Contact fatigue analysis of a dented surface in a dry elastic-plastic circular point contact

The present article proposes a methodology for the computational analysis of damage induced in the vicinity of dents in a dry circular point contact under repeated rolling. The failure risk is evaluated through the use of the Dang Van multiaxial fatigue criterion. The dent is a typical surface defect encountered in rolling element bearings when operating in contaminated environments. It is usually created by a solid particle not removed by seals or filters when passing through an EHL conjunction. Since local plasticity occurs when the debris is first entrapped between the contacting surfaces, and later when the resulting dents are subjected to moving contact load, the elastic-plastic behavior of the material should be captured by the model. First, the dent shape and the subsurface stress and strain fields produced by the presence of a spherical particle are obtained by the finite element method. Second, the rolling of the load over the surface defect is simulated using a semi-analytical elastic-plastic code. The simulations are carried out for two different debris materials, both ductile but one significantly softer than the contacting surfaces, i.e., made of stainless steel 316L, the other one being made of bearing steel AISI 52100 similar to the contacting surfaces. The dent shape and initial stress and strain states are first presented. Subsequent stress and strain states after a few rolling cycles are then presented. Finally the effects of the coefficient of friction, presence of residual stress, and contact load magnitude are highlighted.