Krylov Shipbuilding Res. Inst., 44 Moskovskoe shosse, St. Petersburg 196158, Russia
Complex closed shells divided into separate sections by partitions and decks with various kinds of interior equipment are used in the engineering practice quite frequently. The reduction of vibration and noise for these structures is very important at the stage of designing. The authors have developed an energy approach to an acoustic optimization of complex structures. It is based on a minimization of a total structure oscillation energy spectrum. It was indicated that the total oscillation energy estimates vibration and sound radiation of structures quite fully. As an example, the acoustic optimization of the multi-section cylindrical shell equipped with dynamically loaded interior solid bodies was produced with the help of FEM. The reduction of the total oscillation energy was received by changing of partitions stiffness, sizes of separate sections, and dislocations of interior solid bodies for a wide frequency range. The main rules of complex shell structure acoustic designing were formulated as the result of thorough computation investigations.