基于传统的M-B 模型，在考虑微凸体弹塑性变形的基础上，应用更能符合结合面实际表面形貌的修正的W-M 函数，建立了三维分形结合面法向刚度模型． 通过建立的刚
度模型研究了分形尺度参数和分形维数对法向接触刚度的影响，并对出现的一些现象进行了分析． 随着法向载荷与材料特性参数σy /E 的增加，结合面的法向刚度也增加; 但随着分形尺度参数的增加，结合面的法向刚度却减小; 随着分形维数的增加，当2. 1≤ D ≤2. 6 时，结合面法向刚度增加，而当2. 6≤ D ≤2. 9 时，结合面的法向刚度却减小; 在考虑弹塑性变形的情况下，三维分形结合面的法向刚度要小于二维分形结合面的法向刚度．

On the basis of the traditional M-B model,a three-dimensional fractal model of normal contact stiffness of joint surface is constructed by taking into account the elastic-plastic deformation of micro-bulge and by using the modified W-M function which can better describe the actual surface topography of joint surface.Then,the influences of the fractal scale parameters and the fractal dimension on the normal contact stiffness are investigated through the constructed model,and some phenomena are analyzed.The results show that ( 1) the normal stiffness of joint surface increases with the normal load and the material parameters σy /E ,while it decreases with the increase of the fractal scale parameters; ( 2) with the increase of the fractal dimension,the normal stiffness of joint surface increases when 2. 1≤ D ≤2. 6 but it decreases when 2. 6≤ D ≤2. 9; and ( 3) the normal contact stiffness of the constructed three-dimensional fractal model is less than that of the two-dimensional fractal model with the elastic-plastic deformation.