Crashworthiness Simulation Of A Railway Vehicle And Topology Optimization Design Of Its End Structure

With the rapid development of railway transportation,people pay more attention to the safety performance of trains while enjoying convenient traffic.The passive safety performance of trains as an important part of the overall safety performance of the entire vehicle has received extensive attention from researchers in various countries.In recent years,European and American countries have also issued passive safety standards applicable to rail vehicles.Although passive safety has been widely studied at home and abroad on structural components of rail vehicles,a complete set of suitable optimized design method for simultaneously evaluating crashworthiness and stiffness of railway vehicles has not been found in the existing literatures.In order to fully investigate the crashworthiness of the car body structures,this article referred to the passive safety regulations for trains in Europe and the United States and the bus rollover collision safety standard,and designed two simulation scenarios for assessing the crashworthiness of front and rollover crashes.This paper analyzed the collision response of the railway vehicle based on the explicit dynamics solver LS-DYNA.The results show that the underframe structure in the frontal collision is prone to bending deformation,which affects the energy absorption effect.At the same time,the peak contact force is too large and the contact time is too short.The end wall structure of the vehicle body deforms and absorbs energy in a rollover collision,and has an influence on the deformation of the body during rollover.An unreasonable end wall structure may affect the safety of passengers.During the collision of the railway vehicle,the end structure of the car body as the main energy-absorbing component has an important influence on the crashworthiness of the entire vehicle,and attention should be paid to the study of the crashworthiness of the end structure and its optimal design.In view of the problems existing in the collision of the vehicle body,the static stiffness requirements of the end structure in the EN12663 standard were considered,and a Hybrid Cellular Automata method based on energy-scaling was used to optimize the end structure of the car body for comprehensive crashworthiness and stiffness assessments.The results show that based on the energy-scaling optimization method,the conceptual design that is more in line with the user's intention can be obtained,and the topology optimization result of the end structure under the given conditions is obtained.In order to further determine the parameters of the improved end structure,the grid deformation technology and the adaptive simulated annealing optimization algorithm were used to optimize the parameters of the underframe structure,the objective function reached the optimal value under the constraint conditions.The results show that the deformation of the improved structure in the frontal collision is more reasonable and the contact force is more stable.In the rollover collision,the impact energy can be absorbed more effectively,and the safety distance of the passenger living space is increased,the crashworthiness of the car body has been improved.