A numerical investigation of effects of defect edge discontinuities on contact forces and vibrations for a defective roller bearing

Abstract

Vibration characteristics of a roller bearing caused by a roller passing over the defect on the races are determined by the contact forces between the roller and races of the bearing. The vibration characteristics and contact forces are determined by the sizes and edge discontinuities of the defect. Therefore, it is very useful to investigate the relationships between defect edge discontinuities and the contact forces, and those between defect edge discontinuities and the vibrations for diagnosing the defects with different edge discontinuities in the roller bearings. A dynamic nonlinear finite element model for a roller bearing with a localized surface defect considering different edge discontinuities on its outer race is developed using an explicit dynamics finite element software package in this work. The effects of the defect edge discontinuities, radial load, and shaft speed on the contact force between the roller and outer race of the roller bearing are investigated, as well as the vibrations of the bearing. In-depth analyses of the contact forces between the roller and localized surface defect with different edge discontinuities are presented, which did not study in the previous literatures. The numerical results show that the number of the impacts between the roller and end edge of the defect caused by the re-stressing is more than that between the roller and beginning edge of the defect caused by the de-stressing, which is also affected by the defect edge discontinuities.