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

2pSA2. Response Green's function and scattered pressure from a fluid-loaded cylindrical shell with internal bulkheads.

J. M. Cuschieri

Ctr. for Acoust. and Vib., Dept. of Ocean Eng., Florida Atlantic Univ., Boca Raton, FL 33431

D. Feit

David Taylor Res. Ctr., Bethesda, MD 20084

The response Green's function and the far-field scattered pressure, for a fluid-loaded cylindrical shell, for the circumferential mode n=0, with internal plate bulkheads, are determined from knowledge of the junction forces between the shell and the internal plate bulkheads. These forces are determined using a mobility (impedance) matrix approach, which matches the response of the shell and the plate bulkhead at the junction, together with an input of the shell-free response under the influence of the incident acoust pressure. The results for the Green's function show that for low frequencies, the in-plane response of the plate bulkhead is very small and the junction behaves similar to a pinned junction. As the frequency increases in-plane resonances are set up in the plate bulkhead and the radial influence of the bulkhead is at a minimum. For the far-field scattered pressure, if the angle of incidence of the excitation acoustic wave is less than about 16 deg for a steel shell in water, the scattered pressure has significant contributions from the supersonic longitudinal waves in the shell. Outside this angle of incidence the scattered pressure is dominated by the scattering from the discontinuity. [Work sponsored by ONR.]