Investigation On Acoustic Design Technology And Underwater Noise Prediction Of Ship’s Structure

The controlling of ship’s underwater noise is the main goal of acoustic design of theship structure. As a fundamental rule of acoustic design, the prediction of acoustic characterof the ship structure should be carried out in the period of ship design. A biggish reductionof vibration and noise would be achieved with less cost if considering all kinds of acousticrequirements and reflecting them in the structure design of ship in the early stage.The character of vibration and acoustics of the ship structure, including vibrationtransmission, sound insulation and acoustic radiation, should be considered as much aspossible, which is the basic mission of the acoustic design of the ship structure. As a result,the character of vibration and acoustics of the key components of the ship structure shouldbe studied by means of FEM, BEM and SEA. The effect of different structure parameterson the transmission of vibration should also be investigated, and the underwater noise offuture ship should be predicted, too.In this article, the acoustic design based on CAE of a given ship was carried out,which was based on the initial structure design. First of all, the model of FEM of the initialship was built, and the character of vibration and acoustics was estimated. The vibrationresponses with different structure parameters were obtained through the calculation for keycomponents. Then, the underwater noise in low-frequency band was predicted by acousticcalculation based on FEM. The underwater noise in high-frequency band was thenpredicted by means of SEA. As a result, the prediction of underwater noise of full band wascarried out. According to the simulation results of ship’s vibration and underwater noise,the scheme of acoustic design of the ship structure was finally determined in the premise ofmeeting the efficiency and reliability of the ship.According to the requirement of the ship project, a software of quickly estimating theunderwater noise, which is designed by using GUI of MATLAB and based on theparametric modeling of PCL, was developed based on above methods. As a result, theauxiliary acoustic design of ship structure was achieved. The FEM model of the ship withcertain type can be built immediately through the parametric modeling with this software.The primary structural parameters that affect the vibration and underwater noise of the shipcan be investigated. The underwater noise radiation and the sound pressure level would beobtained as well. The veracity of the software and the feasibility of investigated methods adopted in the article were checked by the real ship test of vibration and acoustics. Itproved valuable in practical application for the research work in accelerating the acousticdesign of special ships.