Piezoelectric effect in strained quantum wells

International Nuclear Information System (INIS)

Dang, L.S.; Andre, R.; Cibert, J.

1995-01-01

This paper describes some physical aspects of the piezoelectric effect which takes place in strained semiconductor heterostructures grown along a polar axis. First we show how piezoelectric fields can be accurately measured by optical spectroscopy. Then we discuss about the origin of the non-linear piezoelectric effect reported recently for CdTe, and maybe for InAs as well. Finally we compare excitonic effects in piezoelectric and non-piezoelectric quantum wells. (orig.)

Piezoelectric MEMS resonators

CERN Document Server

Piazza, Gianluca

2017-01-01

This book introduces piezoelectric microelectromechanical (pMEMS) resonators to a broad audience by reviewing design techniques including use of finite element modeling, testing and qualification of resonators, and fabrication and large scale manufacturing techniques to help inspire future research and entrepreneurial activities in pMEMS. The authors discuss the most exciting developments in the area of materials and devices for the making of piezoelectric MEMS resonators, and offer direct examples of the technical challenges that need to be overcome in order to commercialize these types of devices. Some of the topics covered include: Widely-used piezoelectric materials, as well as materials in which there is emerging interest Principle of operation and design approaches for the making of flexural, contour-mode, thickness-mode, and shear-mode piezoelectric resonators, and examples of practical implementation of these devices Large scale manufacturing approaches, with a focus on the practical aspects associate...

Electromechanical characteristics of piezoelectric ceramic transformers in radial vibration composed of concentric piezoelectric ceramic disk and ring

International Nuclear Information System (INIS)

Lin, Shuyu; Hu, Jing; Fu, Zhiqiang

2013-01-01

A new type of piezoelectric ceramic transformer in radial vibration is presented. The piezoelectric transformer consists of a pairing of a concentric piezoelectric ceramic circular disk and ring. The inner piezoelectric ceramic disk is axially polarized and the outer piezoelectric ring is radially polarized. Based on the plane stress theory, the exact analytical theory for the piezoelectric transformer is developed and its electromechanical equivalent circuit is introduced. The resonance/anti-resonance frequency equations of the transformer are obtained and the relationship between the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient and the geometrical dimensions of the piezoelectric transformer is analyzed. The dependency of the voltage transformation ratio on the frequency is obtained. To verify the analytical theory, a numerical method is used to simulate the electromechanical characteristics of the piezoelectric transformer. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the numerical results. (paper)

A measurement method for piezoelectric material properties under longitudinal compressive stress–-a compression test method for thin piezoelectric materials

International Nuclear Information System (INIS)

Kang, Lae-Hyong; Lee, Dae-Oen; Han, Jae-Hung

2011-01-01

We introduce a new compression test method for piezoelectric materials to investigate changes in piezoelectric properties under the compressive stress condition. Until now, compression tests of piezoelectric materials have been generally conducted using bulky piezoelectric ceramics and pressure block. The conventional method using the pressure block for thin piezoelectric patches, which are used in unimorph or bimorph actuators, is prone to unwanted bending and buckling. In addition, due to the constrained boundaries at both ends, the observed piezoelectric behavior contains boundary effects. In order to avoid these problems, the proposed method employs two guide plates with initial longitudinal tensile stress. By removing the tensile stress after bonding a piezoelectric material between the guide layers, longitudinal compressive stress is induced in the piezoelectric layer. Using the compression test specimens, two important properties, which govern the actuation performance of the piezoelectric material, the piezoelectric strain coefficients and the elastic modulus, are measured to evaluate the effects of applied electric fields and re-poling. The results show that the piezoelectric strain coefficient d 31 increases and the elastic modulus decreases when high voltage is applied to PZT5A, and the compression in the longitudinal direction decreases the piezoelectric strain coefficient d 31 but does not affect the elastic modulus. We also found that the re-poling of the piezoelectric material increases the elastic modulus, but the piezoelectric strain coefficient d 31 is not changed much (slightly increased) by re-poling

Relaxor-PT Single Crystal Piezoelectric Sensors

Directory of Open Access Journals (Sweden)

Xiaoning Jiang

2014-07-01

Full Text Available Relaxor-PbTiO3 piezoelectric single crystals have been widely used in a broad range of electromechanical devices, including piezoelectric sensors, actuators, and transducers. This paper reviews the unique properties of these single crystals for piezoelectric sensors. Design, fabrication and characterization of various relaxor-PT single crystal piezoelectric sensors and their applications are presented and compared with their piezoelectric ceramic counterparts. Newly applicable fields and future trends of relaxor-PT sensors are also suggested in this review paper.

Rare-Earth Calcium Oxyborate Piezoelectric Crystals ReCa4O(BO33: Growth and Piezoelectric Characterizations

Directory of Open Access Journals (Sweden)

Fapeng Yu

2014-07-01

Full Text Available Rare-earth calcium oxyborate crystals, ReCa4O(BO33 (ReCOB, Re = Er, Y, Gd, Sm, Nd, Pr, and La , are potential piezoelectric materials for ultrahigh temperature sensor applications, due to their high electrical resistivity at elevated temperature, high piezoelectric sensitivity and temperature stability. In this paper, different techniques for ReCOB single-crystal growth are introduced, including the Bridgman and Czochralski pulling methods. Crystal orientations and the relationships between the crystallographic and physical axes of the monoclinic ReCOB crystals are discussed. The procedures for dielectric, elastic, electromechanical and piezoelectric property characterization, taking advantage of the impedance method, are presented. In addition, the maximum piezoelectric coefficients for different piezoelectric vibration modes are explored, and the optimized crystal cuts free of piezoelectric cross-talk are obtained by rotation calculations.

Vibration energy harvesting using piezoelectric unimorph cantilevers with unequal piezoelectric and nonpiezoelectric lengths

OpenAIRE

Gao, Xiaotong; Shih, Wei-Heng; Shih, Wan Y.

2010-01-01

We have examined a piezoelectric unimorph cantilever (PUC) with unequal piezoelectric and nonpiezoelectric lengths for vibration energy harvesting theoretically by extending the analysis of a PUC with equal piezoelectric and nonpiezoelectric lengths. The theoretical approach was validated by experiments. A case study showed that for a fixed vibration frequency, the maximum open-circuit induced voltage which was important for charge storage for later use occurred with a PUC that had a nonpiezo...

Torsion sensing based on patterned piezoelectric beams

Science.gov (United States)

Cha, Youngsu; You, Hangil

2018-03-01

In this study, we investigated the sensing characteristics of piezoelectric beams under torsional loads. We used partially patterned piezoelectric beams to sense torsion. In particular, the piezoelectric patches are located symmetrically with respect to the line of the shear center of the beam. The patterned piezoelectric beam is modeled as a slender beam, and its electrical responses are obtained by piezoelectric electromechanical equations. To validate the modeling framework, experiments are performed using a setup that forces pure torsional deformation. Three different geometric configurations of the patterned piezoelectric layer are used for the experiments. The frequency and amplitude of the forced torsional load are systematically varied in order to study the behavior of the piezoelectric sensor. Experimental results demonstrate that two voltage outputs of the piezoelectric beam are approximately out of phase with identical amplitude. Moreover, the length of the piezoelectric layers has a significant influence on the sensing properties. Our theoretical predictions using the model support the experimental findings.

Piezoelectric paint: characterization for further applications

International Nuclear Information System (INIS)

Yang, C; Fritzen, C-P

2012-01-01

Piezoelectric paint is a very attractive piezoelectric composite in many fields, such as non-destructive testing, or structural health monitoring. However, there are still many obstacles which restrict the real application of it. One of the main problems is that piezoelectric paint lacks a standard fabrication procedure, thus characterization is needed before use. The work presented here explores the characterization of piezoelectric paint. It starts with fabrication of samples with certain piezoelectric powder weight percentages. The microstructures of the samples are investigated by a scanning electron microscope; the results indicate that the fabrication method can produce high quality samples. This is followed by measurements of Young’s modulus and sensitivity. The piezoelectric charge constant d 31 is then deduced from the experimental data; the results agree well with a published result, which validates the effectiveness of the fabrication and characterization method. The characterized piezoelectric paint can expand its applications into different fields and therefore becomes a more promising and competitive smart material. (paper)

Piezoelectric Transformers: An Historical Review

Directory of Open Access Journals (Sweden)

Alfredo Vazquez Carazo

2016-04-01

Full Text Available Piezoelectric transformers (PTs are solid-state devices that transform electrical energy into electrical energy by means of a mechanical vibration. These devices are manufactured using piezoelectric materials that are driven at resonance. With appropriate design and circuitry, it is possible to step up and step down the voltages between the input and output sections of the piezoelectric transformer, without making use of magnetic materials and obtaining excellent conversion efficiencies. The initial concept of a piezoelectric ceramic transformer was proposed by Charles A. Rosen in 1954. Since then, the evolution of piezoelectric transformers through history has been linked to the relevant work of some excellent researchers as well as to the evolution in materials, manufacturing processes, and driving circuit techniques. This paper summarizes the historical evolution of the technology.

A Piezoelectric Shear Stress Sensor

Science.gov (United States)

Kim, Taeyang; Saini, Aditya; Kim, Jinwook; Gopalarathnam, Ashok; Zhu, Yong; Palmieri, Frank L.; Wohl, Christopher J.; Jiang, Xiaoning

2016-01-01

In this paper, a piezoelectric sensor with a floating element was developed for shear stress measurement. The piezoelectric sensor was designed to detect the pure shear stress suppressing effects of normal stress generated from the vortex lift-up by applying opposite poling vectors to the: piezoelectric elements. The sensor was first calibrated in the lab by applying shear forces and it showed high sensitivity to shear stress (=91.3 +/- 2.1 pC/Pa) due to the high piezoelectric coefficients of PMN-33%PT (d31=-1330 pC/N). The sensor also showed almost no sensitivity to normal stress (less than 1.2 pC/Pa) because of the electromechanical symmetry of the device. The usable frequency range of the sensor is 0-800 Hz. Keywords: Piezoelectric sensor, shear stress, floating element, electromechanical symmetry

A nanoscale piezoelectric transformer for low-voltage transistors.

Science.gov (United States)

Agarwal, Sapan; Yablonovitch, Eli

2014-11-12

A novel piezoelectric voltage transformer for low-voltage transistors is proposed. Placing a piezoelectric transformer on the gate of a field-effect transistor results in the piezoelectric transformer field-effect transistor that can switch at significantly lower voltages than a conventional transistor. The piezoelectric transformer operates by using one piezoelectric to squeeze another piezoelectric to generate a higher output voltage than the input voltage. Multiple piezoelectrics can be used to squeeze a single piezoelectric layer to generate an even higher voltage amplification. Coupled electrical and mechanical modeling in COMSOL predicts a 12.5× voltage amplification for a six-layer piezoelectric transformer. This would lead to more than a 150× reduction in the power needed for communications.

Structural Origins of Silk Piezoelectricity.

Science.gov (United States)

Yucel, Tuna; Cebe, Peggy; Kaplan, David L

2011-02-22

Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of λ= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d(14) = -1.5 pC/N, corresponding to over two orders of magnitude increase in d(14) due to film drawing. A strong correlation was observed between the increase in the silk II, β-sheet content with increasing draw ratio measured by FTIR spectroscopy (C(β)∝ e(2.5) (λ)), the concomitant increasing degree of orientation of β-sheet crystals detected via WAXD (FWHM = 0.22° for λ= 2.7), and the improvement in silk piezoelectricity (d(14)∝ e(2.4) (λ)). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75°) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the β-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, β-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein.

Piezoelectric MEMS: Ferroelectric thin films for MEMS applications

Science.gov (United States)

Kanno, Isaku

2018-04-01

In recent years, piezoelectric microelectromechanical systems (MEMS) have attracted attention as next-generation functional microdevices. Typical applications of piezoelectric MEMS are micropumps for inkjet heads or micro-gyrosensors, which are composed of piezoelectric Pb(Zr,Ti)O3 (PZT) thin films and have already been commercialized. In addition, piezoelectric vibration energy harvesters (PVEHs), which are regarded as one of the key devices for Internet of Things (IoT)-related technologies, are promising future applications of piezoelectric MEMS. Significant features of piezoelectric MEMS are their simple structure and high energy conversion efficiency between mechanical and electrical domains even on the microscale. The device performance strongly depends on the function of the piezoelectric thin films, especially on their transverse piezoelectric properties, indicating that the deposition of high-quality piezoelectric thin films is a crucial technology for piezoelectric MEMS. On the other hand, although the difficulty in measuring the precise piezoelectric coefficients of thin films is a serious obstacle in the research and development of piezoelectric thin films, a simple unimorph cantilever measurement method has been proposed to obtain precise values of the direct or converse transverse piezoelectric coefficient of thin films, and recently this method has become to be the standardized testing method. In this article, I will introduce fundamental technologies of piezoelectric thin films and related microdevices, especially focusing on the deposition of PZT thin films and evaluation methods for their transverse piezoelectric properties.

Miniature Piezoelectric Macro-Mass Balance

Science.gov (United States)

Sherrit, Stewart; Trebi-Ollennu, Ashitey; Bonitz, Robert G.; Bar-Cohen, Yoseph

2010-01-01

Mass balances usually use a strain gauge that requires an impedance measurement and is susceptible to noise and thermal drift. A piezoelectric balance can be used to measure mass directly by monitoring the voltage developed across the piezoelectric balance, which is linear with weight or it can be used in resonance to produce a frequency change proportional to the mass change (see figure). The piezoelectric actuator/balance is swept in frequency through its fundamental resonance. If a small mass is added to the balance, the resonance frequency shifts down in proportion to the mass. By monitoring the frequency shift, the mass can be determined. This design allows for two independent measurements of mass. Additionally, more than one sample can be verified because this invention allows for each sample to be transported away from the measuring device upon completion of the measurement, if required. A piezoelectric actuator, or many piezoelectric actuators, was placed between the collection plate of the sampling system and the support structure. As the sample mass is added to the plate, the piezoelectrics are stressed, causing them to produce a voltage that is proportional to the mass and acceleration. In addition, a change in mass delta m produces a change in the resonance frequency with delta f proportional to delta m. In a microgravity environment, the spacecraft could be accelerated to produce a force on the piezoelectric actuator that would produce a voltage proportional to the mass and acceleration. Alternatively, the acceleration could be used to force the mass on the plate, and the inertial effects of the mass on the plate would produce a shift in the resonance frequency with the change in frequency related to the mass change. Three prototypes of the mass balance mechanism were developed. These macro-mass balances each consist of a solid base and an APA 60 Cedrat flextensional piezoelectric actuator supporting a measuring plate. A similar structure with 3 APA

Structured Piezoelectric Composites: Materials and Applications

OpenAIRE

Van den Ende, D.A.

2012-01-01

The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits their practical application to certain specific fields. Piezoelectric composites, which contain an active piezoelectric (ceramic) phase in a robust polymer matrix, can potentially have better proper...

Elastic properties of spherically anisotropic piezoelectric composites

International Nuclear Information System (INIS)

En-Bo, Wei; Guo-Qing, Gu; Ying-Ming, Poon

2010-01-01

Effective elastic properties of spherically anisotropic piezoelectric composites, whose spherically anisotropic piezoelectric inclusions are embedded in an infinite non-piezoelectric matrix, are theoretically investigated. Analytical solutions for the elastic displacements and the electric potentials under a uniform external strain are derived exactly. Taking into account of the coupling effects of elasticity, permittivity and piezoelectricity, the formula is derived for estimating the effective elastic properties based on the average field theory in the dilute limit. An elastic response mechanism is revealed, in which the effective elastic properties increase as inclusion piezoelectric properties increase and inclusion dielectric properties decrease. Moreover, a piezoelectric response mechanism, of which the effective piezoelectric response vanishes due to the symmetry of spherically anisotropic composite, is also disclosed. (condensed matter: structure, thermal and mechanical properties)

The giant piezoelectric effect: electric field induced monoclinic phase or piezoelectric distortion of the rhombohedral parent?

International Nuclear Information System (INIS)

Kisi, E H; Piltz, R O; Forrester, J S; Howard, C J

2003-01-01

Lead zinc niobate-lead titanate (PZN-PT) single crystals show very large piezoelectric strains for electric fields applied along the unit cell edges e.g. [001] R . It has been widely reported that this effect is caused by an electric field induced phase transition from rhombohedral (R3m) to monoclinic (Cm or Pm) symmetry in an essentially continuous manner. Group theoretical analysis using the computer program ISOTROPY indicates phase transitions between R3m and Cm (or Pm) must be discontinuous under Landau theory. An analysis of the symmetry of a strained unit cell in R3m and a simple expansion of the piezoelectric strain equation indicate that the piezoelectric distortion due to an electric field along a cell edge in rhombohedral perovskite-based ferroelectrics is intrinsically monoclinic (Cm), even for infinitesimal electric fields. PZN-PT crystals have up to nine times the elastic compliance of other piezoelectric perovskites and it might be expected that the piezoelectric strains are also very large. A field induced phase transition is therefore indistinguishable from the piezoelectric distortion and is neither sufficient nor necessary to understand the large piezoelectric response of PZN-PT

Piezoelectric Transformer Characterization and Application of Electronic Ballast

OpenAIRE

Lin, Ray-Lee

2001-01-01

The characterization and modeling of piezoelectric transformers are studied and developed for use in electronic ballasts. By replacing conventional L-C resonant tanks with piezoelectric transformers, inductor-less piezoelectric transformer electronic ballasts have been developed for use in fluorescent lamps. The piezoelectric transformer is a combination of piezoelectric actuators as the primary side and piezoelectric transducers as the secondary side, both of which work in longitudinal o...

Piezoelectric effects in biomaterials

International Nuclear Information System (INIS)

Zimmerman, R.L.

1976-03-01

Precision methods have been developed for the simultaneous measurement of the complex piezoelectric stress constants and the electric conduction and polarization currents. Samples of Collagen, keratin, and chitin are prepared and measured in such a way to optimize the determination of the position and orientation of the electric dipole moments. The temperature and the hydration state of the samples are varied during the measurement of the piezoelectric constants in an effort to understand the role of water in biological material. Above 40 0 C, the inherent piezolectricity is enhanced by the water of hydration, in contrast to the more easily understood reduction observed at lower temperatures. Gelatin, which has no inherent piezoelectricity, displays a piezoelectricity proportional to the currents of conduction and polarization. An analysis of the new effect shows that it is a measure of the variation of the resistivity with deformation (d rho/dS - rho) in the same way that the electric field induced piezoelectricity is a measure of the variation of the dielectric constant with deformation (dk/dS + k). Both are sensitive to electric dipole relaxation effects. (Author) [pt

Piezoelectric Microstructured Fibers via Drawing of Multimaterial Preforms.

Science.gov (United States)

Lu, Xin; Qu, Hang; Skorobogatiy, Maksim

2017-06-06

We demonstrate planar laminated piezoelectric generators and piezoelectric microstructured fibers based on BaTiO 3 -polyvinylidene and carbon-loaded-polyethylene materials combinations. The laminated piezoelectric generators were assembled by sandwiching the electrospun BaTiO 3 -polyvinylidene mat between two carbon-loaded-polyethylene films. The piezoelectric microstructured fiber was fabricated via drawing of the multilayer fiber preform, and features a swissroll geometry that have ~10 alternating piezoelectric and conductive layers. Both piezoelectric generators have excellent mechanical durability, and could retain their piezoelectric performance after 3 day's cyclic bend-release tests. Compared to the laminated generators, the piezoelectric fibers are advantageous as they could be directly woven into large-area commercial fabrics. Potential applications of the proposed piezoelectric fibers include micro-power-generation and remote sensing in wearable, automotive and aerospace industries.

Piezoelectric transducer array microspeaker

KAUST Repository

Carreno, Armando Arpys Arevalo

2016-12-19

In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

Lead-Free Piezoelectrics

CERN Document Server

Nahm, Sahn

2012-01-01

Ecological restrictions in many parts of the world are demanding the elimination of Pb from all consumer items. At this moment in the piezoelectric ceramics industry, there is no issue of more importance than the transition to lead-free materials. The goal of Lead-Free Piezoelectrics is to provide a comprehensive overview of the fundamentals and developments in the field of lead-free materials and products to leading researchers in the world. The text presents chapters on demonstrated applications of the lead-free materials, which will allow readers to conceptualize the present possibilities and will be useful for both students and professionals conducting research on ferroelectrics, piezoelectrics, smart materials, lead-free materials, and a variety of applications including sensors, actuators, ultrasonic transducers and energy harvesters.

Piezoelectric Vibration Energy Harvesting Device Combined with Damper

Directory of Open Access Journals (Sweden)

Hung-I Lu

2014-05-01

Full Text Available Piezoelectricity is a type of material that enables mechanical energy and electrical energy to be interchangeable, which can be divided into positive piezoelectric effect and inverse piezoelectric effect. The positive piezoelectric effect is that the electric dipole moment of material generates changes when the piezoelectric material is subjected to pressure, resulting in electrical energy. Conversely, the inverse piezoelectric effect is the process of electrical energy converted into mechanical energy.

Energy collection via Piezoelectricity

International Nuclear Information System (INIS)

Kumar, Ch Naveen

2015-01-01

In the present days, wireless data transmission techniques are commonly used in electronic devices. For powering them connection needs to be made to the power supply through wires else power may be supplied from batteries. Batteries require charging, replacement and other maintenance efforts. So, some alternative methods need to be developed to keep the batteries full time charged and to avoid the need of any consumable external energy source to charge the batteries. Mechanical energy harvesting utilizes piezoelectric components where deformations produced by different means are directly converted to electrical charge via piezoelectric effect. The proposed work in this research recommends Piezoelectricity as a alternate energy source. The motive is to obtain a pollution-free energy source and to utilize and optimize the energy being wasted. Current work also illustrates the working principle of piezoelectric crystal and various sources of vibration for the crystal. (paper)

Piezoelectric Transformers: An Historical Review

OpenAIRE

Alfredo Vazquez Carazo

2016-01-01

Piezoelectric transformers (PTs) are solid-state devices that transform electrical energy into electrical energy by means of a mechanical vibration. These devices are manufactured using piezoelectric materials that are driven at resonance. With appropriate design and circuitry, it is possible to step up and step down the voltages between the input and output sections of the piezoelectric transformer, without making use of magnetic materials and obtaining excellent conversion efficiencies. The...

High Temperature, High Power Piezoelectric Composite Transducers

Science.gov (United States)

Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

2014-01-01

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

The direct piezoelectric effect in the globular protein lysozyme

Science.gov (United States)

Stapleton, A.; Noor, M. R.; Sweeney, J.; Casey, V.; Kholkin, A. L.; Silien, C.; Gandhi, A. A.; Soulimane, T.; Tofail, S. A. M.

2017-10-01

Here, we present experimental evidence of the direct piezoelectric effect in the globular protein, lysozyme. Piezoelectric materials are employed in many actuating and sensing applications because they can convert mechanical energy into electrical energy and vice versa. Although originally studied in inorganic materials, several biological materials including amino acids and bone, also exhibit piezoelectricity. The exact mechanisms supporting biological piezoelectricity are not known, nor is it known whether biological piezoelectricity conforms strictly to the criteria of classical piezoelectricity. The observation of piezoelectricity in protein crystals presented here links biological piezoelectricity with the classical theory of piezoelectricity. We quantify the direct piezoelectric effect in monoclinic and tetragonal aggregate films of lysozyme using conventional techniques based on the Berlincourt Method. The largest piezoelectric effect measured in a crystalline aggregate film of lysozyme was approximately 6.5 pC N-1. These findings raise fundamental questions as to the possible physiological significance of piezoelectricity in lysozyme and the potential for technical applications.

Touching force response of the piezoelectric Braille cell.

Science.gov (United States)

Smithmaitrie, Pruittikorn; Kanjantoe, Jinda; Tandayya, Pichaya

2008-11-01

The objective of this research is to investigate dynamic responses of the piezoelectric Braille cell when it is subjected to both electrical signal and touching force. Physical behavior of the piezoelectric actuator inside the piezoelectric Braille cell is analyzed. The mathematical model of the piezoelectric Braille system is presented. Then, data of visually impaired people using a Braille Note is studied as design information and a reference input for calculation of the piezoelectric Braille response under the touching force. The results show dynamic responses of the piezoelectric Braille cell. The designed piezoelectric bimorph has a settling time of 0.15 second. The relationship between the Braille dot height and applied voltage is linear. The behavior of the piezoelectric Braille dot when it is touched during operation shows that the dot height is decreased as the force increases. The result provides understanding of the piezoelectric Braille cell behavior under both touching force and electrical excitation simultaneously. This is the important issue for the design and development of piezoelectric Braille cells in senses of controlling Braille dot displacement or force-feedback in the future.

Base Metal Co-Fired Multilayer Piezoelectrics

Directory of Open Access Journals (Sweden)

Lisheng Gao

2016-03-01

Full Text Available Piezoelectrics have been widely used in different kinds of applications, from the automobile industry to consumer electronics. The novel multilayer piezoelectrics, which are inspired by multilayer ceramic capacitors, not only minimize the size of the functional parts, but also maximize energy efficiency. Development of multilayer piezoelectric devices is at a significant crossroads on the way to achieving low costs, high efficiency, and excellent reliability. Concerning the costs of manufacturing multilayer piezoelectrics, the trend is to replace the costly noble metal internal electrodes with base metal materials. This paper discusses the materials development of metal co-firing and the progress of integrating current base metal chemistries. There are some significant considerations in metal co-firing multilayer piezoelectrics: retaining stoichiometry with volatile Pb and alkaline elements in ceramics, the selection of appropriate sintering agents to lower the sintering temperature with minimum impact on piezoelectric performance, and designing effective binder formulation for low pO2 burnout to prevent oxidation of Ni and Cu base metal.

Piezoelectric wave motor

Science.gov (United States)

Yerganian, Simon Scott

2001-07-17

A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

Piezoelectric energy harvesting

International Nuclear Information System (INIS)

Howells, Christopher A

2009-01-01

Piezoelectric materials can be used to convert oscillatory mechanical energy into electrical energy. This technology, together with innovative mechanical coupling designs, can form the basis for harvesting energy from mechanical motion. Piezoelectric energy can be harvested to convert walking motion from the human body into electrical power. Recently four proof-of-concept Heel Strike Units were developed where each unit is essentially a small electric generator that utilizes piezoelectric elements to convert mechanical motion into electrical power in the form factor of the heel of a boot. The results of the testing and evaluation and the performance of this small electric generator are presented. The generator's conversion of mechanical motion into electrical power, the processes it goes through to produce useable power and commercial applications of the Heel Strike electric generator are discussed.

Ferroelectric and piezoelectric thin films and their applications for integrated capacitors, piezoelectric ultrasound transducers and piezoelectric switches

International Nuclear Information System (INIS)

Klee, M; Boots, H; Kumar, B; Heesch, C van; Mauczok, R; Keur, W; Wild, M de; Esch, H van; Roest, A L; Reimann, K; Leuken, L van; Wunnicke, O; Zhao, J; Schmitz, G; Mienkina, M; Mleczko, M; Tiggelman, M

2010-01-01

Ferroelectric and piezoelectric thin films are gaining more and more importance for the integration of high performance devices in small modules. High-K 'Integrated Discretes' devices have been developed, which are based on thin film ferroelectric capacitors integrated together with resistors and ESD protection diodes in a small Si-based chip-scale package. Making use of ferroelectric thin films with relative permittivity of 950-1600 and stacking processes of capacitors, extremely high capacitance densities of 20-520 nF/mm 2 , high breakdown voltages up to 140 V and lifetimes of more than 10 years at operating voltages of 5 V and 85 deg. C are achieved. Thin film high-density capacitors play also an important role as tunable capacitors for applications such as tuneable matching circuits for RF sections of mobile phones. The performance of thin film tuneable capacitors at frequencies between 1 MHz and 1 GHz is investigated. Finally thin film piezoelectric ultrasound transducers, processed in Si- related processes, are attractive for medical imaging, since they enable large bandwidth (>100%), high frequency operation and have the potential to integrate electronics. With these piezoelectric thin film ultrasound transducers real time ultrasound images have been realized. Finally, piezoelectric thin films are used to manufacture galvanic MEMS switches. A model for the quasi-static mechanical behaviour is presented and compared with measurements.

Structure-Property Study of Piezoelectricity in Polyimides

Science.gov (United States)

Ounaies, Zoubeida; Park, Cheol; Harrison, Joycelyn S.; Smith, Joseph G.; Hinkley, Jeffrey

1999-01-01

High performance piezoelectric polymers are of interest to NASA as they may be useful for a variety of sensor applications. Over the past few years research on piezoelectric polymers has led to the development of promising high temperature piezoelectric responses in some novel polyimides. In this study, a series of polyimides have been studied with systematic variations in the diamine monomers that comprise the polyimide while holding the dianhydride constant. The effect of structural changes, including variations in the nature and concentration of dipolar groups, on the remanent polarization and piezoelectric coefficient is examined. Fundamental structure-piezoelectric property insight will enable the molecular design of polymers possessing distinct improvements over state-of-the-art piezoelectric polymers including enhanced polarization, polarization stability at elevated temperatures, and improved processability.

Piezoelectric Structures and Low Power Generation Devices

Directory of Open Access Journals (Sweden)

Irinela CHILIBON

2016-10-01

Full Text Available A short overview of different piezoelectric structures and devices for generating renewable electricity under mechanical actions is presented. A vibrating piezoelectric device differs from a typical electrical power source in that it has capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. Several techniques have been developed to extract energy from the environment. Generally, “vibration energy” could be converted into electrical energy by three techniques: electrostatic charge, magnetic fields and piezoelectric. Mechanical resonance frequency of piezoelectric bimorph transducers depends on geometric size (length, width, and thickness of each layer, and the piezoelectric coefficients of the piezoelectric material. Manufacturing processes and intended applications of several energy harvesting devices are presented.

Piezoelectric Ceramics Characterization

National Research Council Canada - National Science Library

Jordan, T

2001-01-01

... the behavior of a piezoelectric material. We have attempted to cover the most common measurement methods as well as introduce parameters of interest. Excellent sources for more in-depth coverage of specific topics can be found in the bibliography. In most cases, we refer to lead zirconate titanate (PZT) to illustrate some of the concepts since it is the most widely used and studied piezoelectric ceramic to date.

Using Diffusion Bonding in Making Piezoelectric Actuators

Science.gov (United States)

Sager, Frank E.

2003-01-01

A technique for the fabrication of piezoelectric actuators that generate acceptably large forces and deflections at relatively low applied voltages involves the stacking and diffusion bonding of multiple thin piezoelectric layers coated with film electrodes. The present technique stands in contrast to an older technique in which the layers are bonded chemically, by use of urethane or epoxy agents. The older chemical-bonding technique entails several disadvantages, including the following: It is difficult to apply the bonding agents to the piezoelectric layers. It is difficult to position the layers accurately and without making mistakes. There is a problem of disposal of hazardous urethane and epoxy wastes. The urethane and epoxy agents are nonpiezoelectric materials. As such, they contribute to the thickness of a piezoelectric laminate without contributing to its performance; conversely, for a given total thickness, the performance of the laminate is below that of a unitary piezoelectric plate of the same thickness. The figure depicts some aspects of the fabrication of a laminated piezoelectric actuator by the present diffusion- bonding technique. First, stock sheets of the piezoelectric material are inspected and tested. Next, the hole pattern shown in the figure is punched into the sheets. Alternatively, if the piezoelectric material is not a polymer, then the holes are punched in thermoplastic films. Then both faces of each punched piezoelectric sheet or thermoplastic film are coated with a silver-ink electrode material by use of a silkscreen printer. The electrode and hole patterns are designed for minimal complexity and minimal waste of material. After a final electrical test, all the coated piezoelectric layers (or piezoelectric layers and coated thermoplastic films) are stacked in an alignment jig, which, in turn, is placed in a curved press for the diffusion-bonding process. In this process, the stack is pressed and heated at a specified curing temperature

High-Fidelity Piezoelectric Audio Device

Science.gov (United States)

Woodward, Stanley E.; Fox, Robert L.; Bryant, Robert G.

2003-01-01

ModalMax is a very innovative means of harnessing the vibration of a piezoelectric actuator to produce an energy efficient low-profile device with high-bandwidth high-fidelity audio response. The piezoelectric audio device outperforms many commercially available speakers made using speaker cones. The piezoelectric device weighs substantially less (4 g) than the speaker cones which use magnets (10 g). ModalMax devices have extreme fabrication simplicity. The entire audio device is fabricated by lamination. The simplicity of the design lends itself to lower cost. The piezoelectric audio device can be used without its acoustic chambers and thereby resulting in a very low thickness of 0.023 in. (0.58 mm). The piezoelectric audio device can be completely encapsulated, which makes it very attractive for use in wet environments. Encapsulation does not significantly alter the audio response. Its small size (see Figure 1) is applicable to many consumer electronic products, such as pagers, portable radios, headphones, laptop computers, computer monitors, toys, and electronic games. The audio device can also be used in automobile or aircraft sound systems.

A Capacitance-Based Methodology for the Estimation of Piezoelectric Coefficients of Poled Piezoelectric Materials

KAUST Repository

Al Ahmad, Mahmoud; Alshareef, Husam N.

2010-01-01

A methodology is proposed to estimate the piezoelectric coefficients of bulk piezoelectric materials using simple capacitance measurements. The extracted values of d33 and d31 from the capacitance measurements were 506 pC/N and 247 p

Piezoelectric energy harvesting

Energy Technology Data Exchange (ETDEWEB)

Howells, Christopher A [Power Technology Branch, US Army, CERDEC, C2D, Ft. Belvoir, VA 22060-5816 (United States)

2009-07-15

Piezoelectric materials can be used to convert oscillatory mechanical energy into electrical energy. This technology, together with innovative mechanical coupling designs, can form the basis for harvesting energy from mechanical motion. Piezoelectric energy can be harvested to convert walking motion from the human body into electrical power. Recently four proof-of-concept Heel Strike Units were developed where each unit is essentially a small electric generator that utilizes piezoelectric elements to convert mechanical motion into electrical power in the form factor of the heel of a boot. The results of the testing and evaluation and the performance of this small electric generator are presented. The generator's conversion of mechanical motion into electrical power, the processes it goes through to produce useable power and commercial applications of the Heel Strike electric generator are discussed. (author)

Piezoelectricity in polymers

International Nuclear Information System (INIS)

Kepler, R.G.; Anderson, R.A.

1980-01-01

Piezoelectricity and related properties of polymers are reviewed. After presenting a historical overview of the field, the mathematical basis of piezo- and pyroelectricity is summarized. We show how the experimentally measured quantities are related to the changes in polarization and point out the serious inequlity between direct and converse piezoelectric coefficients in polymers. Theoretical models of the various origins of piezo- and pyroelectricity, which include piezoelectricity due to inhomogeneous material properties and strains, are reviewed. Relaxational effects are also considered. Experimental techniques are examined and the results for different materials are presented. Because of the considerable work in recent years polyimylidene fluoride, this polymer receives the majority of the attention. The numerous applications of piezo-and pyroelectric polymers are mentioned. This article concludes with a discussion of the possible role of piezo- and pyroelectricity in biological system

Strong piezoelectricity in bioinspired peptide nanotubes.

Science.gov (United States)

Kholkin, Andrei; Amdursky, Nadav; Bdikin, Igor; Gazit, Ehud; Rosenman, Gil

2010-02-23

We show anomalously strong shear piezoelectric activity in self-assembled diphenylalanine peptide nanotubes (PNTs), indicating electric polarization directed along the tube axis. Comparison with well-known piezoelectric LiNbO(3) and lateral signal calibration yields sufficiently high effective piezoelectric coefficient values of at least 60 pm/V (shear response for tubes of approximately 200 nm in diameter). PNTs demonstrate linear deformation without irreversible degradation in a broad range of driving voltages. The results open up a wide avenue for developing new generations of "green" piezoelectric materials and piezonanodevices based on bioactive tubular nanostructures potentially compatible with human tissue.

Orthotropic Piezoelectricity in 2D Nanocellulose.

Science.gov (United States)

García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M

2016-10-06

The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V -1 , ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

Orthotropic Piezoelectricity in 2D Nanocellulose

Science.gov (United States)

García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.

2016-10-01

The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V-1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.

Recent Advances in the Control of Piezoelectric Actuators

Directory of Open Access Journals (Sweden)

Ziqiang Chi

2014-11-01

Full Text Available The micro/nano positioning field has made great progress towards enabling the advance of micro/nano technology. Micro/nano positioning stages actuated by piezoelectric actuators are the key devices in micro/nano manipulation. The control of piezoelectric actuators has emerged as a hot topic in recent years. Piezoelectric materials have inherent hysteresis and creep nonlinearity, which can reduce the accuracy of the manipulation, even causing the instability of the whole system. Remarkable efforts have been made to compensate for the nonlinearity of piezoelectric actuation through the mathematical modelling and control approaches. This paper provides a review of recent advances on the control of piezoelectric actuators. After a brief introduction of basic components of typical piezoelectric micro/nano positioning platforms, the working principle and modelling of piezoelectric actuators are outlined in this paper. This is followed with the major control method and recent progress is presented in detail. Finally, some open issues and future work on the control of piezoelectric actuators are extensively discussed.

Nonlinear kinematics for piezoelectricity in ALEGRA-EMMA.

Energy Technology Data Exchange (ETDEWEB)

Mitchell, John Anthony; Fuller, Timothy Jesse

2013-09-01

This report develops and documents nonlinear kinematic relations needed to implement piezoelectric constitutive models in ALEGRA-EMMA [5], where calculations involving large displacements and rotations are routine. Kinematic relationships are established using Gausss law and Faradays law; this presentation on kinematics goes beyond piezoelectric materials and is applicable to all dielectric materials. The report then turns to practical details of implementing piezoelectric models in an application code where material principal axes are rarely aligned with user defined problem coordinate axes. This portion of the report is somewhat pedagogical but is necessary in order to establish documentation for the piezoelectric implementation in ALEGRA-EMMA. This involves transforming elastic, piezoelectric, and permittivity moduli from material principal axes to problem coordinate axes. The report concludes with an overview of the piezoelectric implementation in ALEGRA-EMMA and small verification examples.

The giant piezoelectric effect: electric field induced monoclinic phase or piezoelectric distortion of the rhombohedral parent?

CERN Document Server

Kisi, E H; Forrester, J S; Howard, C J

2003-01-01

Lead zinc niobate-lead titanate (PZN-PT) single crystals show very large piezoelectric strains for electric fields applied along the unit cell edges e.g. [001] sub R. It has been widely reported that this effect is caused by an electric field induced phase transition from rhombohedral (R3m) to monoclinic (Cm or Pm) symmetry in an essentially continuous manner. Group theoretical analysis using the computer program ISOTROPY indicates phase transitions between R3m and Cm (or Pm) must be discontinuous under Landau theory. An analysis of the symmetry of a strained unit cell in R3m and a simple expansion of the piezoelectric strain equation indicate that the piezoelectric distortion due to an electric field along a cell edge in rhombohedral perovskite-based ferroelectrics is intrinsically monoclinic (Cm), even for infinitesimal electric fields. PZN-PT crystals have up to nine times the elastic compliance of other piezoelectric perovskites and it might be expected that the piezoelectric strains are also very large. ...

Theoretical analysis of dynamic property for piezoelectric cantilever triple-layer benders with large piezoelectric and electromechanical coupling coefficients

Directory of Open Access Journals (Sweden)

Li Jiao Gong

2016-09-01

Full Text Available Ferroelectric single crystals, such as PZN-PT, provide novel prospects in piezoelectric bending devices such as actuators, sensors or energy harvesters because of their extraordinarily large piezoelectric coefficients. However, large errors may occur in some analyses on electromechanical behaviors using the conventional models. We find the bending rigidity of piezoelectric composited bender is affected not only by thickness, width and the modulus of elasticity of the different layers but also electromechanical coupling coefficients (EMCCs of the piezoelectric material and the larger EMCCs mean more marked effect. This paper focuses on the derivation of the applied input excitation and output response characteristics in the circular frequency domain for piezoelectric cantilever triple-layer benders (PCTBs, taking into account the secondary piezoelectric effect. Analytic dynamic descriptions of such actuators and transducers are obtained. Based on the presented models dynamic features of PCTB composed of PZN-8%PT are calculated, and numerical results coincide with simulations using the finite element method (FEM.

Multistage Force Amplification of Piezoelectric Stacks

Science.gov (United States)

Xu, Tian-Bing (Inventor); Siochi, Emilie J. (Inventor); Zuo, Lei (Inventor); Jiang, Xiaoning (Inventor); Kang, Jin Ho (Inventor)

2015-01-01

Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

Piezoelectric materials for tissue regeneration: A review.

Science.gov (United States)

Rajabi, Amir Hossein; Jaffe, Michael; Arinzeh, Treena Livingston

2015-09-01

The discovery of piezoelectricity, endogenous electric fields and transmembrane potentials in biological tissues raised the question whether or not electric fields play an important role in cell function. It has kindled research and the development of technologies in emulating biological electricity for tissue regeneration. Promising effects of electrical stimulation on cell growth and differentiation and tissue growth has led to interest in using piezoelectric scaffolds for tissue repair. Piezoelectric materials can generate electrical activity when deformed. Hence, an external source to apply electrical stimulation or implantation of electrodes is not needed. Various piezoelectric materials have been employed for different tissue repair applications, particularly in bone repair, where charges induced by mechanical stress can enhance bone formation; and in neural tissue engineering, in which electric pulses can stimulate neurite directional outgrowth to fill gaps in nervous tissue injuries. In this review, a summary of piezoelectricity in different biological tissues, mechanisms through which electrical stimulation may affect cellular response, and recent advances in the fabrication and application of piezoelectric scaffolds will be discussed. The discovery of piezoelectricity, endogenous electric fields and transmembrane potentials in biological tissues has kindled research and the development of technologies using electrical stimulation for tissue regeneration. Piezoelectric materials generate electrical activity in response to deformations and allow for the delivery of an electrical stimulus without the need for an external power source. As a scaffold for tissue engineering, growing interest exists due to its potential of providing electrical stimulation to cells to promote tissue formation. In this review, we cover the discovery of piezoelectricity in biological tissues, its connection to streaming potentials, biological response to electrical stimulation and

Piezoelectric energy harvesting through shear mode operation

International Nuclear Information System (INIS)

Malakooti, Mohammad H; Sodano, Henry A

2015-01-01

Piezoelectric materials are excellent candidates for use in energy harvesting applications due to their high electromechanical coupling properties that enable them to convert input mechanical energy into useful electric power. The electromechanical coupling coefficient of the piezoelectric material is one of the most significant parameters affecting energy conversion and is dependent on the piezoelectric mode of operation. In most piezoceramics, the d 15 piezoelectric shear coefficient is the highest coefficient compared to the commonly used axial and transverse modes that utilize the d 33 and the d 31 piezoelectric strain coefficients. However, complicated electroding methods and challenges in evaluating the performance of energy harvesting devices operating in the shear mode have slowed research in this area. The shear deformation of a piezoelectric layer can be induced in a vibrating sandwich beam with a piezoelectric core. Here, a model based on Timoshenko beam theory is developed to predict the electric power output from a cantilever piezoelectric sandwich beam under base excitations. It is shown that the energy harvester operating in the shear mode is able to generate ∼50% more power compared to the transverse mode for a numerical case study. Reduced models of both shear and transverse energy harvesters are obtained to determine the optimal load resistance in the system and perform an efficiency comparison between two models with fixed and adaptive resistances. (paper)

New design for inertial piezoelectric motors

Science.gov (United States)

Liu, Lige; Ge, Weifeng; Meng, Wenjie; Hou, Yubin; Zhang, Jing; Lu, Qingyou

2018-03-01

We have designed, implemented, and tested a novel inertial piezoelectric motor (IPM) that is the first IPM to have controllable total friction force, which means that it sticks with large total friction forces and slips with severely reduced total friction forces. This allows the IPM to work with greater robustness and produce a larger output force at a lower threshold voltage while also providing higher rigidity. This is a new IPM design that means that the total friction force can be dramatically reduced or even canceled where necessary by pushing the clamping points at the ends of a piezoelectric tube that contains the sliding shaft inside it in the opposite directions during piezoelectric deformation. Therefore, when the shaft is propelled forward by another exterior piezoelectric tube, the inner piezoelectric tube can deform to reduce the total friction force acting on the shaft instantly and cause more effective stepping movement of the shaft. While our new IPM requires the addition of another piezoelectric tube, which leads to an increase in volume of 120% when compared with traditional IPMs, the average step size has increased by more than 400% and the threshold voltage has decreased by more than 50 V. The improvement in performance is far more significant than the increase in volume. This enhanced performance will allow the proposed IPM to work under large load conditions where a simple and powerful piezoelectric motor is needed.

Nano-Scale Positioning Design with Piezoelectric Materials

Directory of Open Access Journals (Sweden)

Yung Yue Chen

2017-12-01

Full Text Available Piezoelectric materials naturally possess high potential to deliver nano-scale positioning resolution; hence, they are adopted in a variety of engineering applications widely. Unfortunately, unacceptable positioning errors always appear because of the natural hysteresis effect of the piezoelectric materials. This natural property must be mitigated in practical applications. For solving this drawback, a nonlinear positioning design is proposed in this article. This nonlinear positioning design of piezoelectric materials is realized by the following four steps: 1. The famous Bouc–Wen model is utilized to present the input and output behaviors of piezoelectric materials; 2. System parameters of the Bouc–Wen model that describe the characteristics of piezoelectric materials are simultaneously identified with the particle swam optimization method; 3. Stability verification for the identified Bouc–Wen model; 4. A nonlinear feedback linearization control design is derived for the nano-scale positioning design of the piezoelectric material, mathematically. One important contribution of this investigation is that the positioning error between the output displacement of the controlled piezoelectric materials and the desired trajectory in nano-scale level can be proven to converge to zero asymptotically, under the effect of the hysteresis.

Laminated piezoelectric transformer

Science.gov (United States)

Vazquez Carazo, Alfredo (Inventor)

2006-01-01

A laminated piezoelectric transformer is provided using the longitudinal vibration modes for step-up voltage conversion applications. The input portions are polarized to deform in a longitudinal plane and are bonded to an output portion. The deformation of the input portions is mechanically coupled to the output portion, which deforms in the same longitudinal direction relative to the input portion. The output portion is polarized in the thickness direction relative its electrodes, and piezoelectrically generates a stepped-up output voltage.

Piezoelectric energy harvesting from flow-induced vibration

International Nuclear Information System (INIS)

Wang, D-A; Ko, H-H

2010-01-01

A new piezoelectric energy harvester for harnessing energy from flow-induced vibration is developed. It converts flow energy into electrical energy by piezoelectric conversion with oscillation of a piezoelectric film. A finite element model is developed in order to estimate the generated voltage of the piezoelectric laminate subjected to a distributed load. Prototypes of the energy harvester are fabricated and tested. Experimental results show that an open circuit output voltage of 2.2 V pp and an instantaneous output power of 0.2 µW are generated when the excitation pressure oscillates with an amplitude of 1.196 kPa and a frequency of about 26 Hz. The solution of the generated voltage based on the finite element model agrees well with the experiments. Based on the finite element model, the effects of the piezoelectric film dimensions, the fluid pressure applied to the harvester and types of piezoelectric layer on the output voltage of the harvester can be investigated.

Piezoelectric ceramic-reinforced metal matrix composites

OpenAIRE

2004-01-01

Composite materials comprising piezoelectric ceramic particulates dispersed in a metal matrix are capable of vibration damping. When the piezoelectric ceramic particulates are subjected to strain, such as the strain experienced during vibration of the material, they generate an electrical voltage that is converted into Joule heat in the surrounding metal matrix, thereby dissipating the vibrational energy. The piezoelectric ceramic particulates may also act as reinforcements to improve the mec...

Characterization of Piezoelectric Energy Harvesting MEMS

Science.gov (United States)

2015-12-01

of previously fabricated MEMS piezoelectric energy harvesters and use the results to optimize an advanced finite element model to be used in...possibilities of using solar power and the piezoelectric effect to harvest energy [12]. The design goal was to develop an energy harvester with a resonant... The piezoelectric properties of AlN are also relatively constant over a wide range of temperatures [7]. AlN was further characterized

Piezoelectric power converter with bi-directional power transfer

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a bi-directional piezoelectric power converter com¬ prising a piezoelectric transformer. The piezoelectric transformer comprises an input electrode electrically coupled to a primary section of the piezoelectric transformer and an output electrode electrically...... coupled to an output section of the piezoelectric transformer to provide a transformer output signal. A bi-directional switching circuit is coupled between the output electrode and a DC or AC output voltage of the power converter. Forward and reverse current conducting periods of the bi......, a reverse current is conducted through the bi-directional switching circuit from the DC or AC output voltage to the output electrode to discharge the DC or AC output voltage and return power to the primary section of the piezoelectric transformer....

V-stack piezoelectric actuator

Science.gov (United States)

Ardelean, Emil V.; Clark, Robert L.

2001-07-01

Aeroelastic control of wings by means of a distributed, trailing-edge control surface is of interest with regards to maneuvers, gust alleviation, and flutter suppression. The use of high energy density, piezoelectric materials as motors provides an appealing solution to this problem. A comparative analysis of the state of the art actuators is currently being conducted. A new piezoelectric actuator design is presented. This actuator meets the requirements for trailing edge flap actuation in both stroke and force. It is compact, simple, sturdy, and leverages stroke geometrically with minimum force penalties while displaying linearity over a wide range of stroke. The V-Stack Piezoelectric Actuator, consists of a base, a lever, two piezoelectric stacks, and a pre-tensioning element. The work is performed alternately by the two stacks, placed on both sides of the lever. Pre-tensioning can be readily applied using a torque wrench, obviating the need for elastic elements and this is for the benefit of the stiffness of the actuator. The characteristics of the actuator are easily modified by changing the base or the stacks. A prototype was constructed and tested experimentally to validate the theoretical model.

An improved resonantly driven piezoelectric gas pump

International Nuclear Information System (INIS)

Wu, Yue; Liu, Yong; Liu, Jianfang; Jiao, Xiaoyang; Yang, Zhigang; Wang, Long

2013-01-01

Piezoelectric pumps have the potential to be used in a variety of applications, such as in air circulation and compression. However, piezoelectric membrane pumps do not have enough driving capacity, and the heat induced during the direct contact between the driving part and the gas medium cannot be dissipated smoothly. When the gas is blocked, the piezoelectric vibrator generates heat quickly, which may eventually lead to damage. Resonantly driven piezoelectric stack pumps have high performance but no price advantage. In this situation, a novel, resonantly driven piezoelectric gas pump with annular bimorph as the driver is presented. In the study, the working principle of the novel pump was analyzed, the vibration mechanics model was determined, and the displacement amplified theory was studied. The outcome indicates that the displacement amplification factor is related with the original displacement provided by the piezoelectric bimorph. In addition, the displacement amplification effect is related to the stiffness of the spring lamination, adjustment spring, and piezoelectric vibrator, as well as to the systematic damping factor and the driving frequency. The experimental prototypes of the proposed pump were designed, and the displacement amplification effect and gas output performance were measured. At 70 V of sinusoidal AC driving voltage, the improved pump amplified the piezoelectric vibrator displacement by 4.2 times, the maximum gas output flow rate reached 1685 ml/min, and the temperature of the bimorph remained normal after 2000 hours of operation when the gas medium was blocked.

Calculations for Piezoelectric Ultrasonic Transducers

DEFF Research Database (Denmark)

Jensen, Henrik

1986-01-01

Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a boay which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation...

Bone-Inspired Spatially Specific Piezoelectricity Induces Bone Regeneration.

Science.gov (United States)

Yu, Peng; Ning, Chengyun; Zhang, Yu; Tan, Guoxin; Lin, Zefeng; Liu, Shaoxiang; Wang, Xiaolan; Yang, Haoqi; Li, Kang; Yi, Xin; Zhu, Ye; Mao, Chuanbin

2017-01-01

The extracellular matrix of bone can be pictured as a material made of parallel interspersed domains of fibrous piezoelectric collagenous materials and non-piezoelectric non-collagenous materials. To mimic this feature for enhanced bone regeneration, a material made of two parallel interspersed domains, with higher and lower piezoelectricity, respectively, is constructed to form microscale piezoelectric zones (MPZs). The MPZs are produced using a versatile and effective laser-irradiation technique in which K 0.5 Na 0.5 NbO 3 (KNN) ceramics are selectively irradiated to achieve microzone phase transitions. The phase structure of the laser-irradiated microzones is changed from a mixture of orthorhombic and tetragonal phases (with higher piezoelectricity) to a tetragonal dominant phase (with lower piezoelectricity). The microzoned piezoelectricity distribution results in spatially specific surface charge distribution, enabling the MPZs to bear bone-like microscale electric cues. Hence, the MPZs induce osteogenic differentiation of stem cells in vitro and bone regeneration in vivo even without being seeded with stem cells. The concept of mimicking the spatially specific piezoelectricity in bone will facilitate future research on the rational design of tissue regenerative materials.

Ferroelectric materials for piezoelectric actuators by optimal design

International Nuclear Information System (INIS)

Jayachandran, K.P.; Guedes, J.M.; Rodrigues, H.C.

2011-01-01

Research highlights: → Microstructure optimization of ferroelectric materials by stochastic optimization. → Polycrystalline ferroelectrics possess better piezo actuation than single crystals. → Randomness of the grain orientations would enhance the overall piezoelectricity. - Abstract: Optimization methods provide a systematic means of designing heterogeneous materials with tailored properties and microstructures focussing on a specific objective. An optimization procedure incorporating a continuum modeling is used in this work to identify the ideal orientation distribution of ferroelectrics (FEs) for application in piezoelectric actuators. Piezoelectric actuation is dictated primarily by the piezoelectric strain coefficients d iμ . Crystallographic orientation is inextricably related to the piezoelectric properties of FEs. This suggests that piezoelectric properties can be tailored by a proper choice of the parameters which control the orientation distribution. Nevertheless, this choice is complicated and it is impossible to analyze all possible combinations of the distribution parameters or the angles themselves. Stochastic optimization combined with a generalized Monte Carlo scheme is used to optimize the objective functions, the effective piezoelectric coefficients d 31 and d 15 . The procedure is applied to heterogeneous, polycrystalline, FE ceramics which are essentially an aggregate of variously oriented grains (crystallites). Global piezoelectric properties are calculated using the homogenization method at each grain configuration chosen by the optimization algorithm. Optimal design variables and microstructure that would generate polycrystalline configurations that multiply the macroscopic piezoelectricity are identified.

Energy harvesting from low frequency applications using piezoelectric materials

International Nuclear Information System (INIS)

Li, Huidong; Tian, Chuan; Deng, Z. Daniel

2014-01-01

In an effort to eliminate the replacement of the batteries of electronic devices that are difficult or impractical to service once deployed, harvesting energy from mechanical vibrations or impacts using piezoelectric materials has been researched over the last several decades. However, a majority of these applications have very low input frequencies. This presents a challenge for the researchers to optimize the energy output of piezoelectric energy harvesters, due to the relatively high elastic moduli of piezoelectric materials used to date. This paper reviews the current state of research on piezoelectric energy harvesting devices for low frequency (0–100 Hz) applications and the methods that have been developed to improve the power outputs of the piezoelectric energy harvesters. Various key aspects that contribute to the overall performance of a piezoelectric energy harvester are discussed, including geometries of the piezoelectric element, types of piezoelectric material used, techniques employed to match the resonance frequency of the piezoelectric element to input frequency of the host structure, and electronic circuits specifically designed for energy harvesters

Preisach model of hysteresis for the Piezoelectric Actuator Drive

DEFF Research Database (Denmark)

Zsurzsan, Tiberiu-Gabriel; Andersen, Michael A. E.; Zhang, Zhe

2015-01-01

The Piezoelectric Actuator Drive (PAD) is a precise piezoelectric motor generating high-torque rotary motion, which employs piezoelectric stack actuators in a wobblestyle actuation to generate rotation. The piezoelectric stacked ceramics used as the basis for motion in the motor suffer from...

Polymer-ceramic piezoelectric composites (PZT)

International Nuclear Information System (INIS)

Bassora, L.A.; Eiras, J.A.

1992-01-01

Polymer-ceramic piezoelectric transducers, with 1-3 of connectivity were prepared with different concentration of ceramic material. Piezoelectric composites, with equal electromechanical coupling factor and acoustic impedance of one third from that ceramic transducer, were obtained when the fractionary volume of PZT reach 30%. (C.G.C.)

Polarization Stability of Amorphous Piezoelectric Polyimides

Science.gov (United States)

Park, C.; Ounaies, Z.; Su, J.; Smith, J. G., Jr.; Harrison, J. S.

2000-01-01

Amorphous polyimides containing polar functional groups have been synthesized and investigated for potential use as high temperature piezoelectric sensors. The thermal stability of the piezoelectric effect of one polyimide was evaluated as a function of various curing and poling conditions under dynamic and static thermal stimuli. First, the polymer samples were thermally cycled under strain by systematically increasing the maximum temperature from 50 C to 200 C while the piezoelectric strain coefficient was being measured. Second, the samples were isothermally aged at an elevated temperature in air, and the isothermal decay of the remanent polarization was measured at room temperature as a function of time. Both conventional and corona poling methods were evaluated. This material exhibited good thermal stability of the piezoelectric properties up to 100 C.

Piezoelectric Accelerometers Development

DEFF Research Database (Denmark)

Liu, Bin; Bang, Lisbet Fogh

1999-01-01

The paper describes the development of piezoelectric accelerometers using Finite Element (FE) approach. Brüel & Kjær Accelerometer Type 8325 is chosen as an example to illustrate the advanced accelerometer development procedure. The deviation between simulated results and measured results of Type...... 8325 are below 6%. It is proved that the specifications of the accelerometer can be effectively predicted using the FE method, especially when modifications of the accelerometer are required. The development process of piezoelectric accelerometers in Brüel & Kjær is becoming more efficient...

Piezoelectric accelerometeres development

DEFF Research Database (Denmark)

Liu, Bin

1999-01-01

The paper describes the development of piezoelectric accelerometers using Finite Element (FE) approach. Brüel & Kjær Accelerometer Type 8325 is chosen as an example to illustrate the advanced accelerometer development procedure. The deviation between simulated results and measured results of Type...... 8325 are below 6%. It is proved that the specifications of the accelerometer can be effectively predicted using the FE method, especially when modifications of the accelerometer are required. The development process of piezoelectric accelerometers in Brüel & Kjær is becoming more efficient....

Multimodal piezoelectric devices optimization for energy harvesting

Directory of Open Access Journals (Sweden)

G Acciani

2016-09-01

Full Text Available The use of the piezoelectric effect to convert ambient vibration into useful electrical energy constitutes one of the most studied areas in Energy Harvesting (EH research. This paper presents a typical cantilevered Energy Harvester device, which relates the electrical outputs to the vibration mode shape easily. The dynamic strain induced in the piezoceramic layer results in an alternating voltage output. The first six modes of frequencies and the deformation pattern of the beam are carried out basing on an eigenfrequency analysis conducted by the MEMS modules of the COMSOL Multiphysic® v3.5a to perform the Finite Element Analysis of the model. Subsequently, the piezoelectric material is cut around the inflection points to minimize the voltage cancellation effect occurring when the sign changes in the material. This study shows that the voltage produced by the device, increases in as the dimensions of the cuts vary in the piezoelectric layer. Such voltage reaches the optimum amount of piezoelectric material and cuts positioning. This proves that the optimized piezoelectric layer is 16% more efficient than the whole piezoelectric layer.

Shear wave propagation in piezoelectric-piezoelectric composite layered structure

Directory of Open Access Journals (Sweden)

Anshu Mli Gaur

Full Text Available The propagation behavior of shear wave in piezoelectric composite structure is investigated by two layer model presented in this approach. The composite structure comprises of piezoelectric layers of two different materials bonded alternatively. Dispersion equations are derived for propagation along the direction normal to the layering and in direction of layering. It has been revealed that thickness and elastic constants have significant influence on propagation behavior of shear wave. The phase velocity and wave number is numerically calculated for alternative layer of Polyvinylidene Difluoride (PVDF and Lead Zirconate Titanate (PZT-5H in composite layered structure. The analysis carried out in this paper evaluates the effect of volume fraction on the phase velocity of shear wave.

A Capacitance-Based Methodology for the Estimation of Piezoelectric Coefficients of Poled Piezoelectric Materials

KAUST Repository

Al Ahmad, Mahmoud

2010-10-04

A methodology is proposed to estimate the piezoelectric coefficients of bulk piezoelectric materials using simple capacitance measurements. The extracted values of d33 and d31 from the capacitance measurements were 506 pC/N and 247 pC/N, respectively. The d33 value is in agreement with that obtained from the Berlincourt method, which gave a d33 value of 500 pC/N. In addition, the d31 value is in agreement with the value obtained from the optical method, which gave a d 31 value of 223 pC/V. These results suggest that the proposed method is a viable way to quickly estimate piezoelectric coefficients of bulk unclamped samples. © 2010 The Electrochemical Society.

Self-oscillating loop based piezoelectric power converter

DEFF Research Database (Denmark)

2013-01-01

The present invention relates to a piezoelectric power converter comprising an input driver electrically coupled directly to an input or primary electrode of the piezoelectric transformer without any intervening series or parallel inductor. A feedback loop is operatively coupled between an output......- oscillation loop within a zero-voltage-switching (ZVS) operation range of the piezoelectric transformer....

Piezoelectric Energy Harvesting Solutions

Science.gov (United States)

Caliò, Renato; Rongala, Udaya Bhaskar; Camboni, Domenico; Milazzo, Mario; Stefanini, Cesare; de Petris, Gianluca; Oddo, Calogero Maria

2014-01-01

This paper reviews the state of the art in piezoelectric energy harvesting. It presents the basics of piezoelectricity and discusses materials choice. The work places emphasis on material operating modes and device configurations, from resonant to non-resonant devices and also to rotational solutions. The reviewed literature is compared based on power density and bandwidth. Lastly, the question of power conversion is addressed by reviewing various circuit solutions. PMID:24618725

Peritubular dentin lacks piezoelectricity.

Science.gov (United States)

Habelitz, S; Rodriguez, B J; Marshall, S J; Marshall, G W; Kalinin, S V; Gruverman, A

2007-09-01

Dentin is a mesenchymal tissue, and, as such, is based on a collagenous matrix that is reinforced by apatite mineral. Collagen fibrils show piezoelectricity, a phenomenon that is used by piezoresponse force microscopy (PFM) to obtain high-resolution images. We applied PFM to image human dentin with 10-nm resolution, and to test the hypothesis that zones of piezoactivity, indicating the presence of collagen fibrils, can be distinguished in dentin. Piezoelectricity was observed by PFM in the dentin intertubular matrix, while the peritubular dentin remained without response. High-resolution imaging of chemically treated intertubular dentin attributed the piezoelectric effect to individual collagen fibrils that differed in the signal strength, depending on the fibril orientation. This study supports the hypothesis that peritubular dentin is a non-collagenous tissue and is thus an exception among mineralized tissues that derive from the mesenchyme.

Nanoscans of piezoelectric activity using an atomic force microscope

International Nuclear Information System (INIS)

Zheng, Z.; Guy, I.L.; Butcher, K.S.A.; Tansley, T.L.

2002-01-01

Full text: Any crystal which lacks a centre of symmetry is piezoelectric. This includes all of the ferroelectric crystals used in photonics and virtually all compound semiconductors. Such crystals, when grown in thin film form invariably exist in a strained state and thus possess internal piezoelectric fields which can affect their electronic properties. A knowledge of the piezoelectric properties of such crystals is thus important in understanding how they behave in practical devices. It also provides a tool for analysing the crystal structure of such materials. Using an atomic force microscope (AFM) as a probe of piezoelectric activity allows the study of variations in crystal structure on a nanoscale. The AFM piezoelectric technique has been used by several groups to study structures of ceramic materials with large piezoelectric coefficients, intended for applications in piezoelectric actuators. In the AFM method, a driving signal of a few volts at a frequency well below the AFM tip resonance, is applied to a sample of the material mounted in the AFM. This voltage causes the sample dimensions to change in ways determined by the piezoelectric properties of the sample. The AFM signal thus contains the normal surface profile information and an additional component generated by the piezoelectric vibrations of the sample. A lockin amplifier is used to separate the piezoelectric signal from the normal AFM surface profile signal. The result is the simultaneous acquisition of the surface profile and a piezoelectric map of the surface of the material under study. We will present results showing the results of such measurements in materials such as lithium niobate and gallium nitride. These materials have piezoelectric coefficients which are much lower than those of materials to which the technique has normally been applied

Enhanced piezoelectricity of monolayer phosphorene oxides: a theoretical study.

Science.gov (United States)

Yin, Huabing; Zheng, Guang-Ping; Gao, Jingwei; Wang, Yuanxu; Ma, Yuchen

2017-10-18

Two-dimensional (2D) piezoelectric materials have potential applications in miniaturized sensors and energy conversion devices. In this work, using first-principles simulations at different scales, we systematically study the electronic structures and piezoelectricity of a series of 2D monolayer phosphorene oxides (POs). Our calculations show that the monolayer POs have tunable band gaps along with remarkable piezoelectric properties. The calculated piezoelectric coefficient d 11 of 54 pm V -1 in POs is much larger than those of 2D transition metal dichalcogenide monolayers and the widely used bulk α-quartz and AlN, and almost reaches the level of the piezoelectric effect in recently discovered 2D GeS. Furthermore, two other considerable piezoelectric coefficients, i.e., d 31 and d 26 with values of -10 pm V -1 and 21 pm V -1 , respectively, are predicted in some monolayer POs. We also examine the correlation between the piezoelectric coefficients and energy stability. The enhancement of piezoelectricity for monolayer phosphorene by oxidation will broaden the applications of phosphorene and phosphorene derivatives in nano-sized electronic and piezotronic devices.

Piezoelectricity

CERN Document Server

Lubitz, Karl

2008-01-01

Piezoelectric materials play a key role in an innovative market. Advances in applications derive from new materials and their development, as well as to new market requirements. This report elucidates these developments by a broad spectrum of examples, comprising ultrasound in medicine and defence industry, and frequency control.

Giant piezoelectricity on Si for hyperactive MEMS.

Science.gov (United States)

Baek, S H; Park, J; Kim, D M; Aksyuk, V A; Das, R R; Bu, S D; Felker, D A; Lettieri, J; Vaithyanathan, V; Bharadwaja, S S N; Bassiri-Gharb, N; Chen, Y B; Sun, H P; Folkman, C M; Jang, H W; Kreft, D J; Streiffer, S K; Ramesh, R; Pan, X Q; Trolier-McKinstry, S; Schlom, D G; Rzchowski, M S; Blick, R H; Eom, C B

2011-11-18

Microelectromechanical systems (MEMS) incorporating active piezoelectric layers offer integrated actuation, sensing, and transduction. The broad implementation of such active MEMS has long been constrained by the inability to integrate materials with giant piezoelectric response, such as Pb(Mg(1/3)Nb(2/3))O(3)-PbTiO(3) (PMN-PT). We synthesized high-quality PMN-PT epitaxial thin films on vicinal (001) Si wafers with the use of an epitaxial (001) SrTiO(3) template layer with superior piezoelectric coefficients (e(31,f) = -27 ± 3 coulombs per square meter) and figures of merit for piezoelectric energy-harvesting systems. We have incorporated these heterostructures into microcantilevers that are actuated with extremely low drive voltage due to thin-film piezoelectric properties that rival bulk PMN-PT single crystals. These epitaxial heterostructures exhibit very large electromechanical coupling for ultrasound medical imaging, microfluidic control, mechanical sensing, and energy harvesting.

Observation of piezoelectricity in free-standing monolayer MoS₂.

Science.gov (United States)

Zhu, Hanyu; Wang, Yuan; Xiao, Jun; Liu, Ming; Xiong, Shaomin; Wong, Zi Jing; Ye, Ziliang; Ye, Yu; Yin, Xiaobo; Zhang, Xiang

2015-02-01

Piezoelectricity allows precise and robust conversion between electricity and mechanical force, and arises from the broken inversion symmetry in the atomic structure. Reducing the dimensionality of bulk materials has been suggested to enhance piezoelectricity. However, when the thickness of a material approaches a single molecular layer, the large surface energy can cause piezoelectric structures to be thermodynamically unstable. Transition-metal dichalcogenides can retain their atomic structures down to the single-layer limit without lattice reconstruction, even under ambient conditions. Recent calculations have predicted the existence of piezoelectricity in these two-dimensional crystals due to their broken inversion symmetry. Here, we report experimental evidence of piezoelectricity in a free-standing single layer of molybdenum disulphide (MoS₂) and a measured piezoelectric coefficient of e₁₁ = 2.9 × 10(-10) C m(-1). The measurement of the intrinsic piezoelectricity in such free-standing crystals is free from substrate effects such as doping and parasitic charges. We observed a finite and zero piezoelectric response in MoS₂ in odd and even number of layers, respectively, in sharp contrast to bulk piezoelectric materials. This oscillation is due to the breaking and recovery of the inversion symmetry of the two-dimensional crystal. Through the angular dependence of electromechanical coupling, we determined the two-dimensional crystal orientation. The piezoelectricity discovered in this single molecular membrane promises new applications in low-power logic switches for computing and ultrasensitive biological sensors scaled down to a single atomic unit cell.

Piezoelectric nanomaterials for biomedical applications

CERN Document Server

Menciassi, Arianna

2012-01-01

Nanoscale structures and materials have been explored in many biological applications because of their novel and impressive physical and chemical properties. Such properties allow remarkable opportunities to study and interact with complex biological processes. This book analyses the state of the art of piezoelectric nanomaterials and introduces their applications in the biomedical field. Despite their impressive potentials, piezoelectric materials have not yet received significant attention for bio-applications. This book shows that the exploitation of piezoelectric nanoparticles in nanomedicine is possible and realistic, and their impressive physical properties can be useful for several applications, ranging from sensors and transducers for the detection of biomolecules to “sensible” substrates for tissue engineering or cell stimulation.

Development of piezoelectric composites for transducers

Science.gov (United States)

Safari, A.

1994-07-01

For the past decade and a half, many different types of piezoelectric ceramic-polymer composites have been developed intended for transducer applications. These diphasic composites are prepared from non-active polymer, such as epoxy, and piezoelectric ceramic, such as PZT, in the form of filler powders, elongated fibers, multilayer and more complex three-dimensional structures. For the last four years, most of the efforts have been given to producing large area and fine scale PZT fiber composites. In this paper, processing of piezoelectric ceramic-polymer composites with various connectivity patterns are reviewed. Development of fine scale piezoelectric composites by lost mold, injection molding and the relic method are described. Research activities of different groups for preparing large area piezocomposites for hydrophone and actuator applications are briefly reviewed. Initial development of electrostrictive ceramics and composites are also

Vibrations of thin piezoelectric shallow shells: Two-dimensional ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

In this paper we consider the eigenvalue problem for piezoelectric shallow shells and we show that, as the thickness of the shell goes to zero, the eigensolutions of the three-dimensional piezoelectric shells converge to the eigensolutions of a two- dimensional eigenvalue problem. Keywords. Vibrations; piezoelectricity ...

Anomalous piezoelectricity in two-dimensional graphene nitride nanosheets.

Science.gov (United States)

Zelisko, Matthew; Hanlumyuang, Yuranan; Yang, Shubin; Liu, Yuanming; Lei, Chihou; Li, Jiangyu; Ajayan, Pulickel M; Sharma, Pradeep

2014-06-27

Piezoelectricity is a unique property of materials that permits the conversion of mechanical stimuli into electrical and vice versa. On the basis of crystal symmetry considerations, pristine carbon nitride (C3N4) in its various forms is non-piezoelectric. Here we find clear evidence via piezoresponse force microscopy and quantum mechanical calculations that both atomically thin and layered graphitic carbon nitride, or graphene nitride, nanosheets exhibit anomalous piezoelectricity. Insights from ab inito calculations indicate that the emergence of piezoelectricity in this material is due to the fact that a stable phase of graphene nitride nanosheet is riddled with regularly spaced triangular holes. These non-centrosymmetric pores, and the universal presence of flexoelectricity in all dielectrics, lead to the manifestation of the apparent and experimentally verified piezoelectric response. Quantitatively, an e11 piezoelectric coefficient of 0.758 C m(-2) is predicted for C3N4 superlattice, significantly larger than that of the commonly compared α-quartz.

Finite element analysis of piezoelectric materials

International Nuclear Information System (INIS)

Lowrie, F.; Stewart, M.; Cain, M.; Gee, M.

1999-01-01

This guide is intended to help people wanting to do finite element analysis of piezoelectric materials by answering some of the questions that are peculiar to piezoelectric materials. The document is not intended as a complete beginners guide for finite element analysis in general as this is better dealt with by the individual software producers. The guide is based around the commercial package ANSYS as this is a popular package amongst piezoelectric material users, however much of the information will still be useful to users of other finite element codes. (author)

Applications of piezoelectric materials in oilfield services.

Science.gov (United States)

Goujon, Nicolas; Hori, Hiroshi; Liang, Kenneth K; Sinha, Bikash K

2012-09-01

Piezoelectric materials are used in many applications in the oilfield services industry. Four illustrative examples are given in this paper: marine seismic survey, precision pressure measurement, sonic logging-while-drilling, and ultrasonic bore-hole imaging. In marine seismics, piezoelectric hydrophones are deployed on a massive scale in a relatively benign environment. Hence, unit cost and device reliability are major considerations. The remaining three applications take place downhole in a characteristically harsh environment with high temperature and high pressure among other factors. The number of piezoelectric devices involved is generally small but otherwise highly valued. The selection of piezoelectric materials is limited, and the devices have to be engineered to withstand the operating conditions. With the global demand for energy increasing in the foreseeable future, the search for hydrocarbon resources is reaching into deeper and hotter wells. There is, therefore, a continuing and pressing need for high-temperature and high-coupling piezoelectric materials.

A review on one dimensional perovskite nanocrystals for piezoelectric applications

Directory of Open Access Journals (Sweden)

Li-Qian Cheng

2016-03-01

Full Text Available In recent years, one-dimensional piezoelectric nanomaterials have become a research topic of interest because of their special morphology and excellent piezoelectric properties. This article presents a short review on one dimensional perovskite piezoelectric materials in different systems including Pb(Zr,TiO3, BaTiO3 and (K,NaNbO3 (KNN. We emphasize KNN as a promising lead-free piezoelectric compound with a high Curie temperature and high piezoelectric properties and describe its synthesis and characterization. In particular, details are presented for nanoscale piezoelectricity characterization of a single KNN nanocrystal by piezoresponse force microscopy. Finally, this review describes recent progress in applications based on one dimensional piezoelectric nanostructures with a focus on energy harvesting composite materials.

Structured Piezoelectric Composites : Materials and Applications

NARCIS (Netherlands)

Van den Ende, D.A.

2012-01-01

The piezoelectric effect, which causes a material to generate a voltage when it deforms, is very suitable for making integrated sensors, and (micro-) generators. However, conventional piezoelectric materials are either brittle ceramics or certain polymers with a low thermal stability, which limits

Analysis of active piezoelectric energy harvester

Directory of Open Access Journals (Sweden)

Yiliang CUI

2018-02-01

Full Text Available Most of the existing piezoelectric traps are designed for a narrow frequency range of vibration, but the surrounding environment has a very wide frequency range, and the frequency may also be subject to change, causing the problem of difficult to achieve energy capture or capture inefficiency. In order to solve problem, a new T-type piezoelectric cantilever is proposed as a capture energy structure in the paper. To begin with the aspects of structural design and circuit design, the static analysis, modal analysis and resonance analysis of the structure are carried out and the natural frequency and excitation frequency of the device are analyzed. The design and calculation of the power consumption and the loss of the components of the circuit are analyzed by the simulation and verification of the active capture energy circuit, and the active and passive techniques are compared and analyzed, the simulation of the active capture circuit is verified by analyzing the power consumption of the circuit and the maximum power obtained by the active technology is 5 times of that of the passive technology. And then the voltage-controlled active boundary control method can be used for interface circuit design, taking the initiative to use each piezoelectric transduction cycle triggered by the electrical boundary conditions to effectively increase the input piezoelectric pump energy, and then increase output power. The way of utilizing the active trapping of piezoelectric materials is innovated, which has a positive effect on the development of piezoelectric traps.

Dielectric loss against piezoelectric power harvesting

Science.gov (United States)

Liang, Junrui; Shu-Hung Chung, Henry; Liao, Wei-Hsin

2014-09-01

Piezoelectricity is one of the most popular electromechanical transduction mechanisms for constructing kinetic energy harvesting systems. When a standard energy harvesting (SEH) interface circuit, i.e., bridge rectifier plus filter capacitor, is utilized for collecting piezoelectric power, the previous literature showed that the power conversion can be well predicted without much consideration for the effect of dielectric loss. Yet, as the conversion power gets higher by adopting power-boosting interface circuits, such as synchronized switch harvesting on inductor (SSHI), the neglect of dielectric loss might give rise to deviation in harvested power estimation. Given the continuous progress on power-boosting interface circuits, the role of dielectric loss in practical piezoelectric energy harvesting (PEH) systems should receive attention with better evaluation. Based on the integrated equivalent impedance network model, this fast track communication provides a comprehensive study on the susceptibility of harvested power in PEH systems under different conditions. It shows that, dielectric loss always counteracts piezoelectric power harvesting by causing charge leakage across piezoelectric capacitance. In particular, taking corresponding ideal lossless cases as references, the counteractive effect might be aggravated under one of the five conditions: larger dielectric loss tangent, lower vibration frequency, further away from resonance, weaker electromechanical coupling, or using power-boosting interface circuit. These relationships are valuable for the study of PEH systems, as they not only help explain the role of dielectric loss in piezoelectric power harvesting, but also add complementary insights for material, structure, excitation, and circuit considerations towards holistic evaluation and design for practical PEH systems.

Dielectric loss against piezoelectric power harvesting

International Nuclear Information System (INIS)

Liang, Junrui; Shu-Hung Chung, Henry; Liao, Wei-Hsin

2014-01-01

Piezoelectricity is one of the most popular electromechanical transduction mechanisms for constructing kinetic energy harvesting systems. When a standard energy harvesting (SEH) interface circuit, i.e., bridge rectifier plus filter capacitor, is utilized for collecting piezoelectric power, the previous literature showed that the power conversion can be well predicted without much consideration for the effect of dielectric loss. Yet, as the conversion power gets higher by adopting power-boosting interface circuits, such as synchronized switch harvesting on inductor (SSHI), the neglect of dielectric loss might give rise to deviation in harvested power estimation. Given the continuous progress on power-boosting interface circuits, the role of dielectric loss in practical piezoelectric energy harvesting (PEH) systems should receive attention with better evaluation. Based on the integrated equivalent impedance network model, this fast track communication provides a comprehensive study on the susceptibility of harvested power in PEH systems under different conditions. It shows that, dielectric loss always counteracts piezoelectric power harvesting by causing charge leakage across piezoelectric capacitance. In particular, taking corresponding ideal lossless cases as references, the counteractive effect might be aggravated under one of the five conditions: larger dielectric loss tangent, lower vibration frequency, further away from resonance, weaker electromechanical coupling, or using power-boosting interface circuit. These relationships are valuable for the study of PEH systems, as they not only help explain the role of dielectric loss in piezoelectric power harvesting, but also add complementary insights for material, structure, excitation, and circuit considerations towards holistic evaluation and design for practical PEH systems. (fast track communications)

Radial-Electric-Field Piezoelectric Diaphragm Pumps

Science.gov (United States)

Bryant, Robert G.; Working, Dennis C.; Mossi, Karla; Castro, Nicholas D.; Mane, Pooma

2009-01-01

In a recently invented class of piezoelectric diaphragm pumps, the electrode patterns on the piezoelectric diaphragms are configured so that the electric fields in the diaphragms have symmetrical radial (along-the-surface) components in addition to through-the-thickness components. Previously, it was accepted in the piezoelectric-transducer art that in order to produce the out-of-plane bending displacement of a diaphragm needed for pumping, one must make the electric field asymmetrical through the thickness, typically by means of electrodes placed on only one side of the piezoelectric material. In the present invention, electrodes are placed on both sides and patterned so as to produce substantial radial as well as through-the-thickness components. Moreover, unlike in the prior art, the electric field can be symmetrical through the thickness. Tests have shown in a given diaphragm that an electrode configuration according to this invention produces more displacement than does a conventional one-sided electrode pattern. The invention admits of numerous variations characterized by various degrees of complexity. Figure 1 is a simplified depiction of a basic version. As in other piezoelectric diaphragm pumps of similar basic design, the prime mover is a piezoelectric diaphragm. Application of a suitable voltage to the electrodes on the diaphragm causes it to undergo out-of-plane bending. The bending displacement pushes a fluid out of, or pulls the fluid into, a chamber bounded partly by the diaphragm. Also as in other diaphragm pumps in general, check valves ensure that the fluid flows only in through one port and only out through another port.

Phase structure and piezoelectric properties of Li-modified NKLN lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Kim, Sin-Woong; Lee, Sung-Chan; Kim, Min-Soo; Jeong, Soon-Jong; Kim, In-Sung; Song, Jae-Sung

2012-01-01

Through the low-temperature sintering method, a sintered body with excellent characteristics was produced in an eco-friendly niobate-based piezoelectric ceramic, whose application was low in expectation due to poor sinterability. Li 2 CO 3 was added in excess to (Na 0.49 K 0.45 Li 0.06 )NbO 3 , and ceramics were manufactured using a commercial sintering method. Then, the sinterability and the piezoelectric properties of the specimens containing varying amounts of Li 2 CO 3 were investigated. The microstructure demonstrated the typical abnormal grain growth tendencies with the addition of Li 2 CO 3 , and this was explained through changes in the critical driving force in the interface reaction-controlled nucleation and growth theory. When the specimen had been sintered at 1000 .deg. C for 4 hours in air after the addition of 1.5 mol% Li 2 CO 3 , the sintered body showed outstanding characteristics with a piezoelectric coefficient of 180 pC/N, an electromechanical coupling coefficient of 0.32, and a dielectric constant of 975. These results showed that eco-friendly niobate-based ceramics, whose use in applications was expected to be difficult in spite of their excellent properties, could be used to produce piezoelectric materials with outstanding properties through a commercial low-temperature sintering method using additives.

Phase structure and piezoelectric properties of Li-modified NKLN lead-free piezoelectric ceramics

Energy Technology Data Exchange (ETDEWEB)

Kim, Sin-Woong; Lee, Sung-Chan; Kim, Min-Soo; Jeong, Soon-Jong; Kim, In-Sung; Song, Jae-Sung [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

2012-09-15

Through the low-temperature sintering method, a sintered body with excellent characteristics was produced in an eco-friendly niobate-based piezoelectric ceramic, whose application was low in expectation due to poor sinterability. Li{sub 2}CO{sub 3} was added in excess to (Na{sub 0.49}K{sub 0.45}Li{sub 0.06})NbO{sub 3}, and ceramics were manufactured using a commercial sintering method. Then, the sinterability and the piezoelectric properties of the specimens containing varying amounts of Li{sub 2}CO{sub 3} were investigated. The microstructure demonstrated the typical abnormal grain growth tendencies with the addition of Li{sub 2}CO{sub 3}, and this was explained through changes in the critical driving force in the interface reaction-controlled nucleation and growth theory. When the specimen had been sintered at 1000 .deg. C for 4 hours in air after the addition of 1.5 mol% Li{sub 2}CO{sub 3}, the sintered body showed outstanding characteristics with a piezoelectric coefficient of 180 pC/N, an electromechanical coupling coefficient of 0.32, and a dielectric constant of 975. These results showed that eco-friendly niobate-based ceramics, whose use in applications was expected to be difficult in spite of their excellent properties, could be used to produce piezoelectric materials with outstanding properties through a commercial low-temperature sintering method using additives.

Development of High Performance Piezoelectric Polyimides

Science.gov (United States)

Simpson, Joycelyn O.; St.Clair, Terry L.; Welch, Sharon S.

1996-01-01

In this work a series of polyimides are investigated which exhibit a strong piezoelectric response and polarization stability at temperatures in excess of 100 C. This work was motivated by the need to develop piezoelectric sensors suitable for use in high temperature aerospace applications.

Vibrations of Thin Piezoelectric Shallow Shells

Indian Academy of Sciences (India)

Abstract. In this paper we consider the eigenvalue problem for piezoelectric shallow shells and we show that, as the thickness of the shell goes to zero, the eigensolutions of the three-dimensional piezoelectric shells converge to the eigensolutions of a two-dimensional eigenvalue problem.

Dielectric and piezoelectric properties of percolative three-phase piezoelectric polymer composites

Science.gov (United States)

Sundar, Udhay

Three-phase piezoelectric bulk composites were fabricated using a mix and cast method. The composites were comprised of lead zirconate titanate (PZT), aluminum (Al) and an epoxy matrix. The volume fraction of the PZT and Al were varied from 0.1 to 0.3 and 0.0 to 0.17, respectively. The influences of three entities on piezoelectric and dielectric properties: inclusion of an electrically conductive filler (Al), poling process (contact and Corona) and Al surface treatment, were observed. The piezoelectric strain coefficient, d33, effective dielectric constant, epsilon r, capacitance, C, and resistivity were measured and compared according to poling process, volume fraction of constituent phases and Al surface treatment. The maximum values of d33 were 3.475 and 1.0 pC/N for Corona and contact poled samples respectively, for samples with volume fractions of 0.40 and 0.13 of PZT and Al (surface treated) respectively. Also, the maximum dielectric constant for the surface treated Al samples was 411 for volume fractions of 0.40 and 0.13 for PZT and Al respectively. The percolation threshold was observed to occur at an Al volume fraction of 0.13. The composites achieved a percolated state for Al volume fractions >0.13 for both contact and corona poled samples. In addition, a comparative time study was conducted to examine the influence of surface treatment processing time of Al particles. The effectiveness of the surface treatment, sample morphology and composition was observed with the aid of SEM and EDS images. These images were correlated with piezoelectric and dielectric properties. PZT-epoxy-aluminum thick films (200 mum) were also fabricated using a two-step spin coat deposition and annealing method. The PZT volume fraction were varied from 0.2, 0.3 and 0.4, wherein the Aluminum volume fraction was varied from 0.1 to 0.17 for each PZT volume fraction, respectively. The two-step process included spin coating the first layer at 500 RPM for 30 seconds, and the second

Multilayer modal actuator-based piezoelectric transformers.

Science.gov (United States)

Huang, Yao-Tien; Wu, Wen-Jong; Wang, Yen-Chieh; Lee, Chih-Kung

2007-02-01

An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed piezoelectric transformer is comprised of three layers: a multilayered input layer, an insulation layer, and a single output layer. The electrode shape of the input layer is derived from its structural vibration modal shape, which takes advantage of the orthogonal property of the vibration modes to achieve a full modal filtering effect. The insulation layer possesses two functions: first, to couple the mechanical vibration energy between the input and output, and second, to provide electrical insulation between the two layers. To meet the two functions, a low temperature, co-fired ceramic (LTCC) was used to provide the high mechanical rigidity and high electrical insulation. It can be shown that this newly developed piezoelectric transformer has the advantage of possessing a more efficient energy transfer and a wider optimal working frequency range when compared to traditional piezoelectric transformers. A multilayer piezoelectric, transformer-based inverter applicable for use in LCD monitors or portable displays is presented as well.

Cylindrical Piezoelectric Fiber Composite Actuators

Science.gov (United States)

Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

2008-01-01

The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

Photothermoacoustic effect in solids with piezoelectric detection

International Nuclear Information System (INIS)

Kozachenko, V. V.; Kucherov, I.Ya.

2004-01-01

Full text: In the last few years, a growing interest has been expressed in studies of substances in different aggregate states which were performed with the help of the photothermoacoustic PTA effect. Main in this method is use of thermal waves as the carrier of the information about properties of explored substance. The excitation of thermal waves is carried out, as a rule, by modulated light flux. A specific feature of the PTA effect is the dependence of the information obtained from it on the method used for detecting thermal waves. One of the most sensitive methods for detecting a PTA signal is the piezoelectric method. For studies of solids, the PTA effect in plates offers considerable promise. In this work, PTA effect in a solid-piezoelectric layered structure is studied theoretically and experimentally. The layered plate consisting of an isotropic solid and piezoelectric crystal of a class 6 mm (or piezoelectric ceramics) is considered. The surface of a solid body is uniformly irradiated with a modulated light flux. The sample is heated and the thermal waves are generated. In the sample, the temperature field of thermal waves generates, due to the thermoelastic effect, acoustic vibration and waves that are registered by a piezoelectric. Expressions for the potential difference U across an arbitrary layer of piezoelectric transducer are derived. The solid bodies with various optical and thermal properties for cases of one-layer and two-layer piezoelectric transducer are analyzed. In particular, is shown, that for the case two-layer piezoelectric transducer, in the high-frequency region, the amplitude ratio U 1 / U 2 the tangent of the phase difference tg(Δφ) of signals taken from individual layers of the transducer depend almost linearly on the inverse square root of the frequency f -1/2 . With use of these features, the new method of definition of some elastic and thermal parameters of solid bodies offered. An experiment is performed with samples Cu, Fe

Piezoelectric Active Humidity Sensors Based on Lead-Free NaNbO3 Piezoelectric Nanofibers

Directory of Open Access Journals (Sweden)

Li Gu

2016-06-01

Full Text Available The development of micro-/nano-scaled energy harvesters and the self-powered sensor system has attracted great attention due to the miniaturization and integration of the micro-device. In this work, lead-free NaNbO3 piezoelectric nanofibers with a monoclinic perovskite structure were synthesized by the far-field electrospinning method. The flexible active humidity sensors were fabricated by transferring the nanofibers from silicon to a soft polymer substrate. The sensors exhibited outstanding piezoelectric energy-harvesting performance with output voltage up to 2 V during the vibration process. The output voltage generated by the NaNbO3 sensors exhibited a negative correlation with the environmental humidity varying from 5% to 80%, where the peak-to-peak value of the output voltage generated by the sensors decreased from 0.40 to 0.07 V. The sensor also exhibited a short response time, good selectively against ethanol steam, and great temperature stability. The piezoelectric active humidity sensing property could be attributed to the increased leakage current in the NaNbO3 nanofibers, which was generated due to proton hopping among the H3O+ groups in the absorbed H2O layers under the driving force of the piezoelectric potential.

Piezoelectricity in two dimensions: Graphene vs. molybdenum disulfide

Science.gov (United States)

Song, Xiaoxue; Hui, Fei; Knobloch, Theresia; Wang, Bingru; Fan, Zhongchao; Grasser, Tibor; Jing, Xu; Shi, Yuanyuan; Lanza, Mario

2017-08-01

The synthesis of piezoelectric two-dimensional (2D) materials is very attractive for implementing advanced energy harvesters and transducers, as these materials provide enormously large areas for the exploitation of the piezoelectric effect. Among all 2D materials, molybdenum disulfide (MoS2) has shown the largest piezoelectric activity. However, all research papers in this field studied just a single material, and this may raise concerns because different setups could provide different values depending on experimental parameters (e.g., probes used and areas analyzed). By using conductive atomic force microscopy, here we in situ demonstrate that the piezoelectric currents generated in MoS2 are gigantic (65 mA/cm2), while the same experiments in graphene just showed noise currents. These results provide the most reliable comparison yet reported on the piezoelectric effect in graphene and MoS2.

Postbuckling Investigations of Piezoelectric Microdevices Considering Damage Effects

Science.gov (United States)

Sun, Zhigang; Wang, Xianqiao

2014-01-01

Piezoelectric material has been emerging as a popular building block in MEMS devices owing to its unique mechanical and electrical material properties. However, the reliability of MEMS devices under buckling deformation environments remains elusive and needs to be further explored. Based on the Talreja's tensor valued internal state damage variables as well as the Helmhotlz free energy of piezoelectric material, a constitutive model of piezoelectric materials with damage is presented. The Kachanvo damage evolution law under in-plane compressive loads is employed. The model is applied to the specific case of the postbuckling analysis of the piezoelectric plate with damage. Then, adopting von Karman's plate theory, the nonlinear governing equations of the piezoelectric plates with initial geometric deflection including damage effects under in-plane compressive loads are established. By using the finite difference method and the Newmark scheme, the damage evolution for damage accumulation is developed and the finite difference procedure for postbuckling equilibrium path is simultaneously employed. Numerical results show the postbuckling behaviors of initial flat and deflected piezoelectric plates with damage or no damage under different sets of electrical loading conditions. The effects of applied voltage, aspect ratio of plate, thick-span ratio of plate, damage as well as initial geometric deflections on the postbuckling behaviors of the piezoelectric plate are discussed. PMID:24618774

Power enhancement of piezoelectric transformers by adding heat transfer equipment.

Science.gov (United States)

Su, Yu-Hao; Liu, Yuan-Ping; Vasic, Dejan; Wu, Wen-Jong; Costa, François; Lee, Chih-Kung

2012-10-01

It is known that piezoelectric transformers have several inherent advantages compared with conventional electromagnetic transformers. However, the maximum power capacity of piezoelectric transformers is not as large as electromagnetic transformers in practice, especially in the case of high output current. The theoretical power density of piezoelectric transformers calculated by stress boundary can reach 330 W/cm(3), but no piezoelectric transformer has ever reached such a high power density in practice. The power density of piezoelectric transformers is limited to 33 W/cm(3) in practical applications. The underlying reason is that the maximum passing current of the piezoelectric material (mechanical current) is limited by the temperature rise caused by heat generation. To increase this current and the power capacity, we proposed to add a thermal pad to the piezoelectric transformer to dissipate heat. The experimental results showed that the proposed techniques can increase by 3 times the output current of the piezoelectric transformer. A theoretical-phenomenological model which explains the relationship between vibration velocity and generated heat is also established to verify the experimental results.

Low-energy impact of adaptive cylindrical piezoelectric-composite shells

Energy Technology Data Exchange (ETDEWEB)

Saravanos, D.A. [University of Patras (United Kingdom). Dept. of Mechanical Engineering and Aeronautics; Christoforou, A.P. [Kuwait Univ. (Kuwait). Dept. of Mechanical Engineering

2002-04-01

A theoretical framework for analyzing low-energy impacts of laminated shells with active and sensory piezoelectric layers is presented, including impactor dynamics and contact law. The formulation encompasses a coupled piezoelectric shell theory mixing first order shear displacement assumptions and layerwise variation of electric potential. An exact in-plane Ritz solution for the impact of open cylindrical piezoelectric-composite shells is developed and solved numerically using an explicit time integration scheme. The active impact control problem of adaptive cylindrical shells with distributed curved piezoelectric actuators is addressed. The cases of optimized state feedback controllers and output feedback controllers using piezoelectric sensors are analyzed. Numerical results quantify the impact response of cylindrical shells of various curvatures including the signal of curved piezoelectric sensors. Additional numerical studies quantify the impact response of adaptive cylindrical panels and investigate the feasibility of actively reducing the impact force. (author)

Electronically droplet energy harvesting using piezoelectric cantilevers

KAUST Repository

Al Ahmad, Mahmoud Al; Jabbour, Ghassan E.

2012-01-01

A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films

Design and characterization of piezoelectric ultrasonic motors

Science.gov (United States)

Yener, Serra

This thesis presents modeling and prototype fabrication and characterization of new types of piezoelectric ultrasonic micromotors. Our approach in designing these piezoelectric motors was: (i) to simplify the structure including the poling configuration of piezoelectric elements used in the stator and (ii) to reduce the number of components in order to decrease the cost and enhance the driving reliability. There are two different types of piezoelectric motors designed throughout this research. The first of these designs consists of a metal tube, on which two piezoelectric ceramic plates poled in thickness direction, were bonded. Two orthogonal bending modes of the hollow cylinder were superimposed resulting in a rotational vibration. Since the structure and poling configuration of the active piezoelectric elements used in the stator are simple, this motor structure is very suitable for miniaturization. Moreover, a single driving source can excite two bending modes at the same time, thus generate a wobble motion. Three types of prototypes are included in this design. The piezoelectric stator structure is the same for all. However, the dimensions of the motors are reduced by almost 50 percent. Starting with a 10 mm long stator, we reached to 4 mm in the last prototype. The initial diameter was 2.4 mm, which was reduced to 1.6 mm. In the final design, the rotor part of the motor was changed resulting in the reduction in the number of components. In terms of driving circuit, a single driving source was enough to run the motors and a conventional switching power supply type resonant L-C circuit was used. A simple motor structure with a simple driving circuit were combined successfully and fabricated inexpensively. The second design is a shear type piezoelectric linear motor. The behavior of a single rectangular piezoelectric shear plate was analyzed and after optimizing the dimensions and the mode characteristics, a prototype was fabricated. The prototype consists of

Effect of garment design on piezoelectricity harvesting from joint movement

International Nuclear Information System (INIS)

Yang, Jin-Hee; Cho, Hyun-Seung; Park, Seon-Hyung; Song, Seung-Hwan; Yun, Kwang-Seok; Lee, Joo Hyeon

2016-01-01

The harvesting of piezoelectricity through the human body involves the conversion of mechanical energy, mostly generated by the repeated movements of the body, to electrical energy, irrespective of the time and location. In this research, it was expected that the garment design would play an important role in increasing the efficiency of piezoelectricity scavenged in a garment because the mechanical deformation imposed on the energy harvester could increase through an optimal design configuration for the garment parts supporting a piezoelectricity harvester. With this expectation, this research aimed to analyze the effect of the clothing factors, and that of human factors on the efficiency of piezoelectricity harvesting through clothing in joint movements. These analyses resulted in that the efficiency of the piezoelectricity harvesting was affected from both two clothing factors, tightness level depending upon the property of the textile material and design configuration of the garment part supporting the piezoelectricity harvesting. Among the three proposed designs of the garment part supporting the piezoelectricity harvesting, ‘reinforced 3D module design,’ which maximized the value of radius in the piezoelectricity harvester, showed the highest efficiency across all areas of the joints in the human body. The two human factors, frequency of movement and body part, affected the efficiency of the piezoelectricity harvesting as well. (paper)

Computational and Experimental Insight Into Single-Molecule Piezoelectric Materials

Science.gov (United States)

Marvin, Christopher Wayne

Piezoelectric materials allow for the harvesting of ambient waste energy from the environment. Producing lightweight, highly responsive materials is a challenge for this type of material, requiring polymer, foam, or bio-inspired materials. In this dissertation, I explore the origin of the piezoelectric effect in single molecules through density functional theory (DFT), analyze the piezoresponse of bio-inspired peptidic materials through the use of atomic and piezoresponse force microscopy (AFM and PFM), and develop a novel class of materials combining flexible polyurethane foams and non-piezoelectric, polar dopants. For the DFT calculations, functional group, regiochemical, and heteroatom derivatives of [6]helicene were examined for their influence on the piezoelectric response. An aza[6]helicene derivative was found to have a piezoelectric response (108 pm/V) comparable to ceramics such as lead zirconium titanate (200+ pm/V). These computed materials have the possibility to compete with current field-leading piezomaterials such as lead zirconium titanate (PZT), zinc oxide (ZnO), and polyvinylidene difluoride (PVDF) and its derivatives. The use of AFM/PFM allows for the demonstration of the piezoelectric effect of the selfassembled monolayer (SAM) peptidic systems. Through PFM, the influence that the helicity and sequence of the peptide has on the overall response of the molecule can be analyzed. Finally, development of a novel class of piezoelectrics, the foam-based materials, expands the current understanding of the qualities required for a piezoelectric material from ceramic and rigid materials to more flexible, organic materials. Through the exploration of these novel types of piezoelectric materials, new design rules and figures of merit have been developed.

Shunted Piezoelectric Vibration Damping Analysis Including Centrifugal Loading Effects

Science.gov (United States)

Min, James B.; Duffy, Kirsten P.; Provenza, Andrew J.

2011-01-01

Excessive vibration of turbomachinery blades causes high cycle fatigue problems which require damping treatments to mitigate vibration levels. One method is the use of piezoelectric materials as passive or active dampers. Based on the technical challenges and requirements learned from previous turbomachinery rotor blades research, an effort has been made to investigate the effectiveness of a shunted piezoelectric for the turbomachinery rotor blades vibration control, specifically for a condition with centrifugal rotation. While ample research has been performed on the use of a piezoelectric material with electric circuits to attempt to control the structural vibration damping, very little study has been done regarding rotational effects. The present study attempts to fill this void. Specifically, the objectives of this study are: (a) to create and analyze finite element models for harmonic forced response vibration analysis coupled with shunted piezoelectric circuits for engine blade operational conditions, (b) to validate the experimental test approaches with numerical results and vice versa, and (c) to establish a numerical modeling capability for vibration control using shunted piezoelectric circuits under rotation. Study has focused on a resonant damping control using shunted piezoelectric patches on plate specimens. Tests and analyses were performed for both non-spinning and spinning conditions. The finite element (FE) shunted piezoelectric circuit damping simulations were performed using the ANSYS Multiphysics code for the resistive and inductive circuit piezoelectric simulations of both conditions. The FE results showed a good correlation with experimental test results. Tests and analyses of shunted piezoelectric damping control, demonstrating with plate specimens, show a great potential to reduce blade vibrations under centrifugal loading.

Development, Characterization and Piezoelectric Fatigue Behavior of Lead-Free Perovskite Piezoelectric Ceramics

Science.gov (United States)

Patterson, Eric Andrew

Much recent research has focused on the development lead-free perovskite piezoelectrics as environmentally compatible alternatives to lead zirconate titanate (PZT). Two main categories of lead free perovskite piezoelectric ceramic systems were investigated as potential replacements to lead zirconate titanate (PZT) for actuator devices. First, solid solutions based on Li, Ta, and Sb modified (K0.5Na0.5)NbO3 (KNN) lead-free perovskite systems were created using standard solid state methods. Secondly, Bi-based materials a variety of compositions were explored for (1-x)(Bi 0.5Na0.5)TiO3-xBi(Zn0.5Ti0.5)O 3 (BNT-BZT) and Bi(Zn0.5Ti0.5)O3-(Bi 0.5K0.5)TiO3-(Bi0.5Na0.5)TiO 3 (BZT-BKT-BNT). It was shown that when BNT-BKT is combined with increasing concentrations of Bi(Zn1/2i1/2)O3 (BZT), a transition from normal ferroelectric behavior to a material with large electric field induced strains was observed. The higher BZT containing compositions are characterized by large hysteretic strains(> 0.3%) with no negative strains that might indicate domain switching. This work summarizes and analyzes the fatigue behavior of the new generation of Pb-free piezoelectric materials. In piezoelectric materials, fatigue is observed as a degradation in the electromechanical properties under the application of a bipolar or unipolar cyclic electrical load. In Pb-based materials such as lead zirconate titanate (PZT), fatigue has been studied in great depth for both bulk and thin film applications. In PZT, fatigue can result from microcracking or electrode effects (especially in thin films). Ultimately, however, it is electronic and ionic point defects that are the most influential mechanism. Therefore, this work also analyzes the fatigue characteristics of bulk polycrystalline ceramics of the modified-KNN and BNT-BKT-BZT compositions developed. The defect chemistry that underpins the fatigue behavior will be examined and the results will be compared to the existing body of work on PZT. It will

Ab Initio Prediction of Piezoelectricity in Two-Dimensional Materials.

Science.gov (United States)

Blonsky, Michael N; Zhuang, Houlong L; Singh, Arunima K; Hennig, Richard G

2015-10-27

Two-dimensional (2D) materials present many unique materials concepts, including material properties that sometimes differ dramatically from those of their bulk counterparts. One of these properties, piezoelectricity, is important for micro- and nanoelectromechanical systems applications. Using symmetry analysis, we determine the independent piezoelectric coefficients for four groups of predicted and synthesized 2D materials. We calculate with density-functional perturbation theory the stiffness and piezoelectric tensors of these materials. We determine the in-plane piezoelectric coefficient d11 for 37 materials within the families of 2D metal dichalcogenides, metal oxides, and III-V semiconductor materials. A majority of the structures, including CrSe2, CrTe2, CaO, CdO, ZnO, and InN, have d11 coefficients greater than 5 pm/V, a typical value for bulk piezoelectric materials. Our symmetry analysis shows that buckled 2D materials exhibit an out-of-plane coefficient d31. We find that d31 for 8 III-V semiconductors ranges from 0.02 to 0.6 pm/V. From statistical analysis, we identify correlations between the piezoelectric coefficients and the electronic and structural properties of the 2D materials that elucidate the origin of the piezoelectricity. Among the 37 2D materials, CdO, ZnO, and CrTe2 stand out for their combination of large piezoelectric coefficient and low formation energy and are recommended for experimental exploration.

Piezoelectric polydimethylsiloxane films for MEMS transducers

International Nuclear Information System (INIS)

Wang, Jhih-Jhe; Hsu, Tsung-Hsing; Yeh, Che-Nan; Tsai, Jui-Wei; Su, Yu-Chuan

2012-01-01

We have successfully demonstrated the fabrication of piezoelectric polydimethylsiloxane (PDMS) films utilizing multilayer casting, stacking, surface coating and micro plasma discharge processes. To realize the desired electromechanical sensitivity, cellular PDMS structures with micrometer-sized voids are implanted with bipolar charges on the opposite inner surfaces. The implanted charge pairs function as dipoles, which respond promptly to diverse electromechanical stimulation. In the prototype demonstration, cellular PDMS films with various void geometries are fabricated and internally coated with a thin layer of polytetrafluoroethylene, which can help secure the implanted charges. An electric field up to 35 MV m −1 is applied across the fabricated PDMS films to ionize the air in the voids and to accelerate the resulting bipolar charges to bombard the opposite inner surfaces. The resulting charge-implanted, cellular PDMS films show a low effective elastic modulus (E) of about 500 kPa, and a piezoelectric coefficient (d 33 ) higher than 300 pC N −1 , which is more than ten times higher than those of common piezoelectric polymers (e.g. polyvinylidene fluoride). Furthermore, the piezoelectricity of the PDMS films can be tailored by adjusting the dimensions of the cellular structures. As such, the demonstrated piezoelectric PDMS films could potentially serve as flexible and sensitive electromechanical materials, and fulfill the needs of a variety of sensor and energy harvesting applications. (paper)

Human-computer interface glove using flexible piezoelectric sensors

Science.gov (United States)

Cha, Youngsu; Seo, Jeonggyu; Kim, Jun-Sik; Park, Jung-Min

2017-05-01

In this note, we propose a human-computer interface glove based on flexible piezoelectric sensors. We select polyvinylidene fluoride as the piezoelectric material for the sensors because of advantages such as a steady piezoelectric characteristic and good flexibility. The sensors are installed in a fabric glove by means of pockets and Velcro bands. We detect changes in the angles of the finger joints from the outputs of the sensors, and use them for controlling a virtual hand that is utilized in virtual object manipulation. To assess the sensing ability of the piezoelectric sensors, we compare the processed angles from the sensor outputs with the real angles from a camera recoding. With good agreement between the processed and real angles, we successfully demonstrate the user interaction system with the virtual hand and interface glove based on the flexible piezoelectric sensors, for four hand motions: fist clenching, pinching, touching, and grasping.

Piezoelectric coefficients and spontaneous polarization of ScAlN

International Nuclear Information System (INIS)

Caro, Miguel A; Laurila, Tomi; Zhang, Siyuan; Moram, Michelle A; Riekkinen, Tommi; Ylilammi, Markku; Molarius, Jyrki; Lopez-Acevedo, Olga

2015-01-01

We present a computational study of spontaneous polarization and piezoelectricity in Sc x Al 1−x N alloys in the compositional range from x = 0 to x = 0.5, obtained in the context of density functional theory and the Berry-phase theory of electric polarization using large periodic supercells. We report composition-dependent values of piezoelectric coefficients e ij , piezoelectric moduli d ij and elastic constants C ij . The theoretical findings are complemented with experimental measurement of e 33 for a series of sputtered ScAlN films carried out with a piezoelectric resonator. The rapid increase with Sc content of the piezoelectric response reported in previous studies is confirmed for the available data. A detailed description of the full methodology required to calculate the piezoelectric properties of ScAlN, with application to other complex alloys, is presented. In particular, we find that the large amount of internal strain present in ScAlN and its intricate relation with electric polarization make configurational sampling and the use of large supercells at different compositions necessary in order to accurately derive the piezoelectric response of the material. (paper)

Extrusion and properties of lead zirconate titanate piezoelectric ceramics

DEFF Research Database (Denmark)

Cai, S.; Millar, C.E.; Pedersen, L.

1997-01-01

The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates was investi......The purpose of this work was to develop a procedure for fabricating electroceramic actuators with good piezoelectric properties. The preparation of lead zirconate titanate (PZT) piezoelectric ceramic rods and tubes by extrusion processing is described. The microstructure of extrudates...

Energy Harvesting From Low Frequency Applications Using Piezoelectric Materials

Energy Technology Data Exchange (ETDEWEB)

Li, Huidong; Tian, Chuan; Deng, Zhiqun

2014-11-06

This paper reviewed the state of research on piezoelectric energy harvesters. Various types of harvester configurations, piezoelectric materials, and techniques used to improve the mechanical-to-electrical energy conversion efficiency were discussed. Most of the piezoelectric energy harvesters studied today have focused on scavenging mechanical energy from vibration sources due to their abundance in both natural and industrial environments. Cantilever beams have been the most studied structure for piezoelectric energy harvester to date because of the high responsiveness to small vibrations.

Characterization of a Piezoelectric Buzzer Using a Michelson Interferometer

Science.gov (United States)

Lloyd, S.; Paetkau, M.

2010-01-01

A piezoelectric material generates an electric potential across its surface when subjected to mechanical stress; conversely, the inverse piezoelectric effect describes the expansion or contraction of the material when subjected to some applied voltage. Piezoelectric materials are used in devices such as doorbell buzzers, barbeque igniters, and…

Tubular fluoropolymer arrays with high piezoelectric response

Science.gov (United States)

Zhukov, Sergey; Eder-Goy, Dagmar; Biethan, Corinna; Fedosov, Sergey; Xu, Bai-Xiang; von Seggern, Heinz

2018-01-01

Polymers with electrically charged internal air cavities called ferroelectrets exhibit a pronounced piezoelectric effect and are regarded as soft functional materials suitable for sensor and actuator applications. In this work, a simple method for fabricating piezoelectret arrays with open-tubular channels is introduced. A set of individual fluoroethylenepropylene (FEP) tubes is compressed between two heated metal plates. The squeezed FEP tubes are melted together at +270 °C. The resulting structure is a uniform, multi-tubular, flat array that reveals a strong piezoelectric response after a poling step. The fabricated arrays have a high ratio between piezoelectrically active and non-active areas. The optimal charging voltage and stability of the piezoelectric coefficients with pressures and frequency were experimentally investigated for two specific array structures with wall thickness of 50 and 120 μm. The array fabricated from 50 μm thick FEP tubes reveals a stable and high piezoelectric coefficient of {d}33 = 120-160 pC N-1 with a flat frequency response between 0.1 Hz and 10 kHz for pressures between 1 and 100 kPa. An increase of wall thickness to 120 μm is accompanied by a more than twofold decrease in the piezoelectric coefficient as a result of a simultaneously higher effective array stiffness and lower remanent polarization. The obtained experimental results can be used to optimize the array design with regard to the electromechanical performance.

Piezoelectric Templates – New Views on Biomineralization and Biomimetics

Science.gov (United States)

Stitz, Nina; Eiben, Sabine; Atanasova, Petia; Domingo, Neus; Leineweber, Andreas; Burghard, Zaklina; Bill, Joachim

2016-01-01

Biomineralization in general is based on electrostatic interactions and molecular recognition of organic and inorganic phases. These principles of biomineralization have also been utilized and transferred to bio-inspired synthesis of functional materials during the past decades. Proteins involved in both, biomineralization and bio-inspired processes, are often piezoelectric due to their dipolar character hinting to the impact of a template’s piezoelectricity on mineralization processes. However, the piezoelectric contribution on the mineralization process and especially the interaction of organic and inorganic phases is hardly considered so far. We herein report the successful use of the intrinsic piezoelectric properties of tobacco mosaic virus (TMV) to synthesize piezoelectric ZnO. Such films show a two-fold increase of the piezoelectric coefficient up to 7.2 pm V−1 compared to films synthesized on non-piezoelectric templates. By utilizing the intrinsic piezoelectricity of a biotemplate, we thus established a novel synthesis pathway towards functional materials, which sheds light on the whole field of biomimetics. The obtained results are of even broader and general interest since they are providing a new, more comprehensive insight into the mechanisms involved into biomineralization in living nature. PMID:27212583

Low-Temperature Solution Processable Electrodes for Piezoelectric Sensors Applications

Science.gov (United States)

Tuukkanen, Sampo; Julin, Tuomas; Rantanen, Ville; Zakrzewski, Mari; Moilanen, Pasi; Lupo, Donald

2013-05-01

Piezoelectric thin-film sensors are suitable for a wide range of applications from physiological measurements to industrial monitoring systems. The use of flexible materials in combination with high-throughput printing technologies enables cost-effective manufacturing of custom-designed, highly integratable piezoelectric sensors. This type of sensor can, for instance, improve industrial process control or enable the embedding of ubiquitous sensors in our living environment to improve quality of life. Here, we discuss the benefits, challenges and potential applications of piezoelectric thin-film sensors. The piezoelectric sensor elements are fabricated by printing electrodes on both sides of unmetallized poly(vinylidene fluoride) film. We show that materials which are solution processable in low temperatures, biocompatible and environmental friendly are suitable for use as electrode materials in piezoelectric sensors.

State-of-the-art piezoelectric transformer-based switch mode power supplies

DEFF Research Database (Denmark)

Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

2014-01-01

Inductorless switch mode power supplies based on piezoelectric transformers are used to replace conventional transformers in high power density switch mode power supplies. Even though piezoelectric-based converters exhibit a high d egree of nonlinearity, it is desirable to use piezoelectric transfo...... discusses power supplies with the trend evaluation of piezoelectric transformer-based converter topologies and control methods. The challenges of piezoelectric transformers regarding soft switching capability and nonlinearity are addressed. This paper can be used as a guideline f or choosing a proper...... topology of piezoelectric-based switch mode power supply and a control method for the required application....

Electronically droplet energy harvesting using piezoelectric cantilevers

KAUST Repository

Al Ahmad, Mahmoud Al

2012-01-01

A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 μJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 μJ. © 2012 The Institution of Engineering and Technology.

Electromechanical displacement of piezoelectric-electrostrictive monolithic bilayer composites

Science.gov (United States)

Ngernchuklin, P.; Akdoǧan, E. K.; Safari, A.; Jadidian, B.

2009-02-01

We examine the electromechanical displacement of piezoelectric-electrostrictive monolithic bilayer composites with various piezoelectric volume percentage obtained by cosintering piezoelectric 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 and electrostrictive 0.9Pb(Mg1/3Nb2/.3)O3-0.1PbTiO3 under unipolar and bipolar electric field excitation up to 10 kV/cm experimentally. It is shown that the effective d33 of the composites is limited by the electrostrictive layer, which acts as a capacitor in series to the piezoelectric layer, causing incomplete poling. We show that by controlling the volume content of the piezoelectric layer and constraining it with an electrostrictor, substantial strain amplification (15 μm for bipolar excitation) can be achieved while inducing asymmetry to the displacement with respect to the polarity of the applied field, which we discuss in the context of symmetry superposition.

Performance of a piezoelectric energy harvester in actual rain

International Nuclear Information System (INIS)

Wong, Voon-Kean; Ho, Jee-Hou; Chai, Ai-Bao

2017-01-01

When raindrops impact on the surface of a piezoelectric beam, strain energy produced by the impinging raindrop will be converted to harvestable electrical energy by the piezoelectric layers in a cantilever beam. The novelty of this study is to investigate the performance of the harvester in actual rain and provide practical insights on implementation. The influences of rain parameters such as rain rate, rainfall depth, raindrop count, and drop size distribution (DSD) are discussed in this study. The raindrops accumulated on the surface of the piezoelectric beam will form a water layer. It is described using added mass coefficient in this study. In an actual rain experiment, a piezoelectric beam with surface area of 0.0018 m 2 is able to produce 2076 μJ of energy over a duration of 301 min. The energy generation of a raindrop impact piezoelectric energy harvester is highly dependent on the rain rate. Due to the inconsistency of the energy generation, the piezoelectric energy harvester would require an integration of suitable energy storage device for continuous operation. Nevertheless, this work shows the feasibility of harvesting raindrop energy using a piezoelectric beam. - Highlights: • The performance of a piezoelectric rain energy harvester is tested in actual rain. • The energy generation is highly dependent on the rain rate. • Practical insights on the implementation of the harvester are discussed. • A total energy of 2076 μJ is generated over a duration of 301 min.

Biodegradable Piezoelectric Force Sensor.

Science.gov (United States)

Curry, Eli J; Ke, Kai; Chorsi, Meysam T; Wrobel, Kinga S; Miller, Albert N; Patel, Avi; Kim, Insoo; Feng, Jianlin; Yue, Lixia; Wu, Qian; Kuo, Chia-Ling; Lo, Kevin W-H; Laurencin, Cato T; Ilies, Horea; Purohit, Prashant K; Nguyen, Thanh D

2018-01-30

Measuring vital physiological pressures is important for monitoring health status, preventing the buildup of dangerous internal forces in impaired organs, and enabling novel approaches of using mechanical stimulation for tissue regeneration. Pressure sensors are often required to be implanted and directly integrated with native soft biological systems. Therefore, the devices should be flexible and at the same time biodegradable to avoid invasive removal surgery that can damage directly interfaced tissues. Despite recent achievements in degradable electronic devices, there is still a tremendous need to develop a force sensor which only relies on safe medical materials and requires no complex fabrication process to provide accurate information on important biophysiological forces. Here, we present a strategy for material processing, electromechanical analysis, device fabrication, and assessment of a piezoelectric Poly-l-lactide (PLLA) polymer to create a biodegradable, biocompatible piezoelectric force sensor, which only employs medical materials used commonly in Food and Drug Administration-approved implants, for the monitoring of biological forces. We show the sensor can precisely measure pressures in a wide range of 0-18 kPa and sustain a reliable performance for a period of 4 d in an aqueous environment. We also demonstrate this PLLA piezoelectric sensor can be implanted inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction. This piezoelectric sensor offers an appealing alternative to present biodegradable electronic devices for the monitoring of intraorgan pressures. The sensor can be integrated with tissues and organs, forming self-sensing bionic systems to enable many exciting applications in regenerative medicine, drug delivery, and medical devices.

Optimal design of robust piezoelectric unimorph microgrippers

DEFF Research Database (Denmark)

Ruiz, David; Díaz-Molina, Alex; Sigmund, Ole

2018-01-01

Topology optimization can be used to design piezoelectric actuators by simultaneous design of host structure and polarization profile. Subsequent micro-scale fabrication leads us to overcome important manufacturing limitations: difficulties in placing a piezoelectric layer on both top and bottom...

Variational principles for nonlinear piezoelectric materials

Energy Technology Data Exchange (ETDEWEB)

Rodriguez-Ramos, R.; Guinovart-Diaz, R. [Universidad de la Habana, Facultad de Matematica y Computacion, Vedado, Habana (Cuba); Pobedria, B.E. [Moscow State University M. V. Lomonosov, Composites Department, Moscow (Russian Federation); Padilla, P. [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Matematicas Aplicadas y en Sistemas (IIMAS), Cd. Universitaria, Mexico D.F. (Mexico); Bravo-Castillero, J. [Universidad de la Habana, Facultad de Matematica y Computacion, Vedado, Habana (Cuba); Campus Estado de Mexico. Division de Arquitectura e Ingenieria, Instituto Tecnologico de Estudios Superiores de Monterrey, Atizapan de Zaragoza, Estado de Mexico (Mexico); Maugin, G.A. [Universite Pierre et Marie Curie. Case 162, UMR 7607 CNRS, Laboratoire de Modelisation en Mecanique, Paris Cedex 05 (France)

2004-12-01

In the present paper, we consider the behavior of nonlinear piezoelectric materials by generalization for this case of the Hashin-Shtrikman variational principles. The new general formulation used here differs from others, because, it gives the possibility to evaluate the upper and lower Hashin-Shtrikman bounds for specific physical nonlinearities of piezoelectric materials. Geometrical nonlinearities are not considered. (orig.)

Circuit for Driving Piezoelectric Transducers

Science.gov (United States)

Randall, David P.; Chapsky, Jacob

2009-01-01

The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

Piezoelectric MEMS sensors: state-of-the-art and perspectives

International Nuclear Information System (INIS)

Tadigadapa, S; Mateti, K

2009-01-01

Over the past two decades, several advances have been made in micromachined sensors and actuators. As the field of microelectromechanical systems (MEMS) has advanced, a clear need for the integration of materials other than silicon and its compounds into micromachined transducers has emerged. Piezoelectric materials are high energy density materials that scale very favorably upon miniaturization and that has led to an ever-growing interest in piezoelectric films for MEMS applications. At this time, piezoelectric aluminum-nitride-based film bulk acoustic resonators (FBAR) have already been successfully commercialized. Future innovations and improvements in inertial sensors for navigation, high-frequency crystal oscillators and filters for wireless applications, microactuators for RF applications, chip-scale chemical analysis systems and countless other applications hinge upon the successful miniaturization of components and integration of piezoelectrics and metals into these systems. In this article, a comprehensive review of micromachined piezoelectric transducer technology will be presented. Piezoelectric materials in bulk and thin film forms will be reviewed and fabrication techniques for the integration of these materials for microsensor applications will be presented. Recent advances in various piezoelectric microsensors will be presented through specific examples. This review will conclude with a critical assessment of the future trends and promise of this technology. (topical review)

Comparison of effective transverse piezoelectric coefficients e31,f of Pb(Zr,Ti)O3 thin films between direct and converse piezoelectric effects

Science.gov (United States)

Tsujiura, Yuichi; Kawabe, Saneyuki; Kurokawa, Fumiya; Hida, Hirotaka; Kanno, Isaku

2015-10-01

We evaluated the effective transverse piezoelectric coefficients (e31,f) of Pb(Zr,Ti)O3 (PZT) thin films from both the direct and converse piezoelectric effects of unimorph cantilevers. (001) preferentially oriented polycrystalline PZT thin films and (001)/(100) epitaxial PZT thin films were deposited on (111)Pt/Ti/Si and (001)Pt/MgO substrates, respectively, by rf-magnetron sputtering, and their piezoelectric responses owing to intrinsic and extrinsic effects were examined. The direct and converse |e31,f| values of the polycrystalline PZT thin films were calculated as 6.4 and 11.5-15.0 C/m2, respectively, whereas those of the epitaxial PZT thin films were calculated as 3.4 and 4.6-4.8 C/m2, respectively. The large |e31,f| of the converse piezoelectric property of the polycrystalline PZT thin films is attributed to extrinsic piezoelectric effects. Furthermore, the polycrystalline PZT thin films show a clear nonlinear piezoelectric contribution, which is the same as the Rayleigh-like behavior reported in bulk PZT. In contrast, the epitaxial PZT thin films on the MgO substrate show a piezoelectric response owing to the intrinsic and linear extrinsic effects, and no nonlinear contribution was observed.

Piezoelectric Composites by Solid Freeform Fabrication: A Nature-Inspired Approach

Science.gov (United States)

Safari, A.; Akdoğan, E. K.

Piezoelectrics and electrostrictors are indispensable materials for use in transducer technology, as they inherently possess both direct (sensing) and converse (actuation) effects. A piezoelectric/electrostrictive sensor converts a mechanical input (displacement or force) into a measurable electrical output through piezoelectric/electrostrictive energy conversion. In the case of a piezoelectric, an applied mechanical force (stress) induces a voltage across the terminals of the transducer. On the other hand, an applied mechanical force induces a change in the capacitance of an electrostrictive transducer that could be electrically detected. Hence, the mechanical to electrical energy conversion is accomplished directly when a piezoelectric is used, while the same is obtained indirectly if the electroactive material of choice is an electrostrictor. Conversely, both piezoelectric and electrostrictive materials develop an elastic strain under an applied electric field. The said elastic strain is linearly proportional to the applied field in a piezoelectric, whereas electrostrictive coupling involves the second-order (quadratic) coupling of electric field with elastic strain. While piezoelectricity is possible only in noncentrosymetric point groups, electrostriction is observed in all solids, which make it a much more general solid-state phenomenon. Sensing and actuation functions can coexist in a given transducer by the intelligent use of such materials. Piezoelectrics and electrostrictors, therefore, constitute the backbone of modern transducer technology, as mechanical to electric energy (and vice versa) conversion can be accomplished with great efficiency in a way that is second to none among all phenomena known to date [1,2].

Propellant Flow Actuated Piezoelectric Igniter for Combustion Engines

Science.gov (United States)

Wollen, Mark A. (Inventor)

2018-01-01

A propellant flow actuated piezoelectric igniter device using one or more hammer balls retained by one or more magnets, or other retaining method, until sufficient fluid pressure is achieved in one or more charging chambers to release and accelerate the hammer ball, such that it impacts a piezoelectric crystal to produce an ignition spark. Certain preferred embodiments provide a means for repetitively capturing and releasing the hammer ball after it impacts one or more piezoelectric crystals, thereby oscillating and producing multiple, repetitive ignition sparks. Furthermore, an embodiment is presented for which oscillation of the hammer ball and repetitive impact to the piezoelectric crystal is maintained without the need for a magnet or other retaining mechanism to achieve this oscillating impact process.

