To better understand the generation of electric power for piezoelectric PbZrTiO₃ (PZT) ceramic plate (ϕ25 mm), an attempt was made to investigate experimentally and numerically electric-power generation characteristics during cyclic bending under various loading fixtures (ϕ0-ϕ20 mm), i.e., different contact areas. Increasing the load-contact area on the PZT ceramic leads to a nonlinear decrease in the generated voltage. Decreasing contact area basically enhances the generated voltage, although the voltage saturates during loading when the contact area is less than ϕ5 mm. A similar voltage is generated for ϕ0 and ϕ5 mm, which is attributed to strain status (ratio of compressive and tensile strain) and material failure due to different stress distribution in the PZT ceramic. On the basis of the obtained electric generation voltage, suitable loading conditions are clarified by loading with the ϕ5 mm fixture, which generates a higher voltage and a longer lifetime of the PZT ceramic. From this approach, it is appeared that the area contact with the area ratio of 0.04 (ϕ5 mm/ϕ20 mm) is suitable to obtain the high efficiency of the electric voltage.

Electric power generation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic have been examined during cyclic loading with different compressive strain value. A thin PZT ceramic plate attached to a thin brass plate was used. With an increasing compressive strain value in the PZT ceramic plate, the electric voltage increased, and the highest electric voltage was obtained for the sample with the high strain level (0.4%). The electric voltage decreased for the sample with more than 0.45% strain because of the failure in the PZT ceramic. The electric voltage was different depending on the strain condition, where the higher strain and the wider strain range (Δε) made the high electric voltage. Moreover, the electric voltage was attributed to the strain rate, where the higher strain rate made higher electric voltage due to high kinetic energy. The electric generation characteristics could be estimated with an operation of the strain value and strain ratio (ε_min/ε_max) especially for the sample loaded cyclically under the slow loading speed. This was affected by the linear correlation between the electric voltage and the strain value. Based upon the experimental work, suitable loading condition to make high electric voltage could be proposed.