A New Method For Calculating Vibration Characteristics of Elevated Slab Ballastless Track

摘要

In this study, a new finite element model for elevated slab ballastless track is proposed in which the new model can be used for modeling the track structural constituents of elevated slab track. Using finite element method and Hamilton theory, the coupled equation of vehicle-track-bridge can be established and the program has been implemented via Matlab software. As an example, the wheel-rail interaction forces induced by "China Star" vehicle were calculated. Specifically, the four-layer beam model for elevated slab ballastless track has shown high performance in the numerical example of previous research. As an application, the impact of fastenings stiffness on track dynamic responses is investigated. The results show that fastenings stiffness will produce impact on both vibration acceleration amplitude and vibration level. And with the improvement of fastenings' stiffness, vibration acceleration amplitude of rail and the wheel-rail interaction forces will be increased more prominent but the displacement of rail will decrease. The vibration level of rail, in range of 1 ~ 40Hz will decrease prominently with fastenings stiffness increase and in range of above 50 Hz will increase with fastenings stiffness increase. The vibration level of slab, in range of 25 ~ 80Hz will decrease prominently with fastenings stiffness decrease. The average decreased value is 3.5dB and the effect of vibration attenuation will increase with decrease of fastening stiffness. The vibration level of bridge, in range of above 40Hz will decrease prominently with fastenings stiffness decrease. The decrease value can reach 12. 6dB and the effect of vibration attenuation will increase with fastenings stiffness decrease.