The Research Of Broadband Rare-earth Longitudinal Vibration Transducers

With the military requirements and progress of modern sonar technology, require the underwater acoustics transducers developing towards the way of low-frequency, broadband, high-power, small-size. Giant magnetostrictive material Terfenol-D used in low-frequency high-power transducers with higher density of energy and lower sound speed. Two kinds of transducers hybrid longitudinal vibration transducers and rare-earth tonpilz transducers are researched in this paper.First, according to theories about finite-element and method about analogy magnetostrictive-piezoelectric, solved the magnetostrictive problem using the software ANSYS. At the same time, with the equivalent circuit mode to analyzing hybrid longitudinal vibration transducers.Second, transducers'magnetic circuit optimization work is carried out for improving the magnetic circuit and eliminating the eddy current on the giant magnetostrictive material. It making the magnetic flux density on the giant magnetostrictive material equably, advancing the transform efficiency in machine-electricity.Third, hybrid longitudinal vibration transducers are used driving by the material of terfenol-D and PZT, broadband characteristic are realized by multiple-mode-coupling method. Rare-earth tonpilz transducers are used driving by only material of Terfenol-D, broadband characteristic are realized by coupling of longitudinal vibration mode and head mass bending mode. Using the finite element software ANSYS to analysis as well as design the transducers structure. The magnetic circuit optimization methods are given. The magnetic induction intensity on the rare-earth material is improved. At the same time, the characteristic of impedance and radiation had been analyzed by means of software ANSYS.The hybrid longitudinal vibration transducers and rare-earth tonpilz transducers had been prepared measurements, about impedance and radiation had been done. Experimental results show that the hybrid longitudinal vibration transducers has maximum transmitting voltage response 145dB, frequency range 4kHz—16kHz, fluctuation within the frequency range is less than 9dB. Rare-earth tonpilz transducers has maximum transmitting current response 177dB, frequency range 1.6kHz—5.4kHz, fluctuation within the frequency range is less than 7dB.From the result, it can be confirmed that experimental results well coincide with calculated conclusions getting by software ANSYS. Also indicated that the giant magnetostrictive material benefit longitudinal vibration transducers'researching.