Study on the Self-Excited Vibration of Rotor Systems with Bearing Housing Clearance

With the development of advanced aero-engines to higher maneuverability, the inertial loads on the rotor systems would cause larger vibration amplitude and bearing load, which might lead to violent periodic collisions between the bearing housing and limit stop structure. More importantly, the impact load from the collision could change the whirling states of rotor systems, for example resulting in subharmonic, superharmonic, and self-excited vibrations, which might seriously affect the steady and reliable performance of rotor systems. To accurately characterize the influence of bearing housing-limit stop collisions on rotor dynamic response, a new model for the support structure with clearance is proposed considering the energy loss during the collision. A typical rotor-support structure system is studied to investigate the effect of the limit stop on the rotor dynamic response at different rotational speeds. Results show that, in the subcritical speed state, the collision impact does not cause stable self-excited vibration; while in some supercritical states, the rotor may experience self-excited vibration. The frequency of self-excited vibration is approximately equal to the rotor’s low-order forward whirling mode frequency, and will increase with the deepening of the collision indentation. This paper provides a theoretical basis for rotor-support system dynamic response control and vibration troubleshooting.