Effects of 3-D Surface Topography on the EHL Film Thickness and Film Breakdown

Abstract

A systematic analysis is carried out to study the effect of 3-D surface roughness on the film thickness and film breakdown in micro-elastohydrodynamic lubrication (EHL). First, the analysis focuses on the global behavior of EHL film thickness. For simplicity and without loss of generality, a 3-D sinusoidal rough surface in contact with a smooth surface is analyzed, assuming isothermal conditions. Heavily loaded contacts are examined using Hertzian peak pressures up to 2.5 GPa. Two wavelengths are separately used to generate the roughness pattern along the direction of surface motion (i.e. the longitudinal wavelength). Each simulates the surface topography with long or short wavelength. The roughness pattern perpendicular to the direction of surface motion is described by the transverse wavelength which is set independently. The average value of EHL film thickness in the Hertzian region is calculated for various transverse wavelengths of surface roughness and for four values of slide-to-roll ratio. The ana...