The Vertical Vibration Of The Train - Track - Bridges Time-varying Systems

With the constant increase of train speed, the dynamic interaction between vehicle, track and bridge is increasing gradually. Although a large number of problems on vibration of vehicle-track-bridge system have been studied at home and abroad, a variety of research methods are different from each other, and there are still some issues that have not yet been well solved. Vertical vibration of vehicle-track-bridge time-varying system has been further studied in this paper. The major work and achievements are as follows:1. Finite element method was used to establish the vertical vibration equation of the vehicle-track-bridge time-varying system. The "moving-connecting element" which was proposed in this paper realized the coupling of vehicle-track system in element; this can not only simplify the establishment of vertical vibration equation greatly, but also conduce to programming and solving equations.2. The defect of the shape function adopted in beam element which contacts the wheels was studied in analysing vertical vibration questions of vehicle-track-bridge time-varying systems. A new shape functionwhich is suitable for this problem was proposed.3. With "moving-connecting element", the dynamic relationship of wheel-rail was realised easily, and the additional stiffness matrix and damping matrix of the vehicle-track-bridge time-varying system caused by dynamic relationship of wheel-rail were educed.4. Based on the theory of vertical vibration analysis of vehicle-track-bridge time-varying system proposed in this paper, and with the Matlab as the secondary development platform, the dynamic analysis programs were made, and the simulated calculation about examples were carried out. 5. The influence of the additional stiffness and damping matrixes on vibration response of vehicle-track-bridge time-varying system was studied by examples.The results show that for the system of uniaxial car body-simply supported beam, the maximum deviation of acceleration response of the car body between the two cases(considering the additional items and not considering the additional items) is up to 28%;and for the system of four axises vehicle-track-bridge, the maximum influence of additional items on vertical displacement response of the car body is up to 30%.