Cabin Noise Prediction and Control of a Car-Passenger Ferry

This paper investigates the cabin noise prediction and control for a newly-designed car-passenger ferry. The Statistic Energy Analysis (SEA) software VA One is used to predict the noise levels in all cabins of the ferry, while the structure-borne noise and air-borne noise, caused by the external excitation from the water-jet, propelled and auxiliary engines, pumps and fans, etc., are obtained with the empirical formula. The measured air-conditioning vibration is also loaded. The characteristic analysis method is used to analyze the transmission modes of the structure-borne noise and air-borne noise, and the results indicate that the structure-borne noise spreads further than the air-borne noise. Next, the primary noise sources for different cabins are analyzed, where the noise of cabins under the forecastle deck is mainly from the machinery space, and the noise of superstructure is mainly from the air-conditioning. Accordingly, the damping material and sound absorption material are used to reduce the noise in the noise-excessive cabins. Finally, the limitation in the application scope of the statistical energy analysis is pointed out, and the method is seen to be suitable for the cabin noise prediction and acoustic optimization in the stage of ship design. The results obtained in this study may be used to provide a reference for the 100 m class ship design.