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Proceedings Paper

Magneto-thermo-mechanical characterization of magnetostrictive composites
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Paper Abstract

This paper describes magneto-thermo-mechanical characterization of magnetostrictive composites. The purpose of this study is to evaluate the behavior of magnetostrictive composites under combined magnetic, thermal and mechanical loading, and to determine fundamental properties used for design of actuator and sensor systems that incorporate these materials. Currently the composites are being used in sonar transducers. The magnetostrictive composite contains Terfenol-D (Tb0.3Dy0.7Fe2) particulate embedded into an epoxy binder. Composite form is used due to the relative brittleness and limited operational frequencies of monolithic Terfenol-D. Two different tests were performed both at room temperature and under thermal loading: 1) constant magnetic field with cyclically varying load around a bias load and 2) constant pre-load with varying magnetic field. Testing was performed on five different volume fraction composites, namely, 10%, 20%, 30%, 40% and 50%. Parameters that were evaluated include strain output, magnetic field, magnetization and elastic modulus. Results for the constant magnetic field tests indicate that modulus generally increases with increasing volume fraction and increasing magnetic field. However, for low fields, an initial dip is noticed in modulus (i.e. (Delta) E effect) attributed to domains becoming more mobile at lower magnetic field levels. Results also indicate an increase in modulus with decrease in temperature. Results for the constant load test indicate a strong dependence of strain output on applied pre-stress. Results indicate that max strain peaks at a certain value of the pre-stress and then decreases for increasing pre-stress. Results also indicate that strain output peaks between 0 degree(s)C and +10 degree(s)C and that strain generally increases with increasing volume fraction.

Paper Details

Date Published: 11 July 2001
PDF: 12 pages
Proc. SPIE 4333, Smart Structures and Materials 2001: Active Materials: Behavior and Mechanics, (11 July 2001); doi: 10.1117/12.432753
Show Author Affiliations
Nersesse Nersessian, Univ. of California/Los Angeles (United States)
Gregory Paul Carman, Univ. of California/Los Angeles (United States)


Published in SPIE Proceedings Vol. 4333:
Smart Structures and Materials 2001: Active Materials: Behavior and Mechanics
Christopher S. Lynch, Editor(s)

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