Characterization of piezoelectric energy harvesting MEMS

Abstract

Energy conservation and increased efficiency lie at the forefront of defense missions, capabilities, and costs. Expeditionary forces require energy efficient devices embarkable on naval, ground, and air assault vessels. Piezoelectric MEMS (microelectromechanical systems) devices can be used to convert energy— usually lost to mechanical vibrations—into usable electrical energy without adding significant weight or size to existing equipment. Previous work has analyzed materials and processes, and designed a piezoelectric energy harvesting device leading to its fabrication and characterization. This thesis experimentally tests the piezoelectric MEMS device and integrates the results into a refined model. The effects of Rayleigh damping and squeeze film damping are introduced to improve the connection between experimental data and a finite element model using COMSOL Multiphysics. This model exhibits good agreement with experimental results for resonant frequencies and output potential. From this model, the design can be optimized to resonate at 60 Hz.