Browsing by Author "Pan, Ernian"

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Effective magnetoelectric effect in multicoated circular fibrous multiferroic composites
(2011-05-15)
Kuo, Hsin-Yi
;
Pan, Ernian
;
土木工程學系
;
Department of Civil Engineering
Rayleigh's formalism is generalized for the evaluation of the effective material properties in multicoated circular fibrous multiferroic composites. The derived solution is applied to the special three-phase composite in which coated fibers are embedded in a matrix. For composites made of piezoelectric (BaTiO(3)) and piezomagnetic (CoFe(2)O(4) or Terfenol-D) phases, we find that the magnetoelectric effect in the composite made of CoFe(2)O(4) coated BaTiO(3) in matrix Terfenol-D is five times larger than that in the composite made of BaTiO(3) coated Terfenol-D in matrix CoFe(2)O(4). Furthermore, in each case, with appropriate coating to the circular fiber, the magnetoelectric effect in the coated composites can be enhanced by more than one order of magnitude as compared to the corresponding noncoating composite. (C) 2011 American Institute of Physics. [doi:10.1063/1.3583580]
Multilayer multiferroic composites with imperfect interfaces
(2018-07-01)
Kuo, Hsin-Yi
;
Wu, Tien-Jung
;
Pan, Ernian
;
土木工程學系
;
Department of Civil Engineering
We study the macroscopic behaviors of multilayered multiferroic composites with interface imperfections by a direct micromechanical approach. Both generalized interface stress type and generalized linear spring type imperfect interfaces are considered. Concise matrix expressions of the overall behaviors of the layered piezoelectric-piezomagnetic composite with contact imperfection are presented. The key step is to observe that the two types of imperfect interface conditions are equivalent to the perfect ones due to the laminated geometry. Numerical calculations are demonstrated for BaTiO3-CoFe2O4 multilayer media, and are shown in good agreement with the more involved interphase model. Furthermore, it is observed that the interface imperfection would reduce the magnitude of the magnetoelectric voltage coefficients as compared to the corresponding perfect interface case. This feature is opposite to that predicted and observed in the corresponding cylindrical composites.