Definition and Measurement of Radial Mode Coupling Factors in Piezoelectric Ceramic Materials with Large Variations in Poisson's Ratio

Abstract

Abstracr-The standard procedure (IEEE Standard 179) of determining radial mode coupling factor k, in piezoelectric ceramic disks assumes that the variations in Poisson’s ratio # with material composition may be neglected. Furthermore, the analysis from which the equations defining k, were derived was originally formulated for an elastically isotropic, electrically biased, electrostrictive medium. This paper 1 j reports on analysis using the linear piezoelectric constitutive equations including the full elastic anisotropy of a poled ceramic; 2) defines a new radial mode coupling factor kP , 3) relates kP to the standard k, ; 4) describes a measuring procedure that determines # and kP; and 5) applies these techniques to measurements of PLZT ceramics.