Abstract: A finite element model of dualrotor system and the rotor/stator contact model were established to investigate the effects of rubimpact. To make the results more accurate， the influences of shear， inertia distribution， lateral torsional and geometric parameters of the system were considered in the model. The dynamic response of dualrotor system to the varied contact gaps was studied. Results indicate that period3 is present in most parts of the rotor due to the inherent property of the dualrotor system. Aperiodic motion is present in the whole system because of the effect of rubbing contact. Specifically， the aperiodic motion presented in the rotor without rubbing contact (inner rotor) is not obvious due to the intershaft bearing. It is shown that the intershaft bearing can not only couple the inner/outer rotor but isolate the vibration.

Key words: dualrotor system, rub fault, contact, intershaft bearing, chaos