main window toolbar, select > Frequency response.
    The Dynamic frequency response setup dialog will open and automatically link to the Modal analysis results.
  2. For Frequency span, set the Lower limit to 0 and the Upper limit to 21.243.
  3. Select the Modal damping tab.
  4. Set the Default damping ratio to 0.03.
  5. Click OK.
  6. Accept warning message.

Define Frequency Function

Define a standard frequency function for the analysis.

  1. On the main window toolbar, click (Frequency function).
  2. In the dialog, click Standard.
    The Standard frequency functions dialog will open.
  3. Set the Function type to Harmonics.
  4. Verify that Amplitude (A) is set to 1.
  5. Set Period = 2*PI/Omega [Hz] to 10.
  6. Click OK.
    The graph and table in the Frequency function dialog will populate to show the Frequency and Amplitude factor at points.


    Figure 6.
  7. Click OK to close the dialog.

Define Loads

Add rotational inertia loads.

  1. On the Analysis Workbench toolbar, click (Inertia load) > Rotational inertia.
  2. In the dialog, activate the Apply to selected parts radio button.
  3. In the modeling window, select parts highlighted in orange as shown in Figure 7.


    Figure 7.
  4. Activate the Select Cylinder radio button.
  5. In the modeling window, select ths shaft as shown in orange in Figure 8.


    Figure 8.
  6. For Angular acceleration, enter 50.
  7. Click OK.

Run Analysis

Solve the analysis.

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

Review Results

Plot vonMises Stress contour and view animations.

  1. On the Analysis workbench toolbar, click the (Results plot) icon.
  2. Select Von Mises Stress.
    The Legend and Dynamics frequency response windows will open.
    Figure 9.