车辆-轨道系统时-空随机分析模型

Stochastic Model Used for Temporal-spatial Analysis of Vehicle-track Coupled Systems

车辆-轨道耦合系统具有时-空域的随机特征。为了更好地研究车辆-轨道系统的时-空随机演化过程,提出车辆-轨道系统时-空随机分析模型。该模型将车辆-轨道耦合系统分为车辆子系统、轨道子系统及轮轨界面系统,可考虑车辆系统、线路系统参数的随机性及轨道随机不平顺的时变性,同时采用数论法实现不同动力参数的组合,用概率密度演化方程解决系统激励输入与响应输出的概率密度传递问题。最后,采用该模型分析了不同变异系数下的车辆-轨道系统时-空随机振动,分析中假定系统动力参数服从正态分布,并基于实测数据进行轨道不平顺的时-空随机模拟。结果表明:依据本文模型得到的计算结果符合物理概念;由于动力参数的随机变异性直接与时间相关,使得利用此随机分析模型,探讨系统动力响应的随机演化机制、制定考虑长时效的系统动力指标限值及养修计划成为可能。建议完善车线系统参数的基础检测资料。

Vehicle-track coupled system has the random nature in time-space domain.In order to better study the stochastic temporal-spatial evolution process of the vehicle-track systems,this paper proposed a computational model for analyzing temporal-spatial stochastic vibrations of vehicle-track system,which divided the vehicle-track system into vehicle subsystem,track subsystem,and wheel-rail interfacial subsystem,and considered the randomness of the dynamic parameters of vehicle system,the track system and the time variation of the track stochastic irregularity.A numerical theory method was used to ensemble different dynamic parameters.Then the probability density evolution equation was implemented to solve the delivery problem of probability density between excitation inputs and response outputs.Finally,an analysis was carried out on the temporal-spatial stochastic vibrations of vehicle-track systems subjected to different coefficients of variation,in which the dynamic parameters were assumed to be subject to normal distribution,and the time-space stochastic simulation of track irregularities was conducted based on measured data.The results show that the computed results obtained from this model accord with physical conceptions.Due to direct relation of the random variability of dynamic parameters with time,it is possible to explore the temporal-spatial stochastic evolutionary mechanism and formulate the dynamic indices limits by adopting time-space stochastic computation model.It is recommended to improve the basic testing data of vehicle-track system parameters.