Study On Theory And Application Of Track Stiffness In High-Speed Turnouts

The track stiffness of high-speed turnouts is a important parameter that impacts on running comfort of trains and vibration intensity of turnouts when trains passing through turnouts. So the reasonable disposition of the track stiffness in high-speed turnouts is necessary.According to several major issues involved in track stiffness of high-speed turnouts and in reference to domestic and international research, on the basis of theoretical and some experimental studies, some relative research conclusions are drawn. Thesis research work is divided into the following areas:(1) Influence analysis of track stiffness on spacial coupling vibration between high-speed vehicles and turnoutsA complete spacial coupling vibration model between high-speed vehicles and turnouts is set up in this paper. In the model, the longitudinal variety of the fastener and bed stiffness are taken into account. By using the model, the influence analysis of vertical stiffness of the uneven distribution of high-speed turnouts on high-speed vehicles - turnouts coupling vibration performance is feasible. With this model, some analysis about track stiffness influence on the vibration performance of vehicles and turnouts are done. The results show that: track stiffness change has considerable influence on vibration of the movable part of high-speed vehicles, car body and turnouts.(2) Study on dynamic track stiffness characteristics and its influencing factors of high-speed turnoutsdynamic track stiffness calculation model and solution methods of high-speed turnouts are firstly established, and dynamic track stiffness characteristics and its influencing factors of high-speed turnouts are also analyzed. The results show that: there are three resonance peak in various parts of ballest turnouts when frequency ranges from 0 to 250; there are one phase resonance peak in various parts of ballestless turnouts when frequency ranges from 0 to 300;fastener stiffness and damping have greater impact on dynamic stiffness of turnouts than bed stiffness(3) Study on reasonable value of track stiffness and track-part stiffness in high-speed turnoutsTrack stiffness components of high-speed turnouts and related calculational method have been detailed analyzed. Five criteria for evaluating reasonable track stiffness in high-speed turnout have been put forward: the vehicle running behavior, vibration intensity of track, the stress level of track, the deformation of track and coupling relation among track-part stiffness. A method how to determine track stiffness in high-speed turnouts has been established. Its core technologies include dynamic calculation between high-speed vehicles and turnouts, and analysis with dynamically expanded gauge. Finally, according to evaluation criteria of reasonable stiffness about high-speed turnouts and determination methods, some research are made on appropriate value of track stiffness with high-speed turnouts and reasonably coupling stiffness study among components. Some results from the following research can guide designs on fastener stiffness of passenger dedicated line.(4) Study on distribution regularity of track stiffness and influence factors analysis in high-speed turnoutsUsing the finite element method, on the basis of considering some factors such as the rail types, fastener, bed, block space and sliding plate which have impact on track stiffness, a complete calculation model which determine the track stiffness of high-speed turnouts is built and relative calculation program is written. Distribution regularity of track stiffness in turnouts on passenger dedicated line is analyzed through built calculation methods. Likely, some influence factors of track stiffness are studied such sliding plate linking,switch rail cut,block space which can distribute loads,fastener stiffness,bed stiffness. The study results can provide a basis for track stiffness homogenization at high-speed turnouts. (5) Study on homogenization of track stiffness in high-speed turnoutsFrom some aspects such as stiffness values, track deformation and engineering feasibility, homogenization criteria of track stiffness in high-speed turnouts is firstly proposed. A new way to set uniform track stiffness by adjusting stiffness of the tie pad is explained. The calculation method about stiffness of the tie pad by using hyperelastic finite element theory is studied, and it can provide a theoretical foundation for stiffness design of the tie pads. Using homogenization criteria and methods which are described in the paper, some research is done on track stiffness homogenization of turnouts on passenger dedicated line and some corresponding engineering schemes are provided. In addition, Field test on track stiffness of turnouts was carried out, the test results show that the way of track stiffness homogenization in high-speed turnouts is reasonable, and calculation theory on track stiffness in high-speed turnouts is accurate.(6) Study on reasonable stiffness of the transition section around high-speed turnoutsOn the basis of analysis about structure characteristics of the transition section around high-speed turnouts, a method is established for its dynamic analysis. Some principle and evaluation index are set up for reasonably disposing the stiffness of the transition section around high-speed turnouts. By using the dynamic analysis method in this paper, the dynamic characteristics when vehicles passing the transition section around high-speed turnouts are analyzed, and some influence factors such as transition stiffness variance, the running directions and velocity are also analyzed. Lastly, the reasonable stiffness of the transition section around turnouts on passenger dedicated line is studied, and the study results can guide stiffness design of the transition section.