Abstract:

The cymbal-type transducer developed at the Materials Research Laboratory at Penn State Univ., which is similar to the ring/shell flextensional transducer, is currently being investigated as a shallow-water (<250 m) sound projector for the 10--75 kHz frequency range. The standard size cymbal transducer is 12.7 mm in diameter and approximately 2 mm in total thickness. It consists of a poled lead zirconate-titanate (PZT) disk capped symmetrically on each face by identical thin metal caps. Each cap is shaped with a cavity on its inner surface so that an air space exists between the PZT disk and the top of the cap. The size of the air space, the thickness of the cap, and the type of cap material all influence the operating performance and allowable operating depth of the device. Parameters necessary to characterize an underwater projector such as resonance frequency, mechanical Q, electroacoustic efficiency, transmit voltage response (TVR), and source level will be presented. Experimental data will be compared with values calculated from the Ansys(registered) finite-element program. Results from single elements as well as cymbal arrays (both potted and unpotted) will be shown. [This work was funded by the Office of Naval Research Contract No. N00014-96-1-1173.]