Electromechanical behavior of PZT-brass unimorphs

We have examined the static and dynamic electromechanical responses of PZT-brass (piezoelectric-nonpiezoelectric) plate unimorphs of various brass/PZT thickness ratios. The study was performed both experimentally and theoretically. The static measurements showed that, given a PZT layer thickness, there exists a brass/PZT thickness ratio that gives the unimorph the highest static displacement under an applied field. The effects of geometric shape and external loading on the displacement of the unimorphs were also examined. The dynamic measurements showed that, given a PZT layer thickness, the bending-mode resonance frequencies increase with an increasing brass/PZT thickness ratio. These results were in good agreement with the theoretical predictions that were obtained with the plate geometry.