Perform Random Response Analysis

Use the Random Response tool to perform random response analysis using an existing FRF file.

  1. From the Post ribbon, select the Random Response tool.
    Figure 1.


    The Random Response dialog opens.
  2. For Input FRF, click and browse and select a result file with FRF subcases.
    Note: Currently, the supported solvers are OptiStruct (.op2, .h3d), Nastran (.xdb, .op2), Abaqus (.odb), and ANSYS (.rst).
  3. Select a subcase and a preferred frequency range.
    1. For Select Frequency Range, click Subcases.
      The Select Subcase dialog opens displaying a list of complex subcases and their frequencies.
    2. Select one subcase and a preferred frequency range.
      Figure 2. Select Subcase Dialog


    3. Click OK.
  4. For Input PSD Curve From, complete one of the following options.
    OptionProcess
    File
    1. For Input PSD Curve From, select File.
    2. Click and browse and select a .csv file with a PSD curve.
    Note: The .csv must have the following two-column layout with headers, see Figure 3.
    Figure 3. CSV File Layout Example


    The first column represents the frequencies and should include the range of frequencies that are selected in the Select Frequency Range option (see step 3). The second column represents the PSD load.
    Curves
    1. For Input PSD Curve From, select Curves.
    2. Select a PSD curve from an existing curve in the session.
    Charts
    1. For Input PSD Curve From, select Charts.
    2. Select a PSD curve from an existing chart in the session.
    Note: Only charts that have been created from direct data are supported.
  5. For Output, click and browse and select the output directory and result file.
  6. For Output Request, select result data types and components to be exported in the output file.
    All Results
    All result data types and their components will be exported in the output file.
    Select Results
    Select preferred result data types and components to be exported in the output file. By default, all results are selected.
    Figure 4. Select Results


  7. Select the preferred results calculations to be done.
    • PSD Response
    • Positive Zero Crossing
    • RMS
    • Rate of Peak
    • Spectral Moments
  8. Click and define Advanced options.
    1. Select an axis scale type from linear and logarithmic.
  9. Select Import Files After Run to import a output result file of the random response analysis in the active window if the model file is already imported.
  10. Click Run.