关键词: 粗糙表面, 弹塑性接触, 拉应力, 热力耦合

Abstract: A thermo-mechanical coupling model for a rigid flat plane and an elastic-plastic rough surface based on three-dimensional fractal theory is established. The model considers the interaction between asperities, and integrates the heat flux coupling on the contact interface. To obtain the transient stress/temperature distribution of the rough solid, the thermo-mechanical problem under this 3D model is solved by using the nonlinear multiphysics field of the ANSYS software. The numerical results from the analysis and simulation show that the maximum contact temperature of the rough surface increases quickly in the initial sliding due to the velocity mutation, but the temperature rises slowly during the constant sliding process. The results also show that the VonMises equivalent stress distribution of the rough surface is very uneven. And a tension stress zone exists at a certain depth from the contact surface in the rear of the contact asperity. The results demonstrate that the VonMises equivalent stress of the contact surface, the maximum tensile stress and the layer thickness of the tensile stress increase obviously in transient sliding contact and forming of instantaneous flash temperature. These results provide a theoretical basis for crack initiation and propagation.

Key words: Elasto-plastic contact, Rough surface, Tensile stress, Thermo-mechanical coupling