A theoretical study of the coupling effects in piezoelectric ceramics

The objective of this study is to delineate electro-mechanical coupling in piezoceramic materials. The model system investigated is a two-dimensional linear piezoceramic strip polarized in the thickness direction, and it is s ubjected to local symmetric pressures on the upper and lower edges, tractio n-free boundary conditions on both end surfaces, and voltages on portions o f the upper and lower edges. Under a simplifying assumption of the gradient of the electric potential, closed form solutions of the elastic field have been obtained. It is noticed that instead of the nine constants (including the elastic com pliance constants, s(ij), the piezoelectric constants, d(ij), and the diele ctric permittivity constants, epsilon(ij)), the elastic and piezoelectric c haracteristics of the material can be represented by three parameters, beta (1), beta(2) and beta(3,) beta(1) consists of elastic compliance constants only. beta(2) and beta(3) signify the piezoelectric effect. Furthermore, hi gher values of beta(2) imply a more pronounced piezoelectric effect on the elastic field. The identification of these parameters greatly facilitates t he study of coupling effects in piezoelectric ceramics. (C) 1998 Elsevier S cience Ltd. All rights reserved.