Multi-stage contact model between fractal rough surfaces based on multi-scale asperity deformation

Abstract

A novel multi-stage contact model of fractal rough surfaces is proposed in this paper. Actual asperity deformation depending on contact degree is derived at length scale, based on which, the actual deformation mode of asperity is analyzed. In accordance with deformation modes of multi-scale asperities, the contact behavior of the whole surface is distinguished into five stages as the increment of contact force. A complete model of contact characteristics across multi-stage is established, and the corresponding mathematical analytical solution of each stage is provided. Accordingly, the relationship between contact force, normal stiffness, and real contact area are analyzed under the effects of fractal factors. The simulation results of the developed model are also compared with that of available models and experimental data.