磨合表面形貌变化的分形表征

用结构函数法计算磨损表面轮廓的分形维数和尺度系数。研究表明 :分形维数或尺度系数不能实现表面的唯一性表征。因此 ,把分形维数和尺度系数相结合 ,提出一个新的分形参数———特征粗糙度 ,给出了其定义和计算表达式 ,并在推进式试验机上进行摩擦磨损试验 ,对试件表面某一位置在不同磨合阶段的形貌进行精确复位测量 ,用特征粗糙度表征形貌的变化。表征结果表明 :特征粗糙度对反映磨合表面形貌的变化不但表现出很好的灵敏性 ,而且比分形维数更具有规律性。

CHARACTERIZATION OF SURFACE TOPOGRAPHY DURING RUNNING-IN PROCESS WITH FRACTAL PARAMETER

Fractal dimension and scale coefficient of surface profiles are calculated using structure function method. Studies show that there is the imperfection of fractal dimension or scale coefficient in characterizing rough surfaces. In consideration of this case, combing profile fractal dimension and scale coefficient puts a new fractal parameter called characteristic roughness forth. Its definition and calculation expression are given. Friction and wear tests were conducted by using thrust type tester and surface topographies were measured in the same place of the test specimen at different wear time. It's found that it is not only more sensitive but also more regular for characteristic roughness to characterize rough surface during running-in process than fractal dimension or scale coefficient to do.