界面损耗因子与法向阻尼的计算方法

基于赫兹法向接触力学方程与分形几何学理论对界面法向接触刚度进行分析,在改进原有计算模型的基础上,推导出界面法向接触刚度、损耗因子和法向接触阻尼计算方程.结果表明,所提出的计算方法能够较好地预测法向接触刚度、损耗因子和法向接触阻尼的变化规律.减小分形粗糙度和增大法向接触荷载均会使得法向接触刚度增大,而且随着分形维数的增大,法向接触刚度呈现出先增后减的变化趋势;增大分形粗糙度和降低法向接触荷载都会使得损耗因子升高,且损耗因子随着分形维数的增大而呈现出先减后增的变化趋势,当分形维数趋近于2时,损耗因子收敛于某一定值;法向接触阻尼随着分形维数的增大也呈现出先减后增的变化趋势,且其变化过程出现了2个拐点.当分形维数低于第1个拐点值时,法向接触阻尼随着分形粗糙度的增加而增大;当分形维数超过第1个拐点值时,法向接触阻尼随着分形粗糙度的增加而减小;当D≤1.4时,法向接触阻尼随着法向接触荷载的增大而减小;当D1.4时,法向接触阻尼随着法向接触荷载增大而增大.

Calculating Method of Surface Dissipation Factor and Normal Damping

Abstract： Calculating equations of surface normal contact stiffness, loss factor and normal contact damping were explored based on the Hertz normal contact mechanics expression and the fractal geometry theory analyzing surface normal contact stiffness, by improving the previous calculating model. The results reveal that the calculating method proposed can better predict the changing laws of normal contact stiffness, loss factor and normal contact damping. The normal contact stiffness increases by decreasing the fractal roughness and increasing the normal contact load, and it increases at first and then decreases with the increase of fractal dimension. Enhancing the fractal roughness and reducing the normal contact load both make the loss factor ascend which decreases first and then increases with the increase of fractal dimension. The loss factor converges to a certain definite value as the fractal dimension approaches 2. The normal contact damping lessens first and whereafter aggrandizes with the augment of fractal dimension, and there exist two inflexions in the variable process. When the fractal dimension is smaller than the first inflection value, the normal contact damping increases with the increase of fractal roughness. When the fractal dimension is in excess of the first inflection value, the normal contact damping decreases with the increase of fractal roughness. The normal contact damping decreases with the increase of normal contact load for D≤1.4. The normal contact damping increases with the increase of normal contact load for D>1.4.