音響系のモード特性同定と非加振点応答の予測

概要

論文の詳細を見る
In order to reduce the noise level in the cabin, it is important to extract the characteristics of acoustic system (dynamic properties of the cavity). When frequency response functions (FRFs) of the acoustic system are measured, acoustic excitation by an audio speaker is generally used and its capabilities have been already illustrated[1]. However, to expand the availability of the acoustic excitation, it is necessary to reduce the number of excitation points and to predict the FRF with respect to the point where it was not actually excited (the unexcited FRF). It has been well known that in order to predict the unexcited FRF, a set of modal parameter can be used, where the auto FRF is thought to be included in the data set. However, for the acoustic system the auto FRF is hardly measured because the speaker is not able to apply the excitation at an exact point, but to apply a volume velocity at a small area. Therefore, this paper presents a new method to predict the unexcited FRF under the condition that the auto FRF is not included in the data set. In this paper, modal parameters of the acoustic system of a real automobile cabin are estimated, and the FRF is predicted by the proposed approach. The predicted FRFs are compared with the measured FRFs.