Research On Dynamic Characteristic In Different Subway Track Of Urban Rail Transit

In the process of promoting the development of urbanization, in order to solve the increasingly serious problem of urban public transport, China began to develop the subway as the main structural type of urban rail transit. With the continuous construction of the subway, the vibration and noise caused by the operation of the subway is gradually being paid attention to, the research and development of the vibration isolation track structure makes the structure of the underground railway diversified. The according to the different type of subway track vibration, based on the finite element analysis software ANSYS / LS-DYNA, on the orbital structure of the subway in different vibration types were established vertical vehicle track coupling system to the dynamic model, the dynamic characteristics of track structure as the object of study of correlation analysis. The main work and research contents of this paper are as follows:(1)According to coupled dynamics theory in the structure of vehicle-track system, base on the vehicle and track structure system of reasonable simplification and assumption, based on ANSYS / LS-DYNA finite element analysis were established ordinary ballast, vibration device fastenings, trapezoidal sleeper and the steel spring floating slab of four kinds of different damping type track structure of vehicle track coupling system vertical to the dynamic finite element analysis model; according to the nonlinear Hertz spring contact theory equivalent treatment between the wheel and the rail vertical contact force, track irregularity selected the six spectral level irregularity as the input excitation for the relevant calculation.(2) According to the finite element analysis model is established, in traffic speed of 80 km / h, the fastener stiffness 50000N/mm, fastener support spacing 0.625 m conditions, calculation, the dynamic characteristic of the structure of the four tracks and do comparative analysis. In the running process of metro, track structure were as vehicles to and from exhibit oscillatory changes, track structure vibration damping measures to increase, the amplitude of the dynamic response of track structure except indicator displacement with resilient track structure increases outside, acceleration, force were compared to ordinary slab track structure becomes smaller.(3) Through the vehicle body acceleration, wheel rail interaction force, the derailment coefficient and wheel load reduction rate stability and safety of different track structures of the subway in dynamic performance evaluation, the vibration acceleration level and one-third octave of damping effect were analyzed.(4) Analyzed the influence of the orbital parameters, from the different speed and fastener stiffness, fastener damping, fastener spacing calculated dynamic response of track structure, the influence of different parameters on the four track structure, with the increase of speed, track structure indicators showed increasing trend, fastener stiffness changes on rail acceleration and displacement has a obvious effect, damping increases can effectively on rail acceleration "clipping", its amplitude decreases significantly, fastener spacing changes in track stiffness changes, fastener spacing should not be too large should be kept within a reasonable range.Through the analysis and research of this thesis, the subway construction in track structure type selected to provide the corresponding reference value, should follow the local conditions, the principle of economical and reasonable, select suitable and form of subway track structure to meet the requirements.