Research On Dynamic Simulation And Parameter Optimization Of High Speed Maglev Train System

Based on the multi-body dynamics theory,a real high-speed maglev train is taken for case study and reagarded as a nonlinear multi-body system.After introducing magnetic field active control,a 204 DOF dynamics model of the rigid-flexible coupling system of the single vehicle and track is established in multi-body dynamics software Simpack.By applying excitation of harmonic,random track irregularity and crosswind,the vertical and horizontal vibration response under different speed and conditions is analyzed,and the influence of various factors on the ride quality and running safety of high-speed maglev train is studied.Suggestions for vehicle parameter optimization are provided within the range of engineering application parameters of high-speed maglev train.Firstly,the structure composition of high-speed maglev train is introduced,including vehicle formation,suspension frame layout and suspension system.Aiming at the pitch and heave motion of vehicle,the mathematical model of vehicle-track vertical coupling motion is established.Then the dynamic force function and motion differential equations of vehicle structural components are derived in Newton-Euler method.The classification and composition of track irregularities which affect the dynamic performance of high-speed maglev train are described,along with the electromagnetic field model of vehicle suspension and guidance control corresponding to the track.In addition,this paper describes the process and method of rigid-flexible coupling analysis of vehicle-track system by using modal reduction method to generate substructure and construct flexible body of suspension frame in ABAQUS.Secondly,the mechanical relationships among vehicle components are analyzed,including the vibration modal analysis of parts under the vehicle,the modal analysis,static analysis and transient dynamic analysis of the suspension frame.The rigid-flexible coupling stochastic simulation model of high-speed maglev train is established,which has 97 rigid bodies including car body,bolster,C-type suspension bow,suspender,rocker,leviation electromagnet,guide electromagnet and etc,with 204 freedom degrees in total.What’s more,the dynamic performance evaluation specification of maglev vehicle is selected.Thirdly,based on the established Simpack parameterized high-speed maglev train vehicle-track coupling model,the dynamic response process of high-speed maglev train with full load passing through straight line condition is simulated from vertical and horizontal respectively by applying harmonic and random track irregularity excitation.The frequencydomain energy distribution and time-domain amplitude of the vibration of each part of the car body are compared,and the isolation and filtering effect of air spring and transverse rubber spring on the vibration transmission is revealed.Moreover,the coupling effect between the running speed and the track irregularity with respect to wavelength and amplitude in the whole high-speed domain are studied.In this way,the sensitive wavelength interval and amplitude limit of track irregularity for high-speed maglev train are obtained,which are easy to be affected by the high-speed maglev train,and have a certain reference value for the track irregularity management.Besides,the variation trend of the Sperling ride quality index is observed when the parameters of the car body mass and the elastic damping element are changed,and the range of train parameters is considered in terms of robustness and robustness.The simulation results show that,at different speeds,the Sperling ride quality index has a peak value near the track irregularity wavelength of 16-17 m,and a valley value near the wavelength of 23-24 m.Finally,according to the environmental conditions near the high-speed maglev line,the wind speed power spectrum is selected.And the time domain numerical simulation of fluctuating cross wind is carried out by using the inverse Fourier transform method,so as to study the influence of crosswind in the process of vehicle curve negotiation.Crosswind load and lateral track irregularity excitation are applied to simulate the vehicle passing through the curve line with full load.By changing the wind speed and direction of fluctuating crosswind,the radius and superelevation of curve line,the curve negotiation of high-speed maglev train under the action of crosswind is analyzed,and then compared with the condition of the transverse eccentricity of the car mass.In the end,The influence differences and connections of train speed,track irregularity,crosswind speed,curve superelevation,mass eccentricity and other factors on the ride quality and running safety are summarized.The simulation results show that,when the wind speed is greater than 15m/s,the safety of the train will deteriorate significantly,which should be avoided.