Prediction And Optimization Of Cabin Noise Of High-speed Ship Based On Statistical Energy Analysis Method

With the development of the social economy and the improvement of the people’s living standard, the number of people who are in favor of high-speed ships is on the increase. As high speed passenger transportations, official patrol ships, or entertainment tools, high-speed ships are getting more and more attention. However, vibration and noise problem in high-speed ship is severer than that of other ship types, thus designers have to begin the acoustic design in the early stages of high-speed ship design. In this study, statistical energy analysis (SEA) is presented for the prediction of structure-borne sound transmission in the high-speed ship and the first-order sensitivity analysis of vibro-acoustic systems is presented as well. What’s more, the optimum damping location and thickness for the engine room is obtained in the SEA frame work.The main work is as follows:(1) Modeling method for the SEA model is studied and shipboard cabin noise is predicted by using VA One. At first two models depending on whether it contains stiffened plates are modeled. The energy flow rules are analyzed when the calculation don’t consider noise control treatment (NCT) in the two models. Then influence of pillars for the propagation of structure-borne sound is studied. At last, the NCT is included in the models and shipboard cabin noise is predicted. It is found that the stiffened plates, NCT and pillars should be considered in the SEA model in order to improve the accuracy of the model. The mean absolute difference (?) between SEA estimates and measured A-weighted sound pressure levels is0.4±0.8dB when6cabins of a different type are evaluated.(2) A SEA program with MATLAB is compiled in order to study the first-order sensitivity analysis of vibro-acoustic systems. There is a steep change in sensitivity at the values of ηi=0.02, but when ηi changes between0.02and0.1, the sensitivity changes slowly. There is little change at the case of ηi>0.1. Results of those studies can give some references for the design and analysis of the damping system. (3) Through the use of MATLAB, the study takes advantage of optimization tool box and Secondary Development of VA One is implemented. The theory of constrained layer damping treatment such as T54/T60in VA One is discussed. The optimum damping location and thickness for the engine room is obtained by the Secondary Development of VA One. When the thickness ratio is X=(0.97521.16530.93091.36541.4128), the constraining layer thick is Hc=(4.85125.99184.58547.19247.4768), and the total weight of the T54/T60is619.054kg.