Theoretical And Exiperimental Study On Vibration Characteristics Of Slab Track With Vibration Attenuation

With the high-speedy development of social economy,people pay more attention to the improvement of living standards,while people’s demand for living quality and environment is becoming more and more strict.so the noise produced by track vibration cause great concern.It is generally recognized that the smaller of track stiffness,the better of track vibration damping effect,but many other researches still show there is a reasonable track stiffness,which is too large or too small will lead to the decrease of vibration damping effect.This paper suggested that vibration attenuation pad with different stiffness for track vibration with different frequencies has different damping effects,there is a specific interval of damping vibration.The contact ratio between the specific damping vibration interval of different vibration attenuation pad and the vibration frequency of track structure produced by train load determine the damping effects of track structure,so the reasonable stiffness of track vibration attenuation pad is different in different condition of railroad operation.The paper mainly targets the track structures of rubber floating slab track and CRTS III slab track,so a finite element model for spectrum analysis is established and the power spectral density function applied to every frequency is constant white noise load.In this model,the stiffness of vibration attenuation pad is taken as variate to calculate the vibration response in every frequency of track structure,so as to get the effective interval of damping vibration for different vibration attenuation pad.In order to get the vibration response in different speed and different stiffness of vibration attenuation pad,a vehicle-track coupling dynamic model is established.By contrast analysis of the spectrum analysis results,the train speed is the main factors of the distribution of track vibration frequency in the same railroad condition.The higher of the contact ratio between the effective interval of damping vibration and the vibration frequency of track structure produced by train load,the better vibration damping effects of track structure.In order to test the rationality of structural design for the new rubber floating slab track,evaluate the damping performance of rubber isolators scientifically,indicate the distribution in frequency of the effective damping vibration interval,some associated experimentation are conducted according to some track relevant specifications of China.The results show that the vibration damping effect of rubber floating slab track is obvious and the average reducing of vibration is about 23.13 dB;The center frequency of damping vibration interval is nearly 63Hz and the inherent frequency is about 10Hz;According to the MATLAB to identify the track vibration parameters,primary frequency is 9.77Hz and damping ratio of the first modal is 4.91%;the second frequency is 22.10 Hz and damping ratio of the second modal is 5.39%;the third frequency is 31.98Hz and damping ratio of the third modal is 4.34%.