Identification of cracks in shafts using magnetic bearings

This paper shows an experimental approach to the identification of cracks on magnetically levitated rotors. The crack is artificially done to shaft in such a way that the breathing crack model is no longer representative and the responses are compared against the normal shaft operating in the same conditions. The experiments have been conducted the shaft rotates at 400 RPM, away from any natural frequency, and the in uence of this severe crack was assessed using white noise excitation added to the control signal of one of the magnetic bearings. It has been observed shifts on the higher resonances when rotor is either rotating or not of around 10 Hz lower for the damaged rotor. A Finite Element Model is proposed and, using the same identified parameters of the test rig, it reproduced the same changes in the frequency domain.