Dynamic Performance Analysis Of Carbon Fiber Bogie Metro Vehicle

The acceleration of urbanization in China has led to the increasingly prominent urban traffic problems.As a modern urban public transport,subway has become the first choice to solve urban traffic problems in the world because of its fast,punctual and large transport volume.However,the maturity of Metro technology makes it difficult for metro vehicles to make great breakthroughs in energy saving.As a new type of composite material,carbon fiber has been widely used in aerospace and other fields because of its high strength and lightweight characteristics.Therefore,the application of carbon fiber composite materials in the field of urban rail transit can greatly reduce the quality of Metro vehicles,so as to achieve the purpose of energy saving and emission reduction.In this paper,the dynamic performance analysis of a new generation of carbon fiber bogie metro vehicle designed by a domestic company is studied.The lateral stability of the vehicle and the influence of the change of the primary stiffness on the lateral stability of the vehicle are analyzed through the differential equation of the bogie hunting motion and SIMPACK dynamic modeling and simulation aiming at the problem that the primary positioning stiffness of the metro vehicle may lead to the vehicle hunting instability.Considering the physical properties of carbon fiber materials,the bogie frame should be regarded as a flexible body in the process of modeling.The rigid-flexible coupling model of the flexible frame vehicle system should be established,and the analysis results of the rigid frame vehicle system and the flexible frame vehicle system should be compared.The calculation results show that the critical velocity of hunting motion of the rigid frame vehicle system under the original parameters is low,and the lateral stability is poor,which can not meet the design requirements.The critical velocity of hunting motion of the vehicle can be effectively increased and its lateral stability can be enhanced by appropriately reducing the primary positioning stiffness.Flexible frame vehicle system with original parameters has good lateral stability in the calculated speed range which indicates that considering the flexibility of carbon fiber bogie frame will affect the lateral stability of the whole vehicle system.In addition,the running stability and curve-passing performance of rigid and flexible frame vehicle system under empty and heavy vehicle conditions are analyzed respectively under the same working conditions.The results show that the rigid frame and flexible frame vehicle system have good running stability for both empty and heavy vehicles under the same working conditions,and their performance indexes meet the requirements of designstandards.With the increase of vehicle speed,the running stability of flexible frame vehicle system is gradually better than that of rigid frame,which shows that the flexible frame has a greater impact on the running stability of the whole vehicle system at high speed.Comparing the calculation results of empty car system with that of heavy car system,it can be found that the running stability of heavy car is better than that of empty car.For the curve-passing performance of vehicles,both rigid frame and flexible frame vehicle systems have good curve-passing performance under different line conditions,and their performances are similar,which shows that considering the flexibility of the frame has little effect on the curve-passing performance of the whole vehicle system.