Creating Frequency Scenarios

Creating a frequency scenario allows you to create sets of environmental specifications, and to implicitly require a normal modes solution procedure for the computation of the system vibration frequencies and normal modes for a given non-structural mass distribution under given restraints. To be valid a frequency scenario must reference one and only one restraint set. You can also reference masses.

Before you begin: A structural analysis simulation referencing a finite element model and containing an activated Scenario object must be open.
Related Topics
Creating an Analysis Scenario
Modifying the Excitations and the Parameters of a Scenario
Creating Excitations
Updating Scenarios
Executing a Simulation from the Structural Analysis Workbench
Viewing the Structural Analysis Simulation Results

  1. In the Scenarios toolbar, click Frequency Scenario .

    The Frequency Scenario dialog box appears. By default, a new and empty restraint set (New Restraints), and a new and empty mass set (New Masses) are referenced in the Excitations tab. At this stage, the two sets do not exist yet. They are created at the same time as the scenario.

  2. Optional: In the Name box, modify the scenario name.

  3. If the product contains several finite element model representations, select the finite element model representation you want to use in the FE Model box. If the product contains only one finite element model representation, this representation is selected automatically in the FE Model box.

  4. Optional: In the Excitations tab, change the excitation sets that you want to use to define the scenario. To reference an existing set:

    1. Select the desired tab.
    2. In the Available list, select an existing set.
    3. Click .

      The selected set appears in the Referenced list.

    Important: A frequency scenario requires a restraint set. A mass set is optional.

  5. Optional: To define a frequency scenario without additional masses:

    1. Select the Masses tab.
    2. In the Referenced list, select the referenced mass set.
    3. Click .

  6. Optional: In the Parameters tab, modify the scenario parameters. By default, the Iterative subspace method is used for frequency scenario.

    If you select the Lanczos method, the Shift option appears and lets you compute the modes beyond a given value: Auto, 1Hz, 2Hz and so forth. Auto means that the computation is performed on a structure that is partially free.

    Important: The availability of this option depends on your available licenses. See Licensing.

  7. Click OK.

    The scenario is created and appears in the specification tree with the selected excitation sets.

You can find below an example of what you obtain in the specification tree if you keep all the default options: