The Research Of Broadband Longitudinal Transducer

With the progress of underwater acoustic technology, the underwater acoustic transducers are required developed towards low-frequency, broadband and high power. As an part of many transducers, longitudinal vibration transducer, scholars of all countries are working together to obtain a wider bandwidth.Two structure of longitudinal vibration transducers are researched in this paper. One of them is with a cavity inside a head mass, because its structure can produce a variety of modes, better broadband characteristic are realized by Multiple-mode-coupling method. The other one is the Tonpilz transducer with typical configuration, which achieves a wide-band signal transmission by coupling of longitudinal vibration mode and head mass bending mode.Firstly, equivalent circuit method is used to analyze the tonpilz transducer. Secondly, the finite element software ANSYS is used to analyse the transducers, relationship between the change of structure parameters and the transducer bandwidth performance is researched, and the structure size parameters of transducer is optimized, then structure size parameters of the transducer are chosen. The characteristic of impedance and radiation had been obtained by the finite element software. Finally, the tonpilz transducer and longitudinal vibration transducer with a cavity inside a head mass are made, characteristic of impedance and underwater radiation had been measured.The experiment results shows that the tonpilz transducer can be used within frequency range 15-31kHz with peak transmitting voltage response 150.7dB, fluctuation within the frequency range is less than 5.5dB;longitudinal vibration transducer with a cavity inside a head mass has maximum transmitting current voltage response 148.9dB, frequency range 4.5kHz-14kHz, fluctuation within the frequency range is less than 9dB. The results show that, the experiment results are well coincide with the calculated conclusions getting from software ANSYS.