Experimental determination of the three-port impedance matrix for an array of transflexural elements.

Abstract

A transducer has been built that consists of an array of transflexural piezoelectric disks embedded in a soft potting material. This transducer can be configured as a thin layer yet exhibits significant low-frequency (audio band) sensitivity. It has been modeled as a general three-port transducer, and an experimental determination of the three-port impedance matrix over a range of frequencies for a prototype transducer has been made. The matrix is expressed in terms of effective constants (the electromechanical coupling constant, the clamped dielectric constant, and the elasticity constant) of a thickness mode piezoelectric transducer. Predictions of the frequency response of the transducer and its performance as an active surface have been made using the measured impedance matrix. These predictions have been compared to its actual performance as an active surface.