My ANSYS Workbench Simulation 9.0 MSUP (mode superposition) harmonic response
results do not match my full harmonic results in the same software product. Why?
One possibility is that not enough modes are being considered in the MSUP harmonic
analysis. This can occur when the frequency range is set to small. By default, Simulation
uses the following range of frequencies in conducting the MSUP harmonic response:
min = factor/min freq and max = factor*max freq
where factor = the DS system variable (dssysvar) "MSUP expand factor", which defaults
to just 2.0. Setting "MSUP expand factor" to a larger value will include more modes in
your harmonic response analysis and will most likely give better results. Development
is considering exposing this "MSUP expand factor" in the Details Pane in Simulation 10.0.
Other harmonic response analysis discrepancies may be due to different damping or not
not using the same amount of solutions (i.e., you may need to set clustering on for MSUP).
Also, a coarse mesh will often yield differences, so be sure to refine your mesh as needed.