Study On Rigid-flex-coupling Simulation Of Container Flatcar And Vibration Damping Strategy

In order to analyze the vertical vibration problem of single-deck and double-deck container flatcars, the rigid-flex coupling models of flatcars were established by the flex-body interaction transaction technology (FITT), and the full vehicle was constituted with the cross-braced-rod supported 3-piece bogie. In the contrast simulations of rigid-flex coupling systems, the reasons of both vehicles'vibration were found and the corresponding vibration damping strategies were proposed.In the dynamical tests and line measuring tests, some problems of container flatcar is found to be existed, for example, vertical vibration acceleration is on high side of the flatcar body. From the viewpoint of structural modal vibration analysis, the causation of this on-high-side vertical vibration acceleration should be existed, i.e., the vibration sources and the excited modal vibration of flatcar body, therefore, the simulation analysis technologies of rigid-flex coupling system need to be adopted, for instance, FITT which can be represented the deformation characteristics of flex-body, and the dynamical simulations and modal analysis of full vehicle on rails.The following conclusions can be drawn from the multi-line dynamical simulations: for single-deck container flatcar, whose structure has fish-bone feature, so the main reason of flatcar producing vertical vibration is the wedge friction jamming in bolster suspension. The bigger the wedge friction coefficient, the more remarkable the stick-slip vibration caused by the wedge friction jamming in the low-frequency bolster motion process. Therefore, these stick-slip vibrations must bring the flatcar body to produce the high-frequency elastic vibrations, and is referred to the on high-side vertical vibration acceleration problem. The flatcar's elastic vibration is formed by the 2nd vertical bending modal.The reason for double-deck container flatcar vibration is quite different from single-deck container flatcar. The double-deck flatcar body has the structural characteristic of the well-hole wagon, in which the stiffness of side beam is relative low and the frequency of carbody's lateral modal is also low. So the elastic vibration is not excited by the carbody's vertical modal vibration, but is caused by the side beam's lateral modal vibration. The characteristics of carbody's elastic vibration is dependant on the case-loading modes, only when the 20ft×2 cases on the top and bottom decks the 1st vertical bending modal vibration is appeared, in the other modes the carbody's lateral vibrations are arisen mainly.With respect to the different causes of single-deck and double-deck container flatcars, the following proposals of special-design 3-piece bogie were presented: Firstly, for single-deck container flatcar, which body stiffness is relative low, the conbined wedge of high molecular material is required in order to satisfy the lowing of relative friction factor;Secondly, for the double-deck container flatcar, the height of which laden mass center is relative high and carbody's lateral stiffness is also relative low, so the suitable strength mend of carbody's lateral stiffness needs to be considered, and the stiffness of bolster suspension should be increased by the central bolster spring to improve the carbody static stability.