Three-dimensional Numerical Analysis Of Transient Temperature/stress Field For Rough Surface

In real engineering, the two surfaces in sliding contact are rough. And it is an important theoretical part to calculate the coupled temperature and stress of sliding bodies having rough surfaces.At first the research current situation of the flash temperature field of rough surface and the algorithm of contact problems with friction were reviewed in this paper. And after the contact model of rough surfaces was created, the heat transfer between the sliding surfaces was studied. Based on G-W contact model, two rough surfaces in contact were simplified to a smooth one and a rough one which has regular rectangular asperities, and a three-dimensional transient thermal and stress coupled FEM model was established using thermal-structure sequential coupling. The course of the sliding with friction was simulated using the nonlinear multiphysics field FEM, meanwhile considering thermal-elastic problems of the two bodies, to calculate and analyze the temperature, contact pressure and stress of the sliding contact surfaces with frictional heating. The effect of the variation of temperature and contact pressure of the sliding contact surfaces with frictional heating on each other, particularly the relationship of the applied pressure and the contact pressure and the effect of the separate variation of some parameters on the simulation results were taken account into in the course of numerical simulation.The FEM results indicated that as to the rough surfaces in sliding contact, the value of the contact pressure was very high which coursed a high value of the heat flow rate, meanwhile the sliding time was not enough for the frictional heat to transfer, thus the highest value of the body temperature occurred just on the sliding surfaces, which possessed a sharp thermal gradient in direction perpendicular to the sliding surface. So the great thermal stress was caused just by the sharp gradient and the thermal elastic distortion with which the contact pressure changed occurred simultaneously, thus this change of the contact pressure would affect the temperature distribution in return.The regulation of distribution of temperature and stress fields and the division of heat between the sliding surfaces were showed, and the distribution and variation regulation of the temperature, contact pressure and stress field in the sliding process were also analyzed in this paper. The cause of the change of the greatest stress position, which possibly caused heat failure in sliding friction, and the separate effect of the real contact area, applied pressure and sliding velocity on the simulation results were discussed.The results of this paper are the basic for further research the flash temperature, thermal-mechanical problems and the wear mechanisms of the rough surfaces, also helps to develop the excellent frictional material.