Robust design optimization of fixed-fixed beam piezoelectric energy harvester considering manufacturing uncertainties

Kim, Jihoon,Lee, Tae Hee,Song, Yewon,Sung, Tae Hyun Elsevier Sequoia 2017 Sensors and actuators. A Physical Vol.260 No.-

<P><B>Abstract</B></P> <P>The piezoelectric energy harvester, which accumulates electrical energy from ambient vibration energy has emerged as an alternative energy source because of its eco-friendly characteristics. Numerous studies have been conducted on the basis of experimental methods to increase the power generating capabilities of the piezoelectric energy harvester. Recently, research using optimization techniques to improve the performance has been carried out. However, since the previous studies did not consider various uncertainties that exist in the energy harvester, it is difficult to overcome the variance of performance caused by the uncertainties. In order to obtain the highest performance from the piezoelectric energy harvester and simultaneously retain robustness while installed under the road pavement, this paper presents robust design optimization of piezoelectric energy harvester which is insensitive to the uncertainties. Prior to performing the robust optimization, statistical information of the uncertainties that exist in the piezoelectric energy harvester was measured from 30 piezoelectric experiments. Then uncertainty quantification was performed using Akaike information criterion. A statistical model calibration method, used to improve the accuracy of the simulation model for robust optimization, was proposed and implemented, based on the uncertainty data. By using the calibrated simulation model, the piezoelectric energy harvester was evaluated and optimized to achieve maximum performance and robustness simultaneously. Finally, the robust optimum design solution for the piezoelectric energy harvester was verified, showing improved performance and reduced variance.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Robust optimization of beam-type piezoelectric energy harvester is performed. </LI> <LI> Statistical model calibration is proposed to obtain the accurate simulation model of PEH. </LI> <LI> Physical experiments are performed to measure the uncertainty of PEH. </LI> <LI> Robust design optimization of PEH using calibrated simulation model is performed. </LI> <LI> Output voltage of PEH is increased by 22.35% and its variance is reduced by 58.04%. </LI> </UL> </P>

압전-마찰전기 복합 소재 기반의 고출력 에너지 하베스팅 기술 개발 리뷰

Aamir Rasheed,박현제(Hyunje Park),손민균(Min Kyun Sohn),이태형(Tae Hyeong Lee),강대준(Dae Joon Kang) 한국세라믹학회 2020 세라미스트 Vol.23 No.1

Global effort has resulted in tremendous progress with energy harvesters that extract mechanical energy from ambient sources, convert it to electrical energy, and use it for systems such as wrist watches, mobile electronic devices, wireless sensor nodes, health monitoring, and biosensors. However, harvesting a single energy source only still pauses a great challenge in driving sustainable and maintenance-free monitoring and sensing devices. Over the last few years, research on high-performance mechanical energy harvesters at the micro and nanoscale has been directed toward the development of hybrid devices that either aim to harvest mechanical energy in addition to other types of energies simultaneously or to exploit multiple mechanisms to more effectively harvest mechanical energy. Herein, we appraise the rational designs for multiple energy harvesting, specifically state-of-the-art hybrid mechanical energy harvesters that employ multiple piezoelectric and triboelectric mechanisms to efficiently harvest mechanical energy. We identify the critical material parameters and device design criteria that lead to high-performance hybrid mechanical energy harvesters. Finally, we address the future perspectives and remaining challenges in the field.

A Bending-Type Piezoelectric Energy Harvester with a Displacement-Amplifying Mechanism for Smart Highways

안정환,황원섭,조재용,정세영,송경주,홍성도,성태현,정신우,유홍희 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.3

Piezoelectric energy harvesting has gained attention owing to its effectiveness at harvesting electrical energy from various energy sources. Especially, with the increasing demand for smart highways, piezoelectric energy harvesting from road traffic has been increasingly studied. However, existing piezoelectric road-energy harvesters have limitations of low electrical output and low durability. A novel piezoelectric energy harvester was designed and fabricated to overcome these limitations. The proposed harvester had a maximum output power of 3.93 mW at a load resistance of 130 kΩ under an input displacement of 2.5 mm. The proposed harvester had 4.2 times more output power than the existing vibration-type road energy harvesters and was much less susceptible to destruction-in contrast to existing impact-type road-energy harvesters. The proposed road-energy harvester can be used as a power source for wireless sensor networks in smart highways.

