基于车桥耦合随机振动分析的钢桥疲劳可靠度评估

发布时间：2018-10-30 19:18

【摘要】：发展了一种基于车桥耦合系统随机振动分析的铁路钢桥疲劳可靠度评估方法,建立车桥耦合系统模型,选取车速和轨道不平顺作为基本随机变量进行随机振动分析,以此确定桥梁构件等效疲劳应力幅及其循环次数的概率模型。在此基础上,建立基于S-N曲线法的疲劳极限状态函数并进行疲劳可靠度分析。以一座铁路下承式钢桁梁桥为例进行了疲劳可靠度评估,并讨论了车速及轨道平顺性对构件疲劳可靠性的影响。结果表明:该文方法可有效用于铁路钢桥疲劳可靠度评估;受车速及轨道不平顺随机性的影响,列车引起的桥梁构件等效疲劳应力幅及其循环次数均具有一定的不确定性,应视为随机变量,二者可采用对数正态分布表示;车速和轨道不平顺可显著影响桥梁构件的疲劳可靠性,疲劳关键构件的可靠度指标随着轨道平顺性增强而提高。
[Abstract]:Based on the random vibration analysis of vehicle-bridge coupling system, a fatigue reliability evaluation method of railway steel bridge is developed. The model of vehicle-bridge coupling system is established, and the speed and track irregularity are selected as basic random variables for random vibration analysis. The probability model of equivalent fatigue stress amplitude and cycle number of bridge member is obtained. On this basis, the fatigue limit state function based on S-N curve method is established and the fatigue reliability is analyzed. The fatigue reliability of a railway through steel truss bridge is evaluated and the influence of speed and track comfort on the fatigue reliability is discussed. The results show that this method can be used effectively to evaluate the fatigue reliability of railway steel bridges. Under the influence of speed and track irregularity, the equivalent fatigue stress amplitude and cycle times of bridge members caused by train have certain uncertainty and should be regarded as random variables, which can be expressed by logarithmic normal distribution. Speed and track irregularity can significantly affect the fatigue reliability of bridge members, and the reliability index of key fatigue components increases with the increase of track ride comfort.
【作者单位】：东南大学土木工程学院;北京交通大学土木建筑工程学院;
【基金】：国家重点基础研究发展计划973项目(2013CB036203) 国家科技支撑计划项目(2014BAK11B04)
【分类号】：U441;U448.36

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