Modelling and vibration response of a magnetically suspended flexible rotor considering base motion

Abstract

Active magnetic bearings can provide no-friction support, high operating speed, and active vibration control for rotating machinery. The magnetically suspended rotor will inevitably be excited by the base motion when working on the moving carrier, causing the rotor vibration, and even instability. The main purpose of this study is to model a magnetically suspended flexible rotor under base motion and predict the vibration response. A general model of the magnetically suspended flexible rotor under base motion is established based on the finite element method and Lagrange's equation, considering the rotor shrinkage fit and AMB sensor/actuator being not collocated. The accuracy of the rotor model in free-free state is verified in terms of modal frequencies and mode shapes through the modal test. The vibration response of magnetically suspended rotor is experimentally validated using an AMB-rotor test rig mounted on the shaker. The time-domain response of the rotor under base single harmonic and shock excitation in the experiments is close to that predicted by numerical simulation. Finally, the influence of the frequency and amplitude of the base single harmonic excitation, the amplitude and pulse width of the base shock excitation, and the AMB controller parameters on the vibration response of the magnetically suspended rotor are investigated.