Flexible vibration analysis for car body of high-speed EMU

摘要

The resonance of the flexible vibration of car body, which has not been detected before on a passenger coach, occurred recently on a high-speed Electric multi units (EMU) when the train was running at 300 km/h on Beijing-Shanghai line. In this investigation, the force transmission from track to car body via suspensions is elaborated first with possibly induced factors briefly discussed. Both the measurements and experiments in field and in laboratory were conducted to evaluate the resonances and the excitation as well as transmission. Moreover, a three-dimensional railroad vehicle model was built in a computational non-linear Multibody system (MBS) framework, in which the car body flexibility was modeled using Finite element (FE) method. The model was validated and shows good agreements with measurements. Furthermore, the measured wheel and rail profiles were used to analyze the wheel/rail interaction for both new and worn states. The effects of the wheel-rail contact conditions on stabilities, dynamics and riding comforts were also examined. Feasible solutions were promoted to avoid the resonance and following by validating tests. It shows that the high frequency excitation arises from the hunting motion of bogie that closes to the modals of the car body, leads to the resonance of the structure of the car.