改进的连续尺度分形-离散Iwan黏滑接触力学建模

Modeling of Stick-Slip Contact Mechanics Based on Improved Continuous-Scale Fractal-Discrete Iwan Model

零件配合面接触状态是影响高精密产品装配精度的关键因素,而分形-Iwan耦合模型是描述典型配合面黏滑接触的一套行之有效的方法.但现有基于MB的分形-Iwan耦合模型认为所有微凸体发生完全变形,且全局共用一个常量弹塑性临界面积,导致模型对小触点的法向力计算存在偏差.为此,建立了改进的分形-离散Iwan黏滑接触力学模型,提出了一种连续尺度的分形表面凸体分布函数,得到了具有尺度依赖关系的临界面积表达式.基于上述改进的耦合模型,探究了切向载荷作用下的粗糙接触界面滞回特性,获得了接触面几何形貌、接触压力对界面切向力的影响规律.将得到的滞回曲线与文献实验结果进行对比,验证了所提出的改进分形-离散Iwan耦合模型的准确性.

Influencing the assembly precision of high-precision products,the contact state of product mating sur-faces is taken as a crucial factor,and a fractal-Iwan coupling model is provided usually as an effective approach to describe stick-slip contact between typical mating surfaces.In order to solve the deviation problem of the nor-mal force calculation on small contacts with existing fractal-IWAN coupling model based on MB,caused by con-sidering all micro-convex bodies been deformed completely and shared a constant elastic-plastic critical area globally,an improved fractal-discrete Iwan stick-slip contact mechanical model was established and a continu-ous scale fractal convex distribution function was proposed,obtaining a scale-dependent critical area expression.Based on the improved coupling model,the hysteretic characteristics of the rough contact interface were invest-igated under tangential load,obtaining the influence of contact surface geometry and contact pressure on the in-terface tangential force.Comparing the hysteresis curves with experimental results in the literature,the accuracy of the improved fractal-discrete Iwan coupling model was verified.