Study On The Frequency Tuning Mechanism Of Sleeper Vibration Absorption Track In Urban Rail Transit

In order to reduce the environmental vibration caused by the operation of rail transit vehicles,various types of anti-vibration rails are applied in the construction of urban rail transit in China.In the process of large area use of vibration absorption track,rail corrugation phenomenon is more and more serious.Rail corrugation not only aggravates the interaction between wheels and rails,leading to excessive vibration and noise of vehicle track system,affecting ride comfort,but also shortens the fatigue life of vehicle and track parts,resulting in safety hazards.Rail corrugation is one of the most difficult problems in the world,and it is necessary to relieve the rail corrugation.For the team the structure characteristics of new type sleeper vibration damping track,set up a short frequency tuning mechanism of elastic lateral support pillow vibration track and long pillow vibration finite element model of the track,vehicle is established and the vibration damping track dynamic action one large system dynamics model,the frequency tuning machine key parameters on the elastic lateral support short pillow and long pillow vibration track the influence law of natural frequency and dynamic response characteristics.A frequency regulating device is installed on the 1:1 elastic side support long-pillow vibration damping track in the laboratory.The frequency regulating mechanism can not only change the natural frequency of the elastic side support short and long pillow type vibration absorption track structure,but also improve the stability of the vibration absorption track and the vibration absorption effect.The dynamic influence of spring stiffness of frequency tuning mechanism on vibration damping track is more significant than that of preload.For elastic short sleeper,the initial stiffness of frequency tuning mechanism should be set as 1kN/mm,which can not only adjust the vibration frequency of the track up and down,improve the stability,but also facilitate the manufacture.The effective adjustment range of the stiffness of the elastic long-sleeper frequency regulating mechanism is0~20kN/mm,and its initial stiffness should be set to about 5kN/mm,and the adjustment range of the first-order mode natural frequency of the vibration damping track can reach about ±6Hz.In the operation process,the frequency of the track structure should be adjusted by increasing the stiffness of the frequency tuning mechanism.The stiffness of the frequency regulating mechanism is increased from the initial 5kN/mm to 20kN/mm,the first natural frequency of the elastic side-supported long-sleeper vibration absorption track will increase by 6Hz,and the vibration acceleration of the sleeper and the track bed will decrease by 26.7%and 36% respectively.Moreover,the influence trend of frequency tuning mechanism on vibration absorption track of long and short pillow is basically the same.In addition,the multi-body dynamics and finite element method are used to establish the falling axis experimental model of the new sleeper damping track,and the influence law of the frequencytuning mechanism on the dynamic response of the new sleeper damping track is studied.The experiment shows that the frequency tuning mechanism can suppress the vibration of the sleeper and change the main vibration frequency of the sleeper.Then,based on the theory of vehicle-track dynamic interaction,the dynamic model of metro-elastic sleeper-integral track bed with frequency tuning mechanism is established.The track type takes into account the long sleeper damping track which is commonly used in domestic urban rail transit.This paper mainly studies the influence of the main parameters of the frequency tuning mechanism on the vehicle-track system under different irregularity excitation models.The installation of frequency tuning mechanism can suppress the vibration of the vehicle track system and adjust the vibration main frequency of the track system.For the wave mill excitation,adjusting the track frequency and suppressing the vibration can effectively reduce the track resonance under the wave mill excitation and avoid the development of the wave mill and the damage to the vehicle track.Second to use in the laboratory 1:1 elastic lateral support long pillow vibration track installed frequency control device,and adopt the method of hammer experiment contrast analysis to verify this theory study conclusion,suppression of FM device for elastic lateral support long pillow damping the vibration of the rail has obvious inhibitory effect,change by adjusting the parameters of the spring can adjust the natural frequency of vibration isolation track structure.