Multilayer Dielectric Rough Surface Thermal Elastic-plastic Contact Problems

A two-dimensional elasto-plastic contact model of multi-asperities with coating by using the finite element method is presented. Two profiles of multi-asperities which have different topographies with the same root mean square roughness are used. The influences of surface topography, Young' modulus, yield strength of coating materials and coating thickness on contact pressure, contact area, profile deformation and von Mises stress distributions of the contacting bodies are investigated.A thermal elasto-plastic asperity contact model is investigated, which takes into account the steady-state heat transfer and the asperity distortion due to thermal elasto-plastic deformations. A hard coating and a soft coating are applied to study the correlations between contact area and contact pressure, average gap and contact pressure, coating thickness and contours of the contact stress distribution et al. The effects of material properties, the coating thickness, frictional coefficient, and the heat input combinations on the stress distribution and the temperature rise distribution are investigated and discussed. The frictional heat input increases the maximum value of von Mises stress. Application of the soft coating with the high thermal conductivity reduces the asperity temperature peaks. On the other hand the higher pressure peaks and the lower heat conductivity of the hard material make the maximum temperature rise of the hard coating higher. The thicker the hard coating layer, the higher the pressure and temperature peaks. The appropriate thickness of the hard coating is also discussed.A thermal elasto-plastic contact model which can consider the effects of temperature-dependent yield strength is developed to investigate the influences of the steady-state frictional heating on the contact performance of surface asperities and subsurface stress fields between two contacting bodies. The model is verified through the contact analysis of a rigid, isolated cylinder with a thermal elasto-plastic plane. The results show that the contact pressures of elasto-plastic contact with considering the frictional tractions are no longer symmetric. The maximum contact pressure will be overestimated and the contact areas will be underestimated if the effects of temperature-dependent yield strength is ignored. Furthermore, the thermal effects on the contact pressure, real area of contact, and average gap of real rough surface with different frictional heat inputs under the thermal elasto-plastic contact conditions are studied. When the effects is considered, with the same contact pressure, average gaps...