Capped ceramic underwater sound projector: The “cymbal” transducer

A new type of transducer has been developed for use as a shallow-water sound projector at frequencies below 50 kHz. Dubbed the “cymbal,” it is similar to the more commonly known “moonie” and class V ring/shell flextensional designs. Prototype cymbal arrays 2 mm thick with a radiating area of 11.4 cm2 have been developed and calibrated. Two mounting schemes have been examined: unpotted (oil-filled) and potted in a 5-mm thick layer of stiff polyurethane. In both cases, a transmitting response comparable to the more widely used Tonpilz transducer (with an equivalent radiating area) is attainable. When tested under hydrostatic pressures, a standard cymbal configuration has been shown to withstand exposures of 2.5 MPa (which corresponds to 250 m of water depth) before failure.