Electromechanical modeling of localized micro-scale piezoelectric interaction at impact site

Abstract

The non-conformal contact between a moving spherical ball and a fixed piezoelectric layer results in a micro-scale contact area. This research investigates the localized micro-scale piezoelectric interaction at the contact area on the piezoelectric layer's electrical response under the impact excitation. The ball indentation causes time-variable 3D mechanical stress and electric displacement distributions around the impact site in the piezoelectric layer. In this study, an innovative semi-analytical model is developed that divides the piezoelectric layer into two zones. This technique enables 2D-axisymmetric analysis of non-axially symmetric patches, reducing computational complexity. The results indicate that a high-voltage zone appears beneath the contact area, which can significantly contribute to the piezoelectric's electrical response. For instance, under a specific impact excitation and electrical boundary condition, the peak voltage across the piezoelectric thickness reaches 600 V while the output voltage is 1 V. Validation and comparison against experimental tests and the FEM method confirm the accuracy and efficiency of this model in the prediction of piezoelectric's transient voltage signal and voltage peak applicable to energy harvesting and sensory applications. Finally, the developed model is applied in the practical optimization of an implantable energy harvester for biomedical applications.