Dynamic Performance Analysis Of High Speed Freight EMU Based On Coupling Model

Container transportation plays an important role in sea rail transportation,international transportation and road-rail transportation.In order to make full use of China’s huge railway lines and improve transportation efficiency,it is the development direction of railway freight in the future to install container in EMU cars to run high-speed freight EMUs.With the increase of the speed of freight EMUs,the research on vehicle system cannot be limited to multi rigid body model,ignoring the vibration deformation of vehicle body caused by the elasticity of components and the vibration of goods,and even the deterioration of vehicle operation quality.In this thesis,the freight EMU with the maximum design speed of 350 km / h is studied as follows:Firstly,the theory of Vehicle Multi-body system dynamics is introduced,including multi rigid body system dynamics,multi flexible body system dynamics and rigid flexible coupling system dynamics.The basic theory and modeling method of liquid-solid coupling system dynamics of liquid cargo container considering liquid sloshing are introduced,which provides theoretical basis for the following model establishment and calculation.Based on the above theory,considering the arrangement form and specification of the loading container in the car body,considering the loading and reinforcement mode of the container and the car body bottom plate,the "vehicle cargo" coupling model of the trailer of the freight multiple unit is established.On this basis,the rigid flexible coupling model and the equivalent model of liquid-solid coupling considering the flexible car body and the influence of the liquid cargo liquid level sloshing possibly loaded in the container are also established.From the point of view of vehicle system dynamics performance,this thesis analyzes the influence of several key suspension parameters on the vehicle system coupled with the car body and the multi rigid body system with rigid connection,and comprehensively analyzes the difference of the influence on the two models,so as to provide theoretical support for the design of vehicle suspension parameters.In this thesis,the stiffness of the rubber block of the grab used to load the reinforcement device in the "vehicle cargo" coupling vehicle system is analyzed,and the dynamic performance of the vehicle system and the vibration of the container are comprehensively considered.The vibration response of vehicle system is analyzed based on "vehicle cargo" coupling model,rigid flexible coupling model and liquid-solid coupling model.Among them,the vibration of the container in the "vehicle cargo" model is greater than that of the vehicle body,and the gap increases with the increase of the running speed,and the container still appears the lateral natural vibration when it is reinforced;the lateral and vertical vibration of the flexible vehicle body obviously increases compared with the multi rigid body model,and the structural vibration of the vehicle body appears in the vertical vibration,and the running stability performance of the vehicle system is affected,which has little influence on curve performance.The vibration amplitude of the container in the liquid-solid coupling model is obviously larger than that of the multi rigid body model,which affects the running stability of the vehicle system,but has little influence on the curve passing.The results show that the highspeed freight EMU meets the requirements of the maximum design speed of 350 km / h,and there is a certain safety margin for each index.