Browsing by Author "Bhattacharya, Kaushik"

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Fibrous composites of piezoelectric and piezomagnetic phases
(2013-07-01)
Kuo, Hsin-Yi
;
Bhattacharya, Kaushik
;
土木工程學系
;
Department of Civil Engineering
We propose a theoretical framework for evaluation of magnetoelectroelastic potentials in a fibrous composite with piezoelectric and piezomagnetic phases, motivated by the technological desire for materials with large magnetoelectric coupling. We show that the problem with transversely isotropic phases can be decomposed into two independent problems, plane strain with transverse electromagnetic fields and anti-plane shear with in-plane electromagnetic fields. We then consider the second problem in detail, and generalize the classic work of Lord Rayleigh (1892) to obtain the electrostatic potential in an ordered conductive composite and its extension to a disordered system by Kuo and Chen (2008) to the current coupled magnetoelectroelastic problem. We use this method to study BaTiO3-CoFe2O4 composites and provide insights into obtaining large effective magnetoelectric coefficient. (C) 2012 Elsevier Ltd. All rights reserved.
Optimization of magnetoelectricity in piezoelectric-magnetostrictive bilayers
(2010-12-01)
Kuo, Hsin-Yi
;
Slinger, Alex
;
Bhattacharya, Kaushik
;
土木工程學系
;
Department of Civil Engineering
Magnetoelectric coupling is of interest for a variety of applications, but is weak in monolithic materials. Strain-coupled bilayers or multilayers of piezoelectric and magnetostrictive material are an attractive way of obtaining enhanced effective magnetoelectricity. This paper studies the optimization of magnetoelectricity with respect to the crystallographic orientations and the relative thickness of the two materials. We show that the effective transverse (alpha(E,31)) and longitudinal (alpha(E,33)) coupling constants can be enhanced many-fold at the optimal orientation compared to those at normal orientation. For example, we show that the constants are 17 and 7 times larger for the optimal orientation of a lithium niobate/Terfenol-D bilayer of equal thickness compared to the normal orientation. The coupling also increases as the piezoelectric phase gets thinner.
Optimization of magnetoelectricity in piezoelectric-magnetostrictive bilayers
(2010-12-01)
Kuo, Hsin-Yi
;
Slinger, Alex
;
Bhattacharya, Kaushik
;
土木工程學系
;
Department of Civil Engineering
Magnetoelectric coupling is of interest for a variety of applications, but is weak in monolithic materials. Strain-coupled bilayers or multilayers of piezoelectric and magnetostrictive material are an attractive way of obtaining enhanced effective magnetoelectricity. This paper studies the optimization of magnetoelectricity with respect to the crystallographic orientations and the relative thickness of the two materials. We show that the effective transverse (alpha(E,31)) and longitudinal (alpha(E,33)) coupling constants can be enhanced many-fold at the optimal orientation compared to those at normal orientation. For example, we show that the constants are 17 and 7 times larger for the optimal orientation of a lithium niobate/Terfenol-D bilayer of equal thickness compared to the normal orientation. The coupling also increases as the piezoelectric phase gets thinner.