### ASA 127th Meeting M.I.T. 1994 June 6-10

## 5aSA3. Waves on fluid-loaded plates with equally spaced identical ribs.

**Zhang Wang
**

**
Andrew Norris
**

**
**
*Dept. of Mech. & Aerosp. Eng., Rutgers Univ., P. O. Box 909, Piscataway,
NJ 08855-0909
*

*
*
A low-frequency asymptotic dispersion relation for a fluid-loaded plate
with infinite number of equally spaced identical ribs is derived, from which an
equation of motion for the plate is inferred that is valid also at low
frequencies. Both the asymptotic and the exact dispersion curves are computed
and compared. A relatively simple formulation is obtained to compute the
positions and widths of the stopping bands. The dispersion curve and the
stopping bands for a plate in vacuum with infinite number of equally spaced
identical ribs are also presented and compared with those for the fluid-loaded
plate. A scattering matrix method is employed to solve wave propagation
problems on infinite fluid-loaded plates with finite numbers of equally spaced
identical ribs. The response to plane wave incidence of fluid-loaded plates
with infinite and finite numbers of equally spaced identical ribs are compared.
[Work supported by ONR.]