Abstract
The elastic vibration of railway vehicle car body causes deterioration of ride comfort because the natural frequency of the vibration is the same frequency that people feel sensitively. Therefore, it is necessary to reduce the elastic vibration. It has been shown that passenger has large reduction effect against elastic vibration of railway vehicle car body. That effect is considered due to viscoelastic motion and multi-directional motion of human body. This study focuses on the latter one and aiming to develop a new vibration reduction device to mimic the multi-directional motion of passenger. In this paper, an experimented multi-directional dynamic vibration absorber (called MDDVA in this report) is developed. The MDDVA consist of a resiliently supported metal ball and elastic ball to support metal ball bottled in a rigid cylindrical vessel. The metal ball can vibrate multi-directionally in the vessel and is expected to work as a MDDVA. In addition, it can change the natural frequency of MDDVA by pressing the elastic balls from the top according to the natural frequency to the target car body. Excitation test using a scale model of railway vehicle is conducted to evaluate the effectiveness of the MDDVA. As a result, MDDVA can reduce the elastic vibration by adjusting the natural frequency of MDDVA to that of the scale model by pressing the elastic balls, and multi-modal vibration reduction effect is successfully observed.
