Abstract
This work presents a) an analytic model based on homogenizationestimates to obtain explicit solutions for the effective properties ofparticulate piezoelectric composites and b) a three-dimensionalfinite-element model to compare finite-element results and study thebehaviour of porous piezoelectric composites with four differentgeometric configurations. The analytic model extends the Suquet[29] estimates method to the piezoelectric domain where acomplete set of electromechanical constants are obtained for threepiezoelectric ceramics belonging to different symmetry classes.Specific results are generated for the cases of a square arrangementof cylindrical pores, where the alignment of the pores is in thedirection of poling of the matrix phase and a cubic arrangement ofspherical pores. The trends obtained from the analytic model arecompared with the finite-element model and found to be in goodagreement for all components of effective piezoelectric constants uptolarge volume fractions. A three-dimensional finite element model isdeveloped in part II of the thesis to completelycharacterize the behaviour of a general porous piezoelectric compositewith pores of 0-3 type flat cuboidal, 0-3 type cylindrical, 0-3 typespherical, and 1-3 type cylindrical connectivities. By consideringmaterials from different symmetry classes, it is demonstrated thatpiezoelectric composites designed with 0-3 type flat cuboidal poresare more suitable for hydrophone applications by identifying thevariation in piezoelectric strain coefficient and the hydrostaticfigure of merit with varying porosity volume fraction.
