复杂结构部件概率疲劳寿命预测方法与模型

针对多部位损伤(MSD)复杂结构部件的疲劳寿命预测问题,通过定义损伤临界值随机变量,分析、讨论了寿命概率分布、损伤概率分布、损伤临界值概率分布的属性及其之间的关系,研究了概率损伤累积原理,提出确定累积损伤临界值概率分布的方法,建立了概率累积损伤准则。基于多层次统计分析技术和系统层可靠性建模原理,构建了复杂结构部件的概率寿命预测模型;通过各关键部位的损伤累积和结构系统的失效概率计算,实现了复杂结构部件概率疲劳寿命预测,通过典型算例展示了方法及模型的应用。

Probabilistic fatigue life prediction method and modeling for complex structural parts

Aimed at the probabilistic fatigue life prediction of multi-site damage (MSD) structural components, critical damage random variable is defined, the properties of life distribution, damage distribution and critical damage distribution are analyzed, and the relationship between these distribution functions are discussed. Besides, the present paper investigates probabilistic cumulative damage principle, presents a method to determine the probability density function of critical damage and develops probabilistic cumulative damage rule. Probabilistic fatigue life prediction model of MSD structural components is established based on multi-level statistics and system-level reliability modeling technique. Probabilistic fatigue life of an MSD structural component can be predicted through cumulative damage calculation of each damage site and the calculation of system failure probability. A case study is provided to illustrate the application of the method and related model.