An analytical approach to evaluate the effective coefficients of piezoelectric composites

In this paper, the effective coefficients of piezoelectric fiber-reinforced composites are determined through two micromechanics methods. The exact solutions are derived to predict the effective electro-elastic coefficients with modifications in the conventional strength of materials approach and strain energy approach to account for the effects of fiber packing arrangements and orientations on these properties. A representative volume element subjected to a mechanical loading in the longitudinal direction to the fiber and an electrical loading in the transverse direction to the fiber is used to model the problem mathematically and derive the results. The effective elastic, piezoelectric and dielectric coefficients are estimated by these two methods, and the results are compared with those predicted by the strength of materials method of the literature. From the results, it is observed that results obtained for the elastic, piezoelectric and dielectric coefficients by the strength of materials method and modified strength of materials method are in good agreement with each other in a useful range of fiber volume fractions, while the results obtained through the energy approach shows some deviations when compared with previously stated two methods. The strength of actuation capabilities in the direction longitudinal to the fiber shows significant improvements in the results obtained with the strain energy approach compared with those of the other two micromechanics methods.