Dynamic Loads

Dynamic loads can be generally classified as deterministic or non-deterministic. Deterministic loads are well-defined as functions of time and can be predicted precisely. They can be harmonic, periodic, or non-periodic. If the loads are deterministic, the results are also deterministic. Non-deterministic loads cannot be well-defined as explicit functions of time, and they are best described by statistical parameters. If the loads are non-deterministic, the results are also non-deterministic.

Typical dynamic loads are shown below:

To handle different loading environments, SOLIDWORKS Simulation offers three types of linear dynamic studies:
  • Modal Time History Analysis
  • Harmonic Analysis
  • Random Vibration Analysis

Response to Dynamic Loads

Frequency analysis calculates the resonant frequencies and corresponding mode shapes only. Linear dynamic studies use the information to calculate the dynamic response of your structure to dynamic environments.

For nonlinear systems, use nonlinear dynamic studies to calculate the response in the time domain. Nonlinear dynamic studies solve the dynamic response problem as function of time and do not require the calculation of mode shapes and frequencies.

The effect of loads on frequencies and mode shapes is not considered when using linear dynamic studies, as their calculation is based on a stress-free model state. It is recommended to define a Nonlinear Dynamic study instead to account for any possible stress-stiffening or stress-softening effects that can alter the modal characteristics of the model.

The effect of time-varying loads with frequencies less than 1/3 of the lowest resonant frequency of the model, can be approximated by static analysis in most cases.