Enhancement of a unimorph actuator performance implementing the nonlinear characteristics of piezoceramic wafer (3203HD, CTS)

摘要

In this study, the actuation displacement and blocking force of the LIPCA (Lightweight Piezo-Composite Actuator) under various combination of the external compressive load and prescribed voltage have been numerically and experimentally examined. For numerical analysis, the full three-dimensional model of the LIPCA including two end-tabs in the simply supported configuration was used and the measured nonlinear behavior of the bare piezoceramic wafer (3203HD, CTS) was implemented in the geometrically nonlinear finite element analysis. The central out-of-plane displacement of the LIPCA was measured while applying various electric fields and compressive loads at the same time. Dummy weights were added at the center of the LIPCA until the LIPCA cannot produce additional central actuation displacement for a given excitation voltage and the sum of the dummy weight was regarded as the blocking force. The numerical results acquired by geometrical/material nonlinear finite element analysis and the measured data showed a good agreement even for high electric field and compressive load. The investigation showed that the actuation displacement and blocking force of the LIPCA were significantly increased by pre-applied compressive load. At the same electric field, the actuation displacements of the LIPCA under nearly buckling load could be about two times larger than those without compressive load. The results also indicate that the positive voltage should be better applied to the actuator than the negative voltage. Therefore, the high negative electric field, which causes the polarization switching in the piezoceramic wafer, can be avoided in applications. At +150V, the blocking force of the compressed actuator under near buckling load was also increased around 26% higher than that of the actuator without compressive load.