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

International Nuclear Information System (INIS)

Lin Shuyu; Tian Hua

2008-01-01

A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

All-solution-processed flexible thin film piezoelectric nanogenerator

Energy Technology Data Exchange (ETDEWEB)

Chung, Sung Yun; Kim, Sunyoung; Kim, Kyongjun [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744 (Korea, Republic of); Lee, Ju-Hyuck; Kim, Sang-Woo [SKKU Advanced Institute of Nanotechnology, School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Kang, Chong-Yun; Yoon, Seok-Jin [Electronic Materials Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kim, Youn Sang [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744 (Korea, Republic of); Advanced Institutes of Convergence Technology, 864-1 Iui-dong, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-270 (Korea, Republic of)

2012-11-27

An all-solution-processed flexible thin film piezoelectric nanogenerator is demonstrated using reactive zinc hydroxo-condensation and a screen-printing method. The highly elastic thin film allows the piezoelectric energy to be generated through the mechanical rolling and muscle stretching of the piezoelectric unit. This flexible all solution-processed nanogenerator is promising for use in future energy harvesters such as wearable human patches and mobile electronics. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Cellulose Nanofibril Film as a Piezoelectric Sensor Material.

Science.gov (United States)

Rajala, Satu; Siponkoski, Tuomo; Sarlin, Essi; Mettänen, Marja; Vuoriluoto, Maija; Pammo, Arno; Juuti, Jari; Rojas, Orlando J; Franssila, Sami; Tuukkanen, Sampo

2016-06-22

Self-standing films (45 μm thick) of native cellulose nanofibrils (CNFs) were synthesized and characterized for their piezoelectric response. The surface and the microstructure of the films were evaluated with image-based analysis and scanning electron microscopy (SEM). The measured dielectric properties of the films at 1 kHz and 9.97 GHz indicated a relative permittivity of 3.47 and 3.38 and loss tangent tan δ of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7-6.4 pC/N in ambient conditions. This piezoelectric response is expected to increase remarkably upon film polarization resulting from the alignment of the cellulose crystalline regions in the film. The CNF sensor characteristics were compared with those of polyvinylidene fluoride (PVDF) as reference piezoelectric polymer. Overall, the results suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuators, or energy generators with potential applications in the fields of electronics, sensors, and biomedical diagnostics.

PLZT-based photovoltaic Piezoelectric Transformer with light feedback

Energy Technology Data Exchange (ETDEWEB)

Kozielski, L [University of Silesia, Dep. Materials Sc, 2, Sniezna St. Sosnowiec, 41-200 Poland (Poland); Adamczyk, M [University of Silesia, Institute Phys., 4, Uniwersytecka St. Katowice, 40-007 Poland (Poland); Erhart, J, E-mail: lucjan.kozielski@us.edu.pl [Technical University of Liberec, Studencka St. 2, CZ-461 17 Liberec (Czech Republic)

2011-10-29

Piezoelectric Transformer (PT) converts an electrical AC input voltage into ultrasonic vibrations and reconverts back to an output as AC voltage. Hard lead zirconate titanate (PZT) ceramics is typically used for fabrications of such devices. In case of lanthaniun ion La{sup 3+} addition in PZT solid solution we can achieve piezoelectric ceramics with good transparency exhibiting both optical Pockels and Kerr effects. Values of these coefficients in the PLZT system are much bigger than in LiNbO{sub 3} or SBN single crystals. Among the various PLZT compositions 8/65/35, near the morphotropic boundary, exhibit large electrooptic effect and thus have found applications in light shutters and displays. In the present study we have investigated radial mode piezoelectric transformer based on optically transparent PLZT8/65/35 ceramics. The effect of the UV light generated photovoltage and photostriction on the efficiency and voltage step-up ratio of piezoelectric transformer have been demonstrated. Novel functions of this device is proposed by superimposing two sophistically coupled effects of piezoelectricity and photostriction.

Piezoelectric Resonance Investigation of Zr-rich PZT at Room Temperature

NARCIS (Netherlands)

Cereceda, N.; Noheda, B.; Fernandez-del-Castillo, J.R.; Gonzalo, J.A.; Frutos, J. De

1999-01-01

We study the piezoelectric resonances in poled PZT ceramics by means of a microscopic model. It connects the microscopic vibrations of the ionic units, cooperatively producing the piezoelectric effect, with the macroscopic piezoelectric parameters. The behaviour at the resonance is well described in

Eigenstates of coupling factor and loss factor of piezoelectric ceramics

International Nuclear Information System (INIS)

Smits, J.G.

1978-01-01

A short history of piezoelectricity is given and its occurence in nature described. The physical background of piezoelectric loss is discussed together with how material coefficients like susceptibilities can be used to describe the relation between canonical variables and to determine the dissipation of energy. The piezoelectric coupling factor, the applications of the eigencoupling state, elastic and piezoelectric digenstates are dealt with. The composition of the measurement system is described and experimental values of ceramics given. (C.F.)

Tailored piezoelectric thin films for energy harvester

NARCIS (Netherlands)

Wan, X.

2013-01-01

Piezoelectric materials are excellent materials to transfer mechanical energy into electrical energy, which can be stored and used to power other devices. PiezoMEMS is a good way to combine silicon wafer processing and piezoelectric thin film technology and lead to a variety of miniaturized and

Piezoelectricity of a ferroelectric liquid crystal with a glass transition.

Science.gov (United States)

Jákli, A; Tóth-Katona, T; Scharf, T; Schadt, M; Saupe, A

2002-07-01

Pressure-electric (hydrostatic piezoelectric) measurements are reported on bookshelf textures of a ferroelectric smectic-C (Sm C*) liquid crystal with a glass transition. The continuous variation of a partially fluid state to the solid glass enables one to trace how the piezoelectric effect depends on the consistency of the material. It was observed that in the Sm C* samples with poled glass the piezoelectric constants are comparable to conventional piezoelectric crystals and poled piezoelectric polymers. This implies their application possibilities. The magnitude of the piezoelectric constant in the glassy state depends very much on the poling conditions. The studies indicate that there are two counteracting effects, which cancel each other out in the Sm C* phase near the glass transition. Our analysis indicates that the pressure-induced director tilt change has a dominating effect both in the fluid and the glassy Sm C* states.

Piezoelectric actuation of helicopter rotor blades

Science.gov (United States)

Lieven, Nicholas A. J.

2001-07-01

The work presented in this paper is concerned with the application of embedded piezo-electric actuators in model helicopter rotor blades. The paper outlines techniques to define the optimal location of actuators to excite particular modes of vibration whilst the blade is rotating. Using composite blades the distribution of strain energy is defined using a Finite Element model with imposed rotor-dynamic and aerodynamics loads. The loads are specified through strip theory to determine the position of maximum bending moment and thus the optimal location of the embedded actuators. The effectiveness of the technique is demonstrated on a 1/4 scale fixed cyclic pitch rotor head. Measurement of the blade displacement is achieved by using strain gauges. In addition a redundant piezo-electric actuator is used to measure the blades' response characteristics. The addition of piezo-electric devices in this application has been shown to exhibit adverse aeroelastic effects, such as counter mass balancing and increased drag. Methods to minimise these effects are suggested. The outcome of the paper is a method for defining the location and orientation of piezo-electric devices in rotor-dynamic applications.

Piezoelectric properties and thermal stabilities of cobalt-modified potassium bismuth titanate

International Nuclear Information System (INIS)

Guo, Zhen-Lei; Wang, Chun-Ming; Zhao, Tian-Long; Yu, Si-Long; Cao, Zhao-Peng

2013-01-01

The cobalt-modified potassium bismuth titanate (K 0.5 Bi 4.5 Ti 4 O 15 , KBT) piezoelectric ceramics have been prepared using conventional solid–state reaction. X-ray diffraction analysis revealed that the cobalt-modified KBT ceramics have a pure four-layer (m = 4) Aurivillius-type structure. The dielectric, ferroelectric, and piezoelectric properties of cobalt-modified KBT ceramics were investigated in detail. The piezoelectric activities of KBT ceramics were significantly improved by the cobalt modification. The reasons for piezoelectric activities enhancement with cobalt modification were given. The piezoelectric coefficient d 33 and Curie temperature T c for the 5 mol% cobalt-modified KBT ceramics (KBT-Co5) were found to be 28 pC/N and 575 °C, respectively. The DC resistivity, frequency constants (N p and N t ), and electromechanical properties at elevated temperature were investigated, indicating the cobalt-modified KBT piezoelectric ceramics possess stable piezoelectric properties up to 500 °C. The results show the cobalt-modified KBT ceramics are potential materials for high temperature piezoelectric applications. - Highlights: • We examine the piezoelectric properties of the cobalt-modified K 0.5 Bi 4.5 Ti 4 O 15 . • A high level of piezoelectric activities (d 33 = 28 pC/N) are obtained. • High Curie temperature (T c = 575 °C) is acquired for the optimal composition. • The Co-modified K 0.5 Bi 4.5 Ti 4 O 15 is promising as high temperature materials

Enhanced active piezoelectric 0-3 nanocomposites fabricated through electrospun nanowires

International Nuclear Information System (INIS)

Feenstra, Joel; Sodano, Henry A.

2008-01-01

The use of monolithic piezoceramic materials in sensing and actuation applications has become quite common over the past decade. However, these materials have several properties that limit their application in practical systems. These materials are very brittle due to the ceramic nature of the monolithic material, making them vulnerable to accidental breakage during handling and bonding procedures. In addition, they have very poor ability to conform to curved surfaces and result in large add-on mass associated with using a typically lead-based ceramic. These limitations have motivated the development of alternative methods of applying the piezoceramic material, including piezoceramic fiber composites and piezoelectric 0-3 composites (also known as piezoelectric paint). Piezoelectric paint is desirable because it can be spayed or painted on and can be used with abnormal surfaces. However, the piezoelectric paint developed in prior studies has resulted in low coupling, limiting its application. In order to increase the coupling of the piezoelectric paint, this effort has investigated the use of piezoelectric nanowires rather than spherical piezoelectric particle, which are difficult to strain when embedded in a polymer matrix. The piezoceramic wires were electrospun from a barium titanate (BaTiO 3 ) sol gel to produce fibers with 500-1000 nm diameters and subsequently calcinated to acquire perovskite BaTiO 3 . An active nanocomposite paint was formed using the resulting piezoelectric wires and was compared to the same paint with piezoelectric nanoparticles. The results show that the piezoceramic wires produce 0-3 nanocomposites with as high as 300% increase in electromechanical coupling

Preparation and piezoelectric properties of (K0.5Na0.5)NbO3 lead-free piezoelectric ceramics with pressure-less sintering

International Nuclear Information System (INIS)

Du Hongliang; Li Zhimin; Tang Fusheng; Qu Shaobo; Pei Zhibin; Zhou Wancheng

2006-01-01

Lead-free piezoelectric ceramics (K 0.5 Na 0.5 )NbO 3 (abbreviated as KNN) with the relative density of 97.6% have been synthesized by press-less sintering owing to the careful control of processing conditions. The phase structure of KNN ceramics with different sintering temperature and heating rate was analyzed. Results show that the pure perovskite phase with orthorhombic symmetry is in all ceramics specimens. The effect of heating rate and sintering temperature on microstructure and piezoelectric properties of KNN ceramics was investigated. The densification behavior and piezoelectric properties of KNN ceramics were enhanced by improving heating rate and sintering temperature. Pure KNN ceramics sintered at 1120 deg. C with heating rate of 5 deg. C/min showed optimized densification and piezoelectric properties (ρ = 4.4 g/cm 3 , d 33 = 120 pC/N -1 , k p = 0.40 and T c = 400 deg. C). The results show that KNN is a promising candidate for lead-free piezoelectric ceramics

Fabrication and in vitro biological properties of piezoelectric bioceramics for bone regeneration

Science.gov (United States)

Tang, Yufei; Wu, Cong; Wu, Zixiang; Hu, Long; Zhang, Wei; Zhao, Kang

2017-02-01

The piezoelectric effect of biological piezoelectric materials promotes bone growth. However, the material should be subjected to stress before it can produce an electric charge that promotes bone repair and reconstruction conducive to fracture healing. A novel method for in vitro experimentation of biological piezoelectric materials with physiological load is presented. A dynamic loading device that can simulate the force of human motion and provide periodic load to piezoelectric materials when co-cultured with cells was designed to obtain a realistic expression of piezoelectric effect on bone repair. Hydroxyapatite (HA)/barium titanate (BaTiO3) composite materials were fabricated by slip casting, and their piezoelectric properties were obtained by polarization. The d33 of HA/BaTiO3 piezoelectric ceramics after polarization was 1.3 pC/N to 6.8 pC/N with BaTiO3 content ranging from 80% to 100%. The in vitro biological properties of piezoelectric bioceramics with and without cycle loading were investigated. When HA/BaTiO3 piezoelectric bioceramics were affected by cycle loading, the piezoelectric effect of BaTiO3 promoted the growth of osteoblasts and interaction with HA, which was better than the effect of HA alone. The best biocompatibility and bone-inducing activity were demonstrated by the 10%HA/90%BaTiO3 piezoelectric ceramics.

Experiments to Demonstrate Piezoelectric and Pyroelectric Effects

Science.gov (United States)

Erhart, Jirí

2013-01-01

Piezoelectric and pyroelectric materials are used in many current applications. The purpose of this paper is to explain the basic properties of pyroelectric and piezoelectric effects and demonstrate them in simple experiments. Pyroelectricity is presented on lead zirconium titanate (PZT) ceramics as an electric charge generated by the temperature…

Advances in Piezoelectric Systems: An Application-Based Approach

DEFF Research Database (Denmark)

Zsurzsan, Tiberiu-Gabriel

with their low manufacturing costs and high robustness has enabled wide-spread usage in applications ranging from simple spark lighters or pressure sensors to much more complicated energy harvesting systems and piezoelectric transformers. One governing property of piezoelectric devices is the existence....... These three distinct behaviors encountered in any piezoelectric device represents the ba- sis of discussion in the thesis. Therefore the present PhD dissertation is an application-based approach to researching all three behaviors individually, while nding solutions to the challenges encountered along the way...... bidirectional operation of a self-oscillating converter. Feasibility of using the converter in an MRI scanner is demonstrated. The third and nal behavior researched is the resistive behavior. This is widely encountered since most piezoelectric motors, ultrasonic baths and some energy harvesting systems operate...

Recent Progress on PZT Based Piezoelectric Energy Harvesting Technologies

Directory of Open Access Journals (Sweden)

Min-Gyu Kang

2016-02-01

Full Text Available Energy harvesting is the most effective way to respond to the energy shortage and to produce sustainable power sources from the surrounding environment. The energy harvesting technology enables scavenging electrical energy from wasted energy sources, which always exist everywhere, such as in heat, fluids, vibrations, etc. In particular, piezoelectric energy harvesting, which uses a direct energy conversion from vibrations and mechanical deformation to the electrical energy, is a promising technique to supply power sources in unattended electronic devices, wireless sensor nodes, micro-electronic devices, etc., since it has higher energy conversion efficiency and a simple structure. Up to now, various technologies, such as advanced materials, micro- and macro-mechanics, and electric circuit design, have been investigated and emerged to improve performance and conversion efficiency of the piezoelectric energy harvesters. In this paper, we focus on recent progress of piezoelectric energy harvesting technologies based on PbZrxTi1-xO3 (PZT materials, which have the most outstanding piezoelectric properties. The advanced piezoelectric energy harvesting technologies included materials, fabrications, unique designs, and properties are introduced to understand current technical levels and suggest the future directions of piezoelectric energy harvesting.

Piezoelectric Nanotube Array for Broadband High-Frequency Ultrasonic Transducer.

Science.gov (United States)

Liew, Weng Heng; Yao, Kui; Chen, Shuting; Tay, Francis Eng Hock

2018-03-01

Piezoelectric materials are vital in determining ultrasonic transducer and imaging performance as they offer the function for conversion between mechanical and electrical energy. Ultrasonic transducers with high-frequency operation suffer from performance degradation and fabrication difficulty of the demanded piezoelectric materials. Hence, we propose 1-D polymeric piezoelectric nanostructure with controlled nanoscale features to overcome the technical limitations of high-frequency ultrasonic transducers. For the first time, we demonstrate the integration of a well-aligned piezoelectric nanotube array to produce a high-frequency ultrasonic transducer with outstanding performance. We find that nanoconfinement-induced polarization orientation and unique nanotube structure lead to significantly improved piezoelectric and ultrasonic transducing performance over the conventional piezoelectric thin film. A large bandwidth, 126% (-6 dB), is achieved at high center frequency, 108 MHz. Transmission sensitivity of nanotube array is found to be 46% higher than that of the monolithic thin film transducer attributed to the improved electromechanical coupling effectiveness and impedance match. We further demonstrate high-resolution scanning, ultrasonic imaging, and photoacoustic imaging using the obtained nanotube array transducers, which is valuable for biomedical imaging applications in the future.

Piezoelectric materials involved in road traffic applications test system

International Nuclear Information System (INIS)

Vazquez Rodriguez, M.; Jimenez Martinez, F.; Frutos, J. de

2011-01-01

The test bench system described in this paper performs experiments on piezoelectric materials used in road traffic applications, covering a range between 14 and 170 km/h, which is considered enough for testing under standard traffic conditions. A software has been developed to control the three phase induction motor driver and to acquire all the measurement data of the piezoelectric materials. The mass over each systems axis can be selected, with a limit of 60 kg over each wheel. The test bench is used to simulate the real behaviour of buried piezoelectric cables in road traffic applications for both light and heavy vehicles. This new test bed system is a powerful research tool and can be applied to determine the optimal installation and configuration of the piezoelectric cable sensors and opens a new field of research: the study of energy harvesting techniques based on piezoelectric materials. (Author) 10 refs.

A review of piezoelectric polymers as functional materials for electromechanical transducers

International Nuclear Information System (INIS)

Ramadan, Khaled S; Evoy, S; Sameoto, D

2014-01-01

Polymer based MEMS and microfluidic devices have the advantages of mechanical flexibility, lower fabrication cost and faster processing over silicon based ones. Also, many polymer materials are considered biocompatible and can be used in biological applications. A valuable class of polymers for microfabricated devices is piezoelectric functional polymers. In addition to the normal advantages of polymers, piezoelectric polymers can be directly used as an active material in different transduction applications. This paper gives an overview of piezoelectric polymers based on their operating principle. This includes three main categories: bulk piezoelectric polymers, piezocomposites and voided charged polymers. State-of-the-art piezopolymers of each category are presented with a focus on fabrication techniques and material properties. A comparison between the different piezoelectric polymers and common inorganic piezoelectric materials (PZT, ZnO, AlN and PMN–PT) is also provided in terms of piezoelectric properties. The use of piezopolymers in different electromechanical devices is also presented. This includes tactile sensors, energy harvesters, acoustic transducers and inertial sensors. (topical review)

Hysteresis compensation for piezoelectric actuators in single-point diamond turning

Science.gov (United States)

Wang, Haifeng; Hu, Dejin; Wan, Daping; Liu, Hongbin

2006-02-01

In recent years, interests have been growing for fast tool servo (FTS) systems to increase the capability of existing single-point diamond turning machines. Although piezoelectric actuator is the most universal base of FTS system due to its high stiffness, accuracy and bandwidth, nonlinearity in piezoceramics limits both the static and dynamic performance of piezoelectric-actuated control systems evidently. To compensate the nonlinear hysteresis behavior of piezoelectric actuators, a hybrid model coupled with Preisach model and feedforward neural network (FNN) has been described. Since the training of FNN does not require a special calibration sequence, it is possible for on-line identification and real-time implementation with general operating data of a specific piezoelectric actuator. To describe the rate dependent behavior of piezoelectric actuators, a hybrid dynamic model was developed to predict the response of piezoelectric actuators in a wider range of input frequency. Experimental results show that a maximal error of less than 3% was accomplished by this dynamic model.

Piezoelectric peptide-based nanogenerator enhanced by single-electrode triboelectric nanogenerator

Directory of Open Access Journals (Sweden)

Vu Nguyen

2017-07-01

Full Text Available Peptide has recently been demonstrated as a sustainable and smart material for piezoelectric energy conversion. Although the power output was improved compared to other biomaterials, the use of a piezoelectric device alone can only capture the energy from the minute deformation in materials. In comparison, the triboelectric effect can convert mechanical energy from large motion. Consequently, utilizing both piezoelectric and triboelectric effects is of significant research interest due to their complementary energy conversion mechanisms. Here we demonstrated a hybrid nanogenerator that combined a peptide-based piezoelectric nanogenerator with a single-electrode triboelectric nanogenerator. Our device structure enabled the voltage and current outputs of each individual type of nanogenerator to be superposed in the hybrid nanogenerator, producing overall constructive outputs. The design of our device also enabled a simplified configuration of hybrid nanogenerator. This study is important not only for the enhancement of peptide-based piezoelectric device but also for the future design of hybrid piezoelectric and triboelectric nanogenerators.

Theoretical and Experimental Study on Secondary Piezoelectric Effect Based on PZT-5

International Nuclear Information System (INIS)

Zhang, Z H; Sun, B Y; Shi, L P

2006-01-01

The purpose of this paper is to confirm the existence of secondary and multiple piezoelectric effect theoretically and experimentally. Based on Heckmann model showing the relationship among mechanical, electric and heat energy and the physical model on mechanical, electric, heat, and magnetic energy, theoretical analysis of multiple piezoelectric effect is made through four kinds of piezoelectric equations. Experimental research of secondary direct piezoelectric effect is conducted through adopting PZT-5 piles. The result of the experiment indicates that charge generated by secondary direct piezoelectric effect as well as displacement caused by first converse piezoelectric effect keeps fine linearity with the applied voltage

Polarization and Piezoelectric Properties of a Nitrile Substituted Polyimide

Science.gov (United States)

Simpson, Joycelyn; Ounaies, Zoubeida; Fay, Catharine

1997-01-01

This research focuses on the synthesis and characterization of a piezoelectric (beta-CN)- APB/ODPA polyimide. The remanent polarization and piezoelectric d(sub 31) and g(sub 33) coefficients are reported to assess the effect of synthesis variations. Each of the materials exhibits a level of piezoelectricity which increases with temperature. The remanent polarization is retained at temperatures close to the glass transition temperature of the polyimide.

Acoustics of the piezo-electric pressure probe

Science.gov (United States)

Dutt, G. S.

1974-01-01

Acoustical properties of a piezoelectric device are reported for measuring the pressure in the plasma flow from an MPD arc. A description and analysis of the acoustical behavior in a piezoelectric probe is presented for impedance matching and damping. The experimental results are presented in a set of oscillographic records.

Energy harvesting from high-rise buildings by a piezoelectric harvester device

International Nuclear Information System (INIS)

Xie, X.D.; Wang, Q.; Wang, S.J.

2015-01-01

A novel piezoelectric technology of harvesting energy from high-rise buildings is developed. While being used to harness vibration energy of a building, the technology is also helpful to dissipate vibration of the building by the designed piezoelectric harvester as a tuned mass damper. The piezoelectric harvester device is made of two groups of series piezoelectric generators connected by a shared shaft. The shaft is driven by a linking rod hinged on a proof mass on the tip of a cantilever fixed on the roof of the building. The influences of some practical considerations, such as the mass ratio of the proof mass to the main structure, the ratios of the length and flexural rigidity of the cantilever to those of the main structure, on the root mean square (RMS) of the generated electric power and the energy harvesting efficiency of the piezoelectric harvester device are discussed. The research provides a new method for an efficient and practical energy harvesting from high-rise buildings by piezoelectric harvesters. - Highlights: • A new piezoelectric technology in energy harvesting from high-rise buildings is introduced. • A new mathematics model to calculate the energy harvested by the piezoelectric device is developed. • A novel efficient design of the piezoelectric harvester device in provided. • An electric power up to 432 MW under a seismic excitation at a frequency of 30 rad/s is achieved.

System and Method for Monitoring Piezoelectric Material Performance

Science.gov (United States)

Moses, Robert W. (Inventor); Fox, Christopher L. (Inventor); Fox, Melanie L. (Inventor); Chattin, Richard L. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor)

2007-01-01

A system and method are provided for monitoring performance capacity of a piezoelectric material that may form part of an actuator or sensor device. A switch is used to selectively electrically couple an inductor to the piezoelectric material to form an inductor-capacitor circuit. Resonance is induced in the inductor-capacitor circuit when the switch is operated to create the circuit. The resonance of the inductor-capacitor circuit is monitored with the frequency of the resonance being indicative of performance capacity of the device's piezoelectric material.

Electromechanical-Traffic Model of Compression-Based Piezoelectric Energy Harvesting

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Kok B.C.

2016-01-01

Full Text Available Piezoelectric energy harvesting has advantages over other alternative sources due to its large power density, ease of applications, and capability to be fabricated at different scales: macro, micro, and nano. This paper presents an electromechanical-traffic model for roadway compression-based piezoelectric energy harvesting system. A two-degree-of-freedom (2-DOF electromechanical model has been developed for the piezoelectric energy harvesting unit to define its performance in power generation under a number of external excitations on road surface. Lead Zirconate Titanate (PZT-5H is selected as the piezoelectric material to be used in this paper due to its high Piezoelectric Charge Constant (d and Piezoelectric Voltage Constant (g values. The main source of vibration energy that has been considered in this paper is the moving vehicle on the road. The effect of various frequencies on possible generated power caused by different vibration characteristics of moving vehicle has been studied. A single unit of circle-shape Piezoelectric Cymbal Transducer (PCT with diameter of 32 mm and thickness of 0.3 mm be able to generate about 0.12 mW and 13 mW of electric power under 4 Hz and 20 Hz of excitation, respectively. The estimated power to be generated for multiple arrays of PCT is approximately 150 kW/ km. Thus, the developed electromechanical-traffic model has enormous potential to be used in estimating the macro scale of roadway power generation system.

BIOMINERALOGICAL INVESTIGATION OF APATITE PIEZOELECTRICITY

Directory of Open Access Journals (Sweden)

M. Pawlikowski

2016-01-01

Full Text Available Investigation of apatite piezoelectricity was conducted in order to assess piezoelectric properties of bone. In the first stage, mineralogical analysis of different apatite crystals, regarding their purity and fitness for the experiments was performed. After the crystals had been chosen, 0.8 mm-thick plates were cut, perpendicular and parallel to the crystallographic Z axis. The plates were then polished and dusted with gold. Electrodes were attached to the opposite surfaces of the plates with conductive glue. So prepared plates were hooked up to the EEG machine used for measuring electrical activity in the brain. The plates were then gently tapped to observe and register currents generated in them. Acquired data was processed by subtracting from the resulting graphs those generated by a hand movement, without tapping the plate. Results indicate that apatite plates have weak piezoelectric properties. Observed phenomenon may be translated to bone apatite, which would explain, at least partially, piezoelectric properties of bone. Acquired results suggest that there is a relation between the mechanical workload of bones (bone apatite and theirelectrical properties. Considering the massive internal surface of bones, they may be treated as a kind of internal “antenna” reacting not only to mechanical stimuli, but to changes in electromagnetic field as well. Observed phenomena no doubt significantly influence the biological processes occurring in bones and the whole human body.

Fundamental analysis of piezocatalysis process on the surfaces of strained piezoelectric materials.

Science.gov (United States)

Starr, Matthew B; Wang, Xudong

2013-01-01

Recently, the strain state of a piezoelectric electrode has been found to impact the electrochemical activity taking place between the piezoelectric material and its solution environment. This effect, dubbed piezocatalysis, is prominent in piezoelectric materials because the strain state and electronic state of these materials are strongly coupled. Herein we develop a general theoretical analysis of the piezocatalysis process utilizing well-established piezoelectric, semiconductor, molecular orbital and electrochemistry frameworks. The analysis shows good agreement with experimental results, reproducing the time-dependent voltage drop and H₂ production behaviors of an oscillating piezoelectric Pb(Mg₁/₃Nb₂/₃)O₃-32PbTiO₃ (PMN-PT) cantilever in deionized water environment. This study provides general guidance for future experiments utilizing different piezoelectric materials, such as ZnO, BaTiO₃, PbTiO₃, and PMN-PT. Our analysis indicates a high piezoelectric coupling coefficient and a low electrical conductivity are desired for enabling high electrochemical activity; whereas electrical permittivity must be optimized to balance piezoelectric and capacitive effects.

Electromechanical Modeling of Piezoelectric Energy Harvesters

OpenAIRE

Erturk, Alper

2009-01-01

Vibration-based energy harvesting has been investigated by several researchers over the last decade. The ultimate goal in this research field is to power small electronic components (such as wireless sensors) by using the vibration energy available in their environment. Among the basic transduction mechanisms that can be used for vibration-to-electricity conversion, piezoelectric transduction has received the most attention in the literature. Piezoelectric materials are preferred in energy ha...

LC Circuits for Diagnosing Embedded Piezoelectric Devices

Science.gov (United States)

Chattin, Richard L.; Fox, Robert Lee; Moses, Robert W.; Shams, Qamar A.

2005-01-01

A recently invented method of nonintrusively detecting faults in piezoelectric devices involves measurement of the resonance frequencies of inductor capacitor (LC) resonant circuits. The method is intended especially to enable diagnosis of piezoelectric sensors, actuators, and sensor/actuators that are embedded in structures and/or are components of multilayer composite material structures.

Fabrication and calibration of a piezoelectric nanocomposite paint

Science.gov (United States)

Osho, Samuel; Wu, Nan; Aramfard, Mohammad; Deng, Chuang; Ojo, Olanrewaju

2018-03-01

A new liquid form piezoelectric nanocomposite paint material is fabricated with possible applications as dynamic strain sensors and/or piezoelectric transducers. The applied coating is in the form of low-cost paint, which is flexible and bonds strongly on a metallic surface after drying out via the solvent-casting method. The nanocomposite is produced by an ultrasonic mixture of varying percentages of zinc oxide (ZnO) nanoparticle water dispersion, poly vinyl acetate glue (PVA) and carbon nanotubes (CNTs). ZnO nanoparticles are used as the piezoelectric sensing elements in a PVA matrix of the paint, while CNTs are introduced as robust bridge of ZnO particles enhancing the piezoelectricity and material properties. Transmission electron microscopy (TEM) images confirmed the linkages of ZnO nanoparticles in the composite by CNTs. Through piezoelectricity calibration, the optimum mixing ratio with the highest piezoelectricity is 78.1 wt% ZnO, 19.5 wt% PVA glue and 2.4 wt% multi-wall carbon nanotubes (MWCNTs). Through nanoindentation tests for the characterization of the mechanical properties of the nano-composite paint, it is found that Young’s modulus and hardness reached a threshold point in the increment in the addition of CNTs to the paint before showing signs of decline. Detailed analysis and explanation of the calibration results and physical phenomenon are provided. The stable paint material is ready to be applied on rough area of engineering structures as sensor and transducer.

Electronics for Piezoelectric Smart Structures

Science.gov (United States)

Warkentin, D. J.; Tani, J.

1997-01-01

This paper briefly presents work addressing some of the basic considerations for the electronic components used in smart structures incorporating piezoelectric elements. After general remarks on the application of piezoelectric elements to the problem of structural vibration control, three main topics are described. Work to date on the development of techniques for embedding electronic components within structural parts is presented, followed by a description of the power flow and dissipation requirements of those components. Finally current work on the development of electronic circuits for use in an 'active wall' for acoustic noise is introduced.

