Influence of Different External Pressure on the Thermo-Mechanical Coupling of the Rough Surface during Sliding Contact

Abstract

Based on 3D fractal theory the rough surface is characterized. And its structural parameters are determined by measurement of the roughness of a real frictional surface. A thermo-mechanical coupling model for the rough surface sliding friction is established. The model integrates the heat flux coupling between the sliding surfaces and allows the analysis of the effects of elastic deformation of contact subjects and all of the correlation between asperities. To obtain the transient contact process of the rough surfaces during frictional sliding, the thermoelastic problem under this three-dimensional model is solved by the nonlinear finite element multiphysical methods in ANSYS8.1 software. The effects of the different external applied pressure on the highest contact temperature, the maximum surface contact pressure and the biggest equivalent VonMises stress during frictional sliding are analyzed. The numerical results from the analysis and simulation show the highest contact temperature is approximate proportion to the external applied pressure. But some differences exist. The difference becomes more distinctness with the increase of the sliding distance and the temperature rise. The synthetical function of multiple factors such as the elastic deformation, the rising temperature of contact subject, the variation of the number of the contact asperities and the interaction between asperities make the instantaneous maximum contact pressure and the biggest VonMises equivalent stress do not increase linearly with the increase of the external applied pressure.