The analysis of piezoelectric/piezomagnetic composite materials containing ellipsoidal inclusions

A unified method based on the inclusion formulation is proposed to determine the magnetic, electric, and elastic fields in a composite with piezoelectric and piezomagnetic phases. The composite reinforcements are treated as ellipsoidal inclusions that enable the reinforcement geometries ranging from thin flakes to continuous fibers. Utilizing the proposed method, the magneto-electro-elastic tensors analogous to Eshelby tensors for elastic ellipsoidal inclusions are obtained. With these tensors, the magnetic, electric, and elastic fields around the inclusion as well as concentration factors are determined. Furthermore, based upon the Mori-Tanaka mean-field theory [Acta Metall. 21, 571 (1973)] to account for the interaction between inclusions and matrix, the effective magneto-electro-elastic constants (elastic moduli, piezoelectric coefficients, dielectric constants, piezomagnetic coefficients, magnetoelectric, and magnetic permeability) of the composites are expressed explicitly in terms of phase properties, volume fraction, and inhomogeneity shape. The numerical examinations have been conducted for the three-dimensional BaTiO3-CoFe2O4 composite, and the overall composite behavior has been examined numerically. It is found that the composite reveals interesting magnetoelectric coupling which is absent in each constituent. (C) 1997 American Institute of Physics.