Sensing Signal and Energy Generation Analysis on a Flexoelectric Beam

Flexoelectricity is known as an electromechanical gradient coupling effect. The direct flexoelectric effect that can convert mechanical strain gradient into electric polarization (or electric field) plays an important role in charge generation in the situation when piezoelectricity is absent. This study focuses on the application of the direct flexoelectric effect based on a flexoelectric cantilever beam to investigate its effectiveness of sensing signal and energy generation. The dielectric cantilever beam is deposited with electrodes both on top and bottom surfaces to generate an electric voltage. The sensing mechanism of flexo-piezo-electric effect is analyzed and the expression of sensing signal is derived. Results show that the output sensing signal is only contributed by the flexoelectric effect while the piezoelectric effect is eliminated due to the symmetric bending strains through the beam thickness. The spatial distribution of sensing signal when the fully covered electrode is uniformly segmented to 10 patches is evaluated as an illustration, and the flexoelectric sensitivity of about 0.15V/mm for the first mode and 4V/mm for the fourth mode is achieved. The optimal sensing position is dependent of the electrode size and the vibration mode and in general, it locates where the difference between the slopes at two ends of the electrode patch reaches maximum. Based on the flexoelectric voltage, the energy generation power is also conducted when the flexoelectric cantilever beam is treated as distributed energy harvesters. As a result, the maximal power of RMS is about 1.5×10−8W/mm for the first mode and increases to about 0.6mW/mm for the fourth mode. It provides an alternative way to harvest electric energy from the ambient vibration without using piezoelectricity.

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Distributed flexoelectric modal signals on circular cylindrical shells

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406217697999 ◽

2017 ◽

Vol 232 (6) ◽

pp. 952-961 ◽

Cited By ~ 3

Author(s):

Hua Li ◽

Kaiming Hu ◽

HS Tzou

Keyword(s):

Strain Gradient ◽

Cylindrical Shells ◽

Mechanical Strain ◽

Electric Polarization ◽

Design Parameters ◽

Flexoelectric Effect ◽

Bending Strain ◽

Longitudinal Bending ◽

Circular Cylindrical Shells ◽

Sensing Characteristics

Flexoelectricity exhibits both direct effect and converse effect. For direct flexoelectric effect, mechanical strain gradients induce a homogeneous electric polarization in dielectrics. Thus, the induced electric field between the electrodes can be measured. Compared with the piezoelectric sensors, the main advantage of the flexoelectric sensors is that they are not sensitive to the in-plane strains. This paper presents segmented flexoelectric sensors laminated on circular cylindrical shells, and investigates the electromechanical strain-gradient/signal-generation characteristics and distributed modal flexoelectric signals on the cylindrical shells. The dynamic equations of the proposed flexoelectric sensor are derived based on the direct flexoelectric effect and thin shell assumptions. The model of modal signal is derived to investigate the sensing characteristics. In case studies, the effects of design parameters, i.e. size and thickness of the sensors and geometry of the shells, are evaluated and compared. Numerical results indicate that the contribution of longitudinal bending strain gradient is dominant in the total signals of most evaluated modes, except that in modes 1 and 2, where the contribution of the circumferential bending strain gradient is slightly higher. The amplitudes of the modal signals decrease with the shell radius, but increase with the sensor thickness.

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Static Nano-Control of Cantilever Beams Using the Inverse Flexoelectric Effect

Volume 7: Dynamic Systems and Control; Mechatronics and Intelligent Machines, Parts A and B ◽

10.1115/imece2011-65123 ◽

2011 ◽

Cited By ~ 7

Author(s):

S. D. Hu ◽

H. Li ◽

H. S. Tzou

Keyword(s):

