Using a small-scale reverberation chamber to improve a ship’s double sandwich panel noise attenuation performance

Regulations now require passenger ships to have low noise levels in accommodation spaces. Complex structural wall panels such as a double sandwich panels are often used to provide the required high noise attenuation. However, because of their complex structures, the prediction and improvement of the sound transmission loss (STL) of these panels often can not be achieved only with theoretical approaches. In this paper, an experimental approach using a small-scale reverberation chamber is applied to improve the STL of a double sandwich panel for installment in a ship. Firstly, a small-scale reverberation chamber is set up. For test chamber qualification, the STLs of a thin plate, a commercial ship’s sandwich panel and a high noise attenuation panel are measured and compared with those tested in a large-scale reverberation chamber and those calculated by the transfer matrix method (TMM). Secondly, the small-scale reverberation chamber is used to analyze the STL of a double sandwich panel in terms of the influences of the inside perforate plates and air gap thickness on attenuation. In order to improve the attenuation performance of the double sandwich panel, the STLs of test specimens with various materials between sandwich panels are measured and compared. Finally, the panel with the highest noise attenuation is proposed and verified using the large-scale reverberation chamber.