scholarly journals A Broadband Vibration-Based Energy Harvester Using an Array of Piezoelectric Beams Connected by Springs

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
V. Meruane ◽  
K. Pichara
Keyword(s):  
Frequency Band ◽  
Energy Harvester ◽  
Experimental Measurements ◽  
Bernoulli Beam ◽  
Significant Drop ◽  
Energy Harvesters ◽  
Advantages And Disadvantages ◽  
Narrow Frequency Band ◽  
Cantilevered Beams ◽  
Euler Bernoulli Beam

Piezoelectric cantilevered beams have been widely used as vibration-based energy harvesters. Nevertheless, these devices have a narrow frequency band and if the excitation is slightly different there is a significant drop in the level of power generated. To handle this problem, the present investigation proposes the use of an array of piezoelectric cantilevered beams connected by springs as a broadband vibration-based energy harvester. The equations for the voltage and power output of the system are derived based on the analytical solution of the piezoelectric cantilevered energy harvester with Euler-Bernoulli beam assumptions. To study the advantages and disadvantages of the proposed system, the results are compared with those of an array of disconnected beams (with no springs). The analytical model is validated with experimental measurements of three bimorph beams with and without springs. The results show that connecting the array of beams with springs allows increasing the frequency band of operation and increasing the amount of power generated.

Experimental and Theoretical Study of a Dual-Beam Piezoelectric Energy Harvester With Misaligned Magnets

2018 ◽  
Author(s):  
Wei-Jiun Su ◽  
Hsuan-Chen Lu
Keyword(s):  
Energy Harvester ◽  
Theoretical Study ◽  
Beam Theory ◽  
Main Beam ◽  
Bernoulli Beam ◽  
Potential Wells ◽  
Piezoelectric Energy ◽  
Dual Beam ◽  
Frequency Sweeps ◽  
Euler Bernoulli Beam

In this study, a dual-beam piezoelectric energy harvester is proposed. This harvester consists of a main beam and an auxiliary beam with a pair of magnets attached to couple their motions. The potential energy of the system is modeled to understand the influence of the potential wells on the dynamics of the harvester. It is noted that the alignment of the magnets significantly influences the potential wells. A theoretical model of the harvester is developed based on the Euler-Bernoulli beam theory. Frequency sweeps are conducted experimentally and numerically to study the dynamics of the harvester. It is shown that the dual-beam harvester can exhibit hardening effect with different configurations of magnet alignments in frequency sweeps. The performance of the harvester can be improved with proper placement of the magnets.

Analysis of bimorph piezoelectric beam energy harvesters using Timoshenko and Euler–Bernoulli beam theory

2012 ◽  
Vol 24 (2) ◽  
pp. 226-239 ◽  
Author(s):  
Gang Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Slenderness Ratio ◽  
Beam Theory ◽  
Bernoulli Beam ◽  
Energy Harvesters ◽  
Bernoulli Beam Theory ◽  
Spectral Finite Element ◽  
Euler Bernoulli Beam ◽  
Element Method

Single-degree-of-freedom lumped parameter model, conventional finite element method, and distributed parameter model have been developed to design, analyze, and predict the performance of piezoelectric energy harvesters with reasonable accuracy. In this article, a spectral finite element method for bimorph piezoelectric beam energy harvesters is developed based on the Timoshenko beam theory and the Euler–Bernoulli beam theory. Linear piezoelectric constitutive and linear elastic stress/strain models are assumed. Both beam theories are considered in order to examine the validation and applicability of each beam theory for a range of harvester sizes. Using spectral finite element method, a minimum number of elements is required because accurate shape functions are derived using the coupled electromechanical governing equations. Numerical simulations are conducted and validated using existing experimental data from the literature. In addition, parametric studies are carried out to predict the performance of a range of harvester sizes using each beam theory. It is concluded that the Euler–Bernoulli beam theory is sufficient enough to predict the performance of slender piezoelectric beams (slenderness ratio > 20, that is, length over thickness ratio > 20). In contrast, the Timoshenko beam theory, including the effects of shear deformation and rotary inertia, must be used for short piezoelectric beams (slenderness ratio < 5).

Modeling of V-Shaped Beam-Mass Piezoelectric Energy Harvester: Impact of the Angle Between the Beams

2012 ◽  
Author(s):  
Wei-Jiun Su ◽  
Jean W. Zu
Keyword(s):  
Resonant Frequency ◽  
Energy Harvester ◽  
Beam Theory ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Layers ◽  
Cantilevered Beam ◽  
Power Frequency ◽  
Tip Mass ◽  
Euler Bernoulli Beam

Piezoelectric material has been widely utilized in vibration-based energy harvesters (VEH). The most common configuration of piezoelectric energy harvester is a cantilevered beam with unimorph or bimorph piezoelectric layers. In this paper, a new configuration of PEH is proposed. Two beams are assembled as V shape with tip masses attached. The first beam is a cantilevered beam with tip mass while the second beam is attached to the end of the first beam with a certain angle. Piezoelectric layers are attached to both beams in unimorph configuration for power generation. The analytical solution is derived based on Euler-Bernoulli beam theory. In this analysis, the angle varies from 0 to 135 degree to see the influence of angle on voltage and power frequency response. The V-shaped VEH is proven to have the second resonant frequency relatively close to the first resonant frequency when compared with conventional cantilevered VEH. Furthermore, the angle between the two beams will influence the ratio of the second to the first resonant frequency. By choosing a suitable angle, the V-shaped structure can effectively broaden the bandwidth.