Control of piezoelectricity in amino acids by supramolecular packing

Science.gov (United States)

Guerin, Sarah; Stapleton, Aimee; Chovan, Drahomir; Mouras, Rabah; Gleeson, Matthew; McKeown, Cian; Noor, Mohamed Radzi; Silien, Christophe; Rhen, Fernando M. F.; Kholkin, Andrei L.; Liu, Ning; Soulimane, Tewfik; Tofail, Syed A. M.; Thompson, Damien

2018-02-01

Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapatite. Piezoelectric coefficients exhibited by these biological materials are generally low, typically in the range of 0.1-10 pm V-1, limiting technological applications. Guided by quantum mechanical calculations we have measured a high shear piezoelectricity (178 pm V-1) in the amino acid crystal beta (β) glycine, which is of similar magnitude to barium titanate or lead zirconate titanate. Our calculations show that the high piezoelectric coefficients originate from an efficient packing of the molecules along certain crystallographic planes and directions. The highest predicted piezoelectric voltage constant for β-glycine crystals is 8 V mN-1, which is an order of magnitude larger than the voltage generated by any currently used ceramic or polymer.

Control of piezoelectricity in amino acids by supramolecular packing.

Science.gov (United States)

Guerin, Sarah; Stapleton, Aimee; Chovan, Drahomir; Mouras, Rabah; Gleeson, Matthew; McKeown, Cian; Noor, Mohamed Radzi; Silien, Christophe; Rhen, Fernando M F; Kholkin, Andrei L; Liu, Ning; Soulimane, Tewfik; Tofail, Syed A M; Thompson, Damien

2018-02-01

Piezoelectricity, the linear relationship between stress and induced electrical charge, has attracted recent interest due to its manifestation in biological molecules such as synthetic polypeptides or amino acid crystals, including gamma (γ) glycine. It has also been demonstrated in bone, collagen, elastin and the synthetic bone mineral hydroxyapatite. Piezoelectric coefficients exhibited by these biological materials are generally low, typically in the range of 0.1-10 pm V -1 , limiting technological applications. Guided by quantum mechanical calculations we have measured a high shear piezoelectricity (178 pm V -1 ) in the amino acid crystal beta (β) glycine, which is of similar magnitude to barium titanate or lead zirconate titanate. Our calculations show that the high piezoelectric coefficients originate from an efficient packing of the molecules along certain crystallographic planes and directions. The highest predicted piezoelectric voltage constant for β-glycine crystals is 8 V mN -1 , which is an order of magnitude larger than the voltage generated by any currently used ceramic or polymer.

Fabrication and modelling of 3-3 piezoelectric composites

Energy Technology Data Exchange (ETDEWEB)

Perry, Andrew John

2002-07-01

Three-dimensional modelling of a 3-3 piezoelectric structure was carried out using ANSYS finite element modelling software. Hydrophone figures of merit were calculated for structures with increasing amounts of interconnecting porosity. In addition to air being the second phase, polymer fillers were added to the three dimensional model in order to observe the effect of polymer Young's modulus and Poisson's ratio on the piezoelectric response of the composite material. Results show that increasing the porosity has the effect of improving the hydrostatic piezoelectric properties for applications such as low frequency hydrophones. The optimum amount of porosity depends on the figure of merit to be maximised. In order to validate model predictions, porous piezoelectric structures were fabricated by either the BurPS (Burnt out Polymer Spheres) method or polymer foam reticulation. Corresponding measurements of piezoelectric coefficients were carried out on the porous samples. Experimental results confirmed finite element modelling predictions. PZT-porosity composites and PZT-polymer composites were produced exhibiting superior hydrostatic strain constant (d{sub h}), hydrostatic voltage constant (g{sub h}) and hydrostatic figure of merit (d{sub h}g{sub h}) compared to that of dense PZT. (author)

Critical Role of Monoclinic Polarization Rotation in High-Performance Perovskite Piezoelectric Materials.

Science.gov (United States)

Liu, Hui; Chen, Jun; Fan, Longlong; Ren, Yang; Pan, Zhao; Lalitha, K V; Rödel, Jürgen; Xing, Xianran

2017-07-07

High-performance piezoelectric materials constantly attract interest for both technological applications and fundamental research. The understanding of the origin of the high-performance piezoelectric property remains a challenge mainly due to the lack of direct experimental evidence. We perform in situ high-energy x-ray diffraction combined with 2D geometry scattering technology to reveal the underlying mechanism for the perovskite-type lead-based high-performance piezoelectric materials. The direct structural evidence reveals that the electric-field-driven continuous polarization rotation within the monoclinic plane plays a critical role to achieve the giant piezoelectric response. An intrinsic relationship between the crystal structure and piezoelectric performance in perovskite ferroelectrics has been established: A strong tendency of electric-field-driven polarization rotation generates peak piezoelectric performance and vice versa. Furthermore, the monoclinic M_{A} structure is the key feature to superior piezoelectric properties as compared to other structures such as monoclinic M_{B}, rhombohedral, and tetragonal. A high piezoelectric response originates from intrinsic lattice strain, but little from extrinsic domain switching. The present results will facilitate designing high-performance perovskite piezoelectric materials by enhancing the intrinsic lattice contribution with easy and continuous polarization rotation.

Finite element modeling of piezoelectric elements with complex electrode configuration

International Nuclear Information System (INIS)

Paradies, R; Schläpfer, B

2009-01-01

It is well known that the material properties of piezoelectric materials strongly depend on the state of polarization of the individual element. While an unpolarized material exhibits mechanically isotropic material properties in the absence of global piezoelectric capabilities, the piezoelectric material properties become transversally isotropic with respect to the polarization direction after polarization. Therefore, for evaluating piezoelectric elements the material properties, including the coupling between the mechanical and the electromechanical behavior, should be addressed correctly. This is of special importance for the micromechanical description of piezoelectric elements with interdigitated electrodes (IDEs). The best known representatives of this group are active fiber composites (AFCs), macro fiber composites (MFCs) and the radial field diaphragm (RFD), respectively. While the material properties are available for a piezoelectric wafer with a homogeneous polarization perpendicular to its plane as postulated in the so-called uniform field model (UFM), the same information is missing for piezoelectric elements with more complex electrode configurations like the above-mentioned ones with IDEs. This is due to the inhomogeneous field distribution which does not automatically allow for the correct assignment of the material, i.e. orientation and property. A variation of the material orientation as well as the material properties can be accomplished by including the polarization process of the piezoelectric transducer in the finite element (FE) simulation prior to the actual load case to be investigated. A corresponding procedure is presented which automatically assigns the piezoelectric material properties, e.g. elasticity matrix, permittivity, and charge vector, for finite element models (FEMs) describing piezoelectric transducers according to the electric field distribution (field orientation and strength) in the structure. A corresponding code has been

A review of vibration-based MEMS piezoelectric energy harvesters

Energy Technology Data Exchange (ETDEWEB)

Saadon, Salem; Sidek, Othman [Collaborative Microelectronic Design Excellence Center (CEDEC), School of Electrical and Electronic Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)

2011-01-15

The simplicity associated with the piezoelectric micro-generators makes it very attractive for MEMS applications, especially for remote systems. In this paper we reviewed the work carried out by researchers during the last three years. The improvements in experimental results obtained in the vibration-based MEMS piezoelectric energy harvesters show very good scope for MEMS piezoelectric harvesters in the field of power MEMS in the near future. (author)

Flexible Piezoelectric Energy Harvesting from Mouse Click Motions

Directory of Open Access Journals (Sweden)

Youngsu Cha

2016-07-01

Full Text Available In this paper, we study energy harvesting from the mouse click motions of a robot finger and a human index finger using a piezoelectric material. The feasibility of energy harvesting from mouse click motions is experimentally and theoretically assessed. The fingers wear a glove with a pocket for including the piezoelectric material. We model the energy harvesting system through the inverse kinematic framework of parallel joints in a finger and the electromechanical coupling equations of the piezoelectric material. The model is validated through energy harvesting experiments in the robot and human fingers with the systematically varying load resistance. We find that energy harvesting is maximized at the matched load resistance to the impedance of the piezoelectric material, and the harvested energy level is tens of nJ.

Electrostatic potential in a bent piezoelectric nanowire with consideration of size-dependent piezoelectricity and semiconducting characterization

Science.gov (United States)

Wang, K. F.; Wang, B. L.

2018-06-01

Determining the electric potential in a bent piezoelectric nanowire (NW) is a fundamental issue of nanogenerators and nanopiezotronics. The combined influence of the flexoelectric effect, the semiconducting performance and the angle of atomic force microscope (AFM) tip has never been studied previously and will be investigated in this paper. The exact solution for the electric potential of a bent piezoelectric semiconductor NW is derived. The electric potential of the present model with consideration of flexoelectric effect varies along the length of the NW and is different from that of the classical piezoelectric model. Flexoelectric effect enhances but the semiconducting performance reduces the electric potential of the NW. In addition, it is found that if the angle of the AFM tip reaches 30°, the error of the electric potential obtained from the model ignored the effect of the angle of the AFM tip is almost 16%, which is unacceptable.

Force Measurement with a Piezoelectric Cantilever in a Scanning Force Microscope

OpenAIRE

Tansock, J.; Williams, C. C.

1992-01-01

Detection of surface forces between a tip and sample has been demonstrated with a piezoelectric cantilever in a scanning force microscope (SFM). The use of piezoelectric force sensing is particularly advantageous in semiconductor applications where stray light from conventional optical force-sensing methods can significantly modify the local carrier density. Additionally, the piezoelectric sensors are simple, provide good sensitivity to force, and can be batch fabricated. Our piezoelectric fo...

Fabrication of polypeptide-based piezoelectric composite polymer film

International Nuclear Information System (INIS)

Farrar, Dawnielle; West, James E.; Busch-Vishniac, Ilene J.; Yu, Seungju M.

2008-01-01

A new class of molecular composite piezoelectric material was produced by simultaneous poling and curing of a homogeneous solution comprising poly(γ-benzyl α,L-glutamate) and methylmethacrylate via corona discharge methods. This film exhibited high piezoelectricity (d 33 = 23 pC N -1 ), and its mechanical characteristics (modulus = 450 MPa) were similar to those of low molecular weight poly(methylmethacrylate). As it is produced via solution-based fabrication processes, the composite film is conducive to miniaturization for small sensors with integrated electronics, and could also potentially be used in piezoelectric coating applications

Flow energy piezoelectric bimorph nozzle harvester

Science.gov (United States)

Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary

2014-04-01

There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

High-frequency performance for a spiral-shaped piezoelectric bimorph

Science.gov (United States)

Huang, Fang Sheng; Feng, Zhi Hua; Ma, Yu Ting; Pan, Qiao Sheng; Zhang, Lian Sheng; Liu, Yong Bin; He, Liang Guo

2018-04-01

Piezoelectric cantilever is suitable as an actuator for micro-flapping-wing aircraft. Higher resonant frequency brings about stronger flight energy, and the flight amplitude can be compensated by displacement-amplification mechanism, such as lever. To obtain a higher resonant frequency, straight piezoelectric bimorph was rolled into spiral-shaped piezoelectric bimorph with identical effective length in this study, which is verified in COMSOL simulations. Simulation results show that compared with the straight piezoelectric bimorph, the spiral-shaped piezoelectric bimorph with two turns has higher inherent frequencies (from 204.79 Hz to 504.84 Hz in terms of axial oscillation mode, and from 319.77 Hz to 704.48 Hz in terms of tangential torsional mode). The spiral-shaped piezoelectric bimorph is fabricated by a precise laser cutting process and consists of two turns with effective length of 60 mm, width of 2.5 mm, and thickness of 1.6 mm, respectively. With the excitation voltage of 100 Vpp applying an electric field across the thickness of the bimorph, the tip displacement of the actuator in the axial oscillation and tangential torsional modes are 85 μm and 15 μm, respectively.

1D Piezoelectric Material Based Nanogenerators: Methods, Materials and Property Optimization.

Science.gov (United States)

Li, Xing; Sun, Mei; Wei, Xianlong; Shan, Chongxin; Chen, Qing

2018-03-23

Due to the enhanced piezoelectric properties, excellent mechanical properties and tunable electric properties, one-dimensional (1D) piezoelectric materials have shown their promising applications in nanogenerators (NG), sensors, actuators, electronic devices etc. To present a clear view about 1D piezoelectric materials, this review mainly focuses on the characterization and optimization of the piezoelectric properties of 1D nanomaterials, including semiconducting nanowires (NWs) with wurtzite and/or zinc blend phases, perovskite NWs and 1D polymers. Specifically, the piezoelectric coefficients, performance of single NW-based NG and structure-dependent electromechanical properties of 1D nanostructured materials can be respectively investigated through piezoresponse force microscopy, atomic force microscopy and the in-situ scanning/transmission electron microcopy. Along with the introduction of the mechanism and piezoelectric properties of 1D semiconductor, perovskite materials and polymers, their performance improvement strategies are summarized from the view of microstructures, including size-effect, crystal structure, orientation and defects. Finally, the extension of 1D piezoelectric materials in field effect transistors and optoelectronic devices are simply introduced.

Nonlinear free vibration of piezoelectric nanobeams incorporating surface effects

International Nuclear Information System (INIS)

Hosseini-Hashemi, Shahrokh; Nahas, Iman; Fakher, Mahmood; Nazemnezhad, Reza

2014-01-01

In this study, the nonlinear free vibration of piezoelectric nanobeams incorporating surface effects (surface elasticity, surface tension, and surface density) is studied. The governing equation of the piezoelectric nanobeam is derived within the framework of Euler–Bernoulli beam theory with the von Kármán geometric nonlinearity. In order to satisfy the balance conditions between the nanobeam bulk and its surfaces, the component of the bulk stress, σ zz , is assumed to vary linearly through the nanobeam thickness. An exact solution is obtained for the natural frequencies of a simply supported piezoelectric nanobeam in terms of the Jacobi elliptic functions using the free vibration mode shape of the corresponding linear problem. Then, the influences of the surface effects and the piezoelectric field on the nonlinear free vibration of nanobeams made of aluminum and silicon with positive and negative surface elasticity, respectively, have been studied for various properties of the piezoelectric field, various nanobeam sizes and amplitude ratios. It is observed that if the Young’s modulus of a nanobeam is lower, the effect of the piezoelectric field on the frequency ratios (FRs) of the nanobeam will be greater. In addition, it is seen that by increasing the nanobeam length so that the nanobeam cross section is set to be constant, the surface effects and the piezoelectric field with negative voltage values increases the FRs, whereas it is the other way around when the nanobeam cross section is assumed to be dependent on the length of the nanobeam. (paper)

Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems

Science.gov (United States)

Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing

2011-01-01

The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric

Mechanical and Vibration Testing of Carbon Fiber Composite Material with Embedded Piezoelectric Sensors

Science.gov (United States)

Duffy, Kirsten P.; Lerch, Bradley A.; Wilmoth, Nathan G.; Kray, Nicholas; Gemeinhardt, Gregory

2012-01-01

Piezoelectric materials have been proposed as a means of decreasing turbomachinery blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite (PMFC) blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. Before implementation of a piezoelectric element within a PMFC blade, the effect on PMFC mechanical properties needs to be understood. This study attempts to determine how the inclusion of a packaged piezoelectric patch affects the material properties of the PMFC. Composite specimens with embedded piezoelectric patches were tested in four-point bending, short beam shear, and flatwise tension configurations. Results show that the embedded piezoelectric material does decrease the strength of the composite material, especially in flatwise tension, attributable to failure at the interface or within the piezoelectric element itself. In addition, the sensing properties of the post-cured embedded piezoelectric materials were tested, and performed as expected. The piezoelectric materials include a non-flexible patch incorporating solid piezoceramic material, and two flexible patch types incorporating piezoelectric fibers. The piezoceramic material used in these patches was Navy Type-II PZT.

Enhanced Piezoelectric Response of AlN via CrN Alloying

Energy Technology Data Exchange (ETDEWEB)

Manna, Sukriti; Talley, Kevin R.; Gorai, Prashun; Mangum, John; Zakutayev, Andriy; Brennecka, Geoff L.; Stevanović, Vladan; Ciobanu, Cristian V.

2018-03-01

Since AlN has emerged as an important piezoelectric material for a wide variety of applications, efforts have been made to increase its piezoelectric response via alloying with transition metals that can substitute for Al in the wurtzite lattice. We report on density functional theory calculations of structure and properties of the CrxAl1-xN system for Cr concentrations ranging from zero to beyond the wurtzite-rocksalt transition point. By studying the different contributions to the longitudinal piezoelectric coefficient, we propose that the physical origin of the enhanced piezoelectricity in CrxAl1-xN alloys is the increase of the internal parameter u of the wurtzite structure upon substitution of Al with the larger Cr ions. Among a set of wurtzite-structured materials, we find that CrxAl1-xN has the most sensitive piezoelectric coefficient with respect to alloying concentration. Based on these results, we propose that CrxAl1-xN is a viable piezoelectric material whose properties can be tuned via Cr composition. We support this proposal by combinatorial synthesis experiments, which show that Cr can be incorporated in the AlN lattice up to 30% before a detectable transition to rocksalt occurs. At this Cr content, the piezoelectric modulus d33 is approximately 4 times larger than that of pure AlN. This finding, combined with the relative ease of synthesis under nonequilibrium conditions, may position CrxAl1-xN as a prime piezoelectric material for applications such as resonators and acoustic wave generators.

Enhanced Piezoelectric Response of AlN via CrN Alloying

Science.gov (United States)

Manna, Sukriti; Talley, Kevin R.; Gorai, Prashun; Mangum, John; Zakutayev, Andriy; Brennecka, Geoff L.; Stevanović, Vladan; Ciobanu, Cristian V.

2018-03-01

Since AlN has emerged as an important piezoelectric material for a wide variety of applications, efforts have been made to increase its piezoelectric response via alloying with transition metals that can substitute for Al in the wurtzite lattice. We report on density functional theory calculations of structure and properties of the Crx Al1 -x N system for Cr concentrations ranging from zero to beyond the wurtzite-rocksalt transition point. By studying the different contributions to the longitudinal piezoelectric coefficient, we propose that the physical origin of the enhanced piezoelectricity in Crx Al1 -x N alloys is the increase of the internal parameter u of the wurtzite structure upon substitution of Al with the larger Cr ions. Among a set of wurtzite-structured materials, we find that Crx Al1 -x N has the most sensitive piezoelectric coefficient with respect to alloying concentration. Based on these results, we propose that Crx Al1 -x N is a viable piezoelectric material whose properties can be tuned via Cr composition. We support this proposal by combinatorial synthesis experiments, which show that Cr can be incorporated in the AlN lattice up to 30% before a detectable transition to rocksalt occurs. At this Cr content, the piezoelectric modulus d33 is approximately 4 times larger than that of pure AlN. This finding, combined with the relative ease of synthesis under nonequilibrium conditions, may position Crx Al1 -x N as a prime piezoelectric material for applications such as resonators and acoustic wave generators.

Evaluation of electromechanical coupling parameters of piezoelectric materials by using piezoelectric cantilever with coplanar electrode structure in quasi-stasis.

Science.gov (United States)

Zheng, Xuejun; Zhu, Yuankun; Liu, Xun; Liu, Jing; Zhang, Yong; Chen, Jianguo

2014-02-01

Based on Timoshenko beam theory, a principle model is proposed to establish the relationship between electric charge and excitation acceleration, and in quasi-stasis we apply the direct piezoelectric effect of multilayer cantilever with coplanar electrode structure to evaluate the piezoelectric strain coefficient d15 and electromechanical coupling coefficient k15. They are measured as 678 pC/N and 0.74 for the commercial piezoelectric ceramic lead zirconate titanate (PZT-51) bulk specimen and 656 pC/N and 0.63 for the lead magnesium niobate (PMN) bulk specimen, and they are in agreement with the calibration and simulation values. The maximum of relative errors is less than 4.2%, so the proposed method is reliable and convenient.

Study the Postbuckling of Hexagonal Piezoelectric Nanowires with Surface Effect

Directory of Open Access Journals (Sweden)

O. Rahmani

2014-04-01

Full Text Available Piezoelectric nanobeams having circular, rectangular and hexagonal cross-sections are synthesized and used in various Nano structures; however, piezoelectric nanobeams with hexagonal cross-sections have not been studied in detail. In particular, the physical mechanisms of the surface effect and the role of surface stress, surface elasticity and surface piezoelectricity have not been discussed thoroughly. The present study investigated post-buckling behavior of piezoelectric nanobeams by examining surface effects. The energy method was applied to post-buckling of hexagonal nanobeams and the critical buckling voltage and amplitude are derived analytically from bulk and surface material properties and geometric factors.

Electrostatic potential in a bent piezoelectric nanowire with consideration of size-dependent piezoelectricity and semiconducting characterization.

Science.gov (United States)

Wang, Kaifa; Wang, Baolin

2018-03-26

Determining the electric potential in a bent piezoelectric nanowire (NW) is a fundamental issue of nanogenerators and nanopiezotronics. The combined influence of the flexoelectric effect, the semiconducting performance and the angle of atomic force microscope (AFM) tip has never been studied previously and will be investigated in this paper. The exact solution for the electric potential of a bent piezoelectric semiconductor NW is derived. The electric potential of the present model with consideration of flexoelectric effect varies along the length of the NW and is different from that of the classical piezoelectric model. Flexoelectric effect enhances but the semiconducting performance reduces the electric potential of the NW. In addition, it is found that if the angle of the AFM tip reaches 30 degrees, the error of the electric potential obtained from the model ignored the effect of the angle of the AFM tip is almost 16%, which is unacceptable. © 2018 IOP Publishing Ltd.

Inductorless bi-directional piezoelectric transformerbased converters: Design and control considerations

DEFF Research Database (Denmark)

Ekhtiari, Marzieh

electromagnetic interference, compact, light, high power density and low cost allows for promising market in the near future. The piezoelectric transformer technology has the potential to be used in various applications e.g. motor driver for magnetic resonance imaging scans, the electronic ballast for fluorescent...... of inductorless switch-mode power supplies employing piezoelectric transformers. The main focus of this research is on the functionality of the piezoelectric transformer-based power converters and applying control techniques in order to exploit advantages of the piezoelectric transformers for the power converters...... detector applicable for switch-mode power supplies, optimum phase detector, bi-directional wide bandwidth current sensor and a comprehensive analysis of piezoelectric transformer-based switch-mode power supplies for zero-voltage switching, where all finalized with improving the unidirectional topology...

Quantitative Examination of Piezoelectric/Seismoelectric Anomalies from Near-Surface Targets

Directory of Open Access Journals (Sweden)

Lev Eppelbaum

2017-09-01

Full Text Available The piezoelectric and seismo-electrokinetic phenomena are manifested by electrical and electromagnetic processes that occur in rocks under the influence of elastic oscillations triggered by shots or mechanical impacts. Differences in piezoelectric properties between the studied targets and host media determine the possibilities of the piezoelectric/seismoelectric method application. Over a long time, an interpretation of obtained data is carried out by the use of methods developed in seismic prospecting. Examination of nature of piezoelectric/seismoelectric anomalies observed in subsurface indicates that these may be related (mainly to electric potential field. In this paper, it is shown that quantitative analysis of piezoelectric/seismoelectric anomalies may be performed by the advanced and reliable methodologies developed in magnetic prospecting. Some examples from mining geophysics (Russia and ancient metallurgical site (Israel confirm applicability of the suggested approach.

Design of a piezoelectric shaker for centrifuge testing

Science.gov (United States)

Canclini, J. G.; Henderson, J. M.

1979-01-01

The design of a prototype piezoelectric shaker and its development to date is described. Although certain design problems remain to be solved, the piezoelectric system shows promise for adaptation to a larger payload system, such as the proposed geotechnical centrifuge at the Ames Research Center.

Analysis of Piezoelectric Solids using Finite Element Method

Science.gov (United States)

Aslam, Mohammed; Nagarajan, Praveen; Remanan, Mini

2018-03-01

Piezoelectric materials are extensively used in smart structures as sensors and actuators. In this paper, static analysis of three piezoelectric solids is done using general-purpose finite element software, Abaqus. The simulation results from Abaqus are compared with the results obtained using numerical methods like Boundary Element Method (BEM) and meshless point collocation method (PCM). The BEM and PCM are cumbersome for complex shape and complicated boundary conditions. This paper shows that the software Abaqus can be used to solve the governing equations of piezoelectric solids in a much simpler and faster way than the BEM and PCM.

Flow Energy Piezoelectric Bimorph Nozzle Harvester

Science.gov (United States)

Sherrit, Stewart (Inventor); Walkemeyer, Phillip E. (Inventor); Hall, Jeffrey L. (Inventor); Lee, Hyeong Jae (Inventor); Colonius, Tim (Inventor); Tosi, Phillipe (Inventor); Kim, Namhyo (Inventor); Sun, Kai (Inventor); Corbett, Thomas Gary (Inventor); Arrazola, Alvaro Jose (Inventor)

2016-01-01

A flow energy harvesting device having a harvester pipe includes a flow inlet that receives flow from a primary pipe, a flow outlet that returns the flow into the primary pipe, and a flow diverter within the harvester pipe having an inlet section coupled to the flow inlet, a flow constriction section coupled to the inlet section and positioned at a midpoint of the harvester pipe and having a spline shape with a substantially reduced flow opening size at a constriction point along the spline shape, and an outlet section coupled to the constriction section. The harvester pipe may further include a piezoelectric structure extending from the inlet section through the constriction section and point such that the fluid flow past the constriction point results in oscillatory pressure amplitude inducing vibrations in the piezoelectric structure sufficient to cause a direct piezoelectric effect and to generate electrical power for harvesting.

Large In-Plane and Vertical Piezoelectricity in Janus Transition Metal Dichalchogenides.

Science.gov (United States)

Dong, Liang; Lou, Jun; Shenoy, Vivek B

2017-08-22

Piezoelectricity in 2D van der Waals materials has received considerable interest because of potential applications in nanoscale energy harvesting, sensors, and actuators. However, in all the systems studied to date, strain and electric polarization are confined to the basal plane, limiting the operation of piezoelectric devices. In this paper, based on ab initio calculations, we report a 2D materials system, namely, the recently synthesized Janus MXY (M = Mo or W, X/Y = S, Se, or Te) monolayer and multilayer structures, with large out-of-plane piezoelectric polarization. For MXY monolayers, both strong in-plane and much weaker out-of-plane piezoelectric polarizations can be induced by a uniaxial strain in the basal plane. For multilayer MXY, we obtain a very strong out-of-plane piezoelectric polarization when strained transverse to the basal plane, regardless of the stacking sequence. The out-of-plane piezoelectric coefficient d 33 is found to be strongest in multilayer MoSTe (5.7-13.5 pm/V depending on the stacking sequence), which is larger than that of the commonly used 3D piezoelectric material AlN (d 33 = 5.6 pm/V); d 33 in other multilayer MXY structures are a bit smaller, but still comparable. Our study reveals the potential for utilizing piezoelectric 2D materials and their van der Waals multilayers in device applications.

In Situ Poling and Imidization of Amorphous Piezoelectric Polyimides

Science.gov (United States)

Park, Cheol; Ounaies, Zoubeida; Wise, Kristopher E.; Harrison, Joycelyn S.; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

An amorphous piezoelectric polyimide containing polar functional groups has been developed using a combination of experimental and molecular modeling for potential use in high temperature applications. This amorphous polyimide, (Beta-CN)APB/ODPA, has exhibited good thermal stability and piezoelectric response at temperatures up to 150C. Density functional calculations predicted that a partially cured amic acid (open imide ring) possesses a dipole moment four times larger than the fully imidized closed ring. In situ poling and imidization of the partially cured (Beta-CN)APB/ODPA, was studied in an attempt to maximize the degree of dipolar orientation and the resultant piezoelectric response. A positive corona poling was used to minimize localized arcing during poling and to allow use of higher poling fields without dielectric breakdown. The dielectric relaxation strength, remanent polarization, and piezoelectric response were evaluated as a function of the poling profile. The partially cured, corona poled polymers exhibited higher dielectric relaxation strength (delta varepsilon), remanent polarization (Pr) and piezoelectric strain coefficient (d33) than the fully cured, conventionally poled ones.

Proposition for sensorless self-excitation by a piezoelectric device

Science.gov (United States)

Tanaka, Y.; Kokubun, Y.; Yabuno, H.

2018-04-01

In this paper, we propose a method to realize self-excitation in an oscillator actuated by a piezoelectric device without a sensor. In general, the positive feedback associated with the oscillator velocity causes the self-excitation. Instead of measuring the velocity with a sensor, we utilize the electro-mechanical coupling effect in the oscillator and piezoelectric device. We drive the piezoelectric device with a current proportional to the linear combination of the voltage across the terminals of the piezoelectric device and its differential voltage signal. Then, the oscillator with the piezoelectric device behaves like a third-order system, which has three eigenvalues. The self-excitation can be realized because appropriate feedback gains can set two of the eigenvalues to be conjugate complex roots with a positive real part and the other eigenvalue to be a negative real root. To confirm the validity of the proposed method, we experimentally demonstrated the sensorless self-excitation and, as an application example, carried out mass sensing in a sensorless self-excited macrocantilever.

Theoretical and experimental investigations of thickness- stretch modes in 1-3 piezoelectric composites

International Nuclear Information System (INIS)

Yang, Z T; Zeng, D P; He, M; Wang, H

2015-01-01

Bulk piezoelectric ceramics operating in thickness-stretch (TSt) modes have been widely used in acoustic-related devices. However, the fundamental TSt waves are always coupled with other modes, and the occurrence of these spurious modes in bulk piezoelectric ceramics affects its performance. To suppress the spurious modes, 1-3 piezoelectric composites are promising candidates. However, theoretical modeling of multiphase ceramic composite objects is very complex. In this study, a 1-3 piezoelectric composite sample and a bulk piezoelectric sample are fabricated. The electrical impedance of these two samples are compared. A simple analytical TSt vibration mode from the three dimensional equations of linear piezoelectricity is used to model the performance of 1-3 piezoelectric composites. The theoretical results agree well with the experimental results. (paper)

Special topics in the theory of piezoelectricity

CERN Document Server

Yang, Jiashi

2009-01-01

Piezoelectricity has been a steadily growing field, with recent advances made by researchers from applied physics, acoustics, materials science, and engineering. This collective work presents a comprehensive treatment of selected advanced topics in the subject. The book is written for an intermediate graduate level and is intended for researchers, mechanical engineers, and applied mathematicians interested in the advances and new applications in piezoelectricity.

Magnetostrictive-piezoelectric magnetic sensor with current excitation

International Nuclear Information System (INIS)

Prieto, J.L.; Aroca, C.; Lopez, E.; Sanchez, M.C.; Sanchez, P.

2000-01-01

A new working configuration for magnetostrictive-piezoelectric magnetic sensors is presented. In this configuration, the excitation is caused using an electrical current flowing through the ferromagnetic sample and the induced signal is sensed in the piezoelectric support as an electrical voltage. This new idea allows a magnetic field detection without any coil and opens a possibility for a future miniaturisation of the sensor

Vibration of Piezoelectric Nanowires Including Surface Effects

Directory of Open Access Journals (Sweden)

R. Ansari

2014-04-01

Full Text Available In this paper, surface and piezoelectric effects on the vibration behavior of nanowires (NWs are investigated by using a Timoshenko beam model. The electric field equations and the governing equations of motion for the piezoelectric NWs are derived with the consideration of surface effects. By the exact solution of the governing equations, an expression for the natural frequencies of NWs with simply-supported boundary conditions is obtained. The effects of piezoelectricity and surface effects on the vibrational behavior of Timoshenko NWs are graphically illustrated. A comparison is also made between the predictions of Timoshenko beam model and those of its Euler-Bernoulli counterpart. Additionally, the present results are validated through comparison with the available data in the literature.

