Vibration Analysis of Railway Vehicle by Evaluating the Coupled Passenger-Carbody Vibration

摘要

Lightweight railway car body structure is a very important factor for the speeding up and the energy saving of the high-speed railway vehicles, such as magnetically levitated (MAGLEV) vehicles, and high-speed bullet train, Shinkansen. However, as lightening car body decreases the bending rigidity of the car body, the various elastic vibrations are liable to be induced in the car body, which results in deteriorating ride comfort for passengers. The deterioration of riding comfort concerns to this issue, because the natural frequency (around 9 Hz) of the above mentioned vertical vibration overlaps with human's uncomfortable sensitive frequency band (around 6 Hz). However, passenger weight in conventional method of vibration analysis of railway vehicle is often treated as an increase in car body weight and the analysis that considers passenger vibration characteristics was not conducted. Based on experiments using real vehicle, it is reported that there are some car body vibration characteristics with passenger that cannot be explained by considering passenger to be an increase of vehicle body weight. In such case, the dynamics of passenger cannot be neglected, and it is possible that the vibration characteristic of the car body is coupled with the vibration of passengers. To deal with this vibration problem, the active suspension is applied to the secondary suspensions, and the active elastic vibration suppression technique by smart structural technology are carried out as the effective control of vibration for the ride comfort improvement Consequently, conventional method doesn't evaluate that consideration of coupled vibration characteristic of passenger and car body when there are passengers getting on. Therefore, the synthesis of a new evaluation method is expected for more accurate ride comfort evaluation. The establishment of a new evaluation method is expected for an accurate riding comfort evaluation method.rnIn this study, a special experimental setup (vibration platform) was contracted in order to investigate the coupled vibration of human body and flexible car body, the mass ratio of which is analogous to that of passengers and actual railway vehicles. After analyzing the human body behavior affecting flexible car body vibration, computer simulation has been conducted by using multi-degree-of-freedom flexible vehicle model of Shinkansen. The simulation analysis reveals that the resonant frequency of the first bending vibration mode depends on the passenger-seat dynamics, and the sensitiveness of the resonant peak is affected by the dynamic interaction, that is, coupled vibration between passengers and car body.