Comparative Analysis of One-Dimensional and Two-Dimensional Cantilever Piezoelectric Energy Harvesters

2014 ◽  
Vol 1 (3-4) ◽  
Author(s):  
Nathan Sharpes ◽  
Abdessattar Abdelkefi ◽  
Shashank Priya

AbstractA long-standing encumbrance in the design of low-frequency energy harvesters has been the need of substantial beam length and/or large tip mass values to reach the low resonance frequencies where significant energy can be harvested from the ambient vibration sources. This need of large length and tip mass may result in a device that is too large to be practical. The zigzag (meandering) beam structure has emerged as a solution to this problem. In this letter, we provide comparative analysis between the classical one-dimensional cantilever bimorph and the two-dimensional zigzag unimorph piezoelectric energy harvesters. The results demonstrate that depending upon the excitation frequency, the zigzag harvester is significantly better in terms of magnitude of natural frequency, harvested power, and power density, compared to the cantilever configuration. The dimensions were chosen for each design such that the zigzag structure would have 25.4×25.4 mm

2018 ◽  
pp. 826-862
Author(s):  
Abdessattar Abdelkefi

There exist numerous low-frequency excitation sources, such as walking, breathing, and ocean waves, capable of providing viable amounts of mechanical energy to power many critical devices, including pacemakers, cell phones, MEMS devices, wireless sensors, and actuators. Harvesting significant energy levels from such sources can only be achieved through the design of devices capable of performing effective energy transfer mechanisms over low frequencies. In this chapter, two concepts of efficient low-frequency piezoelectric energy harvesters are presented, namely, variable-shaped piezoelectric energy harvesters and piezomagnetoelastic energy harvesters. Linear and nonlinear electromechanical models are developed and validated in this chapter. The results show that the quadratic shape can yield up to two times the energy harvested by a rectangular one. It is also demonstrated that depending on the available excitation frequency, an enhanced energy harvester can be tuned and optimized by changing the length of the piezoelectric material or by changing the distance between the two tip magnets.


Author(s):  
Hichem Abdelmoula ◽  
Nathan Sharpes ◽  
Hyeon Lee ◽  
Abdessattar Abdelkefi ◽  
Shashank Priya

We design and experimentally validate a zigzag piezoelectric energy harvester that can generate energy at low frequencies and which can be used to operate low-power consumption electronic devices. The harvester is composed of metal and piezoelectric layers and is used to harvest energy through direct excitations. A computational model is developed using Abaqus to determine the exact mode shapes and coupled frequencies of the considered energy harvester in order to design a broadband torsion-bending mechanical system. Analysis is then performed to determine the optimal load resistance. The computational results are compared and validated with the experimental measurements. More detailed analysis is then carried out to investigate the effects of the masses on the bending and torsion natural frequencies of the harvester and generated power levels. The results show that due to the coupling between the bending and torsion modes of the zigzag structure, highest levels of the harvested power are obtained when the excitation frequency matches the coupled frequency of torsion type for three different values of the tip mass.


Author(s):  
Abdessattar Abdelkefi

There exist numerous low-frequency excitation sources, such as walking, breathing, and ocean waves, capable of providing viable amounts of mechanical energy to power many critical devices, including pacemakers, cell phones, MEMS devices, wireless sensors, and actuators. Harvesting significant energy levels from such sources can only be achieved through the design of devices capable of performing effective energy transfer mechanisms over low frequencies. In this chapter, two concepts of efficient low-frequency piezoelectric energy harvesters are presented, namely, variable-shaped piezoelectric energy harvesters and piezomagnetoelastic energy harvesters. Linear and nonlinear electromechanical models are developed and validated in this chapter. The results show that the quadratic shape can yield up to two times the energy harvested by a rectangular one. It is also demonstrated that depending on the available excitation frequency, an enhanced energy harvester can be tuned and optimized by changing the length of the piezoelectric material or by changing the distance between the two tip magnets.


Author(s):  
Yang Zhu ◽  
Oumar Barry ◽  
Weijiun Su ◽  
Jean Zu

Vibration-based energy harvesting using piezoelectric materials has gained considerable attention over the past decade. Currently, most piezoelectric energy harvesters (PEHs) are single resonance frequency based. The performance of a single-resonance PEH is often limited to only one resonance frequency. This paper discusses the possibility of improving the performance of a bimorph PEH by tuning the PEH using a spring-mass system attached to the bimorph’s free end. Through adding the spring-mass system, the PEH’s resonance frequency can be tuned to match the ambient vibration frequency, and its voltage/power-generating capability can be improved. An electromechanical model of the PEH is derived based on the Lagrange multiplier method. The model is then used in a harmonic base excitation case study, and the coupled electromechanical outputs are discussed. Simulation results show that the spring-mass attachment can create two resonant frequencies, making the PEH capable of working efficiently at two different frequencies in a low-frequency level. It is also shown that by properly selecting the spring stiffness and the mass, the voltage and power output of the PEH can be greatly increased as compared to a single bimorph without the spring-mass system.


