粗糙表面弹塑性微接触模型分析与改进

Analysis and improvement on elastic-plastic micro-contact model of rough surface

为了准确描述粗糙表面微接触特性,对比分析现有插值多项式类和幂指函数类微接触模型存在的不足,采用量纲归一化方法,提出一种考虑材料属性的弹塑性微接触改进模型.与现有模型相比,改进后的微接触模型在屈服临界点和全塑性临界点处具有良好的连续性和光滑性,且考虑了材料泊松比对最大接触压力因子的影响.结果表明:较经典的KE模型和Lin模型,提出的模型能够连续、光滑和单调地描述微接触特性;微凸体接触面积与材料泊松比无关,且不受最大接触压力因子取值的影响;微凸体的平均接触压力、接触载荷和接触刚度与材料泊松比相关,且与最大接触压力因子成正比.

The shortcomings of existing interpolation polynomial and power-exponential micro-contact models were compared and analyzed,in order to accurately describe the micro-contact characteristics of rough surfaces.An improved elastic-plastic micro-contact model considering the material properties was proposed using a normalization method.Compared with the existing models,the improved model has good continuity and smoothness at the yield critical and full plastic critical points,also taking into account the influence of material’s Poisson’s ratio on the maximum contact pressure factor.Results show that the proposed model can describe the micro-contact characteristics more continuously,smoothly and monotonously,compared with the classical KE model and Lin model;the contact area of asperity is independent of the Poisson's ratio of the material,and is not affected by the maximum contact pressure factor;and the average contact pressure,contact load and contact stiffness of asperity are related to the Poisson's ratio,which are also proportional to the maximum contact pressure factor.