Analysis Of The Dynamic Characteristics Of Fastener System On Wheel/Rail Vibration And Acoustic Radiation

As the connecting parts of rail and sleeper,the fastener system mainly plays the role of connecting rail and sleeper,positioning the rail and providing lateral and vertical stiffness damping for the rail.The vibration and acoustic radiation characteristics of the track are greatly affected by the dynamic characteristics of the fastener.The structure that provides vertical elasticity in the fastener system is an elastic plate structure,and its mechanical characteristics can be generally characterized by stiffness and damping.However,a large number of plate structures are made of rubber materials,and their stiffness and damping will be affected by external excitation frequency,preload,temperature and other external factors.Therefore,the linear constant stiffness and constant damping coupler model can hardly reflect the actual vibration characteristics of rail fastening.In the study of the characteristics of wheel-rail vibration and noise in China,due to the small temperature difference in China,and the problem of wheel and rail vibration noise is high frequency and low amplitude vibration.Therefore,this paper will only analyze the influence of external excitation frequency and preload on the stiffness and damping of the fastener.The research content of this paper is as follows:(1)The dynamic characteristics of fastener system and the research of fastener model at home and abroad were investigated.(2)A wheel-rail vibration noise prediction model which considering the dynamic stiffness of the fastener is established.The stiffness and damping frequency dependent fasteners model and track model are verified respectively.The stiffness and damping rationality of the P-T model was verified.The Adapted P-T model with the preload was Adapted to the test results of foreign countries.The solid finite element model of the wheelset was established to analyze its vibration characteristics.The track structure is the elastic short sleeper track model,the Timoshenko beam model was used to simulates the rail,the mass block unit simulates the sleeper,and the thin plate model simulates the track plate.The vibration and acoustic radiation models of the orbit model are verified by the finite element model.(3)The dynamic stiffness model of the verified fastener was brought into the elastic short sleeper track model,and the track vibration and acoustic radiation characteristics of different fasteners were analyzed with the dynamic stiffness of fasteners taken into account.The corresponding dynamic wheel-rail force is calculated based on the selected roughness grade of the wheel-rail,then the wheel-rail vibration and noise is calculated when considering the external excitation frequency and preload dependent damping and stiffness of the fastener.The results show that the vibration acoustic radiation characteristics of the sleepers and rail are greatly affected when the stiffness and damping frequency dependent characteristics of the fasteners are considered,and the wheel-rail radiated noise is mainly affected at the intermediate frequency rang.