Impacts of stopper type and material on the broadband characteristics and performance of energy harvesters

K Zhou,Q Ni,A Abdelkefi,H L Dai,H Y Zhou

doi:10.1063/1.5086785

Abstract

Exploiting nonlinear impact force induced by a stopper has been widely proposed to broaden the bandwidth of energy harvesters from mechanical vibrations, but the previous studies just directly employed the stopper and did not consider the effect of inherent factors of the stopper like its type and material. This letter devotes to efficiently utilize the stopper to broaden the resonance region of the energy harvester mainly from perspective of stopper type and material. Four stopper types are taken into account including the stopper with rigid and soft materials and the spring stopper. Experimental results show that two sides followed stopper type can greatly increase the bandwidth which is much better than other considered types. Importantly, using the stopper with soft materials or the spring stopper is followed by a wider resonance region and a higher output voltage of the energy harvester compared to that with rigid materials. Moreover, agreements between theoretical predictions and experimental measurements indicate the feasibility of using the trilinear spring model to describe the nonlinear impact force which is determined by stopper type and material. The present study delivers to essentially improve the output performance of energy harvesters by selecting the efficient stopper.

Highlights

Converting ambient vibrational energy into useful electric power through energy harvesters has been increasingly attracted worldwide attention due to its potential application in realizing self-powered operation of wearable electronics1–3 or replacing traditional batteries which are difficult and expensive to maintain.4,5 Three transduction mechanisms like electrostatic,6–8 electromagnetic9–13 and piezoelectric14–20 have been widely utilized for energy harvesting from mechanical vibrations.One of the important goals in vibrational energy harvesting is to achieve ultra-wide bandwidth resonance regions to improve the performance of the energy harvester for whatever mechanism.This is because the traditional vibration-based energy harvesters can output a considerable electric power only in the narrow vicinity of the resonant frequency14,15 and any fluctuation in the excitation frequency can cause a sharp decrease in the output power
This study investigated the effects of the stopper type and material on the broadband characteristics of energy harvesters, with consideration of four stopper types and material
Theoretical predictions agreeing well with experimental measurements demonstrate the description of the nonlinear impact force by virtue of cubic spring model is valid which is dependent on the stopper type and material

Summary

Introduction

Converting ambient vibrational energy into useful electric power through energy harvesters has been increasingly attracted worldwide attention due to its potential application in realizing self-powered operation of wearable electronics1–3 or replacing traditional batteries which are difficult and expensive to maintain.4,5 Three transduction mechanisms like electrostatic,6–8 electromagnetic9–13 and piezoelectric14–20 have been widely utilized for energy harvesting from mechanical vibrations.One of the important goals in vibrational energy harvesting is to achieve ultra-wide bandwidth resonance regions to improve the performance of the energy harvester for whatever mechanism.This is because the traditional vibration-based energy harvesters can output a considerable electric power only in the narrow vicinity of the resonant frequency14,15 and any fluctuation in the excitation frequency can cause a sharp decrease in the output power. 3(a and b), it is seen that in the case of no stopper, the energy harvester has a peak output voltage of 11.2V at excitation frequency of 19Hz where the resonance occurs.

Results

Conclusion