| Magnetic levitation trains have many advantages such as no contact,no friction,energy saving and environmental protection,fast running speed and so on.It is one of the development directions of urban rail transit in the future.Compared with other types of maglev trains,the high-temperature superconducting pinned maglev trains(referred to as high-temperature superconducting Maglev train)use the unique magnetic flux pinning action between the high-temperature superconducting block and the permanent magnet to achieve suspension.Its characteristics of stable suspension without active control and low maintenance cost in low temperature environment(liquid nitrogen)have attracted the attention and research of many scholars at home and abroad.When the train runs at high speed,the suspension frame system will vibrate to a certain extent,thus changing the suspension gap.Therefore,this thesis carries out the dynamic analysis of the suspension frame system of the high-temperature superconducting maglev train.The thesis mainly studies the evolution law of the behavior under free vibration and forced vibration and the influence of different operating conditions on the running law,and evaluates the performance of the train.Specific research contents are as follows:Firstly,the suspension force and magnetic rail relationship of suspension gap between high-temperature superconducting block combination and permanent magnet orbit are fitted,and the dynamic model of vertical vibration of suspension frame system is established.The multi-scale method is used to derive the approximate solution of suspension gap response of the suspension frame system under free vibration,and the approximate solution of the system is compared with the analytical solution to verify its correctness.Based on the study of free vibration characteristics,the expressions of maximum overthrow and maximum acceleration are obtained by the approximate solution of suspension gap.Based on the maglev standard,the feasible domain of system parameters satisfying the response characteristics is obtained,and it is found that the feasible domain of system parameters is approximately a sector.Secondly,Fourier transform is used to obtain the spatial spectrum and wave frequency diagram of the vertical unsmoothness on the right side of the train.The nonlinear vibration differential equation of the suspension frame system under the excitation of track irregularity is established,and the first-order approximate solution of the main resonance response of the system is obtained by multi-scale method,and the correctness of the approximate solution is verified by numerical solution.Then,the amplitude-frequency response equation of the suspension frame system in the main resonance is derived,and the influence law of system parameters on the amplitudefrequency response curve is studied.Based on the safety index of magnetic levitation,the given maximum operating speed range is used to analyze the common feasible domain satisfied by the system parameters.The results show that increasing the wavelength of track irregularity can reduce the difficulty of constructing permanent magnet track.Finally,the suspension frame system including suspension system is selected as the research object,and the dynamic model of suspension system including suspension system under harmonic excitation is established.And the response curve of the acceleration of the body and the steady-state amplitude of the suspension frame are calculated by numerical method.The influence of system design parameters on the vibration characteristics of the suspension system including suspension system is studied.Based on the maglev standard,the feasible domain of parameters satisfying the system safety and comfort indexes is analyzed.This thesis focuses on the simulation analysis of the mechanical characteristics between the high temperature superconducting suspension frame and the permanent magnet track in the high temperature superconducting maglev train.The dynamics model of the train suspension frame under vertical vibration is built to study the influence of system parameters on the operation response.The current safety,stability and comfort standards of maglev train are used to evaluate the performance of train operation,so as to reduce the occurrence of extreme behavior,so as to reduce the probability of train accidents.It provides theoretical guidance for further promoting the maglev train towards engineering application. |
