宽带随机载荷下的疲劳寿命统一模型

针对宽带随机载荷下的疲劳寿命预测精度不足的问题，提出以变参数Weibull模型描述载荷峰值概率密度，而非以修正概率密度的误差函数的方式对疲劳寿命进行预测。首先，给出了一般宽带载荷峰值理论概率密度，用变参数Weibull模型实现了概率密度由窄带Rayleigh分布向宽带Gauss分布转变，并讨论了模型参数的范围；然后，根据变参数Weibull模型得到了疲劳寿命预测模型的解析表达；最后，通过实例计算了双峰宽带和连续宽带随机载荷下的疲劳寿命，并与其他疲劳寿命预测模型进行了精度比较。分析表明，所提出的疲劳寿命预测模型精度理论误差为9.68%，试验误差为12.5%，完全满足工程需要，本方法与Dirlik方法相比应用更方便。

Unified Model of Fatigue Life Under Wide-Band Random Load

In order to improve the poor prediction precision of fatigue life under a wide-band random load, a Weibull model with varied parameters is established to describe the peak value probability density without correcting the probability density error function. The fatigue life is predicted. The theoretical probability density of the peak value is first given and converted from Rayleigh distribution to Gauss distribution using the Weibull model with varied parameters. The range of the model parameters is also discussed. The theoretical expression of the prediction model of fatigue life is obtained according to the Weibull model with varied parameters. The fatigue lives under a wide-band random load with double peaks and under a continuous wide-band random load are calculated, and the accuracy of various models is compared. The results show that the theoretical error of the proposed modelis 9.68% and the experimental error is 12.5%, which satisfies engineering needs. In addition, the proposed method has a more convenient application compared withthe Dirlik method.