### ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

## 2pSA1. Scattering from fluid-loaded junctions of plates and shells.

**Douglas A. Rebinsky
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Andrew N. Norris
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*Dept. of Mech. and Aerospace Eng., Rutgers Univ., Piscataway, NJ
08855-0909
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This paper will review recent results for several related problems
involving plate and shell junctions in the presence of fluid loading. First, a
general solution will be discussed which gives the acoustic and structural
scattered response for two joined flat plates under unilateral fluid loading. By
combining this with a related solution for the admittance matrix of the
fluid-loaded plates, the behavior of a pair of semi-infinite plates in contact
with fluid on one side and a mechanical structure on the other can be modeled.
For simplicity, the internal frame is characterized by an impedance matrix.
Based on these results, a perturbation solution can be developed for two joined
curved shells under unilateral loading. The leading order term in the expansion
is the previously solved case of two joined flat plates, and the next term gives
an approximation of the diffracted longitudinal and shear wave fields
originating from the junction of two shells. In each example considered,
explicit formulas are obtained for the pressure transform, and corresponding
explicit and relatively simple expressions are given for the various diffraction
coefficients associated with the fluid/structure interaction. The general method
of solution uses the Wiener-Hopf technique to solve dual integral equations for
the acoustic pressure. The plates and shells are modeled by the classical theory
of flexure and thin shell theory, respectively. Numerical results of the
diffraction coefficients and the redistribution of energy at structural
junctions will be presented. [Work supported by ONR.]