Effects of Rough Surface Topography on the Characteristics of Mixed Lubrication in Finite Line Contact

A mixed elastohydrodynamic lubrication (mixed EHL) is developed for finite line contact model with the unified Reynolds equation. This model is used to comprehensively show the effects of the wavelength and amplitude of roughness, working conditions on the three types of major roughness orientations: transverse, longitudinal, and isotropic. Results show effects of the wavelength and amplitude, as well as the working conditions were almost similar for three types roughness orientations. As the load increased, the friction coefficient, contact load ratio and contact area ratio increased, while the average film thickness decreased. As the speed increased, the friction coefficient, contact load ratio and contact area ratio decreased, while the average film thickness increased. The characteristic parameters of lubrication varied significantly from the full-film and mixed to boundary lubrication. Along the direction of entrainment velocity, it is misplaced for the distribution of pressure and film thickness fluctuation. The longitudinal roughness is more advantageous to contact lubrication.