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

2pSA6. Acoustic interaction with wedge-shaped structures.

Andrew N. Norris

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

This paper will review recent developments in solving canonical structural acoustics problems involving wedgelike structures composed of plates and membranes. The two cases considered are (i) a membrane held taut over a line constraint, and (ii) two semi-infinite thin plates welded together to form a wedge. The wedge-shaped structures are subject to unilateral fluid loading from an acoustic fluid. The method of Malyuzhinets, which was used in the 1950s for the purpose of dealing with simple impedance-type boundary conditions on the wedge faces, has recently been significantly developed by A.V. Osipov, who has shown how it can be successfully applied to these structural acoustics problems. The central idea of the Malyuzhinets/Osipov method is to express the acoustic pressure using a generalized Sommerfeld integral, similar to a Laplace transform. The main analytical steps in the solution will be discussed, and some numerical results will be presented. The plate structure is particularly interesting because both subsonic flexural and nonleaky supersonic structural waves are excited at the vertex by an incident acoustic wave. Interesting asymptotics emerge when the wedge angle described by the fluid is almost 180[sup o] or 360[sup o]. [Work supported by ONR.]