Vertical Vibration Response Of Vehicle-bridge Coupled Systems Based On Suspension Force Characteristic

The phenomenon that high temperature superconductors(HTS)can suspend in the magnetic field has provided a new idea for rail transit development.HTS magnetic suspension system has the advantages of no source stability,simple and reliable principle,and environmental protection and so on that conforms to the development concept of modern rail transit and shows great potential in future rail transit.Basic research and test line-based research on HTS magnetic levitation systems are being carried out simultaneously.The study of HTS magnetic levitation vehicle-bridge coupling dynamics is one of the important research contents,aiming at making reference for the engineering of HTS magnetic levitation system.This paper starts with the study of the suspension force characteristics of the block,and then simulates and analyzes the vertical vibration response of the high-temperature superconducting magnetic suspension vehicle-bridge system,and obtains some meaningful conclusions.In this paper,a mathematical model of the levitation force of a double exponential function is proposed.The model ignores the hysteresis phenomenon between the HTS bulks and the permanent magnet orbit,and the measured data has a relatively high degree of reduction.The rationality and feasibility of the engineering simulation calculation are analyzed through experiments.The mathematical model of the suspension force is the basis of the next simulation calculation.Then based on the rigid-flexible coupling dynamics technology,the HTS magnetic levitation vehicle-rail beam coupling model is established by the joint simulation of Universal Mechanism(UM)-ANSYS.The vehicle parameters are from the experimental prototype,and the bridge parameters are based on the HSST medium-low speed magnetic levitation system.The interaction relationship between HTS bulks and permanent magnet orbit is simulated by UM’s custom control suspension force control module.This work built a platform for simulation calculation of HTS magnetic levitation system.Based on the above work,the study on the effects of train running speed,bridge span and secondary suspension parameters on the vertical vibration response of the magnetic suspension vehicle-bridge system are conducted when the high-temperature superconducting maglev train runs on the simply supported track beam.The dynamic response of the vehicle body vertical vibration acceleration,the maximum vertical deflection of the track beam,the cryostat suspension gap,the Spelling comfort index,and the vibration acceleration of the track beam are mainly investigated.The analysis shows that the magnetic suspension vehicle-bridge system is less sensitive to parameter changes at medium and low speeds,and the response values are good.At high speeds,the secondary suspension parameters need to be properly optimized to achieve the stability and safety of the vehicle.And when the magnetic levitation vehicles passes through a long-span bridge,its speed needs to be controlled.These conclusions can be used as a reference for further engineering of HTS magnetic levitation systems.As for the problems that may be encountered in the actual operation of HTS magnetic levitation vehicles,this paper explains them mainly through the analysis of the performance of cryostat’s levitation force and individual of cryostats failure.Cryostat levitation reduction and individual cryostat failure are unfavorable factors for driving,but the dynamic response of the HTS magnetic levitation vehicle is limited,and the vehicle operating state will not become particularly bad.This shows that the HTS magnetic levitation vehicle is inclusive of faults and is conducive to the promotion of HTS magnetic levitation systems.At the same time,the improvement of the suspension performance of cryostats will make the vehicle dynamic response better,especially at high speeds.Improving the suspension performance of cryostats is an important part of the HTS magnetic suspension system worthy of further study.