Experimental study on vertical vehicle-rail-bridge coupling of medium and low speed maglev train based on track beam with different stiffness

In order to analyze and verify the adaptability of train to track beams with different stiffness, the dynamic response of vertical vehicle-track-bridge with different stiffness track beam is studied. Firstly, according to the actual vehicle-track-bridge coupling system, the corresponding mechanical and kinematic equations are established. The natural vibration characteristics of track beams (bridges) with different stiffness are studied, and the dynamic response caused by current control algorithm is analyzed. Secondly, combined with the 3-D model of vehicle-track-bridge and the actual system, the dynamic simulation and experiment of the coupling system of track beam with different stiffness in the speed range of 60 km/h are carried out. The results show that the vertical first-order natural frequency of track beam decreases with the decrease of track beam stiffness. When the deflection span ratio increases, the suspension gap fluctuation increases, but the increase of deflection span ratio within a certain range will not affect the tracking performance of control current, and the train is still in a relatively stable suspension state. For the track beam, with the decrease of stiffness, the vertical deflection of the track beam increases and the high-frequency vibration energy increases, which has a great impact on the vibration response of the coupling system. The research results of this paper can provide a useful reference for the optimization of suspension system of medium and low speed maglev train, line design, and the formulation of construction standard of maglev vehicle-track-bridge system. In addition, the research results of this paper can provide a theoretical basis for reducing the construction cost of track beam.