Performance Analysis of Width and Thickness Tapered Geometries on Electrical Power Harvested from a Unimorph Piezoelectric Cantilever Beam

This paper presents a comparative study of a thickness tapered beam (TTB) and width tapered beam (WTB) harvesters for potential vibration-based energy harvesting applications. Prior to the power output analysis, mathematical models are developed to evaluate strain distribution of the two configurations for proper implementation as substrates for unimorph harvester designs. The derived models were validated in commercial finite element analysis (FEA) software, COMSOL Multiphysics, at different dimension ratios. In addition, vibration analysis was conducted to evaluate and compare the Eigen frequency and mode shape of the geometries when coupled with piezoelectric material namely, Lead Zirconate Titanate (PZT-5H). The theoretical studies show that beam truncated in thickness direction exhibits about 18% lower resonant frequency and 6.4% (μW) higher power output than width tapered harvester with equal mass and large output impedance, respectively.