Researches On Wideband Rare-Earth Janus Transducer

With the rapid development of signal processing technology for underwater acoustic, more and more information obtained from the transducer is needed. The wider the frequency band of the transducer is, the more information it will obtain, which is the reason why the wideband is an important development direction of underwater acoustic transducer. A wideband rare-earth Janus transducer is designed and developed with the purpose of achieving wideband, double-end radiation and high sound power performance with a compact size by taking use of the advantage of the transducer in structure and active material.The equivalent circuit diagram of Janus transducer driven by rare-earth giant magnetostrictive material Terfenol-D is drawn, and a series of essential theoretical formulas used for finite element analysis of giant magnetostrictive transducer are deduced according to the classical analytic method and acoustic theory combined with conclusions of Tonpilz transducer's electromechanical equivalent circuit accordingly.Finite element software ANSYS is adopted to model, calculate and analysis the rare-earth Janus transducer, and the performance of the transducer worked in three excitation models (co-phase excitation, reversed-phase excitation and single-ended excitation) is compared, then the excitation model, under which the working performance is best, is selected to optimize and analysis the structure and the size of the transducer aiming to design a better wideband transducer. The simulated calculation results show that a remarkable±4dB bandwidth from 5kHz to 23kHz and maximum sound level over 199dB can be realized.The prototype is manufactured according to the conclusions of optimization analysis, and the impedance characteristic and sound level are measured in the pool.±5dB bandwidth and the sound level in the resonant frequency obtained in actual measurement is from 4.5kHz to 25kHz and 192dB respectively.Both the simulated calculation and the prototype measurement results indicate that the designed transducer with good qualities such as compact size, very broad bandwidth and high power can be achieved by combining the advantages of the multiple-mode-coupling effect of rare-earth longitudinal-vibration Janus transducer with single-ended excitation.