Dynamic evaluation of elastic bar in track transition section of fast-metro system

In China, the rapid development of fast-metro system, along with many dynamic problems in track transition section, threatens the safe operation of the metro system. Aiming at this practical issue, this article presents an evaluation on the dynamic behaviors of elastic bars in track transition section of the fast-metro system. Primarily, an effective global-local method for evaluating the performance of elastic bar is proposed based on vehicle-track-coupled dynamics, in which two important models are established, namely, the vehicle-track transition section-coupled dynamic model and the three-dimensional finite element model of elastic bar. Then, the dynamic property of elastic bar in track transition section of the fast-metro system is evaluated employing the proposed method, focusing on the fastener force, dynamic displacement of elastic bar, and stress of elastic bar. Finally, fatigue analysis is conducted to evaluate the service life of elastic bar in track transition section. Results show that the proposed global-local method is effective to evaluate the dynamic behaviors of elastic bar in track transition section in fast-metro system. Impact appears when vehicles run through the track transition section and it mainly influences the two fasteners on each side. Operational direction of vehicle has little influence on amplitude of displacement of elastic bar. When the vehicle runs at 120 km/h, maximum stress of elastic bar is 1050 MPa, which occurs inside the rear toe. From the perspective of long-term service, traditional track transition section is not suitable for fast-metro system, which should be redesigned.