新的粗糙表面弹塑性接触模型

NEW ELASTIC-PLASTIC MODEL FOR THE CONTACT OF ROUGH SURFACES

提出一种新型的粗糙表面弹塑性微观接触模型。该模型的建立基于接触力学理论和接触微凸体由弹性变形向弹塑性变形及最终向完全塑性变形的转化皆是连续和光滑的假设。研究单个微凸体在载荷逐渐增加时的变形规律,并重点推出弹塑性变形区间的接触方程。在此基础上应用概率统计理论导出了粗糙表面的接触载荷、平均分离和实际接触面积之间的数学关系式。在不同的塑性指数和载荷条件下,该模型与GW弹性模型和CEB弹塑性模型就实际接触面积和法向距离的预测结果进行了对比。结果表明,在同样塑性指数和载荷条件下比GW模型预测的实际接触面积大但法向距离小,且两者的差距随塑性指数和载荷的增加而增大。因此该模型的预测结果更加符合人们的试验观察和直觉,能够更加科学和合理地描述两个粗糙表面的微观和宏观接触状态。

A new elastic-plastic model for the contact of rough surfaces is presented. The model is developed based on contact mechanics and the assumption that the transitions from elastic, through elastic-plastic, to fully plastic deformation of a contacting asperity is continuous and smooth. The deformation behavior of a single contacting asperity is firstly modeled in detail, particularly, for the elastic-plastic deformation. The contact between the two rough flat surfaces is then modeled by using probability theory. The model developed is compared with the GW elastic model and CEB elastic-plastic model on their predicted real contact area and mean separation for a wide range of contact load and plasticity index. It is shown that the present model predicts larger real contact area and smaller mean separation than GW model under the same contact load and plasticity index. Besides, the difference of the predicted results based on the present model and GW model increases with the contact load and plasticity index. The comparison results strongly indicate that the present model is consistent with experimental observation and physical intuition, and is more reasonable in describing the contact behavior between rough surfaces.