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Underwater Acoustic Radiation of an Elastic Rectangular Plate Covered by a Decoupling Coating
Defence Research Establishment Atlantic Dartmouth, Nova Scotia Canada
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The reduction of the sound radiated by a finite structure immersed in water on one side is of concern in this paper. The purpose of this study is to investigate the decoupling effect of adding a compliant layer between a base structure and the fluid. The vibration response and the acoustic radiation of a baffled, elastic plate covered by a decoupling layer immersed in water is analyzed. The theoretical model uses the Love-Kirchhoff theory to describe the motion of the base plate whereas the locally reacting model is used for the behavior of the coating. A parametric study is performed in order to understand the decoupling mechanism and the noise reduction effect of such structures. The locally reacting model assumes that the decoupling layer behaves like evenly distributed springs in the transverse direction. The unknowns of the problem i.e. transverse displacement of the base plate and acoustic pressure in the fluid are expanded with trigonometric functions that satisfy the simply supported boundary condition. The radiation impedances of the plate-fluid system are calculated using a numerical algorithm.
APPROVED FOR PUBLIC RELEASE