Xiao Yuanjie, Chang Zhenxing, Mao Jianfeng, Zhou Sijia, Wang Xiaoming, Wang Weidong, Cai Degou, Zhu Hongwei, Long Yao
School of Civil Engineering, Central South University, Changsha 410075, China.
Ministry of Education Key Laboratory of Engineering Structures of Heavy Haul Railway, Central South University, Changsha 410075, China.
Materials (Basel). 2022 Apr 5;15(7):2675. doi: 10.3390/ma15072675.
Rail fasteners are among the key components of ballasted track of high-speed railway due to their functionality of fixing rails to sleepers. The failure of rail fastening system hinders the transmission of train loads to underlying track substructure and therefore endangers the operation safety and longevity of ballasted track. This paper first established a three-dimensional (3D) numerical model of the train-ballasted track-subgrade coupling system by integrating multibody dynamics (MBD) and finite element method (FEM). Numerical simulations were then performed to investigate the effects of different patterns of rail fastener failure (i.e., consecutive single-side, alternate single-side, and consecutive double-side) on critical dynamic responses of track structures, train running stability, and operation safety. The results show that the resulting influences of different patterns of rail fastener failure descend in the order of consecutive double-side failure, consecutive single-side failure, and alternate single-side failure. As the number of failed fasteners increases, the range where dynamic responses of track structures are influenced extends, and the failure of two consecutive single-side fasteners exerts a similar influence as that of four alternate single-side fasteners. The failure of single-side fasteners affects dynamic responses of the intact side of track structures relatively insignificantly. The influence of rail fastener failure on track structures exhibits hysteresis, thus indicating that special attention needs to be paid to locations behind failed fasteners during track inspection and maintenance. The occurrence of the failure of two or more consecutive fasteners demands timely maintenance work in order to prevent aggravated deterioration of track structures. The findings of this study could provide useful reference and guidance to smart track condition assessment and condition-based track maintenance.
轨道扣件因其将钢轨固定在轨枕上的功能而成为高速铁路有砟轨道的关键部件之一。轨道扣件系统的失效会阻碍列车荷载向下传递至轨道下部结构，从而危及有砟轨道的运营安全和使用寿命。本文首先通过集成多体动力学（MBD）和有限元方法（FEM）建立了列车-有砟轨道-路基耦合系统的三维（3D）数值模型。然后进行数值模拟，研究不同模式的轨道扣件失效（即连续单侧、交替单侧和连续双侧）对轨道结构关键动力响应、列车运行稳定性和运营安全的影响。结果表明，不同模式的轨道扣件失效所产生的影响按连续双侧失效、连续单侧失效和交替单侧失效的顺序递减。随着失效扣件数量的增加，轨道结构动力响应受影响的范围扩大，连续两个单侧扣件失效与四个交替单侧扣件失效产生的影响相似。单侧扣件失效对轨道结构完好侧的动力响应影响相对较小。轨道扣件失效对轨道结构的影响呈现滞后性，因此表明在轨道检查和维护过程中需要特别关注失效扣件后方的位置。两个或更多连续扣件失效的发生需要及时进行维护工作，以防止轨道结构恶化加剧。本研究结果可为智能轨道状态评估和基于状态的轨道维护提供有益的参考和指导。
