考虑轮轨非线性接触的车辆-轨道-桥梁垂向耦合系统随机振动分析

基于列车-轨道-桥梁耦合动力学理论,考虑轮轨接触非线性,采用广义概率密度演化理论建立了列车-轨道-桥梁垂向耦合系统非线性随机振动方程。采用数论选点法结合谱表示-随机函数法生成轨道随机不平顺样本,实现了用两个随机变量和少量样本较精确地反映轨道不平顺功率谱的随机特性。以高速列车-简支梁桥上CRTSⅠ型板式无砟轨道为例,从概率及可靠度角度,考虑非线性轮轨关系中跳轨现象以及轨道随机平顺影响,对比分析了线性与非线性轮轨对车辆运行安全性的影响;计算了不同轨道谱、车辆运行速度下轮重减载率概率密度演化规律及其对车辆运行安全性影响。结果表明,建议的方法可通过较少的随机变量和样本计算得到车辆-轨道-桥梁耦合系统非线性随机动力响应及其概率分布,可为车辆运行安全性评价提供更好的指导。

Random vibration analysis of vehicle-track-bridge vertical coupling system considering wheel-rail nonlinear contact

Based on the theory of vehicle-track-bridge coupling dynamics,considering the nonlinearity of wheel-rail contact,the nonlinear random vibration equation of vehicle-track-bridge vertical coupling system has been established by using the generalized probability density evolution theory.Using the random-orthogonal function combined with strategy of selecting points via number theoretical method,track random irregularity samples have been generated,it also has realized the stochastic characteristic of track random irregularity power spectrum more accurately by two random variables and few samples.Taking the high-speed train and CRTSⅠslab ballastless track structure on simply supported beam as an example,From the perspective of probability and reliability,considering the phenomenon of track jumping in the nonlinear wheel-rail relationship and the random smoothness of the track,the effects of linear and non-linear wheel-rail on vehicle running safety have been comparative analyzed,the evolution law of the probability density of wheel load shedding rate under different track spectra and vehicle running speeds and its influence on vehicle safety have been calculated.The results show that the method proposed in this article can calculate the nonlinear random dynamic response and its probability distribution of vehicle-track-bridge coupling system with two random variables and few samples,which can provide more accurate guidance for vehicle safety evaluation.