Modeling Material Nonlinearities in Piezoelectric Films: Quasi-Static Actuation

Piezoelectric materials guarantee enhanced linearity and lower actuation voltages compared to electrostatic actuation in MEMS. However, when large displacements are desired, strong material nonlinearities arise and they should be efficiently modeled by predictive tools. In this work, we exploit a nonlinear modeling technique derived from Landau-Devonshire theory of ferroelectrics to predict the static response of cantilevers actuated with thin piezoelectric films. An experimental campaign performed on MEMS cantilevers actuated with PZT patches is performed to validate the model. The comparison between numerical and experimental data shows that the proposed model reliably predicts the quasi-static response of MEMS structures during both unipolar and bipolar polarization cycles.