基于分形理论的结合面微观接触特性分析

摘要

In order to study the micro-contact characteristics,a rough surface model based on fractal theory is presented to research the coupling mechanism of the approaching contact surfaces.The simulated analysis of the contact between a rough surface and a smooth surface was performed,which showed the influence mechanism of fractal dimension,surface roughness and displacement load on the micro-contact process.Then,a method for detecting the contact of rough surfaces based on the laser surface acoustic wave was proposed and verified through experiments.The results show that the morphology of the asperity is the decisive factor for the mechanical contact performance;the real contact area is much smaller than the nominal one.In engineering fields,the calculation of the bearing capacity using the nominal contact area will have a large deviation from the actual situation.%为了研究结合面微观接触特性,基于分形理论,建立粗糙表面轮廓模型,进行结合面接触趋近耦合研究.通过二维粗糙表面与光滑表面微观接触趋近过程的仿真分析,研究分形维数、表面粗糙度、位移栽荷对结合面接触状态的影响机理.提出利用激光声表面波检测粗糙结合面接触的方法,并进行了实验验证.研究结果表明,粗糙表面微凸体形貌是决定材料接触性能的关键因素;微凸体接触形成的真实接触面积远小于名义接触面积.工程问题中,通过名义接触面积计算出的载荷与材料表面实际承受的载荷存在较大差异.