Study on accuracy improvement of predicting radiated sounds from interior panels using vibration speakers

Abstract

Interior noises of railway vehicles especially on a high-speed railway are composed of a solid borne sound and a transmitted sound. It is necessary to take measures which consider the contribution ratio of radiated sound from each part in the interior of the car or the propagation path of these sound so as to reduce the interior noises efficiently. Moreover, the effect of reducing interior noise should be predicted before any measures are taken. In this study, we focused on predicting the interior noise with transfer functions and verified the proposed method proposed by conducting experiments using a high-speed railway test car and vibration speakers. In this paper, we made an attempt to improve the accuracy of noise prediction. First, we carried out shaking tests to estimate transfer functions using vibration speakers. On the basis of the acceleration of measuring points and the sound pressure of evaluation points on more interior panels than previously measured in the tests, the transfer functions were estimated. Secondly, we carried out the shaking test to simulate the acceleration of interior panels under the condition of train running. Finally, the interior noises were predicted by multiplying the acceleration obtained in the latter test by the transfer functions. As a result, the proposed method mostly predicted the interior noises and improved the accuracy of noise prediction.