Comparative Analysis On Dynamic Performances Of Two Types Of Medium-low Speed EMS Maglev Vehicles

In recent years,medium-low speed maglev transportation has been developed and applied in Japan,South Korea and China due to the better curve negotiation performance,ride quality and etc.Meanwhile the problem of violent maglev vehicle-track-viaduct coupled vibration under some conditions has also been exposed in actual operation.In order to reduce the dynamics responses of vehicle-track-viaduct coupled vibration,a new style medium-low speed maglev with mid-set air spring levitation bogie has developed,which has better mechanical decoupling ability.However,it has not yet been comprehensively evaluated for its dynamic performance,and the difference in dynamic performance between new-type maglev vehicle and traditional HSST maglev vehicle is still unclear.Therefore,the dynamic responses are compared and analyzed in this thesis as the two kinds of maglev vehicle with mid-set air spring levitation bogie and end-set air spring levitation bogie running on concrete girder and on curved track,and the dynamic responses of the system are analyzed as new-type maglev train running on steel girder.The results provide theoretical support and simulation data for the research and development of new-type maglev vehicle,and also give support to its promotion and application.Firstly,the structural and technical characteristics of levitation frame with mid-set air spring and end-set air spring are introduced,and maglev vehicle models considering PID active levitation control model and electromagnet stop rubber are established using SIMPACK software.Then,the structural and technical characteristics of U-shaped concrete girder and steel structure girder for medium-low speed maglev transportation are further analyzed,and finite element models of concrete girder and steel girder considering track panel are established using ANSYS software.Vibration modes and natural frequency of two kinds of guideway girder models are studied,which provides the basis for the simulation analysis later.Secondly,the dynamic responses of the two kinds of maglev vehicle running on concrete girder at different speeds are compared and analyzed using the maglev train bridge-Distribute Coupler Simulation platform developed by our research group.The results show that the acceleration of U-shaped girder and F-shaped rail under the load of traditional maglev train is larger,and the running stability of traditional maglev train is worse than that of new-type maglev train.The two kinds of maglev vehicles both resonate with track panel slightly as the speed is 20 km/h.However,the resonance of traditional maglev train is more severe.The levitation frame with mid-set air spring is beneficial to weaken vehicle-track-viaduct coupled vibration.Then,the dynamic response of the two kinds of maglev vehicle when passing through horizon curve track is further compared and analyzed.The research results show that the lateral magnet/rail mechanical collision happened to traditional maglev vehicle on the horizon curve track with a radius of 50 m,while new-type maglev vehicle can pass through without collision.Besides,the lateral displacement of carbody and sliding table of new-type maglev vehicle is smaller than that of traditional maglev vehicle.The responses of levitation control system for new-type maglev vehicle is larger in transition curve when passing through plane curve with a radius of 100 m and 300 m,but is still within the allowed range.Finally,coupled vibration responses of new-type maglev train and steel girder is calculated.The results show that the deflection mid-span ratio of steel girder under the load of new-type maglev train is close to 1/3800,and the impact of running speed to coupled vibration of maglev vehicle-track-viaduct system is large.And the acceleration of the plate of steel girder at the mid-span reaches 0.54 g when the speed is 40 km/h,which is slightly greater than the vertical acceleration limit of 0.5 g for the Chinese high-speed railway bridge.The vertical riding index of new-type maglev vehicle basically increases with the increase of speed.And the vertical riding index of the middle vehicle exceeds 2.5 when the speed is 160km/h,its riding level is good.And new-type maglev train resonate with steel girder slightly when the running speed is 20 km/h.