Abstract
Due to the layout of the door in the middle and air-conditioning installation hole at the top of the carbody of some inter-city electric multiple unit (EMU) in China, the flexural rigidity of carbody structural decreased obviously based on the modal frequencies calculated by finite element model (FEM). The theory of dynamic vibration absorber (DVA) was applied to restrain the vibration of carbody. A 3D rigid-flexible coupled vehicle dynamics model was established by combining the multibody dynamics theory with the FEM to simulate the response of carbody and underneath equipment to measured track excitation. The traction transform weighing 5956 kilogram selected to be the only underneath equipment was studied. The result shows that the elastic connection between carbody and traction transform has a significant influence on carbody vibration. Compared with the rigid connection, the elastic connection can reduce the vibration of carbody from the maximum vertical acceleration 0.368m/s^2 to 0.193m/s^2 and the lateral vibration acceleration from 0.276m/s^2 to 0.229m/s^2. The reduction of vertical vibration is more obvious than the lateral vibration. The underneath equipment of carbody can be regarded as a dynamic vibration absorber (DVA) to reduce the flexible vibration of carbody. Also, the suspension parameters of elastic connection affect the carbody and traction transform vibration greatly. To meet the high speed of the vehicle operating conditions, the individual vertical stiffness of traction transformer should be designed in 6MN/m〜10MN/m while the suitable vertical damping ratio can be 0.1.
