Hi,

would like to simulate shaft response when it's rotating at critical speed.

A frequency analysis will give you mode shapes and associated frequencies:

Now suppose you want to know shaft displacement when roating at a speed coinciding with resonant frequency.

You could do this by creating a harmonic analysis.

I've tried to prescribe a uniform base excitation in the form of rotating speed, therefore I've selected a cylindrical face in order to switch to a cylindrical cordinate system and prescibe a tangential velocity. When doing this simulation issues this error:

How could you find out displacement when shaft rotates at a speed coinciding with resonant frequency given that the only known info is rotating speed ?

I'm attaching the shaft with frequency and dynamic study for your reference.

Thanks,

Alex