服从不同分布的疲劳寿命分散系数分析

民机结构的疲劳寿命服从双参数威布尔分布,其分散系数与战斗机基于对数正态分布的疲劳寿命分散系数存在明显的不同.为分析疲劳寿命服从这两种不同分布时分散系数的区别和联系,导出了疲劳寿命服从双参数威布尔分布时的理论和试验用疲劳寿命分散系数计算公式;并从理论基础和数值计算结果两个方面,对服从对数正态分布和双参数威布尔分布的疲劳寿命分散系数进行了对比,所得的结论对确定民机结构疲劳寿命分散系数提供了重要的技术依据.

On Scatter Factors of Fatigue Life Obeying Different Distributions

The fatigue life of civil aircraft structures obeys two parameter Weibull distribution,its scatter factor is significantly different from that obeys logarithm normal distribution .To analyze the difference and relation of these two scatter factors,the scatter factor formulas of fatigue life which obeys two parameter Weibull distribution are presented for theoretical calculation and fatigue testing and the values of scatter factors for different materials are given. Comparison efforts between scatter factors obeying these two distributions are conducted theoretically and numerically. The result provides the important technological approach in determining the fatigue scatter factor of the civil aircraft structures.