A Study on Dynamic Characteristics of a Rotor System with a Coupling Fault of Bearing Outer Ring Defect and Bearing Looseness

Bearing looseness and outer ring defect occur simultaneously, affecting the dynamic characteristics of a rotor system and impeding effective health monitoring of the rotor system.Based on the theory of bearing dynamics, a model of a rotor system with a coupling fault of the outer ring defect and bearing looseness was established.The vibration response was obtained through numerical simulation, and the effect of rotational speed on the vibration characteristics of the system was also discussed.The results showed that fr/2 and its harmonics appeared in the frequency spectrum of the bearing with both looseness and an outer ring defect and their amplitudes were proportional to the rotational speed.In addition, the combined frequency of fr/2 and the outer ring defect frequency fo can be considered as the frequency of the coupling fault, which was also reflected in the other bearing of the rotor system.The research results provide ideas for fault monitoring of the rotor system with a coupling fault of bearing looseness and outer ring defect.