基于跨阈持时的结构疲劳可靠性分析  

Stuctural fatigue reliability analysis based on the duration of stochastic process crossing threshold

作　　者：张振浩 李文彪 ZHANG Zhenhao;LI Wenbiao(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114.China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114

出　　处：《工程建设》2022年第4期1-7,共7页Engineering Construction

基　　金：长沙理工大学研究生创新实践项目(SJCX202131)。

摘　　要：随机响应过程的多次跨阈分析是结构疲劳可靠性评估的一个关键问题,具有重要的理论价值和现实意义。本文以工程中某些具有Wiener特征的结构应力随机过程为研究对象,在Wiener过程多次跨阈概率分析的基础上,建立了考虑随机响应过程跨阈持时的结构疲劳累积损伤及可靠性分析方法。首先,基于累积损伤与跨阈持时之间的关系,推导了考虑Wiener型随机响应跨阈持时的结构疲劳累积损伤指数。然后,将疲劳累积损伤过程建模为带漂移的Wiener过程,以典型应力-时间谱块为基础推导了Wiener过程的漂移系数μ和扩散系数σ。最后,将任意时刻T下的累积损伤指数建模为服从均值为μT,方差为σ^(2) T的正态分布,并与临界疲劳累积损伤指数建立极限状态方程利用JC法求解疲劳可靠度。采用本文方法对某地铁转向架关键部位不同运营时间下的疲劳可靠度进行了分析,验证了本文算法的正确性。The multiple cross-threshold analysis of the random response process is a key problem in the fatigue reliability assessment of structures,which has important theoretical value and practical significance.In this paper,on the basis of the Wiener process multiple times across threshold probability analysis,a method for fatigue cumulative damage and reliability analysis of the structure considering the random response process duration crossing threshold is established,taking as research object the certain structural stress random processes with Wiener characteristics in engineering.First,based on the relationship between the accumulated damage and the crossing-threshold duration,the fatigue accumulated damage index of the structure considering the random response crossing-threshold duration is derived.Then,the fatigue cumulative damage process is modeled as a Wiener process with drift,and the driftμand diffusion coefficientsσof the Wiener process are derived based on a typical stress-time spectrum block.Finally,the cumulative damage index at any time T is modeled as a normal distribution with meanμT and variance σ^(2)T,and the limit state equation is established with the critical fatigue cumulative damage index to solve the fatigue reliability using the JC method.The fatigue reliability of key parts of a subway bogie under different operating hours is analyzed by using the method of this paper,and the correctness of the algorithm in this paper is verified.

关 键 词：疲劳可靠度 WIENER过程 跨阈持时 累积损伤 交叉次数 蒙特卡洛 

分 类 号：U260.331[机械工程—车辆工程]