Research On Lightweight Body Design Of High Temperature Superconducting Maglev Train

As a new superconducting technology system,high–temperature superconducting(HTS)maglev system has attracted more and more attention in the field of rail transit because of its advantages of simple system,passive self stability and low maintenance cost.As the HTS maglev train has gradually entered the stage of engineering application,there are still many system problems to be solved.As the hub of each subsystem,the body of HTS maglev train is also an important bearing structure,which is the core part of the whole system.Because the levitation capacity of HTS maglev train is certain,in order to improve the bearing capacity of maglev train,it is necessary to carry out lightweight design of vehicle body structure to form a lightweight scheme of HTS maglev train body.Starting with the overall stress analysis of HTS maglev train,this thesis focuses on the lightweight design of maglev vehicle body structure,and carries out the following research:Firstly,according to the mutual adaptation requirements between the maglev vehicle and the track,the line parameters such as the minimum horizontal and vertical curve radius are designed.At the same time,the overall system and key parameters of the vehicle are designed and determined,which provides a basis for the stress analysis during the operation of the maglev vehicle.Secondly,referring to the existing design standards of high–speed maglev and wheel rail vehicles,based on the technical principles of suspension,guidance and traction of HTS maglev train,the load condition of maglev vehicle body is analyzed from the four directions of vertical,horizontal,longitudinal and torsional through theoretical analysis and simulation.Finally,10 static load cases and 3 fatigue load cases are determined.Then,with lightweight and modularization as the design idea,the material selection,module division and structural profile of the maglev vehicle body are analyzed and designed accordingly,thus the design scheme of the overall body structure of the large aluminum alloy frame structure combined with the sandwich foam board is determined.According to the design method of equal strength and stiffness,considering that the maglev vehicle is obviously affected by wind load,the ring beam structure is designed to transfer the load to the underframe structure with high strength,so that the vehicle body forms a loop type overall bearing structure.The car body is designed into four large module structures:underframe,side wall,roof and end wall,which can improve the production and assembly efficiency.At the same time,the sandwich foam board is also designed as an independent module,which is convenient for connection and installation with the car body profiles.Finally,the design standards of the high–speed maglev and rail vehicles are analyzed and compared,and the evaluation method of the structural strength of the HTS maglev vehicle is determined.On the basis of the three-dimensional structure,the finite element model of the car body is established,and the corresponding structural strength check and the optimization design of the local structure are carried out.The final simulation results show that the total weight of the optimized car body scheme is only 3.7t,achieving a weight reduction rate of 12%.The car body structure can meet the structural requirements of static strength,fatigue strength and stiffness at the same time,and the safety coefficients of each structural material are all above 1.37.