粗糙表面热弹塑性接触问题的无网格法

Mesh-free Method for Thermal Elasto-plastic Contact of Rough Surfaces

建立可考虑屈服应力温度相关的粗糙表面热弹塑性接触无网格法数值计算模型。研究摩擦力和不同热输入情况下圆柱体与弹塑性平面的接触力学特性,探讨摩擦热效应对表面温升、接触压力和接触面积的影响。结果表明在考虑剪切摩擦力作用后,弹塑性接触压力分布不再关于接触区域中轴线对称而出现了"塌陷"现象。通过无网格法解与有限元法解比较发现不恰当的有限元网格划分会造成接触压力的数值震荡,而无网格法可避免这一现象的发生。发现忽略温度相关效应将高估最大接触压力而低估相应外载荷下产生的接触面积。

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. By comparing the results obtained from the EFG-FE coupling method with those from FEM, it reveals that the contact pressures solved by FEM will have numerical oscillation if the FE meshes are improperly partitioned, while this phenomenon will be avoided by using the meshfree methods. Furthermore, the thermal effects on the contact pressure, the real contact area, and the average gap of real rough surfaces with different frictional heat inputs under the thermal elasto-plastic contact conditions are studied.