Realization of Uniform Bending Strain in Piezoelectric Energy Harvesters by Gamma-Shaped Structures

Abstract

Abstract Cantilever is one of the most popular structures employed for vibration-based piezoelectric energy (PE) harvesters due to its simplicity in mathematical modeling and manufacturing. However, the cantilever-shaped PE harvester (CPEH) has a nonuniform bending strain which is inefficient for piezoelectric energy harvesting. In this study, a new structure, named Γ-shaped PE harvester (ΓPEH), is proposed to achieve a uniform bending strain of the PE harvester by connecting another beam at the end of the harvester beam in 90 degree. A comparison study based on analytical solutions is made to show how the ΓPEH can outperform the CPEH and tapered PE harvester (TPEH). For a more detailed and fair comparison, the numerical models for the PE harvesters are developed using the generalized classical Ritz method, and the shape optimization is conducted under the same material volume, mass, and stress constraints. The comparison results show that the ΓPEH has higher power output than the CPEH and TPEH.