Proposal of suspended floor structure for reducing interior noise of railway vehicle

Abstract

In this study, we propose a new floor structure “suspended floor” as one of the countermeasures against the interior noise of a railway vehicle. The interior noise of a railway vehicle is mainly composed of the transmitted noise and the structure-borne noise from floor panels, where the vibration of the bogie is propagated. Although floor panels are generally supported on joists mounted on the floor structural panels, it is possible to reduce the vibration of floor panels by suspending them from less vibrating points. We investigated the vibrational characteristics of the car body and clarified that the vertical vibration of the side structural panel is less than that of the floor structural panel. Therefore, it was expected that the floor structure in which floor panels are suspended from side structural panels is effective in reducing the vibration of floor panels. The floor structure prototype was fabricated in the test car, and experiments have been made to verify the vibrational reduction effect. As a result, the sound power radiated from the floor panel was reduced by 5-10 dB. In conclusion, the suspended floor structure is effective in reducing structure-borne noise in a railway vehicle.