界面分形参数对法向接触刚度影响的研究

基于最小二乘法将分形表面简化为三角函数的叠加，采用弹塑性有限元方法计算界面的接触刚度，定量表征了法向接触压力、法向接触变形及法向接触刚度的关系，研究结果揭示了粗糙面分形维数和特征尺度参数对法向接触刚度的影响机制。结果表明:存在基体最优建模厚度，可有效提高粗糙面接触刚度的计算效率；法向接触刚度随法向接触变形及法向接触压力的增加呈现非线性增加趋势；表面分形维数和特征尺度参数对法向接触刚度影响显著，法向接触刚度随分形维数增加而增加，但随特征尺度参数增加而减小。

EFFECTS OF INTERFACE FRACTAL PARAMETERS ON NORMAL CONTACT STIFFNESS

In this study, the complex rough surface is simplified as the superposition of a series of trigonometric curves based on the least square method. In order to calculate the interface contact stiffness, the optimal substrate modeling thickness is determined by the elastic-plastic finite element method. The relationship between normal contact pressure and normal contact deformation and normal contact stiffness is quantitatively investigated. The mechanism of fractal dimension and characteristic scale parameters of rough surface on normal contact stiffness is revealed. The results show that there is an optimal thickness of the substrate, which can effectively improve the calculation efficiency of the contact stiffness of the rough surface. The normal contact stiffness increases nonlinearly with the increase of normal contact deformation and normal contact pressure. The surface fractal dimension and characteristic scale parameters have significant effects on the normal contact stiffness, and the normal contact stiffness increases with the increase of the fractal dimension. However, the normal contact stiffness decreases with the increase of characteristic scale parameters.