分形表面形貌对应力集中系数的影响

THE EFFECT OF FRACTAL SURFACE TOPOGRAPHY ON STRESS CONCENTRATION FACTOR

提出了复杂表面形貌有限元建模的新方法,依据线弹性力学计算了分形W-M函数构造的表面形貌在不同测量尺度下的应力集中系数,分析了分形参数及轮廓谱矩参数与应力集中系数之间的关系.结果表明表面形貌对应力集中系数的影响与轮廓仪器分辨率密切相关,轮廓二阶谱矩能够反映表面形貌的应力集中程度,在分析表面形貌对结构疲劳特性的影响时需界定表面形貌的截止频率.

In this paper,a new method was proposed to build the finite element model of complex sur- face topography. Based on linear elastic mechanics, the stress concentration factors induced by surface to- pographies which are simulated by W-M fractal function were investigated under various degrees of meas- urement. And the relations between fractal parameters, profile moments and stress concentration factors were obtained. The results show that the stress concentration factor of fractal surface topography depends strongly on the resolution of the roughness-measuring instrument, the second profile moment can reflect the degree of stress concentration induced by surface topography, and the high frequency cut-off should be determined to evaluate the effect of surface topography on structural fatigue behavior.