2012 ◽  
Vol 9 (1) ◽  
pp. 47-52
Author(s):  
R.Kh. Bolotnova ◽  
V.A. Buzina

The two-dimensional and two-phase model of the gas-liquid mixture is constructed. The validity of numerical model realization is justified by using a comparative analysis of test problems solution with one-dimensional calculations. The regularities of gas-saturated liquid outflow from axisymmetric vessels for different geometries are established.


Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 203
Author(s):  
Xiaohua Huang ◽  
Cheng Zhang ◽  
Keren Dai

Using the piezoelectric effect to harvest energy from surrounding vibrations is a promising alternative solution for powering small electronic devices such as wireless sensors and portable devices. A conventional piezoelectric energy harvester (PEH) can only efficiently collect energy within a small range around the resonance frequency. To realize broadband vibration energy harvesting, the idea of multiple-degrees-of-freedom (DOF) PEH to realize multiple resonant frequencies within a certain range has been recently proposed and some preliminary research has validated its feasibility. Therefore, this paper proposed a multi-DOF wideband PEH based on the frequency interval shortening mechanism to realize five resonance frequencies close enough to each other. The PEH consists of five tip masses, two U-shaped cantilever beams and a straight beam, and tuning of the resonance frequencies is realized by specific parameter design. The electrical characteristics of the PEH are analyzed by simulation and experiment, validating that the PEH can effectively expand the operating bandwidth and collect vibration energy in the low frequency. Experimental results show that the PEH has five low-frequency resonant frequencies, which are 13, 15, 18, 21 and 24 Hz; under the action of 0.5 g acceleration, the maximum output power is 52.2, 49.4, 61.3, 39.2 and 32.1 μW, respectively. In view of the difference between the simulation and the experimental results, this paper conducted an error analysis and revealed that the material parameters and parasitic capacitance are important factors that affect the simulation results. Based on the analysis, the simulation is improved for better agreement with experiments.


2021 ◽  
Vol 13 (5) ◽  
pp. 2865 ◽  
Author(s):  
Sungryong Bae ◽  
Pilkee Kim

In this study, optimization of the external load resistance of a piezoelectric bistable energy harvester was performed for primary harmonic (period-1T) and subharmonic (period-3T) interwell motions. The analytical expression of the optimal load resistance was derived, based on the spectral analyses of the interwell motions, and evaluated. The analytical results are in excellent agreement with the numerical ones. A parametric study shows that the optimal load resistance depended on the forcing frequency, but not the intensity of the ambient vibration. Additionally, it was found that the optimal resistance for the period-3T interwell motion tended to be approximately three times larger than that for the period-1T interwell motion, which means that the optimal resistance was directly affected by the oscillation frequency (or oscillation period) of the motion rather than the forcing frequency. For broadband energy harvesting applications, the subharmonic interwell motion is also useful, in addition to the primary harmonic interwell motion. In designing such piezoelectric bistable energy harvesters, the frequency dependency of the optimal load resistance should be considered properly depending on ambient vibrations.


Author(s):  
Virgilio J Caetano ◽  
Marcelo A Savi

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.


Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1206 ◽  
Author(s):  
Wei-Jiun Su ◽  
Jia-Han Lin ◽  
Wei-Chang Li

This paper investigates a piezoelectric energy harvester that consists of a piezoelectric cantilever and a tip mass for horizontal rotational motion. Rotational motion results in centrifugal force, which causes the axial load on the beam and alters the resonant frequency of the system. The piezoelectric energy harvester is installed on a rotational hub in three orientations—inward, outward, and tilted configurations—to examine their influence on the performance of the harvester. The theoretical model of the piezoelectric energy harvester is developed to explain the dynamics of the system and experiments are conducted to validate the model. Theoretical and experimental studies are presented with various tilt angles and distances between the harvester and the rotating center. The results show that the installation distance and the tilt angle can be used to adjust the resonant frequency of the system to match the excitation frequency.


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