Finding the optimum polarization boundary line for enhancing the performance of clamped piezoelectric circular plates

Abstract

The piezoelectric unimorph circular diaphragm is a valuable configuration in many applications of smart structures and smart martials. Piezoelectric energy harvesting, sensing and actuating in a pressure-load system are main applications of this configuration. Structural optimization could be used to improve the performance of this configuration. In this paper, a piezoelectric unimorph energy harvester is considered for capturing energy from pressure fluctuations of a system and converting it to electrical energy. This theoretical study includes comprehensive analytical modelling followed by a parametric study to optimize the polarization boundary of a clamped piezoelectric circular diaphragm. The results indicate that by considering the generated electric field along the diameter of the piezoelectric layer, the location of zero-strain points is found to be dependant on the radii of both the piezoelectric layer and substrate. Moreover, it is observed that these points are almost independent of the thicknesses of the layers and external pressure load. Changes of these parameters can only shift the amplitude of the generated electric field to higher or lower values. The results confirm that the derived closed-form equation for the electric field in Z direction along the diameter of the piezoelectric disc is worthwhile for further investigation in this field.