Creating Harmonic Motion Excitations

You can create harmonic dynamic base motion excitations in a harmonic dynamic scenario. A motion excitation allows you to define a motion load on the system that scales as a function of frequency.

The base motion is defined by an acceleration function given for each coordinate direction over the frequency domain.

Before you begin: A structural analysis simulation that contains a harmonic dynamic scenario must exist and must be open.
Related Topics
Defining Harmonic Dynamic Scenarios
Using Modulations
Reviewing Specifications

  1. In the Dynamic Excitations toolbar, click Harmonic Motion .

    The Harmonic Motion dialog box appears.

  2. Optional: In the Name box, modify the name of the excitation.

  3. Optional: By default, the motion components are defined relative to the fixed global axis system (fixed global rectangular coordinate system). To choose a different axis system, select User in the Type list, and select a user axis system in the specification tree.

    The name of the user axis system is displayed automatically in the Current axis box, and the motion components are defined relative to the specified rectangular axis system.

  4. In the Axis direction list, select the axis along which the motion is applied.

  5. Define the modulation both for the Translational Acceleration and the Rotational Acceleration. Select:

    • White Noise to use a constant modulation that is equal to one (unit function over all frequencies).
    • Modulation to use a modulation that is a function of frequency. See Using Modulations.

  6. For the Translational Acceleration and the Rotational Acceleration, enter an acceleration value in the Acceleration box.

  7. For the Translational Acceleration and the Rotational Acceleration, enter an angle value to define the phase in the Phase box.

  8. Click OK.

    An harmonic motion appears in the specification tree under Harmonic Motions.1.