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题名	稀土超磁致伸缩水声换能器的研究
作者	莫喜平
学位类别	博士
答辩日期	2000
授予单位	中国科学院声学研究所
授予地点	中国科学院声学研究所
关键词	换能器 超磁致伸缩材料 低频大功率 闭合磁路 超声换能器 ANSYS软件
中文摘要	Terfenol-D是一种稀土－铁合金，它是近几年兴起的新型换能器材料，这种材料具有比通常的镍大10～100倍的磁致伸缩系数，故又称其为超磁致伸缩材料。它以高能量密度和低声速的特点而被广泛应用于低频大功率水声换能器中。论文设计了一系列Terfenol-D“鱼唇式”弯张换能器，谐振频率分别为1200Hz、860Hz、410Hz、220Hz。换能器设计中采用永磁材料提供偏磁场和能有效抑制涡流损耗的闭合磁路结构，实验与模拟计算结果证明这种新型弯张换能器具有小尺寸、重量轻、谐振频率低、频带宽、声源级高和深水特性好等特点。克服了连续直流提供偏磁场发热效应强的缺点，并且仅需要普通的功率放大器，更适于长时间连续工作，使这一新型低频大功率水声换能器趋于实用化。Terfenol-D材料具有较低的声速，因此频率相同的Terfenol-D换能器与PZT换能器相比尺寸更小，这一特点对设计低频换能器是有利的，而设计超声频段换能器就变成不利因素，原因在于有源材料的体积减小了，而尺寸小了给工艺上又带来新的问题。为了克服这一不利因素，我们采用非基频振动模式，即利用二阶纵振动模或者弯曲模式，设计制作了22kHz Terfenol-D水声换能器。换能器采用复合棒结构，将前盖板弯曲频率设计在22kHz,纵振动频率设计在13kHz，这样既可以保证换能器中Terfenol-D棒具有足够的长度，又可通过振动模式耦合获得较宽的频带。用ANSYS有限元软件对所设计的换能器电声性能进行模拟计算，计算结果与实验测量结果相吻合。采用非基频模式的设计思想可为稀土超磁致伸缩材料应用于功率超声换能器提供一种思路。
英文摘要	Terfenol-D, one of the rare earth-iron alloys, is arisen the new transducer material in recent years. It is called giant magnetostrictive material, because the material has larger magnetostrictive coefficient 10 to 100 times than that of Ni. Terfenol-D is a better material for use in low-frequency high-power transducers with higher density of energy and lower sound speed. A series of the Terfenol-D "Fish-mouth" flextensional transducers are developed in this report, their resonance frequencies are 1200Hz, 860Hz, 410Hz and 220Hz. A close magnetic circuit with permanent magnet biasing and structure, that is able to control eddy current, is developed in the design. Theoretical analysis and experiments are showed that the new type flextensional transducer has advantages of small size, less weight, low resonance frequency, broad band, powerful source level and great operating depth. The effect of heat due to using DC bias magnetic field is eliminated in the design of the new type flextensional transducer, which needs a general power amplifier and is better for continued work for a long time. The new type of low-frequency high-power transducers is evolved into utility. The Terfenol-D material has lower sound speed, therefor transducers with it as the active material are smaller than with PZT at same frequency. That is an advantage for using to low frequency transducers, but for design ultrasonic transducers it is a disadvantage, because the volume of active material is reduced, and new technological problems are brought with the decreased size of transducer. For the reason that to eliminate this disadvantage, in the design of a 22kHz Terfenol-D underwater acoustic transducer the non-fundamental frequency vibration mode is utilized, which is such as the second order longitudinal vibration mode or bend modes. A complex-bar transducer with a head-mass bend frequency of 22kHz and a longitudinal vibration frequency of 13kHz is developed for that, the Terfenol-D rod with enough length is used in the transducer and wider bandwidth is obtained by coupling between the vibration modes. Using the ANSYS software, electroacoustical parameters of the developed transducer are simulated, and the calculated results are in good agreement with measurements. The ideal of using the non-fundamental frequency vibration mode is able to give some consultions for design power ultrasonic transducer with the rare earth giant magnetostrictive material.
语种	中文
公开日期	2011-05-07
页码	50
内容类型	学位论文
源URL	[http://159.226.59.140/handle/311008/662]
专题	声学研究所_声学所博硕士学位论文_1981-2009博硕士学位论文
推荐引用方式 GB/T 7714	莫喜平. 稀土超磁致伸缩水声换能器的研究[D]. 中国科学院声学研究所. 中国科学院声学研究所. 2000.

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