Electric Field ◽

Cantilever Beam ◽

Mechanical Strain ◽

Effective Control ◽

Bottom Surface ◽

Control Force ◽

Dirac Delta ◽

Flexoelectric Effect ◽

Afm Probe ◽

Converse Piezoelectric Effect

Flexoelectricity, an electromechanical coupling effect, exhibits two opposite electromechanical properties. One is the direct flexoelectric effect that mechanical strain gradient induces an electric polarization (or electric field); the other is the inverse flexoelectric effect that polarization (or electric field) gradient induces internal stress (or strain). The later can serve as an actuation mechanism to control the static deformation of flexible structures. This study focuses on an application of the inverse flexoelectric effect to the static displacement control of a cantilever beam. The flexoelectric layer is covered with an electrode layer on the bottom surface and an AFM probe tip on the top surface in order to generate an inhomogeneous electric field when powered. The control force induced by the inverse flexoelectric effect is evaluated and its spatial distribution resembles a Dirac delta function. Therefore, a “buckling” characteristic happens at the contact point of the beam under the inverse flexoelectric control. The deflection results of the cantilever beam with respect to the AFM probe tip radius indicate that a smaller AFM probe tip achieves a more effective control effect. To evaluate the control effectiveness, the flexoelectric deflections are also compared with those resulting from the converse piezoelectric effect. It is evident that the inverse flexoelectric effect provides much better localized static deflection control of.flexible beams.

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Varying spatial orientation of photoelectric panels as method of managing graph of electric energy generation

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1019/1/012082 ◽

2021 ◽

Vol 1019 ◽

pp. 012082

Author(s):

Y Daus ◽

I Yudaev ◽

D Desyatnichenko

Keyword(s):

Spatial Orientation ◽

Electric Energy ◽

Energy Generation

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Comparison of Solar Tracking and Solar Fix Mode on the Efficiency Electric Energy Generation Based on Microcontroller

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/537/1/012030 ◽

2020 ◽

Vol 537 ◽

pp. 012030

Author(s):

Dean Corio ◽

Alvino Ramadian ◽

Rheyuniarto Sahlendar Asthan ◽

Mia Maria Ulfah

Keyword(s):

Electric Energy ◽

Energy Generation ◽

Solar Tracking

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Dynamic Response of Spiral Cantilever Undergoing Magnetic Coupling

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455414400215 ◽

2014 ◽

Vol 14 (08) ◽

pp. 1440021

Author(s):

Xiaoling Bai ◽

Yumei Wen ◽

Ping Li ◽

Jin Yang ◽

Xiao Peng ◽

...

Keyword(s):

Dynamic Response ◽

Cantilever Beam ◽

Magnetic Force ◽

Coupling Effect ◽

Magnetic Coupling ◽

Resonant Frequencies ◽

Energy Harvesters ◽

Magnetic Transducer ◽

Underlying Mechanisms ◽

Tip Mass

Cantilever beams have found intensive and extensive uses as underlying mechanisms for energy transduction in sensors as well as in energy harvesters. In magnetoelectric (ME) transduction, the underlying cantilever beam usually will undergo magnetic coupling effect. As the beam itself is either banded with magnetic transducer or magnets, the dynamic motion of the cantilever can be modified due to the magnetic force between the magnets and ME sensors. In this study, the dynamic response of a typical spiral cantilever beam with magnetic coupling is investigated. The spiral cantilever acts as the resonator of an energy harvester with a tip mass in the form of magnets, and a ME transducer is positioned in the air gap and interacts with the magnets. It is expected that this spiral configuration is capable of performing multiple vibration modes over a small frequency range and the response frequencies can be magnetically tunable. The experimental results show that the magnetic coupling between the magnets and the transducer plays a favorable role in achieving tunable resonant frequencies and reducing the frequency spacings. This will benefits the expansion of the response band of a device and is especially useful in energy harvesting.

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Conservation Integrals in Nonhomogeneous Materials with Flexoelectricity

Applied Sciences ◽

10.3390/app11020681 ◽

2021 ◽

Vol 11 (2) ◽

pp. 681

Author(s):

Pengfei Yu ◽

Weifeng Leng ◽

Yaohong Suo

Keyword(s):

