ASA 126th Meeting Denver 1993 October 4-8

5aSA7. Experimental investigation of nonspecular scattering from a framed shell.

Brian H. Houston Joseph A. Bucaro Douglas M. Photiadis

Phys. Acoust. Branch, Naval Res. Lab., 4355 Overlook Ave., Washington, DC 20375

Recently the existence of flexural Bloch waves contributing significantly to features observed in far-field experimental data was reported [Photiadis et al., J. Acoust. Soc. Am. 93, 2413(A) (1993)]. In this previous work, broadband scattering data from framed and unframed low aspect ratio fluid-loaded shells (l/a=3) were studied. Calculations of the dispersion curves for an infinite ribbed shell were used to predict the locations of the peaks in the backscattered cross section. Here, the results of the scattering from a high aspect ratio (l/a=8) pseudoperiodically framed shell are reported. The various elastic wave types using the infinite framed shell dispersion relations are identified and the relevant contributions are quantified.