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

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

Douglas A. Rebinsky

Andrew N. Norris

Dept. of Mech. and Aerospace Eng., Rutgers Univ., Piscataway, NJ 08855-0909

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.]