Analysis of the resonance modes of PZT/epoxy 1-3 composite rings

Abstract

PZT/epoxy 1-3 composite rings with PZT volume fractions /spl Phi/ ranging from 0.58 to 0.93 are fabricated. They have sufficiently small epoxy width (/spl sim/77 81 /spl mu/m) and can be treated as effective homogeneous media. The mode coupling theory and a finite element model (FEM) are applied to predict the thickness (f/sub T/), lateral (f/sub L/), radial (f/sub R/) and wall-thickness (f/sub W/) resonances of the composite rings. As the frequencies and electromechanical coupling coefficients play a significant role in the performance of composite transducer, it is important to know how these parameters change with /spl Phi/. Good agreements are found between the experimental results and the FEM simulations. It is obvious that f/sub R/ and f/sub W/ vibrations greatly deteriorate at low value of /spl Phi/. To avoid unwanted modes from coupling to f/sub T/, the thickness and configuration of the PZT elements in the rings should be optimized.