A novel vibration analytical model for thin-walled box-like long cylindrical structures combining elastic plates and straight and curved beams

Abstract

This paper proposes a novel analytical model for elastic vibrations of thin-walled box-like long cylindrical structures, commonly observed in railway vehicle carbodies, aircraft, and buses. Here, we focus on railway vehicle carbody, where three-dimensional elastic vibrations are a significant problem for improving ride quality. The carbody is modeled as a box-like structure consisting of elastic plates and beams. The condition to connect those structural members is satisfied by introducing artificial springs at their joints. From observations of some actual carbody's elastic vibration modes, it has already been found that the relative vertical deformation between the roof and floor interacts with lateral deformation of side structures. To express this three-dimensional deformation simply, the authors introduce curved elastic beams as pillars in the side structures in this study; therefore, the newly proposed model is called the curved box model. The free vibration of the curved box model has been investigated in this paper by applying the Ritz method to derive the eigenvalue problem. The modal characteristics (natural frequencies and mode shapes) of elastic vibrations are calculated. The vibration analysis procedure is validated by comparing those results with those obtained from a finite element model. As some numerical examples, the effects of cross-sectional shape changes on the natural frequencies of elastic vibration modes are presented.