Why I cannot apply a constant speed in the Harmonic Response? (Like the "rotational velocity" in the static structural analysis)

 In harmonic response analysis, applying a constant speed like in static structural analysis isn't possible because harmonic analysis focuses on the response of a system to varying excitation forces over a range of frequencies.

Instead, harmonic response analysis utilizes a rotating force with a synchronous ratio and amplitude to simulate a rotating rotor. The synchronous ratio relates the force frequency to the rotational speed of the rotor. This approach accurately captures the vibratory response of the rotor at different excitation frequencies.

So, using a rotating force with a synchronous ratio and amplitude in harmonic response analysis is the correct way to represent a rotating rotor.