Abstract:
Floating lining systems have been adopted to reduce the noise level in cabins, and the reduction level has been about 10 dB(A) as compared with no floating lining system. The authors pointed out the reason the conventional floating lining systems have poor effects and proposed a concept for a new floating lining system, which consists of a box made of four lining walls and a ceiling set on a floating floor, and the box has as few connecting points with steel structures as possible. In order to promote the system for practical use, experiments were carried out by using a two-third scale model of a cabin. The first experiment with the lining set on a floating floor was carried out without a connecting point to the steel structures, and, in the second step, a rubber piece connected the lining ceiling with the steel structures to prevent lining deformation by the motion of a ship. The second experiment was done to investigate the influence of a connecting point on the vibration level of the lining. As a result, the proposed system could be expected to reduce the vibration level by about 20 dB in the high-frequency range as compared with the conventional floating lining systems.