Electromechanical Coupling ◽

Energy Momentum Tensor ◽

Great Influence ◽

Operator Method ◽

Electric Polarization ◽

Momentum Tensor ◽

Noether Theorem ◽

Strain Gradients ◽

Flexoelectric Effect ◽

Nonhomogeneous Materials

The flexoelectricity, which is a new electromechanical coupling phenomenon between strain gradients and electric polarization, has a great influence on the fracture analysis of flexoelectric solids due to the large gradients near the cracks. On the other hand, although the flexoelectricity has been extensively investigated in recent decades, the study on flexoelectricity in nonhomogeneous materials is still rare, especially the fracture problems. Therefore, in this manuscript, the conservation integrals for nonhomogeneous flexoelectric materials are obtained to solve the fracture problem. Application of operators such as grad, div, and curl to electric Gibbs free energy and internal energy, the energy-momentum tensor, angular momentum tensor, and dilatation flux can also be derived. We examine the correctness of the conservation integrals by comparing with the previous work and discuss the operator method here and Noether theorem in the previous work. Finally, considering the flexoelectric effect, a nonhomogeneous beam problem with crack is solved to show the application of the conservation integrals.

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New challenges emerged from the development of more efficient electric energy generation units

2011 IEEE Electric Ship Technologies Symposium ◽

10.1109/ests.2011.5770901 ◽

2011 ◽

Cited By ~ 28

Author(s):

J. M. Prousalidis ◽

G. J. Tsekouras ◽

F. Kanellos

Keyword(s):

Electric Energy ◽

Energy Generation ◽

New Challenges

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Flywheel energy storage systems and their applications in power engineering

Energy Safety and Energy Economy ◽

10.18635/2071-2219-2021-6-26-34 ◽

2021 ◽

Vol 6 ◽

pp. 26-34

Author(s):

Vladimir Poltavets ◽

Irina Kolchanova

Keyword(s):

Renewable Energy ◽

Energy Storage ◽

Storage Systems ◽

Renewable Energy Sources ◽

Supply And Demand ◽

Electric Energy ◽

Energy Generation ◽

Flywheel Energy Storage ◽

Energy Storage Systems ◽

Continuous Growth

The continuous growth of renewable energy sources has drastically changed the paradigm of electric energy generation and distribution. Flywheel energy storage systems are a clean and efficient method to level supply and demand in energy grids, including those incorporating renewable energy generation. Environmental safety, resilience, high power capacity and quality make flywheel energy storage very promising. This paper contains a review of flywheel energy storage systems, already being in operation, and applications of flywheel energy storage in general.

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NEW PARAMETERS FOR THE FOREST BIOMASS WASTE ECOFIREWOOD MANUFACTURING PROCESS OPTIMIZATION

Periódico Tchê Química ◽

10.52571/ptq.v16.n32.2019.578_periodico32_pgs_560_571.pdf ◽

2019 ◽

Vol 16 (32) ◽

pp. 560-571

Author(s):

Ana Cristina RUOSO ◽

Lisiane Corrêa BITENCOURT ◽

Lucas Urach SUDATI ◽

Marcos Antônio KLUNK ◽

Nattan Roberto CAETANO

Keyword(s):

Pinus Taeda ◽

Forest Biomass ◽

Electric Energy ◽

Chemical Characterization ◽

Energy Generation ◽

Economic Benefits ◽

Production Costs ◽

Raw Material ◽

Forest Residues ◽

Biomass Waste

Biomass has a large share in the energy generation matrix, due to the regional economic benefits. This work has as main objective to evaluate the parameters used in the manufacture of briquettes produced with forest residues and the economic engineering for the manufacturer. The forest residues were: wood chips and chips of Eucalyptus spp. and barks of Pinus taeda. The evaluations were the chemical characterization of forest residues and the costs involved in the briquetting process. The forest residues presented extractive chemical composition and lignin. The production costs of the briquettes were affected mainly by the equipment, being the Pinus taeda barks the one that presented higher production cost. However, the production costs obtained in this study are approximately 20% lower than the production costs using traditional methods for forest firewood. The energy value from biomass allows the reduction of the dependence of energy, which can be used for the generation of steam or electricity, for subsistence. A fact for energy conversion is to evaluate the material moisture. It is suitable to burn residues with moisture between 45 to 55%. The consumed electric energy is important to evaluate the total costs. The energy required depends on the quality of raw material and the system employed. Forest residues is an important source for eco firewood production, contributing to energy generation and decreasing of the solid waste stored at the company. In this way, the new parameters for briquetting biomass forest wastes shown in this work, which is an important stage of the process, make economically viable and environmentally suitable the eco firewood production.

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