Elastohydrodynamic Lubrication Analysis for Transversely Isotropic Coating Layer

Abstract

The effects of the transversely isotropic coating layer on the elastohydrodynamic lubrication (EHL) circular contact problems are analyzed and discussed under constant load condition. The equivalent elastic modulus for an equivalent isotropic halfspace problem is applied to simplify the present transversely isotropic coating. The finite element method (FEM) is utilized to solve the Reynolds equation, the load balance equation, the rheology equations, and the elastic deformation equation simultaneously. The simulation results of the present equivalent model are compared with those of an anisotropic material elasticity matrix to evaluate the applicable range of coating thickness under a fixed relative error. The pressure distribution tends to gradually escalating and concentrating toward the center with increasing longitudinal Young's modulus. The variations of pressure and film thickness become significant as the coating thickness becomes thinner. The deformations of interface are smaller than the deformations of the surface. The film thickness and pressure characteristics of the lubricant are discussed for various parameters. These characteristics are important for the design of the mechanical element with coating layer.