A non-Standard shear resonator for the matrix characterization of piezoceramics and its validation study by finite element analysis

Abstract

Standard shear samples used for piezoceramic characterization lead to underestimation of the piezoelectric shear coefficients due to its dynamical clamping at resonance. This work presents the application of Alemany et al's automatic iterative method to the resonance of a non-Standard shear sample, in order to determine the related complex parameters of piezoceramics, thus including losses, from impedance measurements. The matrix of dielectric, elastic and piezoelectric complex parameters that fully characterize a piezoceramic, a 6 mm symmetry material, can be obtained from such shear data combined with the application of the method to three other electromechanical resonances, namely: the length extensional mode of long rods or rectangular bars, length poled; the thickness extensional mode of a thin plate or disc, thickness poled; and the radial mode of a thin disc, thickness poled. The shear results obtained here are those of non-Standard samples of a commercial Navy type II piezoceramic, thus solving the underestimation of the coefficients in the Standard shear sample and allowing the improvement of the previously reported characteristic matrix from Standard samples. Three-dimensional finite element analysis (FEA) modelling of the resonances of the three material samples used in the matrix characterization was here accomplished using the improved matrix of dielectric elastic and piezoelectric material coefficients including all losses. The comparison of the experimental resonance spectra of these piezoceramic samples and the FEA results obtained for the elastically, dielectrically and piezoelectrically homogeneous items modelled is presented and discussed here.