Vehicle modelling for high-frequency vibration transmission through primary suspensions

A great part of interior noise of high-speed trains results from vibrations above 100 Hz, which is transmitted through the bogie. To describe the dynamic behaviour of the bogie in this frequency range, the multibody vehicle model is extended by taking into account the structural dynamics of the wheelsets, axle boxes and bogie frames, and by employing more detailed models, which describe the dynamic stiffness of the primary suspension components such as roller bearings, hydraulic dampers, rubber bushings and coil springs. The extended vehicle model is then coupled to a track model by wheel-rail contact models to build an enhanced coupled vehicle-track model. Laboratory measurements for individual components such as the bogie frame and the hydraulic damper and field measurements for the entire vehicle are carried out to verify the enhanced model with special focus on its capability to describe the transmission of high-frequency vibrations. By using the enhanced model, it is investigated which components are the most relevant ones for the transmission of the vibrations from the axle box to the bogie frame. Results show that the vibrations are mainly transmitted by the rubber bushings. These findings provide a better understanding of the dynamic behaviour of the bogie.