Coupling Coefficients and the Three Dimensional, Piezoelectric Ceramic Cylinder

摘要

Antiresonant frequency equations for piezoelectric, ceramic cylinders of any dimensions are defined and combined with previously derived resonant frequency equations to show the types of errors that could be encountered if frequency data from thick disks and short rods were used to calculate the coupling coefficients k sub p and k sub 33 using equations that are reported in the literature for samples having dimension ratios less than 0.1. It is shown that although Poisson's ratio alters the effect of the characteristic frequencies of such samples on coupling coefficient, the coupling coefficients will not necessarily be miscalculated. In addition, when calculated coefficients are erroneous, the values may be either high or low, depending upon the cylinder properties. This information supplements the IRE (IEEE) Standards which mentions high values only when such calculations are made. (Author)