Research On Optimization Of Vibration Damping Parameters Of Metro Steel Spring Floating Slab Track

With the rapid development of urban metro networks construction,the impact of vibration caused by subway operation on social life has become increasingly serious.In order to reduce the influence of subway vibration,extensive research has been carried out on the vibration damping parameters of metro track structures.Most of the research focuses on the influence of single parameter variation on the damping effect,and does not comprehensively consider the influence of multi-parameter changes on the vibration damping performance and frequency sensitivity of different damping parameters.Different damping parameters have certain differences in frequency distribution.According to the distribution characteristics of the excitation frequency and the frequency sensitivity of the damping parameters,matching the reasonable damping parameters can achieve the best damping effect.(1)In order to clarify the frequency sensitivity of different damping parameters,the vibration transfer function of the steel spring floating slab track structure is solved and analyzed in the paper.The vibration transmission coefficient of different fasteners and steel springs in the vertical stiffness has a frequency sensitive interval in the frequency domain distribution.When the excitation frequency is greater than 80 Hz,the fastener and steel spring stiffness values have no effect on the vibration transmission coefficient.The vibration transmission coefficient of the vertical damping of different fasteners and steel springs appears at the intersection near the frequency of 40 Hz.When the excitation frequency is less than 12.5Hz,the vertical damping value of the fastener and the steel spring has no influence on the vibration transmission coefficient.The vibration transfer coefficient of the distribution quality of different floating slabs has some differences in the frequency domain distribution.(2)Through the static and modal analysis of the steel spring floating slab track and combined with the relevant floating slab track design specifications,it is recommended that the long steel spring floating slab track fasteners have a value of 20~40kN/mm,and the vertical stiffness of the steel spring is taken the value is 10~15kN/mm.The vertical stiffness of the short floating slab track steel spring is 12~15kN/mm.When the vertical stiffness of the steel spring is 12kN/mm,the matching vertical stiffness of the fastener should not be less than 36kN/mm.(3)The vehicle-track coupling dynamics calculation model is established to calculate the vibration response of the steel spring floating plate track under the combination of different fastener vertical stiffness and steel spring vertical stiffness under different subwaytrain speeds.For the short steel spring floating slab track,when the train speed is70km/h~100km/h,the vertical stiffness of the steel spring is 14kN/mm,and the vertical stiffness of the fastener is 32kN/mm,which can achieve better damping effect.When the train speed is 60km/h,the vertical stiffness of the steel spring is 14kN/mm,and the vertical stiffness of the fastener is 24kN/mm,which can achieve better damping effect.(4)For the long steel spring floating slab track,when the train speed is 100km/h,the vertical stiffness of the steel spring is 10kN/mm,and the vertical stiffness of the fastener is40kN/mm,which can achieve better vibration reduction effect.When the speed is 90km/h,the vertical stiffness of the steel spring is 10kN/mm,and the vertical stiffness of the fasteners is 40kN/mm,36kN/mm and 32kN/mm,which can achieve better damping effect.When the train speed is 80km/h,the vertical stiffness of the steel spring is 10kN/mm,and the vertical stiffness of the fastener is 32kN/mm,which can achieve better damping effect.When the train speed is 70km/h,the vertical stiffness of the steel spring is 10kN/mm,and the vertical stiffness of the fastener is 24kN/mm,which can achieve better damping effect.When the train speed is 60km/h,the vertical stiffness of the steel spring is 12kN/mm,and the vertical stiffness of the fastener is 24kN/mm,which can achieve better damping effect.