Frequency Response

The frequency response of a system quantitatively describes how the output's magnitude and phase vary with changes to the input frequency. You may find it useful to study the frequency response of your models created using MotionSolve.

Frequency Response Analysis

The MotionSolve frequency response analysis (FRF) gives the steady state transfer of a set of specified frequency input to all Body_Rigid and Body_Flexible displacements as well as the specified Post_Request at a given frequency ƒ. The model is linearized at the current working point to calculate the frequency response. For amplitude dependent responses, behavior Frequency_Force elements can be added to the model.

Frequency inputs apply an excitation with a specified amplitude and phase angle to a given marker/direction pair. The excitation can be of type displacement, velocity, acceleration, or force. A model can have an arbitrary number of frequency inputs that can be applied at the same time or throughout the course of multiple simulations.
Note: Frequency inputs cannot contradict the model configuration or each other. For example, you cannot apply a displacement to a direction constrained by another constraint, like a joint, and you cannot have multiple frequency inputs of the type displacement to the same marker.

The solver run creates a single output "\_frf.h3d" file that combines all frequency response simulations in the model. It can be reviewed from HyperView To visualize the frequency dependent deformation, stress, and strain, review the file in HyperView. To show the bode-plot response of individual marker request results, review the file in HyperGraph.

Additional outputs, such as modal participation factors, frequency dependent energy distribution, and transfer path contributions, can be requested from the simulation.

See Also

Parameters: Frequency Response command statement in the MotionSolve Reference Guide

Parameters: Frequency Response model statement in the MotionSolve Reference Guide