Study On The Influence Of Flexible Car Body On Vehicle Dynamics

For the moment,High-speed train is developing in the direction of fast speed and light weight,which puts forward higher requirements for the safe operation of the vehicle.The conventional structure of the vehicle system dynamics in the study as a rigid body,not considering the elastic deformation of structure of vehicle system dynamics,the influence of however driving speed increasing,lightweight design and the environment is more complex,exacerbated by the elastic vibration of car body,architecture and other devices to produce,affect the quality of high speed vehicle running.In order to make the theoretical research more practical,it is necessary to introduce flexible body to study the vehicle system dynamics performance.This paper first describes the research background and significance of the subject,summarizes the basic theory of rigid-flexible coupling dynamics,calculation methods and ideas,etc.,and introduces the relevant vehicle system dynamics indicators analyzed in this paper.Then,two kinds of vehicle simulation models,multi-rigid body and rigid-flexible coupling,were established to calculate the dynamics indexes of the two,and the interaction between flexible body and rigid body in the vehicle model was compared and analyzed,so as to improve the accuracy of the calculation results of vehicle system dynamics performance.The main work of this paper is as follows:(1)Establish a multi-rigid vehicle simulation model according to the main structural technical parameters of a certain type of vehicle body.The nonlinear characteristics of some bogie structures are considered and the damping of anti-snake shock absorber and transverse shock absorber are defined by input functions.(2)Firstly,the vehicle body was modeled by I-DEAS software,and the Hyper Mesh software was used to process the mesh of the vehicle body.Then,ANSYS software was used to obtain the required files of the flexible car body.Finally,the FEMBS interface program was used to generate the flexible car body to create the rigid-flexible coupling vehicle simulation model.(3)study the vehicle under different curved line conditions and Beijing-Tianjin spectrum excitation,respectively calculate the two vehicle models’ snaking stability,curve passing safety and vehicle movement perling dynamics indexes.The Sperling dynamics indexes of the two vehicle models were analyzed at different speeds.(4)Study the influence of the variation of the vertical stiffness value and the transverse stiffness value parameter value of the second suspension on the vehicle running perling,and analyze the influence of the failure of anti-snaking shock absorber on the stability of vehicle running snaking.Finally,wind load was applied to the multi-rigid vehicle model and the rigidflexible coupling vehicle model to analyze the performance of wind load at different speeds on the safe operation of the vehicle.The results show that the nonlinear and linear critical velocities of the flexible vehicle model are reduced compared with the rigid vehicle model.The decrease is not obvious.When the vehicle passes through the curve,the safety index of the flexible car body model increases greatly.As the vehicle passes through curves and straight lines,the Sperling index of the vehicle’s stationarity increases.Selecting reasonable vertical and transverse stiffness values of the second train can improve the running quality of the vehicle,while neglecting the anti-snake shock absorber will seriously reduce the motion stability of the vehicle.Compared with the rigid vehicle body model,some operating safety indexes of the flexible vehicle body model deteriorate more seriously under crosswind conditions.