Nonlinear piezoelectricity in PZT ceramics for generating ultrasonic phase conjugate waves

Science.gov (United States)

Yamamoto; Kokubo; Sakai; Takagi

2000-03-01

We have succeeded in the generation of acoustic phase conjugate waves with nonlinear PZT piezoelectric ceramics and applied them to ultrasonic imaging systems. Our aim is to make a phase conjugator with 100% efficiency. For this purpose, it is important to clarify the mechanism of acoustic phase conjugation through nonlinear piezoelectricity. The process is explained by the parametric interaction via the third-order nonlinear piezoelectricity between the incident acoustic wave at angular frequency omega and the pump electric field at 2 omega. We solved the coupling equations including the third-ordered nonlinear piezoelectricity and theoretically derived the amplitude efficiency of the acoustic phase conjugation. We compared the efficiencies between the theoretical and experimental values for PZT ceramics with eight different compositions. Pb[(Zn1/3Nb2/3)(1 - x)Tix]O3 (X = 0.09, PZNT91/9) piezoelectric single crystals have been investigated for high-performance ultrasonic transducer application, because these have large piezoelectric constants, high electrical-mechanical coupling factors and high dielectric constants. We found that they have third-order nonlinear piezoelectric constants much larger than PZT and are hopeful that the material as a phase conjugator has over 100% efficiency.

Simulation and parallel connection of step-down piezoelectric transformers

International Nuclear Information System (INIS)

Thang, Vo Viet; Kim, In Sung; Jeong, Soon Jong; Kim, Min Soo; Song, Jae Sung

2012-01-01

Piezoelectric transformers have been used widely in electronic circuits due to advantages such as high efficiency, miniaturization and no flammability; however the output power has been limited. For overcoming this drawback, some research has recently been focused on connections between piezoelectric transformers. Based on these operations, the output power has been improved compared to the single operation. Parallel operation of step-down piezoelectric transformers is presented in this paper. An important factor affecting the parallel operation of piezoelectric transformer was the resonance frequency, and a small difference in resonance frequencies was obtained with transformers having the same dimensions and fabricating processes. The piezoelectric transformers were found to operate in first radial mode at a frequency of 68 kHz. An equivalent circuit was used to investigate parallel driving of piezoelectric transformers and then to compare the result with experimental observations. The electrical characteristics, including the output voltage, output power and efficient were measured at a matching resistive load. Effects of frequency on the step-down ratio and of the input voltage on the power properties in the simulation were similar to the experimental results. The output power of the parallel operation was 35 W at a load of 50 Ω and an input voltage of 100 V; the temperature rise was 30 .deg. C and the efficiency was 88%.

Piezoelectric stack actuator parameter extraction with hysteresis compensation

DEFF Research Database (Denmark)

Zsurzsan, Tiberiu-Gabriel; Mangeot, Charles; Andersen, Michael A. E.

2014-01-01

The Piezoelectric Actuator Drive (PAD) is a type of rotary motor that transforms the linear motion of piezoelectric stack actuators into a precise rotational motion. The very high stiffness of the actuators employed make this type of motor suited for open-loop control, but the inherent hysteresis...

Hydroelectromechanical modelling of a piezoelectric wave energy converter

Science.gov (United States)

Renzi, E.

2016-11-01

We investigate the hydroelectromechanical-coupled dynamics of a piezoelectric wave energy converter. The converter is made of a flexible bimorph plate, clamped at its ends and forced to motion by incident ocean surface waves. The piezoceramic layers are connected in series and transform the elastic motion of the plate into useful electricity by means of the piezoelectric effect. By using a distributed-parameter analytical approach, we couple the linear piezoelectric constitutive equations for the plate with the potential-flow equations for the surface water waves. The resulting system of governing partial differential equations yields a new hydroelectromechanical dispersion relation, whose complex roots are determined with a numerical approach. The effect of the piezoelectric coupling in the hydroelastic domain generates a system of short- and long-crested weakly damped progressive waves travelling along the plate. We show that the short-crested flexural wave component gives a dominant contribution to the generated power. We determine the hydroelectromechanical resonant periods of the device, at which the power output is significant.

Fundamentals of piezoelectric sensorics mechanical, dielectric, and thermodynamical properties of piezoelectric materials

CERN Document Server

Tichý, Jan; Kittinger, Erwin; Prívratská, Jana; Privatska, Jana; Janovec, Vaclav

2010-01-01

This book presents the physics of piezoleletric sensors in a straight-forward and easy-to-grasp way, from the fundamentals of phenomenological crystal physics through more complex concepts, to its explanation of several important piezoelectric materials.

Multidirection Piezoelectricity in Mono- and Multilayered Hexagonal α-In2Se3

KAUST Repository

Xue, Fei

2018-04-25

Piezoelectric materials have been widely used for sensors, actuators, electronics, and energy conversion. Two-dimensional (2D) ultrathin semiconductors, such as monolayer h-BN and MoS2 with their atom-level geometry, are currently emerging as new and attractive members of the piezoelectric family. However, their piezoelectric polarization is commonly limited to the in-plane direction of odd-number ultrathin layers, largely restricting their application in integrated nanoelectromechanical systems. Recently, theoretical calculations have predicted the existence of out-of-plane and in-plane piezoelectricity in monolayer α-In2Se3. Here, we experimentally report the coexistence of out-of-plane and in-plane piezoelectricity in monolayer to bulk α-In2Se3, attributed to their noncentrosymmetry originating from the hexagonal stacking. Specifically, the corresponding d33 piezoelectric coefficient of α-In2Se3 increases from 0.34 pm/V (monolayer) to 5.6 pm/V (bulk) without any odd-even effect. In addition, we also demonstrate a type of α-In2Se3-based flexible piezoelectric nanogenerator as an energy-harvesting cell and electronic skin. The out-of-plane and in-plane piezoelectricity in α-In2Se3 flakes offers an opportunity to enable both directional and nondirectional piezoelectric devices to be applicable for self-powered systems and adaptive and strain-tunable electronics/optoelectronics.

Relevance of collagen piezoelectricity to "Wolff's Law": a critical review.

Science.gov (United States)

Ahn, Andrew C; Grodzinsky, Alan J

2009-09-01

According to "Wolff's Law", bone is deposited and reinforced at areas of greatest stress. From a clinical perspective, this "law" is supported by the strong association between bone density and physical activity. From a mechanistic standpoint, however, the law presents a challenge to scientists seeking to understand how osteocytes and osteoblasts sense the mechanical load. In the 1960s, collagen piezoelectricity was invoked as a potential mechanism by which osteocytes could detect areas of greater stress but piezoelectricity diminished in importance as more compelling mechanisms, such as streaming potential, were identified. In addition, accumulating evidence for the role of fluid-related shear stress in osteocyte's mechanosensory function has made piezoelectricity seemingly more obsolete in bone physiology. This review critically evaluates the role of collagen piezoelectricity (if any) in Wolff's Law--specifically, the evidence regarding its involvement in strain-generated potentials, existing alternate mechanisms, the present understanding of bone mechanosensation, and whether piezoelectricity serves an influential role within the context of this newly proposed mechanism. In addition to reviewing the literature, this review generates several hypotheses and proposes future research to fully address the relevance of piezoelectricity in bone physiology.

Piezoelectric antibacterial fabric comprised of poly(l-lactic acid) yarn

Science.gov (United States)

Ando, Masamichi; Takeshima, Satoshi; Ishiura, Yutaka; Ando, Kanako; Onishi, Osamu

2017-10-01

A lactic acid monomer has an asymmetric carbon in the molecule, so there are optical isomer l- and d-type. The most widely used poly(lactic acid) (PLA) for commercial applications is poly(l-lactic acid) (PLLA). PLLA is the polymerization product of l-lactide. Certain treatments of PLLA can yield a film that exhibits shear piezoelectricity. Thus, piezoelectric PLLA fiber can be generated by micro slitting piezoelectric PLLA films or by a melt spinning method. We prepared left-handed helical multi fiber yarn (S-yarn) and right-handed helical yarn (Z-yarn) using piezoelectric PLLA fiber. PLLA exhibited shear mode piezoelectricity, causing the electric polarity of the yarn surface to be reversed on the S-yarn and Z-yarn when tension was applied. An SZ-yarn was produced by combining the S-yarn and Z-yarn, and fabric was prepared using the SZ-yarn. This study demonstrated that the fabric has a strong antibacterial effect, which is thought to be due to the strong electric field between the yarns. The field is generated by a piezoelectric effect when the fabric was extended and contracted.

Energy harvesting performance of piezoelectric ceramic and polymer nanowires.

Science.gov (United States)

Crossley, Sam; Kar-Narayan, Sohini

2015-08-28

Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in certain cases, to have similar energy conversion efficiencies, ceramics are more promising in strain-driven NGs while polymers are more promising for stress-driven NGs

Outer hair cell piezoelectricity: frequency response enhancement and resonance behavior.

Science.gov (United States)

Weitzel, Erik K; Tasker, Ron; Brownell, William E

2003-09-01

Stretching or compressing an outer hair cell alters its membrane potential and, conversely, changing the electrical potential alters its length. This bi-directional energy conversion takes place in the cell's lateral wall and resembles the direct and converse piezoelectric effects both qualitatively and quantitatively. A piezoelectric model of the lateral wall has been developed that is based on the electrical and material parameters of the lateral wall. An equivalent circuit for the outer hair cell that includes piezoelectricity shows a greater admittance at high frequencies than one containing only membrane resistance and capacitance. The model also predicts resonance at ultrasonic frequencies that is inversely proportional to cell length. These features suggest all mammals use outer hair cell piezoelectricity to support the high-frequency receptor potentials that drive electromotility. It is also possible that members of some mammalian orders use outer hair cell piezoelectric resonance in detecting species-specific vocalizations.

Piezoelectric materials mimic the function of the cochlear sensory epithelium.

Science.gov (United States)

Inaoka, Takatoshi; Shintaku, Hirofumi; Nakagawa, Takayuki; Kawano, Satoyuki; Ogita, Hideaki; Sakamoto, Tatsunori; Hamanishi, Shinji; Wada, Hiroshi; Ito, Juichi

2011-11-08

Cochlear hair cells convert sound vibration into electrical potential, and loss of these cells diminishes auditory function. In response to mechanical stimuli, piezoelectric materials generate electricity, suggesting that they could be used in place of hair cells to create an artificial cochlear epithelium. Here, we report that a piezoelectric membrane generated electrical potentials in response to sound stimuli that were able to induce auditory brainstem responses in deafened guinea pigs, indicating its capacity to mimic basilar membrane function. In addition, sound stimuli were transmitted through the external auditory canal to a piezoelectric membrane implanted in the cochlea, inducing it to vibrate. The application of sound to the middle ear ossicle induced voltage output from the implanted piezoelectric membrane. These findings establish the fundamental principles for the development of hearing devices using piezoelectric materials, although there are many problems to be overcome before practical application.

A study of principle and testing of piezoelectric transformer

International Nuclear Information System (INIS)

Liu Weiyue; Wang Yanfang; Huang Yihua; Shi Jun

2002-01-01

The operating principle and structure of a kind of piezoelectric transformer which can be used in a particle accelerator are investigated. The properties of piezoelectric transformer are tested through equivalent circuit combined with experiment

Development of a Piezoelectric Rotary Hammer Drill

Science.gov (United States)

Domm, Lukas N.

2011-01-01

The Piezoelectric Rotary Hammer Drill is designed to core through rock using a combination of rotation and high frequency hammering powered by a single piezoelectric actuator. It is designed as a low axial preload, low mass, and low power device for sample acquisition on future missions to extraterrestrial bodies. The purpose of this internship is to develop and test a prototype of the Piezoelectric Rotary Hammer Drill in order to verify the use of a horn with helical or angled cuts as a hammering and torque inducing mechanism. Through an iterative design process using models in ANSYS Finite Element software and a Mason's Equivalent Circuit model in MATLAB, a horn design was chosen for fabrication based on the predicted horn tip motion, electromechanical coupling, and neutral plane location. The design was then machined and a test bed assembled. The completed prototype has proven that a single piezoelectric actuator can be used to produce both rotation and hammering in a drill string through the use of a torque inducing horn. Final data results include bit rotation produced versus input power, and best drilling rate achieved with the prototype.

Novel Mechano-Luminescent Sensors Based on Piezoelectric/Electroluminescent Composites

Directory of Open Access Journals (Sweden)

Yunzhang Fang

2011-04-01

Full Text Available A high-sensitivity mechano-luminescent sensor was fabricated on the basis of piezoelectric/electroluminescent composites. The working principle of this mechano-luminescent sensor was elucidated by analyzing the relationship between the piezoelectric-induced charges and the electroluminescent effects. When a stress is applied on the piezoelectric layer, electrical charges will be induced at both the top and bottom sides of the piezoelectric layer. The induced electrical charges will lead to a light output from the electroluminescent layer, thus producing a mechano-luminescence effect. By increasing the vibration strength or frequency applied, the mechano-luminescence output can be obviously enhanced. Mechano-luminescence sensors have potential in smart stress-to-light devices, such as foot-stress-distribution-diagnosis systems and dynamic-load-monitors for bridge hanging cables.

Design and implementation of a versatile and variable-frequency piezoelectric coefficient measurement system.

Science.gov (United States)

Wu, J S; Huang, Y K; Wu, F L; Lin, D Y

2012-08-01

We present a simple but versatile piezoelectric coefficient measurement system, which can measure the longitudinal and transverse piezoelectric coefficients in the pressing and bending modes, respectively, at different applied forces and a wide range of frequencies. The functionality of this measurement system has been demonstrated on three samples, including a PbZr(0.52)Ti(0.48)O(3) (PZT) piezoelectric ceramic bulk, a ZnO thin film, and a laminated piezoelectric film sensor. The static longitudinal piezoelectric coefficients of the PZT bulk and the ZnO film are estimated to be around 210 and 8.1 pC/N, respectively. The static transverse piezoelectric coefficients of the ZnO film and the piezoelectric film sensor are determined to be, respectively, -0.284 and -0.031 C/m(2).

Modeling and analysis of circular flexural-vibration-mode piezoelectric transformer.

Science.gov (United States)

Huang, Yihua; Huang, Wei

2010-12-01

We propose a circular flexural-vibration-mode piezoelectric transformer and perform a theoretical analysis of the transformer. An equivalent circuit is derived from the equations of piezoelectricity and the Hamilton's principle. With this equivalent circuit, the voltage gain ratio, input impedance, and the efficiency of the circular flexural-vibration-mode piezoelectric transformer can be determined. The basic behavior of the transformer is shown by numerical results.

Optimal materials selection for bimaterial piezoelectric microactuators

OpenAIRE

Srinivasan, P.; Spearing, S.M.

2008-01-01

Piezoelectric actuation is one of the commonly employed actuation schemes in microsystems. This paper focuses on identifying and ranking promising active material/substrate combinations for bimaterial piezoelectric (BPE) microactuators based on their performance. The mechanics of BPE structures following simple beam theory assumptions available in the literature are applied to evolve critical performance metrics which govern the materials selection process. Contours of equal performance are p...

Magnetocaloric piezoelectric composites for energy harvesting

International Nuclear Information System (INIS)

Cleveland, Michael; Liang, Hong

2012-01-01

Magnetocaloric alloy, Gd 5 Si 2 Ge 2 , was developed into a composite with the poly(vinylidene fluoride) (PVDF) piezoelectric polymer. This multifunctional material possesses unique properties that are suitable for energy conversion and harvesting. Experimental approaches include using an arc melting technique to synthesize the Gd 5 Si 2 Ge 2 (GSG) alloy and the spinning casting method to fabricate the composite. The materials were characterized using various techniques at different length scales. These include atomic force microscopy (AFM), optical microscopy, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS). The results indicated that the phase transformation of the magnetocaloric material close to its Curie temperature induced a significant increase in power generation in the piezoelectric polymer. The power output of a laminated structure was 1.1 mW, more than 200 thousand times higher than the piezoelectric materials alone (5.1 nW). (technical note)

New technique for fabrication of high frequency piezoelectric Micromachined Ultrasound Transducers

DEFF Research Database (Denmark)

Pedersen, T; Thomsen, Erik Vilain; Zawada, T

2008-01-01

A novel technique for fabrication of linear arrays of high frequency piezoelectric Micromachined Ultrasound Transducers (pMUT) on silicon substrates is presented. Piezoelectric elements are formed by deposition of PZT ((PbZrxTi1-x)O3) into etched features of the silicon substrate such that the de......A novel technique for fabrication of linear arrays of high frequency piezoelectric Micromachined Ultrasound Transducers (pMUT) on silicon substrates is presented. Piezoelectric elements are formed by deposition of PZT ((PbZrxTi1-x)O3) into etched features of the silicon substrate...

LEAD-FREE BNKT PIEZOELECTRIC ACTUATOR

Directory of Open Access Journals (Sweden)

A. Moosavi

2016-03-01

Full Text Available An actuator is a device that converts input energy into mechanical energy. According to various types of input energy, various actuators have been advanced. Displacement in the electromagnetic, hydraulic and pneumatic actuators achieve by moving a piston via electromagnetic force or pressure, however the piezoelectric actuator (piezoceramic plates displace directly. Therefore, accuracy and speed in the piezoelectric device are higher than other types of actuators. In the present work, the high-field electromechanical response of high-quality (1−x(Bi 0.5Na0.5TiO3–x(Bi0.5K0.5TiO3 samples abbreviated to BNKTx with x = 0.18, 0.20, 0.22 and 0.24 ceramic materials across its MPB was investigated. The piezoelectrics and actuation characteristics were characterized. Ourresults indicate that x = 0.20, indeed, constitutes the best choice for the MPB composition in the system. Maximum of remanent polarization (37.5 μC cm−2 was obtained for x=0.20. High-field electromechanical responses were also obtained for BNKT0.20 samples. This material exhibited giant field induced strains of 0.13% under 1 kV mm -1 at room temperature.

Fabrication of flexible piezoelectric PZT/fabric composite.

Science.gov (United States)

Chen, Caifeng; Hong, Daiwei; Wang, Andong; Ni, Chaoying

2013-01-01

Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24 h, and reaction temperature 200°C.

Loss Factor Characterization Methodology for Piezoelectric Ceramics

International Nuclear Information System (INIS)

Zhuang Yuan; Ural, Seyit O; Uchino, Kenji

2011-01-01

The key factor for the miniaturization of piezoelectric devices is power density, which is limited by the heat generation or loss mechanisms. There are three loss components for piezoelectric vibrators, i.e., dielectric, elastic and piezoelectric losses. The mechanical quality factor, determined by these three factors, is the figure of merit in the sense of loss or heat generation. In this paper, quality factors of resonance and antiresonance for k 31 , k 33 , and k 15 vibration modes are derived, and the methodology to determine loss factors in various directions is provided. For simplicity, we focus on materials with ∞mm (equivalent to 6mm) crystal symmetry for deriving the loss factors of polycrystalline ceramics, and 16 different loss factors among total 20 can be obtained from the admittance/ impedance measurements.

Characterization of Piezoelectric Actuators for Flow Control over a Wing

Science.gov (United States)

Mossi, Karla M.; Bryant, Robert G.

2004-01-01

During the past decade, piezoelectric actuators as the active element in synthetic jets demonstrated that they could significantly enhance the overall lift on an airfoil. However, durability, system weight, size, and power have limited their use outside a laboratory. These problems are not trivial, since piezoelectric actuators are physically brittle and display limited displacement. The objective of this study is to characterize the relevant properties for the design of a synthetic jet utilizing three types of piezoelectric actuators as mechanical diaphragms, Radial Field Diaphragms, Thunders, and Bimorphs so that the shape cavity volume does not exceed 147.5 cubic centimeters on a 7centimeter x 7centimeter aerial coverage. These piezoelectric elements were selected because of their geometry, and overall free-displacement. Each actuator was affixed about its perimeter in a cavity, and relevant parameters such as clamped displacement variations with voltage and frequency, air velocities produced through an aperture, and sound pressure levels produced by the piezoelectric diaphragms were measured.

Enhanced piezoelectric effect at the edges of stepped molybdenum disulfide nanosheets.

Science.gov (United States)

Song, Xiaoxue; Hui, Fei; Gilmore, Keith; Wang, Bingru; Jing, Guangyin; Fan, Zhongchao; Grustan-Gutierrez, Enric; Shi, Yuanyuan; Lombardi, Lucia; Hodge, Stephen A; Ferrari, Andrea C; Lanza, Mario

2017-05-18

The development of piezoelectric layered materials may be one of the key elements enabling expansion of nanotechnology, as they offer a solution for the construction of efficient transducers for a wide range of applications, including self-powered devices. Here, we investigate the piezoelectric effect in multilayer (ML) stepped MoS 2 flakes obtained by liquid-phase exfoliation, which is especially interesting because it may allow the scalable fabrication of electronic devices using large area deposition techniques (e.g. solution casting, spray coating, inkjet printing). By using a conductive atomic force microscope we map the piezoelectricity of the MoS 2 flakes at the nanoscale. Our experiments demonstrate the presence of electrical current densities above 100 A cm -2 when the flakes are strained in the absence of bias, and the current increases proportional to the bias. Simultaneously collected topographic and current maps demonstrate that the edges of stepped ML MoS 2 flakes promote the piezoelectric effect, where the largest currents are observed. Density functional theory calculations are consistent with the ring-like piezoelectric potential generated when the flakes are strained, as well as the enhanced piezoelectric effect at edges. Our results pave the way to the design of piezoelectric devices using layered materials.

Three-dimensional piezoelectric fibrous scaffolds selectively promote mesenchymal stem cell differentiation.

Science.gov (United States)

Damaraju, Sita M; Shen, Yueyang; Elele, Ezinwa; Khusid, Boris; Eshghinejad, Ahmad; Li, Jiangyu; Jaffe, Michael; Arinzeh, Treena Livingston

2017-12-01

The discovery of electric fields in biological tissues has led to efforts in developing technologies utilizing electrical stimulation for therapeutic applications. Native tissues, such as cartilage and bone, exhibit piezoelectric behavior, wherein electrical activity can be generated due to mechanical deformation. Yet, the use of piezoelectric materials have largely been unexplored as a potential strategy in tissue engineering, wherein a piezoelectric biomaterial acts as a scaffold to promote cell behavior and the formation of large tissues. Here we show, for the first time, that piezoelectric materials can be fabricated into flexible, three-dimensional fibrous scaffolds and can be used to stimulate human mesenchymal stem cell differentiation and corresponding extracellular matrix/tissue formation in physiological loading conditions. Piezoelectric scaffolds that exhibit low voltage output, or streaming potential, promoted chondrogenic differentiation and piezoelectric scaffolds with a high voltage output promoted osteogenic differentiation. Electromechanical stimulus promoted greater differentiation than mechanical loading alone. Results demonstrate the additive effect of electromechanical stimulus on stem cell differentiation, which is an important design consideration for tissue engineering scaffolds. Piezoelectric, smart materials are attractive as scaffolds for regenerative medicine strategies due to their inherent electrical properties without the need for external power sources for electrical stimulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Piezoelectric Lead Zirconate Titanate (PZT) Ring Shaped Contour-Mode MEMS Resonators

Science.gov (United States)

Kasambe, P. V.; Asgaonkar, V. V.; Bangera, A. D.; Lokre, A. S.; Rathod, S. S.; Bhoir, D. V.

2018-02-01

Flexibility in setting fundamental frequency of resonator independent of its motional resistance is one of the desired criteria in micro-electromechanical (MEMS) resonator design. It is observed that ring-shaped piezoelectric contour-mode MEMS resonators satisfy this design criterion than in case of rectangular plate MEMS resonators. Also ring-shaped contour-mode piezoelectric MEMS resonator has an advantage that its fundamental frequency is defined by in-plane dimensions, but they show variation of fundamental frequency with different Platinum (Pt) thickness referred as change in ratio of fNEW /fO . This paper presents the effects of variation in geometrical parameters and change in piezoelectric material on the resonant frequencies of Platinum piezoelectric-Aluminium ring-shaped contour-mode MEMS resonators and its electrical parameters. The proposed structure with Lead Zirconate Titanate (PZT) as the piezoelectric material was observed to be a piezoelectric material with minimal change in fundamental resonant frequency due to Platinum thickness variation. This structure was also found to exhibit extremely low motional resistance of 0.03 Ω as compared to the 31-35 Ω range obtained when using AlN as the piezoelectric material. CoventorWare 10 is used for the design, simulation and corresponding analysis of resonators which is Finite Element Method (FEM) analysis and design tool for MEMS devices.

Monitoring of bone healing by piezoelectric-EMI method

Science.gov (United States)

Mazlina, M. H.; Sarpinah, Bibi; Tawie, Rudy; Daho, Claira Dalislone; Annuar, Ishak

2016-02-01

Smart Piezoelectric devices which have excellent piezoelectric properties have been employed for various sensor and actuators applications. The work presented here is an attempt to demonstrate the feasibility of bone healing monitoring by using piezoelectric-electromechanical impedance (EMI) method that have several advantages such as low cost, portable, light weight and simplicity in measurement. A Piezoelectric sensor (PZT) has been widely used in damage detection of various structures including concrete, pipes and bones due to their unique sensing and actuating properties. The EMI technique has emerged as a universal Structural Health Monitoring (SHM) tool suitable for almost all engineering materials and structures. The method used for this proposed study consists of put healing agent in the host structure in particular cracks bone to be monitored by PZT-needle sensor which is embedded to the host structure. The measurements were taken in the frequency range between 0.04 to 100 kHz at 1 kHz interval using AD5933 evaluation board. The signals retrieved from the AD5933 evaluation board, were quantify and analyse to obtain Root Mean Square Deviation (RMSD) percentage value. Measurements were taken every hour for 12 hours. The result from the study shows the feasibility of the piezoelectric-EMI method to effectively detect changes during bone-cracks healing process until the cracks bone is fully recovered.

Fuzzy PID Feedback Control of Piezoelectric Actuator with Feedforward Compensation

OpenAIRE

Ziqiang Chi; Minping Jia; Qingsong Xu

2014-01-01

Piezoelectric actuator is widely used in the field of micro/nanopositioning. However, piezoelectric hysteresis introduces nonlinearity to the system, which is the major obstacle to achieve a precise positioning. In this paper, the Preisach model is employed to describe the hysteresis characteristic of piezoelectric actuator and an inverse Preisach model is developed to construct a feedforward controller. Considering that the analytical expression of inverse Preisach model is difficult to deri...

Vibration energy harvesting based on integrated piezoelectric components operating in different modes.

Science.gov (United States)

Hu, Junhui; Jong, Januar; Zhao, Chunsheng

2010-01-01

To increase the vibration energy-harvesting capability of the piezoelectric generator based on a cantilever beam, we have proposed a piezoelectric generator that not only uses the strain change of piezoelectric components bonded on a cantilever beam, but also employs the weights at the tip of the cantilever beam to hit piezoelectric components located on the 2 sides of weights. A prototype of the piezoelectric generator has been fabricated and its characteristics have been measured and analyzed. The experimental results show that the piezoelectric components operating in the hit mode can substantially enhance the energy harvesting of the piezoelectric generator on a cantilever beam. Two methods are used and compared in the management of rectified output voltages from different groups of piezoelectric components. In one of them, the DC voltages from rectifiers are connected in series, and then the total DC voltage is applied to a capacitor. In another connection, the DC voltage from each group is applied to different capacitors. It is found that 22.3% of the harvested energy is wasted due to the series connection. The total output electric energy of our piezoelectric generator at nonresonance could be up to 43 nJ for one vibration excitation applied by spring, with initial vibration amplitude (0-p) of 18 mm and frequency of 18.5 Hz, when the rectified voltages from different groups of piezoelectric components are connected to their individual capacitors. In addition, the motion and impact of the weights at the tip of the cantilever beam are theoretically analyzed, which well explains the experimental phenomena and suggests the measures to improve the generator.

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair.

Science.gov (United States)

Tandon, Biranche; Blaker, Jonny J; Cartmell, Sarah H

2018-04-16

The process of bone repair and regeneration requires multiple physiological cues including biochemical, electrical and mechanical - that act together to ensure functional recovery. Myriad materials have been explored as bioactive scaffolds to deliver these cues locally to the damage site, amongst these piezoelectric materials have demonstrated significant potential for tissue engineering and regeneration, especially for bone repair. Piezoelectric materials have been widely explored for power generation and harvesting, structural health monitoring, and use in biomedical devices. They have the ability to deform with physiological movements and consequently deliver electrical stimulation to cells or damaged tissue without the need of an external power source. Bone itself is piezoelectric and the charges/potentials it generates in response to mechanical activity are capable of enhancing bone growth. Piezoelectric materials are capable of stimulating the physiological electrical microenvironment, and can play a vital role to stimulate regeneration and repair. This review gives an overview of the association of piezoelectric effect with bone repair, and focuses on state-of-the-art piezoelectric materials (polymers, ceramics and their composites), the fabrication routes to produce piezoelectric scaffolds, and their application in bone repair. Important characteristics of these materials from the perspective of bone tissue engineering are highlighted. Promising upcoming strategies and new piezoelectric materials for this application are presented. Electrical stimulation/electrical microenvironment are known effect the process of bone regeneration by altering the cellular response and are crucial in maintaining tissue functionality. Piezoelectric materials, owing to their capability of generating charges/potentials in response to mechanical deformations, have displayed great potential for fabricating smart stimulatory scaffolds for bone tissue engineering. The growing

Propagation of extensional waves in a piezoelectric semiconductor rod

Directory of Open Access Journals (Sweden)

C.L. Zhang

2016-04-01

Full Text Available We studied the propagation of extensional waves in a thin piezoelectric semiconductor rod of ZnO whose c-axis is along the axis of the rod. The macroscopic theory of piezoelectric semiconductors was used which consists of the coupled equations of piezoelectricity and the conservation of charge. The problem is nonlinear because the drift current is the product of the unknown electric field and the unknown carrier density. A perturbation procedure was used which resulted in two one-way coupled linear problems of piezoelectricity and the conservation of charge, respectively. The acoustic wave and the accompanying electric field were obtained from the equations of piezoelectricity. The motion of carriers was then determined from the conservation of charge using a trigonometric series. It was found that while the acoustic wave was approximated by a sinusoidal wave, the motion of carriers deviates from a sinusoidal wave qualitatively because of the contributions of higher harmonics arising from the originally nonlinear terms. The wave crests become higher and sharper while the troughs are shallower and wider. This deviation is more pronounced for acoustic waves with larger amplitudes.

Auxetic piezoelectric energy harvesters for increased electric power output

Directory of Open Access Journals (Sweden)

Qiang Li

2017-01-01

Full Text Available This letter presents a piezoelectric bimorph with auxetic (negative Poisson’s ratio behaviors for increased power output in vibration energy harvesting. The piezoelectric bimorph comprises a 2D auxetic substrate sandwiched between two piezoelectric layers. The auxetic substrate is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezoelectric layers when the bimorph is subjected to a longitudinal stretching load. As a result, both 31- and 32-modes are simultaneously exploited to generate electric power, leading to an increased power output. The increasing power output principle was theoretically analyzed and verified by finite element (FE modelling. The FE modelling results showed that the auxetic substrate can increase the transverse stress of a bimorph by 16.7 times. The average power generated by the auxetic bimorph is 2.76 times of that generated by a conventional bimorph.

Investigating the Electromechanical Coupling in Piezoelectric Actuator Drive Motor Under Heavy Load

DEFF Research Database (Denmark)

Zsurzsan, Tiberiu-Gabriel; Andersen, Michael A. E.; Zhang, Zhe

2014-01-01

The Piezoelectric Actuator Drive (PAD) is an accurate, high-torque rotary piezoelectric motor that employs piezoelectric stack actuators and inverse hypocycloidal motion to generate rotation. Important factors that determine motor performance are the proper concentric alignment between the motor...

