磁轴承失灵后坠落转子瞬态振动灾变机理研究

研究一个带磁轴承的转子系统,在磁轴承失灵后转子坠入备用轴承引起的非线性瞬态振动。通过严格建立运动方程和数值仿真计算,详尽地分析了坠落转子转动角速度变化和轴颈与备用轴承接触点法向力变化的时间历程及备用轴承振动位移的频谱,发现系统发生灾变破坏的原因是由于高速不平衡阻尼转子减速通过临界速度时引起的强烈非稳态受迫弯曲振动加上轴颈与备用轴承接触点碰摩的非线性引起的高频颤振。

Study on Catastrophic Mechanism for Rotor Drop Transient Vibration Following Magnetic Bearing Failure

The nonlinear and transient vibration of a rotor,which dropped onto back-up bearings when its active magnetic bearings were out of order,was investigated.After strictly deriving its equations of motion and performing numerical simulations,the time-histories of rotating speed of the dropping rotor,and normal force at the rubbing contact point as well as the frequency spectrum of the vibration displacement of back-up bearings are fully analyzed.It is found that the strong and unsteady forced bending vibration of the unbalancced and damped rotor decelerating through its first bending vibtation of the unbalaned and damped rotor decelerating through its first critical speed as well as chattering at high frequencies caused by the non-linearity at the rubbing contact point between the journal and back-up bearings may lead to the catastrophic damage of the system.