The free strain during unipolar electrical activation and the blocking stress are important figures of merit for actuator applications. The lead-free (1 − x)Ba(Zr0.2Ti0.8)O3−x(Ba0.7Ca0.3)TiO3 (BZT-xBCT) system has been shown to display exceptional unipolar strain at room temperature, making it very attractive as an electroactive material for large displacement, low frequency actuation systems. In this work, the temperature- and composition-dependent blocking stress is measured with the proportional loading method. It was found that BZT-xBCT outperformed Pb(Zr1−xTix)O3 and Bi1/2Na1/2TiO3–based ceramics for electric fields up to 2 kV/mm.

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This paper presents the construction and performance of a PVF, [polg(vinglidene fluoride), (CH,CF,)J thin film piezoektric actuator. In addition, the paper discusses the methods used to characterize the viscoleastic properties of the actuator materia!. I. L\XRODUCTION Development of a low force, large displacement actuator constructed of PVF, is c m U y undmay for active vibration suppression of k!nment packages in orbiting spacecraft.Because PVF, is a low CO% lightweight, robust, piezoelectric material that can easily be shaped for specific applications, it is ideally suited for this QFe of actuator. Several actuator designs have been constmckd and aduatcd under a variety of conditions. Research is also axeat@ in progress concerning the mechanical tating and material &axactmintion of PVFr Static tests indicate that the mechanical beha\kir of PVF, thin fiEms is time dependent, i.e. samples of this material creep under room tempature condirions. Because accurate predictions of the h edependent effects due to the tiscoelastic properties are critical in the design of active viiration wntrol devioes, material characterization of PVF, is also in p r o p s . n. ACTUATOR DESIGN A\D C O S S T R ~~O ~The primary component of the c m t actuator design, Fig. 1, is a thEn sheet of PVF, film, 28 microns thick, about 3.4 cm wide