腐蚀环境下的随机耐久性分析方法

Stochastic Crack Growth Approach under Corrosive Environment for Durability Analysis

为了对恶劣环境下工作的飞机结构进行耐久性分析 ,建立了腐蚀环境下的随机耐久性分析方法 .假设地面停放预腐蚀和空中飞行腐蚀疲劳相互独立 ,腐蚀环境下的结构疲劳质量服从威布尔分布 ,采用对数正态随机变量模型描述裂纹扩展过程 ,得到了裂纹超越概率的表达式 .通过与一般环境下和腐蚀环境下的概率断裂力学方法的对比 ,证实方法更接近于飞机结构的真实使用情况 。

In order to analyze the aircraft structural reliability under corrosive environment, stochastic crack growth approach (Cor SCGA) for durability analysis is established. Assuming the influence of the pre corrosion in park and the influence of corrosion in flight are independent, the fatigue quality of structure under corrosive environment has a Weibull distribution. Using a log normal stochastic variable model to describe crack propagation, an equation for predicting the probability of crack exceedance is established. Compared with the probability fracture mechanics approach under corrosive environment (Cor PFMA) and probability fracture mechanics approach under normal environment (Nor PFMA), Cor SCGA is more efficient. This approach will be better used for durability based design.