Highly Localized and Efficient Energy Harvesting in a Phononic Crystal Beam: Defect Placement and Experimental Validation

Xu-Feng Lv,Xiang Fang,Zhi-Qiang Zhang,Zhi-Long Huang,Kuo-Chih Chuang

doi:10.3390/cryst9080391

Abstract

We study energy harvesting in a binary phononic crystal (PC) beam at the defect mode. Specifically, we consider the placement of a mismatched unit cell related to the excitation point. The mismatched unit cell contains a perfect segment and a geometrically mismatched one with a lower flexural rigidity which serves as a point defect. We show that the strain in the defect PC beam is much larger than those in homogeneous beams with a defect segment. We suggest that the defect segment should be arranged in the first unit cell, but not directly connected to the excitation source, to achieve efficient less-attenuated localized energy harvesting. To harvest the energy, a polyvinylidene fluoride (PVDF) film is attached on top of the mismatched segment. Our numerical and experimental results indicate that the placement of the mismatched segment, which has not been addressed for PC beams under mechanical excitation, plays an important role in efficient energy harvesting based on the defect mode.

Highlights

With the growing need for portable, wireless, or wearable electronic devices, highly efficient alternative power generation has increasingly become a necessity
We mainly focus on the placement of the connected to the rest of the phononic crystal (PC) beam
We mainly focus on the placement of the mismatched unit cell mismatched unit cell related to the mechanical excitation point and the associated energy related to the mechanical excitation point and the associated energy harvesting at the defect modes

Summary

Introduction

With the growing need for portable, wireless, or wearable electronic devices, highly efficient alternative power generation has increasingly become a necessity. Crystals 2019, 9, 391 airborne sound configuration, placement of the point defect in finite PCs or metamaterials under mechanical excitation has not been addressed [15]. Placement of the play an important role in energy harvesting for minimizing the influence of wave attenuation inside mismatched unit cell should play an important role in energy harvesting for minimizing the influence the frequency band gaps. Since PC beams have received great attention due to their engineering of wave attenuation inside the frequency band gaps. Propagation of elastic waves is completely forbidden inside the band gaps in ideally infinite PC beams, it is only attenuated away from the excitation point in practical finite ones.

Piezoelectric Energy Harvesting

Schematic

Method

Findings

Unit: Hz