An elasto-plastic-damage model for initiation and propagation of spalling in rolling bearings

Abstract

This study develops an elasto-plastic-damage model to investigate the spalling initiation and propagation behavior of bearings under rolling contact fatigue loading. The intrinsic coupling relationship between the fatigue damage and the elasto-plastic behavior of materials is considered by specifying the damage-related Helmholtz free energy and dissipative potential function in the thermodynamic framework. The damage evolution law is derived based on the plastic strain and the non-proportional cyclic stress. The developed model is implemented into finite element analysis for rolling contact of cylindrical bearings to evaluate the evolutions of the stress, strain and fatigue damage. The initiation and propagation processes of spalling in bearings are simulated. The predicted results of the spalling lifetime are compared with the experimental data from the literature. The damage-induced plastic deformation causes the shear stress-strain curve to possess hysteresis loops. It is observed that the fatigue damage competes with the plastic deformation to influence the shear stress that plays a major driving role in spalling. Moreover, the effects of the contact pressure and the coefficient of friction on the spalling process are studied.