At-sea measurements of acoustic elastic scattering by a 1.5m-long cylinder made of composite materials

Abstract

Monostatic and bistatic acoustic scattering measurements were performed on solid-filled fibreglass objects (a sphere and a cylinder with hemispherical endcaps) deployed proud on a sandy seabed and insonified by a rail-mounted parametric source at low frequency (roughly ka=5-40). The paper is limited to monostatic measurements of the cylinder. It consists of a thin-walled shell made of an approximately isotropic randomfibre material, and then filled partially with an isotropic epoxy resin and partially with sea water. The cylinder is simple enough in shape to be treated by currently available modeling techniques, but realistic enough to give a first insight into the physics of the elastic waves present in such material combinations. Preliminary data analysis indicates that the scattering signatures are dominated by the solid filling. The experimental data were acquired in October 2006 during the EVA-06 trial off the Island of Elba.