Research On Parametric Model And Overriding Influencing Factors Of Train Collision Dynamics

This paper studied the mechanism of overriding behavior due to train collision based on the simulation methods,and established a vehicle-track collision dynamics parametric simulation platform.After the validation,the influence of train parameters on the overriding behavior was studied by using the wheel lifts as the evaluation criterion.The relevant results can provided some guidance for train parameters in train crashworthiness design,so as to prevent the occurrence of train overriding behavior after collision.Firstly,a vehicle model and a track model based on typical vehicle dynamics model were established,and the rigid body motion equations were derived according to the motion and mechanical characteristics of centering head-on collision of two trains on the straight track.The simplification,description and calculation method of nonlinear wheel-rail force,coupler and draft gear,anti-climbing device,suspension device mathematical models were introduced.For the purpose of reducing calculation error of wheel lifts,the correctness of each rigid bodies motion state at the initial moment of collision was guaranteed by adding vehicle static balance algorithm.With the help of Matlab GUI module,a vehicle-track collision dynamics parametric simulation analysis platform including a human-computer interface was established.Secondly,a finite element model of train collision was established.Taking the 25km/h head-on collision scenario of the 4-marshalled trains as a instance,the finite element model and the dynamics model were simulated using identical calculation parameter.Based on the former results,the results of two models were compared by using velocity,acceleration,system energy and wheel lifts as the major collision response indexes.The overall develop trend and the motion of each rigid bodies are consistent,the absolute error of the result is small,and the relative error can be guaranteed within 10%,which ensured the accuracy of vehicle-track collision dynamics parametric simulation analysis platform.Then,the train collision overriding mechanism was obtained by comparing 3 kinds of finite element collision models with or without primary and second stopper.Furthermore,the effect of the selected 14 train parameters on overriding behavior was explored on the basis of vehicle-track collision dynamics parametric simulation platform.And in view of 5 parameters with strong sensitivity,the influence on the train collision overriding behavior was deeply analyzed.Ultimately,some suggestions are given for the design of train crashworthiness parameters: the reducing of primary suspension vertical stiffness and the increasing of the second suspension vertical stiffness can restrain overriding behavior to a certain extent.However,as the second suspension vertical stiffness continues to increase,the change in wheel lifts is not sensitive.In addition,the reduction in the vertical distance from the mount point of the coupler and anti-climbing device to the centroid of the vehicle body also has a positive effect on the suppressing of overriding behavior.With the increase of the body mass,the wheel lift decreases first and then increases.There is an optimal solution,which makes weakest overriding in the process of collision.