疲劳强度-寿命关系的概率密度演化方法  

Probability density evolution method of fatigue strength-life relationship

作　　者：徐亚洲[1] 白国良[1] 

机构地区：[1]西安建筑科技大学土木工程学院,西安710055

出　　处：《振动与冲击》2013年第8期35-38,共4页Journal of Vibration and Shock

基　　金：国家自然科学基金(51208410)

摘　　要：基于疲劳强度随加载循环次数增加不断劣化的物理事实,采用Euler描述推导出疲劳强度与随机参数联合概率密度函数满足的演化方程。采用数值求解方法,给出疲劳强度-寿命概率密度曲面(probability density S-N),并可据此计算给定存活率的p-S-N曲线。基于疲劳试验结果的算例分析表明,疲劳强度-寿命概率密度曲面、MonteCarlo模拟及具有给定分位数参数的S-N关系三者计算的p-S-N曲线吻合良好。疲劳强度-寿命概率密度演化方法可不依赖分布假定给出S-N关系的完备概率描述。Taking degradation of fatigue strength with increase in loading cycles into account, the joint probability density evolution equation of fatigue strength and random factors was derived using Euler description. A probability density S-N （p-S-N） surface was obtained with a numerical method, it was used to calculate the p-S-N curve with a given survivability. The analysis based on experimental fatigue data indicated that p-S-N curves with 95 % survivability predicted by p-S-N, Monte Carlo simulation and S-N relation ship having parameters with a given fractile agree well ; p-S-N provides a complete probability description of S-N relationship, independent of a probability distribution assumption.

关 键 词：疲劳强度 疲劳寿命 概率密度演化 p—S-N 

分 类 号：TU318[建筑科学—结构工程]