Mechanical responses of coated solids in elastohydrodynamically lubricated line contacts

For layered solids consisting of physical vapour deposition coatings on steel substrates in lubricated line contacts, the elastohydrodynamic lubrication (EHL) behaviour is studied by the full-system finite element approach. Numerical solutions illustrate that the coating thickness, elastic modulus, and operating conditions have significant influences upon the EHL film pressure and thickness profiles, along with the coefficient of friction. Results for stress distributions provide insight into the tendency for yielding, pitting, and interfacial delamination in coated bodies. Furthermore, the film pressure and stress status induced by the interfacial micro-valley as well as rough coating surface and interface are investigated. It is demonstrated that optimised multi-layer coatings are propitious to reduce the stress gradient and failure risks of coated materials.