Micromechanics determination of the effective properties of piezoelectric composites containing spatially oriented short fibers

This article presents an analytical unified method for determining the effective electroelastic properties of piezoelectric composites containing spatially oriented short fibers, which are treated as spheroidal inclusions. Both the matrix and inclusions are assumed to be linearly piezoelastic and transversely isotropic. The electroelastic tensors analogous to Eshelby tensors for elastic ellipsoidal inclusions have been obtained and also evaluated numerically for finite fiber aspect ratios. Utilizing these tensors and applying the Mori-Tanaka mean field theory to account for the interaction between inclusions and matrix, the effective electroelastic properties of the composites are expressed analytically in terms of phase properties, orientation angles, volume fraction and inhomogeneity shape. It is indicated that the proposed methods yield identical results when either a traction-electric displacement or an elastic displacement-electric field is prescribed on the composite boundary. Finally, numerical examples are given for a BaTiO3/PZT-5H composite. The results show that the longitudinal and in-plane shear moduli increase with fiber length, while the other moduli, piezoelectric and dielectric constants decrease. Copyright (C) 1996 Acta Metallurgica Inc.