Research On Vibration Reduction Performance Of Long Sleeper Vibration Attenuation Track With Elastic Composite Support

The environmental vibration problem caused by urban rail transit trains in China has become increasingly prominent,so various rail vibration attenuation measurements have been widely used on the rail lines.The sleeper attenuation track has many advantages,including medium volume and large vibration mass and convenient construction.But the elastic short sleeper damping track has some disadvantages,such as mud pouring,component aging and difficultly replacing.In this paper,the key dynamic parameters,vibration reduction effect and stability of a new type of the damping track equipped with long sleeper of elastic and composite support was theoretically studied and experimentally verified.The main research contents of this dissertation are as follows:(1)Aimed at the damping track equipped with long sleeper of elastic and composite support,a three-dimensional finite element vehicle-track foundation coupled model is established.The rubber Yeoh hyper-elastic constitutive model is used for the sleeper elastic support cushion,and the dynamic response of sleeper and bed foundation is taken as the evaluation index.Compared with the existing elastic sleeper damping track,it is found that the damping track equipped with long sleeper of elastic and composite support can significantly improve the stability and vibration attenuation capacity of the track structure.(2)The dynamic characteristics of the elastic composite support sleeper damping track under different stiffness levels were studied.By changing the stiffness of the elastic cushion of the composite support sleeper,the vibration reduction effect and track stability variation are studied when the vertical displacement of the sleeper is assigned as 1 mm,2 mm and 3 mm,respectively.With the decrease of the support stiffness of the elastic pads,the vibration reduction effect of the track is significantly improved,but the vibration acceleration of the sleeper will be obviously increased.Therefore,while reducing the support stiffness of the elastic pads to obtain higher effect of vibration reduction,relevant measurements should be adopted to suppress the vibration of the sleeper.(3)Based on the global optimization algorithm,the reasonable matching rule and parameter range of the stiffness parameters of the elastic cushion on the sleeper side and the elastic pads under the sleeper are studied.It is found that the sleeper elastic cushion can give full play to the damping capacity of the track when it plays a major supporting role.Comprehensive stiffness value of support under sleeper should be less than 5k N/mm,when the vertical displacement of the sleeper is controlled at 1mm,2mm and 3mm,the corresponding general stiffness of the sleeper side support should be set to 150 k N/mm,107 k N/mm and 54 k N/mm.(4)Through the hammer impact test,the dynamic characteristics of the test models of general monolithic roadbed,sleeper damping track equipped with side elastic support and elastic composite support long sleeper damping track are compared and analyzed.The test results show that the elastic composite support damping track has obvious advantages in reducing the vibration of the foundation and maintaining the stability of the track structure,and the obtained law is consistent with the theoretical calculation results.The damping track equipped with long sleeper of elastic and composite support adopts special track structure design,which eliminates the shortcomings of the existing sleeper damping track,such as difficult replacement of elastic components and unable to discharge the accumulated water in the bearing groove.It can obtain better vibration attenuation effect than the existing sleeper damping track,and has the prospect of popularization and application in engineering.