Application of modal parameters on ride quality improvement of railway vehicles

In this paper, a synthesised performance analysis with modal parameters (SPAMP) method is proposed to solve vibration problems of railway vehicle. With the SPAMP method, relations between modal parameters, physical parameters and ride quality are built at first with a unified ‘track–vehicle–human’ model. Then they are used with experimentally identified modal parameters and response power spectral densities to find ways to improve ride quality. Using this method, the low-frequency vibration problem of a kind of speed-up vehicle in China is researched. It was found that low-frequency vibration of the vehicle is mainly caused by lower sway mode vibration, whose identified damping ratio is very low. So once excited, it cannot be effectively suppressed. With the help of relations built with a virtual prototype, the physical parameters of the bogie are changed, and then the low-frequency vibration problem is solved.