Discussion of the finite-element modelling and performance of ring-shell projectors

The paper discusses the finite-element modelling and performance of ring-shell projectors, a particular type of flextensional projector. A ring-shell projector can be used near its resonance frequency as a high-power source, or as a moderate-power broadband source. The most recent design of ring-shell projector has a resonance frequency of 349 Hz, a mechanical Q-factor of 10.6 and a source level of 205 dB relative to 1 ¿¿Pa at 1 m. Finite-element predictions of the transmitting response and admittance show good agreement with the measured values. Ring-shell projectors that are passively pressure compensated have a maximum operating depth in excess of 300 m and a safe immersion depth of at least 450 m.