Influence of a single asperity on stresses during lubricated sliding contact on DLC-coated system

Abstract : Extreme low wear rates of Diamond-Like Carbon (DLC) coatings are one the properties that makes them particularly interesting for numerous applications, like automotive ones. This property is often observed during characterisation tests under basic sollicitations like fretting, sliding, rolling-sliding. However, tests on cam-tappet systems show the coating lifetime can be highly reduced under special coupled conditions, such as the presence of an asperity breaking through the lubrication film into the contact area. Its influence on surface and subsurface stresses has to be quanti ed to eventually obtain a predictive model of the coating lifetime. The purpose of this study is to develop a simpli ed numerical model that is consistent with elasto-hydrodynami-lubrication (EHD) approxima- tions for estimating the stress perturbation due to such an asperity.