粘着摩擦系数的分形几何研究

ON ADHESIVE FRICTION COEFFICIENT WITH FRACTAL GEOMETRY

计及作用于接触斑点上的切向力,通过比较作用于接触斑点上的法向弹性载荷与法向塑性载荷,确定了区分弹性接触与塑性接触区域的临界接触斑点面积.总的粘着摩擦系数被表示为弹性接触区与塑性接触区的粘着摩擦系数的组合.假设屈服压力及局部粘着摩擦系数不依赖于接触斑点且等于塑性接触区中的平均值,则总的粘着摩擦系数可用简单的表达式描述.分形几何参数及归一接触面积对于粘着摩擦系数的效应已通过算例表明,研究中,分别考虑了忽略与计及接触斑点的微粒问的相互作用,两种情况的结果完全不同.

Considering the tangential force applied on a contact spot, the critical area demarcating the elastic and plastic regimes is obtained by comparing the normal elastic load with the normal plastic load. The total adhesive friction coefficient is expressed as a combination of adhesive friction coefficients in elastic and plastic contact regime. Assuming that the yield pressure and the local adhesive friction coefficient are independent on the contact spot and equal to the average values in the plastic contact regimes, the total adhesive friction coefficient is given by simple formulae. Effects of fractal geometry parameters and normalized contact area on the adhesive friction coefficient are given by some calculated examples. Neglecting and considering the interaction between asperities are both involved in calculations, respectively, and different results are obtained.