A new method to model a localized surface defect in a cylindrical roller-bearing dynamic simulation

The main failure mode of cylindrical roller element bearings is localized surface defects such as spalls and pits on the surfaces of its races or rollers.(1) However, it is difficult to describe the time-varying deflection excitation generated by a defect and the time-varying contact stiffness excitation due to the changes in contact conditions between a roller and the defect when the roller passes over the defect by using the previous defect models for the cylindrical roller bearing. In this work, a new dynamic analysis method is proposed to formulate a localized surface defect more accurately for a cylindrical roller bearing dynamic modeling. A two-degree of freedom dynamic model for a cylindrical roller bearing with a localized surface defect on its races is proposed, which considers both the time-varying deflection excitation and the time-varying contact stiffness excitation produced by the defect. The load-deflection relationship between the roller and the race is considered as non-Hertzian one, which can be used to determine the load-deflection relationship between the logarithmic-profile roller and the races of the cylindrical roller bearing. The numerical results are compared with the available results from the previous defect models in the literature. The effects of the defect width, depth, and types are investigated. To validate the proposed model, an experiment is also presented. The results show that the proposed method describes a more accurate in describing the real excitation produced by the defect and provides a new method to simulate the effects of a localized surface defect on the vibration response of a cylindrical roller bearing.