Low Frequency Acoustic Performance of Close-Fitting Sandwich Panels

The experiment presented in this paper was to investigate and analyse the noise reduction at low frequency of porous material used to line the cavity between two panels of a double-panel structure. The effects of panel construction, fibreglass and cavity depth have also been studied. The structural-acoustic coupled system of a sandwich structure, backed by a rectangular acoustic cavity of rigid walls is discussed. It is found that the sound insulation of a combination of a stiff thick and a thin flexible plate panel, with air cavities and porous material in-between, is more effective than that of the conventional double-wall panel at low frequency.