Modeling of directional friction on a fully lubricated surface with regular anisotropic asperities

Abstract

The modern surface technology now promises to fabricate surfaces with regular asperities. The regular asperity means that asperities, which are related to surface roughness in a conventional tribology, have similar shape and size, and their distribution over the surface is controllable. The regular asperity surface technology may have transformative impact to contemporary tribology. In this paper, we present a study of friction on the surface with regular anisotropic asperities (RAA) in a fully lubrication status. By anisotropic asperity, it is meant that the geometry of the asperity presents different to different motion directions, which is further speculated to have different friction behaviors along different motion directions. The primary goal of the study was to develop a model of friction force on the RAA surface in a fully lubrication status. The secondary goal was to exhibit the directional friction behavior based on our model. We employed Computational Fluid Dynamics (CFD) software to assist in the modeling and used the published data in the literature to validate our model. As a result, accuracy of our model was shown much better than that of the model reported in the current literature. With our model, we successfully demonstrated several interesting directional friction behaviors on the fully lubricated RAA surface.