EHL OF COATED SURFACES - .1. NEWTONIAN RESULTS

A complete solution for the Newtonian elastohydrodynamic lubrication o f coated surfaces in line contact is introduced in this paper. The for mulation is based mainly on solving the Reynolds equation coupled with the elasticity equations of the multilayered elastic halfspace. The e ffects of pressure inside the lubricated conjunction on the lubricant viscosity and density are considered. The mathematical model for this problem is a nonlinear one, and an iterative Newton-Raphson scheme is used for numerical solutions. The effects of coating material and coat ing thickness on the pressure profiles and the film shapes are present ed. Two different coating materials (molybdenum disulfide as a soft co ating and titanium nitride as a hard coating) are considered. The resu lts show that the pressure spike is higher for hard coatings than for uncoated surfaces but that the pressure spike disappears for soft coat ings. Furthermore, the coating thickness has a significant influence o n the minimum film thickness and the maximum contact pressure for both soft and hard coatings.