A magnetostrictive underwater transducer directly driven by Iron-Gallium alloy (Galfenol) without bias magnetic field

This paper developed a Janus underwater transducer driven by slotted Galfenol rods and the transducer has no permanent magnet bias and is driven by current of half the mechanical resonant frequency. The mechanical resonant frequency of the prototype is about 4.8 kHz. The performances such as transmitting current response, sound level, the impedance and the phase between the driving voltage and the current are measured in anechoic tank. The frequency of the underwater sound is twice as that of the driving voltage or current in the frequency range around the resonant frequency. The maximum of the tested sound level is about 189dB (0dB=1μPa/A@1m) with a driving current 7.4 A_rms at the resonant frequency 4.8 kHz.