双粗糙平面法向接触建模方法的有限元对比分析

摘要

Based on statistics model,Greenwood and Tripp (GT model) have proposed that the normal contact between two rough surfaces(two-rough-surface model) could be equivalent as a single rough surface in contact with a rigid flat (single-rough-surface model).However,this equivalence treatment lacks the analysis of contact stress field as well as the consideration of material hardening.In order to further elaborate the GT model by means of Gaussian rough surface,by means of autocorrelation length and filter approach,the rough surface in the two-rough-surface model and the equivalent rough surface in single-rough-surface model were all obtained perfectly.By virtue of finite element method (FEM),the two-rough-surface model and the equivalent single-rough-surface model were developed and analyzed.The results show that the predicted contact stiffness and contact area by the two models have great agreements with each other,but the relationship between contact force and contact area is different.The distribution of equivalent stress and contact pressure predicted by the two models are roughly the same,but their amplitudes in two-rough-surface model are slightly lower than those in single-rough-surface model due to the effect of shoulder-to-shoulder contact,which weakens the contact status and material hardening.%基于统计学方法,Greenwood和Tripp(GT模型)提出双粗糙平面法向接触(双粗模型)可以等效为单粗糙平面与刚性平板之间的接触(单粗模型),但这种等效处理缺乏对接触应力场分析以及材料硬化的考虑.为进一步研究GT模型,基于高斯粗糙表面数字化表征,通过控制自相关长度和滤波方法,得到双粗糙平面及其等效单粗糙平面;借助有限元软件ABAQUS对2组模型法向接触进行建模及分析.结果表明:2组模型预测的接触刚度和接触面积符合较好,但接触压力与接触面积关系存在差异;2组模型预测的等效应力和接触压强的应力幅值以及云图的分布区域大致相近,但双粗模型由于存在大量微凸体侧接触,弱化接触状态以及材料硬化,因而应力幅值偏低.