Improving transverse actuation of piezoceramics using interdigitated surface electrodes

The possibility of using interdigitated surface electrode patterns to improve the transverse actuation capability of electroceramic actuators is investigated. This pattern produces nonuniform electrical fields in the plane of the wafer which utilize the longitudinal piezoelectric effect to generate larger, more anisotropic planar actuation than conventional piezoelectric devices. Analytical models are developed for a representative electroceramic volume element of a piezoelectric wafer with interdigitated electrodes. These models incorporate full electromechanical coupling through the constitutive relations and are solved using approximate energy methods. The analytical models are compared to piezoelectric finite element solutions. The analysis predicts a range of electrode thickness and spacings which can increase the achievable transverse actuation. An experimental program was performed to validate the analytical results. The experimental results verified the analytical prediction of highly orthotropic large magnitude in plane strains.