To reduce the vibration of flexible rotor supported by active magnetic bearings

metal rubber annuluses were introduced and set around the active magnetic bearings

which are called as complex bearings.Dynamic characteristics of the system supported by the complex bearings were studied in this paper by theoretical analysis

experimental modal analysis and actual operation of the system.The results show that the metal rubber annulus can increase the first bending modal damping of the system obviously

and help the system to get across the first bending critical speed safely.