Magnetostrictive 1-3 composites with internal field biasing

Owen Thomas, Simon Busbridge, George Tomka

Research output: Contribution to journalArticle

Abstract

1-3 composites comprising an array of square Terfenol-D rods continuous in the direction of actuation and separated by an epoxy matrix have been produced. The benefits of a Terfenol-D 1-3 composite over bulk Terfenol-D and powder composites has been investigated. A higher frequency capability is realized while maintaining a greater coupling coefficient, k33, to that of powder composites. 1-3 composites were produced containing between 40% and 70% volume fraction of Terfenol-D. Magnetic biasing was achieved using Nd2Fe14B powder located within the epoxy matrix at 40% volume fraction. Internal bias fields of 75 and 45 kA/m were measured for the 1-3 composites containing 40% and 70% Terfenol-D, respectively. A coupling coefficient of 0.53 was measured for the composites filled with epoxy alone while the coupling coefficient varied from 0.33 to 0.48 for the biased composites with between 40% and 70% volume fraction of Terfenol-D, respectively. The acoustic impedance was determined using the radial resonance and observed to decrease with decreasing Terfenol-D volume fraction. A 50% volume fraction Terfenol-D 1-3 composite containing microspheres within the epoxy had the lowest measured acoustic impedance of 6.8 Mrayl, making this composite the most suitable for coupling acoustic energy into tissue/water for ultrasound/SONAR applications.
Original languageEnglish
Pages (from-to)2763-2765
Number of pages3
JournalIEEE transactions on magnetics
Volume40
Issue number4
DOIs
Publication statusPublished - 24 Aug 2004

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composite materials
coupling coefficients
acoustic impedance
acoustic coupling
matrices
actuation
rods
water

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Thomas, Owen ; Busbridge, Simon ; Tomka, George. / Magnetostrictive 1-3 composites with internal field biasing. In: IEEE transactions on magnetics. 2004 ; Vol. 40, No. 4. pp. 2763-2765.
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abstract = "1-3 composites comprising an array of square Terfenol-D rods continuous in the direction of actuation and separated by an epoxy matrix have been produced. The benefits of a Terfenol-D 1-3 composite over bulk Terfenol-D and powder composites has been investigated. A higher frequency capability is realized while maintaining a greater coupling coefficient, k33, to that of powder composites. 1-3 composites were produced containing between 40{\%} and 70{\%} volume fraction of Terfenol-D. Magnetic biasing was achieved using Nd2Fe14B powder located within the epoxy matrix at 40{\%} volume fraction. Internal bias fields of 75 and 45 kA/m were measured for the 1-3 composites containing 40{\%} and 70{\%} Terfenol-D, respectively. A coupling coefficient of 0.53 was measured for the composites filled with epoxy alone while the coupling coefficient varied from 0.33 to 0.48 for the biased composites with between 40{\%} and 70{\%} volume fraction of Terfenol-D, respectively. The acoustic impedance was determined using the radial resonance and observed to decrease with decreasing Terfenol-D volume fraction. A 50{\%} volume fraction Terfenol-D 1-3 composite containing microspheres within the epoxy had the lowest measured acoustic impedance of 6.8 Mrayl, making this composite the most suitable for coupling acoustic energy into tissue/water for ultrasound/SONAR applications.",
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Magnetostrictive 1-3 composites with internal field biasing. / Thomas, Owen; Busbridge, Simon; Tomka, George.

In: IEEE transactions on magnetics, Vol. 40, No. 4, 24.08.2004, p. 2763-2765.

Research output: Contribution to journalArticle

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AB - 1-3 composites comprising an array of square Terfenol-D rods continuous in the direction of actuation and separated by an epoxy matrix have been produced. The benefits of a Terfenol-D 1-3 composite over bulk Terfenol-D and powder composites has been investigated. A higher frequency capability is realized while maintaining a greater coupling coefficient, k33, to that of powder composites. 1-3 composites were produced containing between 40% and 70% volume fraction of Terfenol-D. Magnetic biasing was achieved using Nd2Fe14B powder located within the epoxy matrix at 40% volume fraction. Internal bias fields of 75 and 45 kA/m were measured for the 1-3 composites containing 40% and 70% Terfenol-D, respectively. A coupling coefficient of 0.53 was measured for the composites filled with epoxy alone while the coupling coefficient varied from 0.33 to 0.48 for the biased composites with between 40% and 70% volume fraction of Terfenol-D, respectively. The acoustic impedance was determined using the radial resonance and observed to decrease with decreasing Terfenol-D volume fraction. A 50% volume fraction Terfenol-D 1-3 composite containing microspheres within the epoxy had the lowest measured acoustic impedance of 6.8 Mrayl, making this composite the most suitable for coupling acoustic energy into tissue/water for ultrasound/SONAR applications.

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