计及摩擦的球面弹塑性分形模型与应用

A fractal model of spherical elastoplastic contactors with friction and its application

为了研究球面接触微凸体的弹塑性变化规律,在M-B分形模型的基础上考虑基底直径的实际变化情况,引入摩擦力修正因子,并基于修正的球面接触基底直径密度分布函数,最终建立了考虑摩擦因素的球面弹塑性分形模型;并以两球体接触为研究对象,分析了模型中的相关变量对接触强度的影响规律。仿真分析结果表明:当载荷不变时,分形维数的增加会导致真实接触面积先保持不变后增大再减小;当分形维数在1.35~1.7区间时,接触面积上升的速度最快;增大摩擦系数或降低材料特性参数,有利于提高接触承载能力;粗糙度幅值参数对真实接触面积和弹性接触面积占比的影响大略一致;当粗糙度幅值增加时,真实接触面积和弹性接触面积占比都随之降低。

In order to study the elastoplastic variation law of spherical contact micro protrusions,based on the M-B fractal model,the friction correction factor is introduced by considering the actual variation of the substrate diameter;and by employing the modified spherical contact base diameter density distribution function,an improved spherical elastoplastic fractal model considering friction factors is finally established.The two spheres are taken as the research object,and the influence of relevant variables on the contact intensity is analyzed.The results show that when the load is constant,the increase of the fractal dimension causes the real contact area to remain unchanged first,then increase and then decrease.When the fractal dimension is in the range of 1.35~1.7,the rising speed of contact area is the fastest;increasing the friction coefficient or reducing the material property parameters is beneficial to improve the contact bearing capacity;the roughness amplitude parameter has a similar influence on the real contact area and the elastic contact area ratio.As the roughness amplitude increases,both the true contact area and the elastic contact area ratio decrease.