I am running a basic frequency analysis to find first mode frequency and deflection magnitudes for a vibration table adapter plate. The plate contains a circular hole pattern to mate to the shaker's head and a hole pattern for mounting the UUT. I created fixed constraints along the bottom edge of the shaker head mounting holes, default meshed, and ran a sine sweep. My frequency magnitude is in the ballpark as verified from hand calculations but my resulting deflection magnitudes are huge (20 plus inches for an 18 x 18 in plate)!

A fellow mechanical engineer I work with ran the same simulation on his own PC and obtianed the same exact results. Am I missing a simple software setting?

Thanks,

Chris

A frequency analysis only calculates frequency. Results for deflection are meaningless. To determine actual deflection you must run an analysis with an actual input load to get a meaningful resultant deflection, displacement, stress, etc.