Nonlinear slipping dynamics of locally faulted bearings considering rolling-sliding-elastic-fluid coupling

Abstract

Rolling bearings are key components of transmission systems and their dynamic behaviors are closely related to health conditions during equipment operation. However, the nonlinear slipping behaviors of rolling bearings with local faults currently have not been sufficiently investigated. A novel coupled excitation modeling framework for locally faulted rolling bearings is developed in this work. The rolling-sliding-elastic-fluid contact mechanics is incorporated to accurately characterize the nonlinear slipping dynamics. Distinguished from over-simplified traditional models, the proposed model integrates cage flexibility, hydrodynamic lubrication, roller-raceway rolling-sliding-elastic coupling, and cage-roller collisions to guarantee the accuracy of the dynamic model. An experiment is carried out to verify the proposed dynamic model. Moreover, an in-depth analysis of the slipping characteristics of the faulty bearings are carried out to reveal the underlying mechanism of fault-slipping interaction. Through the nonlinear tribo-dynamic analysis, the slipping characteristics of the rolling bearings are investigated to uncover the key factors of bearing slipping. By comparing the slip rate under various fault severities, the slipping characteristics of rolling elements of locally faulted bearings are analyzed, which fundamentally explains why the local faults aggravate the slipping phenomenon of bearings. These findings provide fundamental insights into the nonlinear dynamic behaviors of faulty bearings, offering a theoretical foundation for model-based fault diagnosis.