ABSTRACT
Combined with the vibrating testrig of full vehicle, the coupling vibrations were investigated by applying the rigid-flex coupling simulation techniques for 160 km/h rapid freight covered car with full opening side-doors. The consistent conclusions derived from both simulations and tests indicate that the ca. 8.5 Hz dominant frequency of vertical resonance occurs at the fore or rear partial centre of roof, which can be proved the 1st vertical bending mode of floor frame, instead of the roof inherent modal vibration. The improvements are then necessary to reinforce the end partial floors and the end walls. Otherwise some vibration failures will take place if the deformation compatibility of roof becomes one of the sensitive factors to the dynamical load effects of constraint inner forces. So the correlative excitations produced between lightweight-designed carbodies and running gears are avoided as possible by decreasing the local general masses at both ends of floor frame.
