随机载荷作用下疲劳寿命分布预测模型  

Prediction on probability distribution of fatigue life under spectrum loading

作　　者：武滢[1] 谢里阳[1] 

机构地区：[1]东北大学机械工程与自动化学院,辽宁沈阳110819

出　　处：《工程设计学报》2010年第6期435-438,共4页Chinese Journal of Engineering Design

基　　金：国家高技术研究发展计划(863计划)资助项目(2007AA04Z428);中央高校基本科研业务费专项资金资助项目(N090603005)

摘　　要：为了研究构件在随机载荷下的疲劳寿命分布,建立疲劳寿命分布预测模型.应用雨流计数法,将随机载荷-时间历程处理成以载荷幅值和均值为随机变量的二维联合概率密度函数,得到构件的二维疲劳载荷谱.从Miner累积损伤的定义出发,分析了累积损伤分散性的来源.以此为基础,通过建立等幅疲劳中值Sa-Sm-N曲面,提出了基于二维载荷谱的疲劳寿命分布预测模型,当累积损伤的概率分布已知时,可以估算出构件的疲劳寿命分布,进而得到零件在任一时刻的可靠度.最后,给出了一个具体应用实例.结果表明所提出的疲劳寿命分布预测方法具有较好的工程实用价值.In order to analyze fatigue life distribution under random loading,a new fatigue life distribution prediction model was established.Using rainflow method,the range and mean of random load were regarded as two random variables in two-dimensional fatigue load spectrum which was gained by rainflow method.Joint probability density function of two-variables was built up on the statistical analysis of load histories.Based on the definition of Miner cumulative damage theory,the causes of scattering of the cumulative damage were analyzed.The function of constant amplitude median Sa-Sm-N surface was established.According to statistical property analysis of Miner cumulative damage rule,probability distribution of fatigue life based on two-dimensional load spectrum was predicted.When the probability distribution of the cumulative damage was known,the fatigue life distribution could be predicted.Furthermore,component reliability at any pointed time could be available.In the end,an example of application was presented.The result shows that the above method is quite effective in prediction of the distribution of fatigue reliability analysis for engineering structures.

关 键 词：二维疲劳载荷谱 等幅中值Sa-Sm-N曲面 Miner线性累积损伤准则 疲劳寿命分布 

分 类 号：O346.2[理学—固体力学] TB114.3[理学—力学]