粗糙机械结合面的接触刚度研究

Contact Stiffness of Rough Mechanical Joint Surface

为准确进行计入粗糙接触界面影响的组合结构动力分析,基于弹塑性理论对具有粗糙表面的长方微元体进行有限元接触分析,给出了根据受力和变形关系计算粗糙表面接触刚度的方法,得到了不同载荷作用下的法向和切向界面接触刚度.计算结果表明:表面形貌造成的接触应力分布不均匀和局部塑性变形导致法向界面接触刚度随着压力的增加先增大后减小,并随着表面粗糙度的增加而降低;切向界面接触刚度随着法向载荷和摩擦系数的增加而增加,随着切向载荷的增加而减小.当切向载荷增加到一定值时,接触界面将由微观滑移转化为宏观滑动,摩擦界面连接失效.

To accurately analyze the dynamic characteristics of combined structure considering the effects of rough interface, the cuboid finite element contact model with rough surface is considered based on elastic-plastic theory, and the method for calculating contact stiffness of rough surface is given according to the relationship between force and deformation, then the normal and tangential interface contact stiffness under different loads is obtained. The results show that normal interface contact stiffness increases firstly and then decreases with the increasing pressure, and decreases with the increasing surface roughness because of uneven distribution of contact stress and localized plastic deformation due to surface topography. The tangential interface con- tact stiffness increases with the increasing normal load and friction coefficient, and decreases with the increasing tangential load. When tangential load increases at a certain level, the micro-slip of contact interface changes into macro-sliding, and the friction interface connection becomes invalid.