Asymmetry In Orbit Around The Train-of Fbs Type Track System Dynamic Response Analysis

With the rapid development of passenger dedicated lines and city mass transit in China, ballastless tracks have been rapidly constructed for its higher stability, less maintenance and mature technique. As a result of the high-speed of train, the dynamic responses of the train and ballastless track attract more and more attention by scientists.Most of the vehicle-track models in the literature assumed symmetric vehicle-track in order to simplify the calculation. Generally speaking, this simplification is reasonable for many cases, such as vertical irregularity appear at the same position on both rails, or the left and right rails with symmetrical support etc. However, for the asymmetrical cases, such as the left and right rails with asymmetrical support, and the vertical irregularity of the left and right rails being asymmetry and so on, an symmetrical vehicle-track model is not accurate. Therefore, an asymmetrical vehicle-track model should be developed to solve asymmetrical problems. This thesis studies the vertical dynamic response of train-FBS ballastless track system, which the left and right track are asymmetric. The major jobs completed are as follows.1. The vehicle and track are considered as an entire system. The vehicle is modeled as a multi-rigid body with 14 degrees of freedom connected by springs and dampers. The left and right rails are simulated as two long Euler beams supported by discrete viscoelastic supports, and the slab is simulated as a short Euler beam supported by continuously viscoelastic foundation. The vibration equation of the train-track system are formulated by using the principle of total potential energy with stationary value in elastic system dynamics and the " set-in-right-position " rule for formulating matrixes. The equations are solved by the Wilson-θstep-in-step integration method, then the dynamic responses of the system can be obtained. The corresponding computer program is compiled with MATLAB.2. With certain sine wave periodical irregularity as vibrating resource, some time-history of the system are given. Compared with the results obtained by the literature, the correctness of the presented model and program are verified.3. On the basis of the track vertical free vibration model, the free vibration of the FBS ballastless track is analyzed by means of subspace iteration method. The first five vertical free vibration frequencies and modes are put forward.4. The random vertical irregularity samples are formulated by trigonometric progression method and corresponding computer program is compiled with MATLAB, the random vertical irregularity samples of Zhengzhou-Wuchang line are put forward.5. The effects of the left rail fastener looseness, the left rail with local vertical irregularity, the left and right rails with random vertical irregularity on the dynamic responses of the vehicle-FBS ballastless track system are studied, and the dynamic response rule of the system at different speed is analyzed.