심벌형 압전 에너지 하베스터 에너지 수율 향상 연구

나영민(Yeong-Min Na),박종규(Jong-Kyu Park) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.1

The pollution problem of fossil energy sources has caused the development of green energy harvesting systems. Piezoelectric energy harvesting technology has been developed under those external environmental factors. A piezoelectric energy harvester can be defined as a device which transforms mechanical vibration or impact energy into electrical energy. Most researches have focused on bender structures. However, these have a limitation on energy efficiency because of the small effective electromechanical coupling factor, around 10%. Therefore, we should look for a new design for energy harvesting. A cymbal energy harvester can be a good candidate for the high-power energy harvester because it uses a high amplification mechanism using endcaps while keeping a higher electromechanical coupling factor. In this research, we focused on energy efficiency improvements of the cymbal energy harvester by changing the polarization direction, because the electromechanical coupling factor of the k33 mode and the k15 mode is larger than that of the k31 mode. Theoretically, we checked the cymbal harvester with radial polarization and it could obtain 6 times larger energy than that with the k31 direction polarization. Furthermore, we verified the theoretical expectation using the finite element method program. Consequently, we could expect a more efficient cymbal harvester with the radial polarization by comparing two polarization directions.

Flexible piezoelectric polymer-based energy harvesting system for roadway applications

Jung, Inki,Shin, Youn-Hwan,Kim, Sangtae,Choi, Ji-young,Kang, Chong-Yun Elsevier 2017 APPLIED ENERGY Vol.197 No.-

<P>Interest in energy harvesters has grown rapidly over the last decade. The research effort in large-scale energy harvesting has mainly focused on piezoelectric ceramic based devices, due to its high piezoelectric constants. In this study, we demonstrate a piezoelectric energy harvester module based on polyvinylidene fluoride (PVDF) polymer for roadway applications. Flexible energy harvesters are fabricated with PVDF films and it exhibited stable performance and durability over the repeated number of bending cycles. In order to structurally optimize the design, finite element analysis was performed on two possible module configuration, with detailed input conditions on how the flexible energy harvester must be bent. A piezoelectric energy harvester module is then constructed with the fabricated unit energy harvesters inserted in the vertical direction, with initial radii of curvature as high as possible. The module was tested with a model mobile load system (MMLS3) and exhibited up to 200 mW instantaneous power output across a 40 k Omega resistor. The power output scaled linearly with the number of parallel connected harvesters. The calculated power density at this impedance reaches up to 8.9 W/m(2), suggesting that the flexible energy harvesters based on the piezoelectric polymers may provide energy density as high as those based on piezoelectric ceramics. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Broadband dual phase energy harvester: Vibration and magnetic field

Song, Hyun-Cheol,Kumar, Prashant,Sriramdas, Rammohan,Lee, Hyeon,Sharpes, Nathan,Kang, Min-Gyu,Maurya, Deepam,Sanghadasa, Mohan,Kang, Hyung-Won,Ryu, Jungho,Reynolds Jr., William T.,Priya Jr., Shashank Elsevier 2018 APPLIED ENERGY Vol.225 No.-

<P><B>Abstract</B></P> <P>Broadband mechanical energy harvesting implies stable output power over a wide range of source frequency. Here we present a cost-effective solution towards achieving broadband response by designing a magnetically coupled piezoelectric energy harvester array that exhibits a large power density of 243 μW/cm<SUP>3</SUP> g<SUP>2</SUP> at natural frequency and bandwidth of more than 30 Hz under 1 g acceleration. The magnetically coupled piezoelectric energy harvester array exhibits dual modes of energy harvesting, responding to both stray magnetic field as well as ambient vibrations, and is found to exhibit the output power density of 36.5 μW/cm<SUP>3</SUP> Oe<SUP>2</SUP> at 79.5 Hz under the ambient magnetic field while maintaining the broadband nature. The magnetically coupled piezoelectric energy harvester array was demonstrated to harvest continuous power from a rotary pump vibration, an automobile engine vibration and a parasitic magnetic field surrounding a cable of an electric kettle. These demonstrations suggest that the magnetically coupled piezoelectric energy harvester array could serve the role of a standalone power source for wireless sensor nodes and small electronic devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Magnetically coupled energy harvester array is demonstrated for broadband operation. </LI> <LI> Energy harvester provides dual mode energy harvesting in magnetic field and vibration. </LI> <LI> Energy harvester exhibits 243 μW/cm<SUP>3</SUP> g<SUP>2</SUP> power density and over 30 Hz bandwidth. </LI> <LI> Energy harvester is implemented in practical environments of a rotary pump, power cable, and car engine. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Flexible ceramic-elastomer composite piezoelectric energy harvester fabricated by additive manufacturing

Park, Jae-Il,Lee, Gil-Yong,Yang, Jinkyu,Kim, Chung-Soo,Ahn, Sung-Hoon SAGE Publications 2016 Journal of composite materials Vol.50 No.12

