Effect of elastic modulus of cantilever beam on the performance of unimorph type piezoelectric energy harvester

Mahesh Peddigari,Jungho Ryu,Miso Kim,Kyung-Won Lim,Woon-Ha Yoon,Chan Hee Park,Geon-Tae Hwang

doi:10.1063/1.5070087

Abstract

Piezoelectric energy harvesting is a technique that can utilize ambient vibration energy to generate useful electrical energy, which is promising for powering small-scale autonomous devices such as sensors for wearable, biomedical, and industrial applications. Typically, cantilever-type piezoelectric energy harvesters (PEHs) are operated under resonance condition to achieve the maximum output power at low frequency stimuli. Along with resonance matching, it is also necessary to optimize the PEH configuration with high electromechanical properties for the efficient energy conversion. The purpose of this study is to investigate the effect of the elastic modulus of the passive layer in the cantilever structured PEH on the electromechanical properties and thus harvesting performance. In this regard, two unimorph type PEHs having the identical geometry, piezoelectric properties, and proof mass but with different elastic modulus (55 GPa and 97 GPa) of Ti alloy-based passive layers were fabricated and their output performance was compared under the same acceleration amplitude excitation stimuli. The PEH with the smaller elastic modulus passive layer exhibited almost 53% improvement in the maximum power than that with the higher elastic modulus passive layer, which is attributed to a smaller mechanical damping ratio, higher quality factor, and larger vibration amplitude.

Highlights

Effect of elastic modulus of cantilever beam on the performance of unimorph type piezoelectric energy harvester
The conventional piezoelectric energy harvester (PEH) consists of a cantilever beam, a piezoelectric layer, and proof mass, which mainly operates in a bending mode to extract the electrical energy by inducing aE-mail: gthwang@kims.re.kr bE-mail: jhryu@ynu.ac.kr
Many efforts have been made for improving the output power, frequency bandwidth, and conversion efficiency of PEH via advanced device design,[5,6,7,8,9,10,11,12] proof mass tuning,[13,14,15] utilization of various operational modes,[16,17] optimization of the thickness of piezoelectric and passive layers,[18,19] and development of high performance anisotropic piezoelectric materials and flexible passive layers.[20,21,22,23,24,25,26]

Summary

Introduction

Effect of elastic modulus of cantilever beam on the performance of unimorph type piezoelectric energy harvester. 121107-3 Peddigari et al Earlier, Wang et al.[32] investigated the electromechanical coupling mechanism based on the thickness and elastic modulus of piezoelectric and passive layers using constitutive equations and suggested that the passive layer with the larger E is required to improve the electromechanical coupling and mechanical energy of PEHs. there are many studies that have been reported on the relation between mechanical properties of the passive layer and the performance of PEHs.[29,33,34] there is no systematic experimental study available on the effect of both E and ζm of the passive layer with an identical dimension on the energy harvesting performance under the same excitation condition (identical proof mass and acceleration).

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Results

Conclusion