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.]