Dynamic Behavior Analysis of a Rotor-Bearing-Squeeze Film Damper Coupling System with Bearing Outer Race Localized Defect

The rotor-bearing-squeeze film damper coupling (RBSC) system is the core part of aero-engines, determining operation safety and reliability. The dynamic behavior of the RBSC system is easily affected by the bearing outer race localized defect, which is difficult to identify accurately. Inappropriate dynamic analysis of system behavior will further affect monitoring and diagnosis of the system. This paper presents a mathematical model of the RBSC system with bearing outer race localized defect to study the dynamic behavior of the system. The model develops a smooth spalling path in the bearing outer race to simulate the successive passage of the balls. The model also considers the effect of centrifugal load on the bearing force. The impact of the bearing outer race localized defect on the RBSC system during the acceleration process is analyzed. The numerical results show the bearing outer race localized defect will aggravate the nonlinear behavior of the RBSC system and is prone to chaotic motion. Meanwhile, affected by the bearing outer race localized defect, the vibration of the RBSC system will increase in the speed range of relatively low and relatively high. Especially in the high-speed range, the impact of a bearing outer race localized defect on system vibration covers more speeds. This study provides a theoretical basis for condition monitoring and fault diagnosis of the RBSC system.