采用缺口件等效与渐进插值法预测构件疲劳极限

以发动机曲轴为例,以等效椭圆孔板长轴长度、短轴长度及均布载荷为变量,采用拟合方法使等效椭圆孔板的应力集中处应力场与曲轴受载荷时应力集中处的应力场尽可能一致,将曲轴应力集中等效为标准椭圆孔缺口件.通过等效处理,曲轴疲劳极限载荷的求解问题可以转换为椭圆孔缺口件的疲劳极限求解问题,结合已有曲轴的疲劳强度试验数据得出该曲轴材料的特征尺寸,采用渐进插值法结合短裂纹扩展理论,推导出预测曲轴的疲劳极限载荷.

Component fatigue limit prediction based on notched specimen equivalence and asymptotic interpolation integrated method

An integrated method of notched specimen equivalence and asymptotic interpolation to predict component fatigue limit was put forward.The engine crankshaft was given as an example,the length of long axis,length of short axis and the uniform load of the equivalent elliptic orifice plate were taken as variables,and the fitting method was used to make the stress field of the crankshaft stress concentration range under load and the stress field of the equivalent elliptic orifice plate stress concentration range as consistent as possible.By this way,the fatigue limit load of the crankshaft can be simplified into that of the equivalent elliptic orifice plate.The feature size of crankshaft material can be reasoned with the experimental data,the fatigue limit load of crankshaft can then be predicted using an asymptotic interpolation method and the short crack growth theory.