## 5pSA7. Interaction of structural and acoustical waves at a wedge-shaped junction of two fluid-loaded plates.

### Session: Friday Afternoon, May 17

### Time: 3:35

**Author: Andrew N. Norris**

**Location: Rutgers Univ., Piscataway, NJ 08855-0909**

**Abstract:**

Two semi-infinite elastic plates are joined along a line forming a wedge
structure with unilateral fluid loading in the sector of angle 2(Phi). The
structure is modeled using thin plate theory, allowing freely propagating
flexural and longitudinal waves. The junction is mechanically connected with an
applied force and moment acting there to simulate a possible internal
connection. The general 2-D solution is described for incidence of time harmonic
structural or acoustical waves. The method of Osipov is used to express the
total pressure as a Sommerfeld integral, the integrand comprising Malyuzhinets
functions and particular solutions of certain difference equations. The junction
conditions reduce to a system of eight linear equations. Numerical examples
indicate the coupling between the modes for different wedge angles, specifically
(Phi)=112.5(degrees), 135(degrees), and 157.5(degrees), for steel plates in
water. Acoustic plane wave incidence on the flatter junction (112.5(degrees)) is
converted almost equally, in terms of energy, among diffracted flexural and
longitudinal waves. The coupling to flexural energy increases with the wedge
angle, at the expense of the longitudinal energy which vanishes as
(Phi)->180(degrees). An incident longitudinal wave generates relatively little
acoustic sound for all values of (Phi) considered, with most of its energy
redistributed among structural modes. The acoustical diffraction is generally
greater for flexural incidence. [Work supported by ONR.]

from ASA 131st Meeting, Indianapolis, May 1996