<P>As a renewable energy harvesting method, interest in piezoelectric energy harvesting has increased significantly. Despite the piezoelectric energy-harvesting technology expanding its area to the flexible (elastic, amendable) devices, striking use or application of the technology is hardly found in the market. Here, we report a novel flexible piezoelectric energy harvester fabricated by using an additive manufacturing process, which enables both effective and customized manufacturing technique. By taking advantages of additive manufacturing, further application of the piezoelectric energy-harvesting technology is highly expected. Particles of BaTiO3, a ceramic with a large piezoelectric constant, were mixed with polyether block amide elastomer to form a flexible piezoelectric composite. The energy harvester was fabricated using an additive manufacturing process, by printing the piezoelectric composite on a laser-patterned flexible Indium-tin-oxide-coated polyethylene terephthalate substrate. Performance of fabricated energy harvester was evaluated by applying a mechanical stress to the energy harvester; voltage and current output were 2V and 40 nA, respectively. An analytical model of the piezoelectric energy harvester was developed and discussed to explain the form of the voltage waveforms in response to the applied stress.</P>

Bimorph piezoelectric energy harvester structurally integrated on a trapezoidal plate

Ahmet Levent Avsar,Melin Sahin 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.2

A bimorph piezoelectric energy harvester is developed for harvesting energy under the vortex induced vibration and it is integrated to a host structure of a trapezoidal plate without changing its passive dynamic properties. It is aimed to select trapezoidal plate as similar to a vertical fin-like structure which could be a part of an air vehicle. The designed energy harvester consists of an aluminum beam and two identical multi fiber composite (MFC) piezoelectric patches. In order to understand the dynamic characteristic of the trapezoidal plate, finite element analysis is performed and it is validated through an experimental study. The bimorph piezoelectric energy harvester is then integrated to the trapezoidal plate at the most convenient location with minimal structural displacement. The finite element model is constructed for the new combined structure in ANSYS Workbench 14.0 and the analyses performed on this particular model are then validated via experimental techniques. Finally, the energy harvesting performance of the bimorph piezoelectric energy harvester attached to the trapezoidal plate is also investigated through wind tunnel tests under the air load and the obtained results indicate that the system is a viable one for harvesting reasonable amount of energy.

3차원 유한요소 해석을 통한 압전에너지 도로의 장기 공용성 예측

김현욱,남정희,최지영,Kim, Hyun Wook,Nam, Jeong-Hee,Choi, Ji Young 한국도로학회 2017 한국도로학회논문집 Vol.19 No.5

PURPOSES : The piezoelectric energy road analysis technology using a three-dimensional finite element method was developed to investigate pavement behaviors when piezoelectric energy harvesters and a new polyurethane surface layer were installed in field conditions. The main purpose of this study is to predict the long-term performance of the piezoelectric energy road through the proposed analytical steps. METHODS : To predict the stresses and strains of the piezoelectric energy road, the developed energy harvesters were embedded into the polyurethane surface layer (50 mm from the top surface). The typical type of triaxial dump truck loading was applied to the top of each energy harvester. In this paper, a general purpose finite element analysis program called ABAQUS was used and it was assumed that a harvester is installed in the cross section of a typical asphalt pavement structure. RESULTS : The maximum tensile stress of the polyurethane surface layer in the initial fatigue model occurred up to 0.035 MPa in the transverse direction when the truck tire load was loaded on the top of each harvester. The maximum tensile stresses were 0.025 MPa in the intermediate fatigue model and 0.013 MPa in the final fatigue model, which were 72% and 37% lower than that of the initial stage model, respectively. CONCLUSIONS : The main critical damage locations can be estimated between the base layer and the surface layer. If the crack propagates, bottom-up cracking from the base layer is the main cracking pattern where the tensile stress is higher than in other locations. It is also considered that the possibility of cracking in the top-down direction at the edge of energy harvester is more likely to occur because the material strength of the energy harvester is much higher and plays a role in the supporting points. In terms of long-term performance, all tensile stresses in the energy harvester and polyurethane layer are less than 1% of the maximum tensile strength and the possibility of fatigue damage was very low. Since the harvester is embedded in the surface layer of the polyurethane, which has higher tensile strength and toughness, it can assure a good, long-term performance.

Modelling and experimental investigations on stepped beam with cavity for energy harvesting

A. Rami Reddy,M. Umapathy,D. Ezhilarasi,G. Uma 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.4

This paper presents techniques to harvest higher voltage from piezoelectric cantilever energy harvester by structural alteration. Three different energy harvesting structures are considered namely, stepped cantilever beam, stepped cantilever beam with rectangular and trapezoidal cavity. The analytical model of three energy harvesting structures are developed using Euler-Bernoulli beam theory. The thickness, position of the rectangular cavity and the taper angle of the trapezoidal cavity is found to shift the neutral axis away from the surface of the piezoelectric element which in turn increases the generated voltage. The performance of the energy harvesters is evaluated experimentally and is compared with regular piezoelectric cantilever energy harvester. The analytical and experimental investigations reveal that, the proposed energy harvesting structures generate higher output voltage as compared to the regular piezoelectric cantilever energy harvesting structure. This work suggests that through simple structural modifications higher energy can be harvested from the widely reported piezoelectric cantilever energy harvester.