提出一种基于实测应力数据的研究城市轨道车辆构架疲劳可靠性变化规律的方 法． 为了建立结构损伤与可靠性之间的关系，通过新型启发式算法拟合出每一日应力谱的 概率密度函数，进而基于统计分布特征推导了一种考虑载荷相互作用的概率累积损伤模 型;然后考虑到某一结构区域不同传感器结果的差异性，采用具有随机效应的 Wiener 过 程通过概率损伤统计量与马尔可夫链-蒙特卡洛方法求得结构可靠度随运营里程的总体 变化规律． 实测数据计算结果表明，提出的可靠性计算方法可以得到与工程经验相符的构 架疲劳可靠性结果．

A method for studying fatigue reliability variation of urban rail vehicle frame based on measured stress data was put forward． In order to establish the relationship between structural damage and reliability，firstly，a new heuristic algorithm was used to fit the probability density function of the stress spectrum for each day． And a probabilistic cumulative damage model considering load interaction was derived based on the statistical distribution of stress． Then，considering the difference of the results of different sensors in a certain structure area，the gene- ral variation law of structural reliability with operational mileage was obtained by using Wiener process with random effect based on Probabilistic Damage statistics and Markov chain-Monte Carlo method． The calculation results show that the reliability calculation method can obtain the fatigue reliability results of the frame which are consistent with the engineering experience．