表面微观形貌对疲劳强度影响的定量分析

利用原子力显微镜对表面定量测量的结果,通过建立有限元模型,分析了表面微观形貌表征参数对微应力集中的影响,研究了四种不同表面处理方式对lCrllNi2w2MoV不锈钢疲劳性能的影响。结果表明:各表征参数包括微缺陷温度、微缺陷的谷底半径和单峰平均间距对微压力集中都有影响,仅靠表面粗糙度参数无法真实反映表面微观形貌对微应力分布的影响;不同表面微观形貌所引起疲劳性能的变化与其表征参数的变化是一致的,利用表面形貌参数可以定量分析不同表面所导致的疲劳性能的改变。

Quantitative Analysis of the Effect of Surface Topography on Fatigue Strength

Micro surface topographies of four differently machined surfaces of lCrllNi2W2MoV stainless steel were quantitatively characterized by atomic force microscopy, and the effects of different characteristic parameters on micro-stress concentration and different micro topographies on fatigue strength reduction were analyzed using finite element methods. It is found that the characteristic parameters may affect the micro-stress concentration obviously and it is insufficient to use a single surface roughness parameter to represent the effects of surface quality on micro-stress distribution. The difference of the fatigue resistance between different surfaces can be perfectly correlated with the surface characteristic parameters, and it is reasonable to use them to analyze the change of fatigue performance caused by different surface fabrication.