Analysis and simulation of piezoelectric vibration energy harvesters having uniform stress profile

Abstract

The objective of the presented work is to improve the electrical power output by modifying the geometry of the piezoelectric vibration energy harvester (PVEH). The key contributions of the thesis are, modification of the thickness profile of conventional cantilever-based bimorph PVEH to achieve uniform stress along the beam length. In this regard, two thickness-tapered geometries are proposed: PVEH-1, which consists of a thickness-tapered substrate sandwiched between two uniform thickness piezoelectric layers, and PVEH-2, which consists of a bimorph cantilever with a substrate of uniform thickness sandwiched between two thickness-tapered piezoelectric layers. In diaphragm based PVEH, radial cuts are introduced to reshape it in identical slices (sectors) of 32.7o each resulting in improved harvested power. Further, a broadband energy harvester is designed using several slices of different central angles.