Analysis of bimorph piezoelectric beam energy harvesters using superconvergent element

2019 ◽  
Vol 30 (15) ◽  
pp. 2299-2313 ◽  
Author(s):  
Peyman Hajheidari ◽  
Ion Stiharu ◽  
Rama Bhat
Keyword(s):  
Beam Energy ◽  
Slenderness Ratio ◽  
Mechanical Energy ◽  
Beam Model ◽  
Bernoulli Beam ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Piezoelectric Beam ◽  
Euler Bernoulli Beam ◽  
Beam Theories

Cantilever-based piezoelectric energy harvesters have been utilized as structures to extract mechanical energy from the ambient mechanical vibrations and transfer it into the electrical output. In this article, the performance of bimorph piezoelectric beam energy harvesters is investigated. The cantilever beam is modeled by using both Timoshenko and Euler–Bernoulli beam theories. The equations are discretized using the conventional finite element method and superconvergent element. Besides the high rate of convergence, easy switching between the above beam theories is enabled by such type of element. The current model is presented for a Timoshenko beam model, but it could as well be used for a Euler–Bernoulli beam model. In addition, voltage, current, and power frequency response functions for different ranges of load resistance varying from the short-circuit to open-circuit conditions are determined to reach the maximum values. Effects of the slenderness ratio and the required beam model based on the geometric properties of the piezoelectric energy harvesters are discussed in the final part of this study. The results show that only for smaller values of the slenderness ratio (below 5), it is necessary to model the beam using the Timoshenko assumptions; otherwise both beam theories provide approximately the same responses.

Power Generation From Mastication Forces Using a Smart Tooth

2016 ◽  
Author(s):  
Muath Bani-Hani ◽  
M. Amin Karami
Keyword(s):  
Energy Harvester ◽  
Pulse Generator ◽  
Exact Analytical Solution ◽  
Vibration Energy Harvester ◽  
Mechanical Coupling ◽  
Pulse Generators ◽  
Energy Harvesters ◽  
Piezoelectric Beam ◽  
Bimorph Beam ◽  
Euler Bernoulli Beam

The batteries of the current pacing devices are relatively large and occupy over 60 percent of the size of pulse generators. Therefore, they cannot be placed in the subtle areas of human body. In this paper, the mastication force and the resulting tooth pressure are converted to electricity. The pressure energy can be converted to electricity by using the piezoelectric effect. The tooth crown is used as a power autonomous pulse generator. We refer to this envisioned pulse generator as the smart tooth. The smart tooth is in the form of a dental implant. A piezoelectric vibration energy harvester is designed and modeled for this purpose. The Piezoelectric based energy harvesters investigated and analyzed in this paper initially includes a single degree of freedom piezoelectric based stack energy harvester which utilizes a harvesting circuit employing the case of a purely resistive circuit. The next step is utilizing and investigating a bimorph piezoelectric beam which is integrated/embedded in the smart tooth implant. Mastication process causes the bimorph beam to buckle or return to unbuckled condition. The transitions result in vibration of the piezoelectric beam and thus generate energy. The power estimated by the two mechanisms is in the order of hundreds of microwatts. Both scenarios of the energy harvesters are analytically modeled. The exact analytical solution of the piezoelectric beam energy harvester with Euler-Bernoulli beam assumptions is presented. The electro-mechanical coupling and the geometric nonlinearities have been included in the model for the piezoelectric beam.

LMI-based hybrid temporal-spatial differential control design for a class of Euler-Bernoulli beam system

2021 ◽  
pp. 095440622110036
Author(s):  
Jiaqi Zhong ◽  
Xiaolei Chen ◽  
Yupeng Yuan ◽  
Jiajia Tan
Keyword(s):  
Vibration Suppression ◽  
Direct Method ◽  
Recursive Algorithm ◽  
Linear Matrix ◽  
Bernoulli Beam ◽  
Hybrid Controller ◽  
Beam System ◽  
Active Vibration ◽  
Differential Control ◽  
Euler Bernoulli Beam

This paper addresses the problem of active vibration suppression for a class of Euler-Bernoulli beam system. The objective of this paper is to design a hybrid temporal-spatial differential controller, which is involved with the in-domain and boundary actuators, such that the closed-loop system is stable. The Lyapunov’s direct method is employed to derive the sufficient condition, which not only can guarantee the stabilization of system, but also can improve the spatial cooperation of actuators. In the framework of the linear matrix inequalities (LMIs) technology, the gain matrices of hybrid controller can obtained by developing a recursive algorithm. Finally, the effectiveness of the proposed methodology is demonstrated by applying a numerical simulation.

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