A coupled FEM/BEM for solving fluid-structure interaction problem in structure-borne noise propagation and underwater acoustic radiation is present in this paper. In order to improve the habitability and stealth low noise condition is required in various types of ships. One of the dominant components is the radiated airborne and underwater noise caused by ship hull vibration. Accordingly, the estimation of structure-borne sound characteristics of a ship is important in the design of a quieter ship-structure. The hull vibration response and pressure distribution on the wetted surface of a ship subjected to excitation sources can be analyzed by utilizing the developed method. Further discussions on the evaluation of surface complex power, radiation and reactance power have been conducted. Two cases were studied, a submerged spherical shell subjected to a uniformly harmonic pressure excitation and a scale model of engine room structure subjected to machine excitations, to illustrate the applications of the analytical model. The surface pressure, the normal velocity on the wetted surface, the surface complex power, the radiation power, the reactance power, the vibrational displacement and the radiated underwater sound pattern have been computed. Comparison of the predicted results and that by measurement indicates that the numerical model is creditable. In addition, the effect on underwater acoustic radiation at the elastic mounts for the engine is discussed.

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