On the optimal bending deflection of piezoelectric scavengers

Abstract

This study aims at exploring the possibility to optimize the electromechanical efficiency of piezoelectric cantilevers by imposing an optimal deflection to classical rectangular devices, rather than designing non-conventional geometries. Focusing on non-vibrating loading conditions, the proposed approach is to apply a constant bending moment to the beam in order to reach the maximum allowable stress on the whole outermost surface. This is realized in practice by pressing the cantilever over a cylindrical-shaped support. Theoretical and numerical models with electromechanical coupling are developed to evaluate the performance improvement compared to the deflection of a classical tip-load configuration. Finally, experimental tests have been performed to further verify the electrical power enhancement given by the proposed optimized layout.