Dynamics Of Vehicle/Track Coupled Systems In High Temperature Superconducting Maglev Vehicle

High temperature superconducting?HTS?maglev is a means of self-stable levitation,based on the flux pinning effect of the non-ideal type-?superconductor YBa₂Cu₃O_7-x,it has wide application prospects with the advantages of simple,credible,environment-friendly and so on.Many HTS maglev test lines have been developed all over the world so far,and a large number of basic research on service performance has been carried out,which show that HTS maglev has the potential to operate at medium-low speed,high-speed or even ultra-high-speed.So,at a critical stage of engineering and commercialization,it's urgent to explore the possible problems in engineering application of the HTS maglev.This thesis studies the coupled vibration of HTS maglev vehicle and flexible track.The main research contents and conclusions are as follow:By improving the existing models of nonlinear levitation force and guidance force,a two-dimensional mathematical model of track relationship for HTS maglev is established.The model takes into account the effects of levitation height,lateral displacement,vertical and lateral vibration.Compared with the experimental data,the calculation date of levitation and guidance force by the simulation model are in good agreement with the experimental results;A multiple rigid-body HTS vehicle dynamics model and a flexible bridge based on Euler-Bernoulli models were built.The equations were solved by Matlab program,the calculating program has the functions of displaying real-time progress and post-processing;Study the dynamic response of HTS maglev vehicle passing through track at a speed of300 km/h,the responses of vehicle and track meet the design specification limits at this time.The influence of the vertical stiffness of the secondary suspension,the span of the track and the running speed on the system dynamic response was further analyzed.And the recommended vertical stiffness of the secondary suspension and span of the bridge is 100kN/m,25 m for the dynamic model.In addition,it is found that the running speed of the vehicle has a great influence on the response of the track beam,the vertical vibration acceleration of the track exceeds the limit at the speed of 800 km/h.To study the random vibration of HTS train/track coupled system,the German irregularities PSD was adopted here.Results showed that the vertical irregularities of permanent magnetic track have little influence on the responses of bridge,but it has impact on the motion of HTS vehicle,and the lateral irregularities have obvious influence both on the responses of bridge and HTS vehicle.The Sperling index was introduced in this thesis,and the HTS vehicle vertical and lateral index are all less than 2.5 means excellent performance,when the speed at the range of 100⁸00 km/h.