peteroznewman
Subscriber

The harmonic response will show you the peak stress in the model over a range of frequencies. There could be many requirements on the design. One example of a requirement is: The peak stress in the structure shall stay below the fatigue limit of the material at operating frequencies (RPM). Another example of a requirement is: The peak stress in the structure shall stay below the yield strength for any frequency below operating frequencies. In other words, during startup and shutdown the pump may pass through a resonant frequency which will create larger values of stress. Lower values of stress are found at the operating frequency but because it stays at that frequency for a long time, fatigue failure is a concern.