Thin-layer composite unimorph ferroelectric driver and sensor properties

Tests were conducted on 13 different configurations of a new class of piezoelectric devices called THUNDER (thin-layer composite unimorph ferroelectric driver and sensor). These configurations consisted of a combination of 1, 3, 5, 7, and 9 layers of 25.4 mu m thick aluminum as backing material, with and without a top layer of 25.4 mu m aluminum. All of these configurations used the same piezoelectric ceramic wafer (PZT-5A) with dimensions of 5.08 X 3.81 X 0.018 cm. The above configurations were tested at two stages of the manufacturing process: before and after re-poling. The parameters measured included frequency, driving voltage, displacement, capacitance, and radius of curvature. An optic sensor recorded the displacement at a fixed voltage (100-400 V peak-to-peak), over a predetermined frequency range (1-1000 Hz). These displacement measurements were performed using a computer that controlled the process of activating and measuring the displacement of the device. A parameter cu was defined which can be used to predict which configuration will produce the most displacement for a free standing device. (C) 1998 Elsevier Science B.V.