To investigate the vehicle-induced fatigue damage evolution of fastener clips and their impact on the vehicle-track (VT) system, a numerical dynamic model is established to achieve probabilistic evaluation. The “rain flow” counting method is adopted to describe the stress cycles of the hazard area of the clips, and the S-N curve is used to predict the fatigue life of the clips. The solution of the dynamic equation of motion is obtained by the time-domain Green's function method, which is an effective method to improve computational efficiency. A versatile iterative algorithm is adopted to solve the nonlinear system considering the damaged clips. In the probabilistic evaluation framework, a novel random field method is employed to depict the spatial variability of clips’ strength. The applicability of the model established in this work in aspects of expressing random damage of fasteners and evaluating the dynamic behavior of the system is demonstrated by different numerical examples. The results show that the dynamic responses of the train and track system significantly exacerbate as the number of train cycles increases, which is closely related to the variability and non-uniform damage of the fasteners. The probability of cumulative damage to the fasteners induced by the train follows a three-stage rule, and the fatigue damage of the non-uniform fastener system caused by the train is greater than that of the uniform situation. In addition, the short wave components of track irregularity will significantly exacerbate the damage to fasteners and therefore degrade the status of the railway line. As the driving speed increases, the damage to the fasteners also increases, but the impact of vehicle speed on the fastener damage is smaller than that of track irregularity, especially in the range of fatigue damage greater than 0.9. Therefore, maintaining the geometric smoothness of the track, controlling the uniformity of the mechanical properties of the fasteners, and reducing the driving speed are feasible measures to extend the service life of the fastener system, thereby ensuring the operation of high-speed trains.

中文翻译：

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高速铁路扣件疲劳对车轨动力相互作用的影响：数值分析与概率评估


为了研究紧固件夹子的车辆引起的疲劳损伤演化及其对车辆-轨道（VT）系统的影响，建立了数值动态模型以实现概率评估。采用“雨流”计数法描述夹子危险区域的应力循环，并利用S-N曲线预测夹子的疲劳寿命。采用时域格林函数法求解动态运动方程，是提高计算效率的有效方法。采用通用迭代算法来求解考虑损坏夹子的非线性系统。在概率评估框架中，采用一种新颖的随机场方法来描述剪辑强度的空间变异性。通过不同的数值算例证明了本文建立的模型在表达紧固件随机损伤和评估系统动态行为方面的适用性。结果表明，随着列车循环次数的增加，列车和轨道系统的动态响应显着加剧，这与紧固件的变异性和非均匀损伤密切相关。列车引起扣件系统累积损伤的概率遵循三阶段规则，非均匀情况下列车引起的扣件系统疲劳损伤大于均匀情况。此外，轨道不平顺的短波分量会显着加剧紧固件的损坏，从而降低铁路线路的状况。 随着行驶速度的增加，扣件的损伤也随之增加，但车速对扣件损伤的影响小于轨道不平顺，特别是在疲劳损伤大于0.9的范围内。因此，保持轨道的几何光滑度、控制扣件力学性能的均匀性、降低行车速度是延长扣件系统使用寿命的可行措施，从而保证高速列车的运行。