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 conta ining 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 a nalogous to Eshelby tensors for elastic ellipsoidal inclusions have be en obtained and also evaluated numerically for finite fiber aspect rat ios. Utilizing these tensors and applying the Mori-Tanaka mean field t heory to account for the interaction between inclusions and matrix, th e 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 me thods yield identical results when either a traction-electric displace ment or an elastic displacement-electric field is prescribed on the co mposite boundary. Finally, numerical examples are given for a BaTiO3/P ZT-5H composite. The results show that the longitudinal and in-plane s hear moduli increase with fiber length, while the other moduli, piezoe lectric and dielectric constants decrease. Copyright (C) 1996 Acta Met allurgica Inc.