A Novel Bi-Stable Piezoelectric Energy Harvester Inspired by the Venus Flytrap

Abstract

This paper studies the nonlinear dynamics and energy harvesting performance of a novel bi-stable piezoelectric energy harvester inspired by the rapid shape transition of the Venus flytrap leaves. The harvester is composed of a piezoelectric MFC transducer, a tip mass, and two sub-beams. The two sub-beams are akin to the bidirectionally curved Venus flytrap leaves that could rapidly snap-through from the open state to the closed state. To realize the bistability of the Venus flytrap leaves induced by the stored potential energy, an in-plane pre-displacement constraint is applied to the free ends of the sub-beams. The pre-displacement constraint leads to bending and twisting deformations and creates the potential energy in the harvester. The bio-inspired design is introduced in detail and a prototype is fabricated to validate the conceptual design. The nonlinear dynamics of the bio-inspired bi-stable piezoelectric energy harvester is investigated under base acceleration excitations. Results show that the sub-beams of the harvester experience more complicated local vibrations containing broadband high-frequency components as the snap-through motion happens. The energy harvesting performance of the harvester is evaluated at different excitation levels. The broadband energy harvesting is achieved at higher excitation levels and an average power output of 0.193 mW is attained under the excitation of 10 Hz and 4.0 g.