EXPERIMENTAL AND NUMERICAL INVESTIGATION OF THE DYNAMICS OF THE FLOATING FLOOR AND PASSENGER SEATS OF A RAILWAY VEHICLE

In recent years, passenger comfort has gained greater attention from service providers and rail vehicle manufactures. Carbody vibrations perceived by the passengers mainly contribute in the low frequency range (i.e., below 50 Hz) and originate from the geometric defects of both wheel and track. The vibrations are then transmitted to the passengers through the suspension stages, and finally reach the carbody, the floor, and the seats. For an accurate estimation of the transmitted vibration, which is particularly important at the design stage, the dynamic behaviour of all the vehicle subsystems should be thoroughly studied and correctly modelled. Furthermore, the coupling effects of the assembled system should be appropriately accounted for. In the current work, the coupled dynamics of two vehicle subsystems, namely the floating floor and the passenger seat, is investigated. Laboratory tests are carried out to firstly determine the modal parameters and frequency response of the floating floor system. Then a test bench of the coupled floor-seat assembly is set up. The results demonstrate a strong effect of the floor-seat coupling on the assembly's frequency response. In parallel, FE models are developed based on the experimental results, and a satisfactory agreement between the simulated and the identified vibration modes is reached. Hence, the developed models are believed to be useful tools for the estimation of the vibration levels perceived by the passengers, and for the assessment of ride comfort. Moreover, the proposed methodology relying on both labora-tory tests and numerical models proves to be a promising approach towards the design and optimization of rail vehicle subsystems.