中介轴承故障动力学建模与振动特征分析

Inter-shaft bearings is one of the key supporting components of aero-engine rotor. The inter-shaft bearings is prone to failure because of the high speed and poor lubrication working conditions. Dynamic model based fault mechanism analysis can provide guidance for fault diagnosis of bearings. A dynamic model for inter-shaft bearings is proposed based on Gupta's model with considering the movement of the outer ring. And the model is validated by experiments. Based on that, a faulty dynamic model of wear is proposed with considering the change of surface morphology of raceway and bearing clearance. Besides, a faulty dynamic model of localized defects is proposed by considering the change of the geometrical interaction and the direction of contact force. Then the vibration responses of inter-shaft bearing under different wear conditions are analyzed by this model. The results show that many random components appear in the vibration response for bearings with wear faults. For the bearing with compound faults as localized defect and wear, as wear goes more serious, the amplitude of vibration response becomes lager; the random components increase. The fault characteristics are not obvious.