Improving the noise reduction performance of gangway bellows by using multilayered structures

Abstract

Excessive interior noise in railway vehicles is a major cause of fatigue and discomfort for passengers. In particular, the between-cars sections of high-speed trains experience considerable interior noise due to the poor noise reduction performance of the bellows, which are primarily made of silicone rubber and thus have a lower density than that of other components, made of extruded aluminum. Therefore, the objective of this study was to improve the noise reduction performance of such bellows. First, the material properties of silicone rubber were analyzed. Based on the results, the noise transmission of a simple model was analyzed to determine approaches required to reduce the low-frequency interior noise of the between-cars sections. It was confirmed that the low-frequency noise could be reduced by incorporating a multilayered panel of silicone rubber. Therefore, multilayered structures were considered for incorporation in the interior space of the between-cars sections of an actual high-speed train. A curved driving simulation of the between-cars sections indicated that no interference occurs when applying the proposed approach. Furthermore, a comparative test regarding the noise reduction performance was conducted considering cases involving bellows with and without multiple layers. The results of the verification test demonstrated that the noise reduction performance when using the proposed approach was improved by 4 dB compared with that in the case involving the conventional bellows, and an improvement of 8 dB or more was observed for noise with a low-frequency of 100 Hz.