Numerical analysis of contact stress and strain distributions for greased and ungreased high loaded oscillating bearings

Nowadays rolling bearings are subject to extreme operating conditions due to the increasing of the transmitted power and the optimized design. Consequently, the reduction of the bearing dimensions can lead to a reduction of the contact area and an increasing of the power transmitted per unit of contact area. Some special applications as space engineering, robotics, aeronautics and wind energy require rolling bearings subjected to high contact pressure while the movement is governed by an oscillating motion; such extreme conditions can lead to degradation and failure scenarios which are not linked to classical contact fatigue and are not completely understood yet. The aim of this work is to investigate the contact stress and strain distribution of rolling bearings under high loaded oscillating motion, i.e. high contact pressure and deformation. 3D finite element simulations with elasto-plastic material law have been carried out and a comparison of the results with the classical elastic law is presented. The effect of the friction coefficient, the radial load and the surface conformity have been investigated. The numerical results have been compared with the tribological observations of the degraded bearings under the same load conditions. The presented results contribute to the tribological and physical interpretation of the degradation scenario, for greased and ungreased bearings, by a mechanical point of view.