Weibull分布参数估计值对细节疲劳额定强度的影响

将新材料、新工艺应用于民机结构设计时，细节疲劳额定强度（DFR）法仍是重要的评估方法。根据新型铝合金疲劳试验数据，全面分析了Weibull分布形状参数对DFR计算参数的影响；分析标准S-N曲线斜度参数对DFR的影响时，应考虑可靠性寿命的变化，采用低可靠度寿命计算曲线斜度参数可降低Weibull分布形状参数的影响；比较了采用不同分布参数估计值与传统上采用波音公司给定值进行DFR计算的差异。结果表明，对于通过符合性检验的试验数据，使用不同Weibull分布的参数估计值计算得到的DFR都大于按传统方法（用波音公司给定值）的计算结果，其中，三参数Weibull分布计算的DFR最大，至少增加10%以上。

Influence of parameter estimates of Weibull distributions on detail fatigue rating

When applying new materials and new processes to the structural design of civil aircraft, the Detail Fatigue Rating (DFR) method is still an important evaluation method. According to the fatigue test data of the new aluminum alloy, the influence of shape parameters of Weibull distributions on the DFR calculation parameters is comprehensively analyzed. When analyzing the influence of the slope parameter of standard S-N curves on the DFR, the change of the reliability life should be considered, and this influence of can be reduced by calculating the value of low reliability life. The differences between the DFR calculation based on different distribution parameter estimates and that based on the traditional Boeing’s given values are compared. The results show that for the experimental data that passed the conformity test, the DFR calculated by using the parameter estimation values of different Weibull distributions is greater than that calculated by the traditional method with the given value of Boeing Company. Among them, the DFR calculated by three parameter Weibull distribution is the largest, increasing by at least 10%.