### ASA 124th Meeting New Orleans 1992 October

## 4pSA2. Acoustic radiation from a multilayer sandwich plate subjected to a
point-harmonic excitation.

**M. Kim
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Y. F. Hwang
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*Carderock Div., Naval Surface Warfare Ctr., Bethesda, MD 20084-5000
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An exact mathematical formalism was developed to calculate the acoustic
response of a fluid-loaded, multilayer, sandwich plate subjected to a
point-harmonic excitation. The plate can be fluid loaded on each side with
arbitrary acoustic media. The solution was verified with asymptotic solution of
a fluid-loaded thin steel plate. Numerical examples are presented for the
acoustic radiation into water from various plate configurations subjected to a
point force acting on its dry (air) side. The plate configurations considered
are: (1) a two-layer elastic/viscoelastic plate, (2) a three-layer symmetric
elastic/viscoelastic/elastic sandwich plate, and (3) a three-layer nonsymmetric
elastic/viscoelastic/elastic sandwich plate with the viscoelastic layer given a
range of different material properties (elastic constants, damping) and
thicknesses. To elucidate the radiation mechanisms, the behavior of the modes
of wave propagation in the plate is discussed. [Work supported by ONR.]