3.2.1.2. Fast PSD Response Object Details

  • PSD Load

    Load Data

    Specifies the input method for the PSD Load. You have the option to input Frequency vs. G Acceleration data in the tabular view.

    Direction

    Indicates the direction of applied PSD excitation.

    Damping Ratio

    Specifies the structural damping used in the analysis. Default setting is 0.01.

  • Definition

    Result Type

    Specifies the type of result to be computed. Options are Force Reaction, Moment Reaction, Stress, and Strain.

    Location Method

    Determines where the result is computed. For the Force and Moment Reaction result types, valid input are Boundary Condition, Contact Region, Beam, and Spring, meaning that results will be extracted from predefined boundary conditions or connection locations. See Reactions: Forces and Moments in the Mechanical User's Guide for more information.

    For Stress and Strain, Geometry Selection is the only supported option.

    • Boundary Condition - Choose the specific boundary condition applied for result extraction from those available in the drop-down list. Valid boundary conditions are Fixed Support, Displacement and Remote Displacement.

      Note:  Since the application uses participation factors from modal analysis to compute PSD response, you must use Rigid Behavior if Remote Displacement is applied as contraint, otherwise results may be inaccurate.

    • Contact Region - Choose the contact region for result extraction from those available in the drop-down list. Supports contact reactions using the underlying element option (Extraction - Contact Underlying Element).

    • Beam - Choose the beam connection object for result extraction from those available in the drop-down list. You must also set the On Demand Expansion Option property to No in the Analysis Settings.

    • Spring - Choose the spring object for result extraction from those available in the drop-down list. Only grounded springs (springs with Body-Ground scoping) are valid.

    • Geometry Selection - Since Fast PSD Response (Stress/Strain) is a point-based result, you can select a vertex or a node for this option.

    Orientation

    Defines the coordinate system used for interpreting direction-specific results. Only supports Global Coordinate System for Force Reaction and Moment Reaction. For Stress and Strain results, both Solution and Global Coordinate System are supported.

    Summation

    This is available for most Location Method property selections for the Moment Reaction result type and enables you to select Centroid or Orientation System for your scoped entity. If your selected Location Method does not display this property, the application automatically uses the centroid of the scoped entity for the moment calculation.

    Reference

    Supports Relative to base motion. This means the response of any location in a structural component is calculated in terms of the relative motion between the base and the structural component, and vice versa.

  • Options

    Result Selection

    Defines the direction/component for PSD plot display, as shown in the figure below. For Force and Moment Reaction result types, options are X Axis, Y Axis and Z Axis. For Stress and Strain results, equivalent (von-Mises) Normal and Shear components are computed.

    Note:  Stress and Strain PSD results are not supported for beam element nodes or for mid-side nodes of any element type.

  • Results

    For the Force and Moment Reaction result types, this displays the computed force/moment reaction values due to the PSD load in each direction (X, Y and Z Axes).

    For the Stress and Strain result types, this displays Node ID, RMS Value, RMS Percentage and Expected Frequency.

    • Node ID - Displays the mesh Node ID used for the Fast PSD Response result. The application selects the node nearest to the specified scoping of the probe.

    • RMS Value - Displays the value calculated during solution (square root of the area under the PSD response).

    • RMS Percentage - Displays the percentage of the root-mean-square of the selected frequency range over the entire available frequency range.

    • Expected Frequency - Displays the value calculated during solution (the centroid of the area under the PSD response with respect to frequency).