Conventional passive suspension is effective for a particular frequency for which it is designed and fails to serve the purpose below a fixed frequency. Semi-active and active suspensions provide better isolation than passive ones but have limitations. The present work proposes a finite element model of a railway vehicle coach. A Nishimura air spring with a non-linear damper is provided between bogie frame and wheel axle to isolate vibrations in carbody. The ride behavior of the system is analyzed based on ISO comfort specifications and compared the same with passive suspension in the secondary suspension system. Present analytical and FE models are validated by comparing vertical and lateral PSD acceleration curves obtained from these formulations with the same obtained from the experimental test. It is observed that a non-linear air spring in secondary suspension provides a significant improvement in the vertical ride behavior of the railway vehicle system.
Sharma et al. (Wed,) studied this question.