腐蚀疲劳裂纹扩展的马尔可夫链模型及实验验证  

Markov Chain Model of Corrosion Fatigue Crack Growth and Its Experimental Verification

作　　者：石伯妹[1] 吕国志[1] 张有宏[1] 李仲[1,2] 

机构地区：[1]西北工业大学航空学院 [2]中国飞机强度研究所,西安710065

出　　处：《科学技术与工程》2007年第19期5182-5185,共4页Science Technology and Engineering

摘　　要：在腐蚀环境下对LY12CZ铝合金试验件进行疲劳裂纹扩展实验,通过高倍显微镜观测并记录裂纹长度及相应的循环数。基于腐蚀条件下疲劳裂纹扩展数据的分散性及统计特性,提出用马尔可夫链模型模拟腐蚀疲劳裂纹的扩展,建立腐蚀疲劳裂纹扩展规律的概率模型,得到给定疲劳寿命时的裂纹超出数概率分布和给定裂纹长度时的疲劳寿命累积概率分布。将模拟结果与实验结果进行比较表明:马尔可夫链模型能够相当好地描述腐蚀疲劳裂纹扩展规律,为飞机结构的寿命预测提供参考。Experimental work is carried out to study the problems of fatigue crack growth under corrosion conditions. Due to the scatter and statistical nature of corrosion fatigue crack growth data, a rather universal stochastic Markov chain model is employed to analyze the data. The model gives us the crack exceedance probabilities of random crack size as well as the cumulative distributions of random loading cycle to reach a specified crack size. Through comparison between the analytical results and experimental data, it is found that the model can fit the experimental data rather well. It can be used for the prediction of fatigue life of aircraft structures made of the tested material.

关 键 词：腐蚀 疲劳 裂纹扩展 马尔可夫链 

分 类 号：V216.3[航空宇航科学与技术—航空宇航推进理论与工程] O346.21[理学—固体力学]