One of the biggest assumptions you can make that effects the response calculated is the amount of damping your structure has. The percent-critical-damping is input by the user and is assumed to act globally over the entire model. Material damping (loss factors) and discrete dampers are not supported by the current version of Creo Simulate.
In general, for Dynamic Time studies the damping will have the greatest effect on settling time. Damping has a relatively small effect on maximum response for these studies. Often, if settling time is not important, damping may be left at zero for a time transient study. For Dynamic Frequency and Random analysis studies damping will have a big impact on the maximum response. Zero damping should not be used since the response will try to be infinite. For Random studies damping will have less of an impact on RMS results since the RMS values equal the square root of the area under the PSD response curves.
Dynamic Shock studies do not require damping to be input as a Creo Simulate parameter since the damping is built into the amplitude of the Response Spectra curve.
Damping is assigned as a function of frequency. It may be input as an equation, assumed to be uniform or assigned to individual mode frequencies.
The best way to determine how much damping to assign is to evaluate test data for similar structures. If test data is not available the following table lists some typical values for various structure types.
