A complete deterministic model of point contact mixed lubrication coupling dual-mode effects of surface fractal characteristics

For mixed lubrication under point contact, a complete model is proposed including two modes of direct effects of surface roughness on the oil film thickness and rough solid contact characteristic. A new method to describe initial oil film thickness is established based on the effects of the holistic interface roughness. The real contact area of the interface is directly obtained by the sum of all solid nodes in a discrete grid, based on which, the solid contact characteristics are calculated by the fractal method considering the surface roughness. This fills the gap in mixed lubrication where the calculation of the solid part has no basis since solid contact force is unknown. The total load balance is taken as the convergence condition, and film thickness and pressure distribution of mixed lubrication are solved ultimately. The direct influences of fractal factors on lubrication characteristics are analyzed, and a comparison between the classical statistical method and the fractal method is conducted.