HYBRID MAGNETOSTRICTIVE/PIEZOELECTRIC TONPILZ TRANSDUCER

A combined magnetostrictive/piezoelectric hybrid sonar tonpilz transducer which produces enhanced motion at one end and cancelled motion at the opposite end has been developed. The transducer combines the high strain magnetostrictive material Terfenol-D with that of Lead Zirconate Titanate (PZT-4) piezoelectric ceramic. The transducer has the ability to electrically self-tune and shows an improved effective coupling coefficient 25% greater than a conventional tonpilz type transducer. The in-water mechanical resonance and electrical self-tuning occur in the vicinity of 4.25 kHz, where a 15 dB front-to-back pressure ratio was obtained under a 12 element array loading condition. The high coupling coefficient and double resonant system makes this transducer attractive for wide bandwidth operation. With simple manipulation of the design parameters analytical results predict a vastly increased bandwidth of the transducer. An increase in bandwidth from the traditional tonpilz value of 20% to over 100% can be achieved.