MEMS Accelerometer with Screen Printed Piezoelectric Thick Film

DEFF Research Database (Denmark)

Hindrichsen, Christian Carstensen; Lau-Moeller, R.; Bove, T.

2006-01-01

A bulk-micromachined piezoelectric MEMS accelerometer with screen printed piezoelectric Pb(ZrxTil )O3(PZT) thick film (TF) as the sensing material has been fabricated and characterized. The accelerometer has a four beam structure with a central seismic mass (3600x3600x500 pm3) and a total chip size...

Nonlinear piezoelectricity in epitaxial ferroelectrics at high electric fields.

Science.gov (United States)

Grigoriev, Alexei; Sichel, Rebecca; Lee, Ho Nyung; Landahl, Eric C; Adams, Bernhard; Dufresne, Eric M; Evans, Paul G

2008-01-18

Nonlinear effects in the coupling of polarization with elastic strain have been predicted to occur in ferroelectric materials subjected to high electric fields. Such predictions are tested here for a PbZr0.2Ti0.8O3 ferroelectric thin film at electric fields in the range of several hundred MV/m and strains reaching up to 2.7%. The piezoelectric strain exceeds predictions based on constant piezoelectric coefficients at electric fields from approximately 200 to 400 MV/m, which is consistent with a nonlinear effect predicted to occur at corresponding piezoelectric distortions.

Piezoelectric motor development at AlliedSignal Inc., Kansas City Division

Science.gov (United States)

Pressly, Robert B.; Mentesana, Charles P.

1994-11-01

The Kansas City Division of AlliedSignal Inc. has been investigating the fabrication and use of piezoelectric motors in mechanisms for United States Department of Energy (DOE) weapons applications for about four years. These motors exhibit advantages over solenoids and other electromagnetic actuators. Prototype processes have been developed for complete fabrication of motors from stock materials, including abrasive machining of piezoelectric ceramics and more traditional machining of other motor components, electrode plating and sputtering, electric poling, cleaning, bonding and assembly. Drive circuits have been fabricated and motor controls are being developed. Laboratory facilities have been established for electrical/mechanical testing and evaluation of piezo materials and completed motors. Recent project efforts have focused on the potential of piezoelectric devices for commercial and industrial use. A broad range of various motor types and application areas has been identified, primarily in Japan. The Japanese have been developing piezo motors for many years and have more recently begun commercialization. Piezoelectric motor and actuator technology is emerging in the United States and quickly gaining in commercial interest. The Kansas City Division is continuing development of piezoelectric motors and actuators for defense applications while supporting and participating in the commercialization of piezoelectric devices with private industry through various technology transfer and cooperative development initiatives.

Energy harvesting from radio frequency propagation using piezoelectric cantilevers

KAUST Repository

Al Ahmad, Mahmoud; Alshareef, Husam N.

2012-01-01

This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates

Using Piezoelectric Devices to Transmit Power through Walls

Science.gov (United States)

Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi

2008-01-01

A method denoted wireless acoustic-electric feed-through (WAEF) has been conceived for transmitting power and/or data signals through walls or other solid objects made of a variety of elastic materials that could be electrically conductive or nonconductive. WAEF would make it unnecessary to use wires, optical fibers, tubes, or other discrete wall-penetrating signal-transmitting components, thereby eliminating the potential for structural weakening or leakage at such penetrations. Avoidance of such penetrations could be essential in some applications in which maintenance of pressure, vacuum, or chemical or biological isolation is required. In a basic WAEF setup, a transmitting piezoelectric transducer on one side of a wall would be driven at resonance to excite ultrasonic vibrations in the wall. A receiving piezoelectric transducer on the opposite side of the wall would convert the vibrations back to an ultrasonic AC electric signal, which would then be detected and otherwise processed in a manner that would depend on the modulation (if any) applied to the signal and whether the signal was used to transmit power, data, or both. An electromechanical-network model has been derived as a computationally efficient means of analyzing and designing a WAEF system. This model is a variant of a prior model, known in the piezoelectric-transducer art as Mason's equivalent-circuit model, in which the electrical and mechanical dynamics, including electromechanical couplings, are expressed as electrical circuit elements that can include inductors, capacitors, and lumped-parameter complex impedances. The real parts of the complex impedances are used to account for dielectric, mechanical, and coupling losses in all components (including all piezoelectric-transducer, wall, and intermediate material layers). In an application to a three-layer piezoelectric structure, this model was shown to yield the same results as do solutions of the wave equations of piezoelectricity and acoustic

Simulation Study on Material Property of Cantilever Piezoelectric Vibration Generator

Directory of Open Access Journals (Sweden)

Yan Zhen

2014-06-01

Full Text Available For increasing generating capacity of cantilever piezoelectric vibration generator with limited volume, relation between output voltage, inherent frequency and material parameter of unimorph, bimorph in series type and bimorph in parallel type piezoelectric vibration generator is analyzed respectively by mechanical model and finite element modeling. The results indicate PZT-4, PZT- 5A and PZT-5H piezoelectric materials and stainless steel, nickel alloy substrate material should be firstly chosen.

Diaphragm Pump With Resonant Piezoelectric Drive

Science.gov (United States)

Izenson, Michael G.; Kline-Schoder, Robert J.; Shimko, Martin A.

2007-01-01

A diaphragm pump driven by a piezoelectric actuator is undergoing development. This pump is intended to be a prototype of lightweight, highly reliable pumps for circulating cooling liquids in protective garments and high-power electronic circuits, and perhaps for some medical applications. The pump would be highly reliable because it would contain no sliding seals or bearings that could wear, the only parts subject to wear would be two check valves, and the diaphragm and other flexing parts could be designed, by use of proven methods, for extremely long life. Because the pump would be capable of a large volumetric flow rate and would have only a small dead volume, its operation would not be disrupted by ingestion of gas, and it could be started reliably under all conditions. The prior art includes a number piezoelectrically actuated diaphragm pumps. Because of the smallness of the motions of piezoelectric actuators (typical maximum strains only about 0.001), the volumetric flow rates of those pumps are much too small for typical cooling applications. In the pump now undergoing development, mechanical resonance would be utilized to amplify the motion generated by the piezoelectric actuator and thereby multiply the volumetric flow rate. The prime mover in this pump would be a stack of piezoelectric ceramic actuators, one end of which would be connected to a spring that would be part of a spring-and-mass resonator structure. The mass part of the resonator structure would include the pump diaphragm (see Figure 1). Contraction of the spring would draw the diaphragm to the left, causing the volume of the fluid chamber to increase and thereby causing fluid to flow into the chamber. Subsequent expansion of the spring would push the diaphragm to the right, causing the volume of the fluid chamber to decrease, and thereby expelling fluid from the chamber. The fluid would enter and leave the chamber through check valves. The piezoelectric stack would be driven electrically to

Piezoelectric Polymer Ultrasound Transducers and Its Biomedical Applications

Energy Technology Data Exchange (ETDEWEB)

Ha, Kang Lyeol; Cao, Yanggang [Department of Physics, Pukyong National University, Busan (Korea, Republic of)

2012-10-15

PVDF(poly vinylidene fluoride) and P(VDF-TrFE)(poly vinylidene fluoride-tetrafluoroethylene) are the typical piezoelectric polymers with unique properties. Even they are inferior to conventional piezoelectric ceramics PZT in electromechanical conversion efficiency and interior loss, though they are superior in receiving sensitivity and frequency bandwidth. Their acoustic impedances are relatively close to water or biological tissue and it is easier to make thin film than other piezoelectric materials. Furthermore, the film is so flexible that it is easy to attach on a complex surface. Those properties are suitable for the ultrasound transducers which are useful for medical and biological application, so that various types of polymer transducers have been developed. In this paper, several important considerations for design and fabrication of piezoelectric polymer transducers were described and their effect on the transducer performance were demonstrated through the KLM model analysis. Then, it was briefly reviewed about the structures of the polymer transducers developed for obtaining images as well as the characteristics of the images in several important medical and biological application fields.

Wind energy harvesting with a piezoelectric harvester

International Nuclear Information System (INIS)

Wu, Nan; Wang, Quan; Xie, Xiangdong

2013-01-01

An energy harvester comprising a cantilever attached to piezoelectric patches and a proof mass is developed for wind energy harvesting, from a cross wind-induced vibration of the cantilever, by the electromechanical coupling effect of piezoelectric materials. The vibration of the cantilever under the cross wind is induced by the air pressure owing to a vortex shedding phenomenon that occurs on the leeward side of the cantilever. To describe the energy harvesting process, a theoretical model considering the cross wind-induced vibration on the piezoelectric coupled cantilever energy harvester is developed, to calculate the charge and the voltage from the harvester. The influences of the length and location of the piezoelectric patches as well as the proof mass on the generated electric power are investigated. Results show that the total generated electric power can be as high as 2 W when the resonant frequency of the cantilever harvester is close to the vortex shedding frequency. Moreover, a value of total generated electric power up to 1.02 W can be practically realized for a cross wind with a variable wind velocity of 9–10 m s −1 by a harvester with a length of 1.2 m. This research facilitates an effective and compact wind energy harvesting device. (paper)

A mechatronic power boosting design for piezoelectric generators

International Nuclear Information System (INIS)

Liu, Haili; Liang, Junrui; Ge, Cong

2015-01-01

It was shown that the piezoelectric power generation can be boosted by using the synchronized switch power conditioning circuits. This letter reports a self-powered and self-sensing mechatronic design in substitute of the auxiliary electronics towards a compact and universal synchronized switch solution. The design criteria are derived based on the conceptual waveforms and a two-degree-of-freedom analytical model. Experimental result shows that, compared to the standard bridge rectifier interface, the mechatronic design leads to an extra 111% increase of generated power from the prototyped piezoelectric generator under the same deflection magnitude excitation. The proposed design has introduced a valuable physical insight of electromechanical synergy towards the improvement of piezoelectric power generation

A mechatronic power boosting design for piezoelectric generators

Energy Technology Data Exchange (ETDEWEB)

Liu, Haili; Liang, Junrui, E-mail: liangjr@shanghaitech.edu.cn; Ge, Cong [School of Information Science and Technology, ShanghaiTech University, No. 8 Building, 319 Yueyang Road, Shanghai 200031 (China)

2015-10-05

It was shown that the piezoelectric power generation can be boosted by using the synchronized switch power conditioning circuits. This letter reports a self-powered and self-sensing mechatronic design in substitute of the auxiliary electronics towards a compact and universal synchronized switch solution. The design criteria are derived based on the conceptual waveforms and a two-degree-of-freedom analytical model. Experimental result shows that, compared to the standard bridge rectifier interface, the mechatronic design leads to an extra 111% increase of generated power from the prototyped piezoelectric generator under the same deflection magnitude excitation. The proposed design has introduced a valuable physical insight of electromechanical synergy towards the improvement of piezoelectric power generation.

Surface effects on the electroelastic responses of a thin piezoelectric plate with nanoscale thickness

International Nuclear Information System (INIS)

Yan Zhi; Jiang Liying

2012-01-01

This work aims to investigate the electroelastic responses of a thin piezoelectric plate under mechanical and electrical loads with the consideration of surface effects. Surface effects, including surface elasticity, residual surface stress and surface piezoelectricity, are incorporated into the conventional Kirchhoff plate theory for a piezoelectric plate via the surface piezoelectricity model and the generalized Young-Laplace equations. Different from the results predicted by the conventional plate theory ignoring the surface effects, the proposed model predicts size-dependent behaviours of the piezoelectric thin plate with nanoscale thickness. It is found that surface effects have significant influence on the electroelastic responses of the piezoelectric nanoplate. This work is expected to provide more accurate predictions on characterizing nanofilm or nanoribbon based piezoelectric devices in nanoelectromechanical systems. (paper)

Energy harvesting performance of piezoelectric ceramic and polymer nanowires

International Nuclear Information System (INIS)

Crossley, Sam; Kar-Narayan, Sohini

2015-01-01

Energy harvesting from ubiquitous ambient vibrations is attractive for autonomous small-power applications and thus considerable research is focused on piezoelectric materials as they permit direct inter-conversion of mechanical and electrical energy. Nanogenerators (NGs) based on piezoelectric nanowires are particularly attractive due to their sensitivity to small-scale vibrations and may possess superior mechanical-to-electrical conversion efficiency when compared to bulk or thin-film devices of the same material. However, candidate piezoelectric nanowires have hitherto been predominantly analyzed in terms of NG output (i.e. output voltage, output current and output power density). Surprisingly, the corresponding dynamical properties of the NG, including details of how the nanowires are mechanically driven and its impact on performance, have been largely neglected. Here we investigate all realizable NG driving contexts separately involving inertial displacement, applied stress T and applied strain S, highlighting the effect of driving mechanism and frequency on NG performance in each case. We argue that, in the majority of cases, the intrinsic high resonance frequencies of piezoelectric nanowires (∼tens of MHz) present no barrier to high levels of NG performance even at frequencies far below resonance (<1 kHz) typically characteristic of ambient vibrations. In this context, we introduce vibrational energy harvesting (VEH) coefficients η S and η T , based on intrinsic materials properties, for comparing piezoelectric NG performance under strain-driven and stress-driven conditions respectively. These figures of merit permit, for the first time, a general comparison of piezoelectric nanowires for NG applications that takes into account the nature of the mechanical excitation. We thus investigate the energy harvesting performance of prototypical piezoelectric ceramic and polymer nanowires. We find that even though ceramic and polymer nanowires have been found, in

Subatomic deformation driven by vertical piezoelectricity from CdS ultrathin films.

Science.gov (United States)

Wang, Xuewen; He, Xuexia; Zhu, Hongfei; Sun, Linfeng; Fu, Wei; Wang, Xingli; Hoong, Lai Chee; Wang, Hong; Zeng, Qingsheng; Zhao, Wu; Wei, Jun; Jin, Zhong; Shen, Zexiang; Liu, Jie; Zhang, Ting; Liu, Zheng

2016-07-01

Driven by the development of high-performance piezoelectric materials, actuators become an important tool for positioning objects with high accuracy down to nanometer scale, and have been used for a wide variety of equipment, such as atomic force microscopy and scanning tunneling microscopy. However, positioning at the subatomic scale is still a great challenge. Ultrathin piezoelectric materials may pave the way to positioning an object with extreme precision. Using ultrathin CdS thin films, we demonstrate vertical piezoelectricity in atomic scale (three to five space lattices). With an in situ scanning Kelvin force microscopy and single and dual ac resonance tracking piezoelectric force microscopy, the vertical piezoelectric coefficient (d 33) up to 33 pm·V(-1) was determined for the CdS ultrathin films. These findings shed light on the design of next-generation sensors and microelectromechanical devices.

A new smart traffic monitoring method using embedded cement-based piezoelectric sensors

International Nuclear Information System (INIS)

Zhang, Jinrui; Lu, Youyuan; Lu, Zeyu; Liu, Chao; Sun, Guoxing; Li, Zongjin

2015-01-01

Cement-based piezoelectric composites are employed as the sensing elements of a new smart traffic monitoring system. The piezoelectricity of the cement-based piezoelectric sensors enables powerful and accurate real-time detection of the pressure induced by the traffic flow. To describe the mechanical-electrical conversion mechanism between traffic flow and the electrical output of the embedded piezoelectric sensors, a mathematical model is established based on Duhamel’s integral, the constitutive law and the charge-leakage characteristics of the piezoelectric composite. Laboratory tests show that the voltage magnitude of the sensor is linearly proportional to the applied pressure, which ensures the reliability of the cement-based piezoelectric sensors for traffic monitoring. A series of on-site road tests by a 10 tonne truck and a 6.8 tonne van show that vehicle weight-in-motion can be predicted based on the mechanical-electrical model by taking into account the vehicle speed and the charge-leakage property of the piezoelectric sensor. In the speed range from 20 km h −1 to 70 km h −1 , the error of the repeated weigh-in-motion measurements of the 6.8 tonne van is less than 1 tonne. The results indicate that the embedded cement-based piezoelectric sensors and associated measurement setup have good capability of smart traffic monitoring, such as traffic flow detection, vehicle speed detection and weigh-in-motion measurement. (paper)

Iterative Learning Control of Hysteresis in Piezoelectric Actuators

Directory of Open Access Journals (Sweden)

Guilin Zhang

2014-01-01

input in hysteretic systems. In the analysis, the Prandtl-Ishlinskii model is utilized to capture the nonlinear behavior in piezoelectric actuators. Finally, we apply the control algorithm to an experimental piezoelectric actuator and conclude that the tracking error is reduced to 0.15% of the total displacement, which is approximately the noise level of the sensor measurement.

Progress in engineering high strain lead-free piezoelectric ceramics

International Nuclear Information System (INIS)

Leontsev, Serhiy O; Eitel, Richard E

2010-01-01

Environmental concerns are strongly driving the need to replace the lead-based piezoelectric materials currently employed as multilayer actuators. The current review describes both compositional and structural engineering approaches to achieve enhanced piezoelectric properties in lead-free materials. The review of the compositional engineering approach focuses on compositional tuning of the properties and phase behavior in three promising families of lead-free perovskite ferroelectrics: the titanate, alkaline niobate and bismuth perovskites and their solid solutions. The 'structural engineering' approaches focus instead on optimization of microstructural features including grain size, grain orientation or texture, ferroelectric domain size and electrical bias field as potential paths to induce large piezoelectric properties in lead-free piezoceramics. It is suggested that a combination of both compositional and novel structural engineering approaches will be required in order to realize viable lead-free alternatives to current lead-based materials for piezoelectric actuator applications. (topical review)

Progress in engineering high strain lead-free piezoelectric ceramics

Science.gov (United States)

Leontsev, Serhiy O; Eitel, Richard E

2010-01-01

Environmental concerns are strongly driving the need to replace the lead-based piezoelectric materials currently employed as multilayer actuators. The current review describes both compositional and structural engineering approaches to achieve enhanced piezoelectric properties in lead-free materials. The review of the compositional engineering approach focuses on compositional tuning of the properties and phase behavior in three promising families of lead-free perovskite ferroelectrics: the titanate, alkaline niobate and bismuth perovskites and their solid solutions. The ‘structural engineering’ approaches focus instead on optimization of microstructural features including grain size, grain orientation or texture, ferroelectric domain size and electrical bias field as potential paths to induce large piezoelectric properties in lead-free piezoceramics. It is suggested that a combination of both compositional and novel structural engineering approaches will be required in order to realize viable lead-free alternatives to current lead-based materials for piezoelectric actuator applications. PMID:27877343

Millipede-inspired locomotion through novel U-shaped piezoelectric motors

International Nuclear Information System (INIS)

Avirovik, Dragan; Butenhoff, Bryan; Priya, Shashank

2014-01-01

We report a novel piezoelectric motor that operates at a resonance frequency of 144 Hz, much lower than that of conventional ultrasonic motors, and meets the displacement and gait requirements for designing the locomotion mechanism of a millipede-inspired robot (millibot). The motor structure consists of two piezoelectric bimorphs arranged in a U-shaped configuration. Using the first bending mode for both the piezoelectric bimorphs an elliptical motion was obtained at the tip which led to the successful implementation of millipede inspired locomotion. At an input voltage of 70.7 V rms , the piezoelectric motor operating at resonance frequency was able to generate torque of 0.03 mN m, mechanical power of 0.84 mW and maximum velocity of 62 rad s −1 . Detailed discussion is provided about the principle of operation of the millibot. (technical note)

Mathematical model and characteristic analysis of hybrid photovoltaic/piezoelectric actuation mechanism

Science.gov (United States)

Jiang, Jing; Li, Xiaonan; Ding, Jincheng; Yue, Honghao; Deng, Zongquan

2016-12-01

Photovoltaic materials can turn light energy into electric energy directly, and thus have the advantages of high electrical output voltages and the ability to realize remote or non-contact control. When high-energy ultraviolet light illuminates polarized PbLaZrTi (PLZT) materials, high photovoltages will be generated along the spontaneous polarization direction due to the photovoltaic effect. In this paper, a novel hybrid photovoltaic/piezoelectric actuation mechanism is proposed. PLZT ceramics are used as a photovoltaic generator to drive a piezoelectric actuator. A mathematical model is established to define the time history of the actuation voltage between two electrodes of the piezoelectric actuator, which is experimentally validated by the test results of a piezoelectric actuator with different geometrical parameters under irradiation at different light intensities. Some important characteristics of this novel actuation mechanism are analyzed and it can be concluded that (1) it is experimentally validated that there is no hysteresis between voltage and deformation which exists in a PLZT actuator; (2) the saturated voltage and response speed can be improved by using a multi-patch PLZT generator to drive the piezoelectric actuator; and (3) the initial voltage of the piezoelectric actuator can be acquired by controlling the logical switch between the PLZT and the piezoelectric actuator while the initial voltages increase with the rise of light intensity.

A new piezoelectric energy harvesting design concept: multimodal energy harvesting skin.

Science.gov (United States)

Lee, Soobum; Youn, Byeng D

2011-03-01

This paper presents an advanced design concept for a piezoelectric energy harvesting (EH), referred to as multimodal EH skin. This EH design facilitates the use of multimodal vibration and enhances power harvesting efficiency. The multimodal EH skin is an extension of our previous work, EH skin, which was an innovative design paradigm for a piezoelectric energy harvester: a vibrating skin structure and an additional thin piezoelectric layer in one device. A computational (finite element) model of the multilayered assembly - the vibrating skin structure and piezoelectric layer - is constructed and the optimal topology and/or shape of the piezoelectric layer is found for maximum power generation from multiple vibration modes. A design rationale for the multimodal EH skin was proposed: designing a piezoelectric material distribution and external resistors. In the material design step, the piezoelectric material is segmented by inflection lines from multiple vibration modes of interests to minimize voltage cancellation. The inflection lines are detected using the voltage phase. In the external resistor design step, the resistor values are found for each segment to maximize power output. The presented design concept, which can be applied to any engineering system with multimodal harmonic-vibrating skins, was applied to two case studies: an aircraft skin and a power transformer panel. The excellent performance of multimodal EH skin was demonstrated, showing larger power generation than EH skin without segmentation or unimodal EH skin.

In situ health monitoring of piezoelectric sensors

Science.gov (United States)

Jensen, Scott L. (Inventor); Drouant, George J. (Inventor)

2013-01-01

An in situ health monitoring apparatus may include an exciter circuit that applies a pulse to a piezoelectric transducer and a data processing system that determines the piezoelectric transducer's dynamic response to the first pulse. The dynamic response can be used to evaluate the operating range, health, and as-mounted resonance frequency of the transducer, as well as the strength of a coupling between the transducer and a structure and the health of the structure.

Performance Analysis of Wind-Induced Piezoelectric Vibration Bimorph Cantilever for Rotating Machinery

Directory of Open Access Journals (Sweden)

Gongbo Zhou

2015-01-01

Full Text Available Harvesting the energy contained in the running environment of rotating machinery would be a good way to supplement energy to the wireless sensor. In this paper, we take piezoelectric bimorph cantilever beam with parallel connection mode as energy collector and analyze the factors which can influence the generation performance. First, a modal response theory model is built. Second, the static analysis, modal analysis, and piezoelectric harmonic response analysis of the wind-induced piezoelectric bimorph cantilever beam are given in detail. Finally, an experiment is also conducted. The results show that wind-induced piezoelectric bimorph cantilever beam has low resonant frequency and stable output under the first modal mode and can achieve the maximum output voltage under the resonant condition. The output voltage increases with the increase of the length and width of wind-induced piezoelectric bimorph cantilever beam, but the latter increasing amplitude is relatively smaller. In addition, the output voltage decreases with the increase of the thickness and the ratio of metal substrate to piezoelectric patches thickness. The experiment showed that the voltage amplitude generated by the piezoelectric bimorph cantilever beam can reach the value simulated in ANSYS, which is suitable for actual working conditions.

Modelling piezoelectric energy harvesting potential in an educational building

International Nuclear Information System (INIS)

Li, Xiaofeng; Strezov, Vladimir

2014-01-01

Highlights: • Energy harvesting potential of commercialized piezoelectric tiles is analyzed. • The parameters which will affect the energy harvesting efficiency are determined. • The potential could cover 0.5% of the total energy usage of the library building. • A simplified evaluation indicator is proposed to test the considered paving area. - Abstract: In this paper, potential application of a commercial piezoelectric energy harvester in a central hub building at Macquarie University in Sydney, Australia is examined and discussed. Optimization of the piezoelectric tile deployment is presented according to the frequency of pedestrian mobility and a model is developed where 3.1% of the total floor area with the highest pedestrian mobility is paved with piezoelectric tiles. The modelling results indicate that the total annual energy harvesting potential for the proposed optimized tile pavement model is estimated at 1.1 MW h/year. This potential energy generation may be further increased to 9.9 MW h/year with a possible improvement in piezoelectric energy conversion efficiency integrated into the system. This energy harvesting potential would be sufficient to meet close to 0.5% of the annual energy needs of the building. The study confirms that locating high traffic areas is critical for optimization of the energy harvesting efficiency, as well as the orientation of the tile pavement significantly affects the total amount of the harvested energy. A Density Flow evaluation is recommended in this study to qualitatively evaluate the piezoelectric power harvesting potential of the considered area based on the number of pedestrian crossings per unit time

Modeling and Tuning for Vibration Energy Harvesting using a Piezoelectric Bimorph

Science.gov (United States)

Cao, Yongqing

With the development of wireless sensors and other devices, the need for continuous power supply with high reliability is growing ever more. The traditional battery power supply has the disadvantage of limited duration of continuous power supply capability so that replacement for new batteries has to be done regularly. This can be quite inconvenient and sometimes quite difficult especially when the sensors are located in places not easily accessible such as the inside of a machine or wild field. This situation stimulates the development of renewable power supply which can harvest energy from the environment. The use of piezoelectric materials to converting environment vibration to electrical energy is one of the alternatives of which a broad range of research has been done by many researchers, focusing on different issues. The improvement of efficiency is one of the most important issues in vibration based energy harvesting. For this purpose different methods are devised and more accurate modeling of coupled piezoelectric mechanical systems is investigated. In the current paper, the research is focused on improving voltage generation of a piezoelectric bimorph on a vibration beam, as well as the analytical modeling of the same system. Also an initial study is conducted on the characteristics of the vibration of Zinc oxide (ZnO) nanowire, which is a promising material for its coupled semiconducting and piezoelectric properties. The effect on the voltage generation by different placement of the piezoelectric bimorph on the vibrating beam is investigated. The relation between the voltage output and the curvature is derived which is used to explain the effect of placement on voltage generation. The effect of adding a lumped mass on the modal frequencies of the beam and on the curvature distribution is investigated. The increased voltage output from the piezoelectric bimorph by using appropriately selected mass is proved analytically and also verified by experiment. For

Improvement of the piezoelectric properties of glass fiber-reinforced epoxy composites by poling treatment

International Nuclear Information System (INIS)

Oh, S M; Hwang, H Y

2013-01-01

Recently, a new non-destructive method has been proposed for damage monitoring of glass fiber-reinforced polymer composite materials using the piezoelectric characteristics of a polymeric matrix. Several studies of the piezoelectric properties of unidirectional glass fiber epoxy composites and damage monitoring of double-cantilever beams have supported the claim that the piezoelectric method is feasible and powerful enough to monitor the damage of glass fiber epoxy composites. Generally, conventional piezoelectric materials have higher piezoelectric characteristics through poling treatment. In this work, we investigated the change of the piezoelectric properties of glass fiber-reinforced epoxy composites before and after poling treatment. The piezoelectric constants (d 33 ) of glass fiber-reinforced epoxy composites increased by more than 400%. Also, x-ray diffraction tests revealed that poling treatment changed the degree of crystallinity of the epoxy matrix, and this led to the improvement of the piezoelectric characteristics of glass fiber-reinforced epoxy composites. (paper)

Model and Design of a Power Driver for Piezoelectric Stack Actuators

Directory of Open Access Journals (Sweden)

Chiaberge M

2010-01-01

Full Text Available A power driver has been developed to control piezoelectric stack actuators used in automotive application. An FEM model of the actuator has been implemented starting from experimental characterization of the stack and mechanical and piezoelectric parameters. Experimental results are reported to show a correct piezoelectric actuator driving method and the possibility to obtain a sensorless positioning control.

3D optical printing of piezoelectric nanoparticle-polymer composite materials.

Science.gov (United States)

Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

2014-10-28

Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ∼ 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning.

Fuzzy PID Feedback Control of Piezoelectric Actuator with Feedforward Compensation

Directory of Open Access Journals (Sweden)

Ziqiang Chi

2014-01-01

Full Text Available Piezoelectric actuator is widely used in the field of micro/nanopositioning. However, piezoelectric hysteresis introduces nonlinearity to the system, which is the major obstacle to achieve a precise positioning. In this paper, the Preisach model is employed to describe the hysteresis characteristic of piezoelectric actuator and an inverse Preisach model is developed to construct a feedforward controller. Considering that the analytical expression of inverse Preisach model is difficult to derive and not suitable for practical application, a digital inverse model is established based on the input and output data of a piezoelectric actuator. Moreover, to mitigate the compensation error of the feedforward control, a feedback control scheme is implemented using different types of control algorithms in terms of PID control, fuzzy control, and fuzzy PID control. Extensive simulation studies are carried out using the three kinds of control systems. Comparative investigation reveals that the fuzzy PID control system with feedforward compensation is capable of providing quicker response and better control accuracy than the other two ones. It provides a promising way of precision control for piezoelectric actuator.

Polymeric Nanofibers with Ultrahigh Piezoelectricity via Self-Orientation of Nanocrystals.

Science.gov (United States)

Liu, Xia; Ma, Jing; Wu, Xiaoming; Lin, Liwei; Wang, Xiaohong

2017-02-28

Piezoelectricity in macromolecule polymers has been gaining immense attention, particularly for applications in biocompatible, implantable, and flexible electronic devices. This paper introduces core-shell-structured piezoelectric polyvinylidene fluoride (PVDF) nanofibers chemically wrapped by graphene oxide (GO) lamellae (PVDF/GO nanofibers), in which the polar β-phase nanocrystals are formed and uniaxially self-oriented by the synergistic effect of mechanical stretching, high-voltage alignment, and chemical interactions. The β-phase orientation of the PVDF/GO nanofibers along their axes is observed at atomic scale through high resolution transmission electron microscopy, and the β-phase content is found to be 88.5%. The piezoelectric properties of the PVDF/GO nanofibers are investigated in terms of piezoresponse mapping, local hysteresis loops, and polarization reversal by advanced piezoresponse force microscopy. The PVDF/GO nanofibers show a desirable out-of-plane piezoelectric constant (d 33 ) of -93.75 pm V -1 (at 1.0 wt % GO addition), which is 426% higher than that of the conventional pure PVDF nanofibers. The mechanism behind this dramatic enhancement in piezoelectricity is elucidated by three-dimensional molecular modeling.

Deflection of Cross-Ply Composite Laminates Induced by Piezoelectric Actuators

Directory of Open Access Journals (Sweden)

Chi-Sheng Lin

2010-01-01

Full Text Available The coupling effects between the mechanical and electric properties of piezoelectric materials have drawn significant attention for their potential applications as sensors and actuators. In this investigation, two piezoelectric actuators are symmetrically surface bonded on a cross-ply composite laminate. Electric voltages with the same amplitude and opposite sign are applied to the two symmetric piezoelectric actuators, resulting in the bending effect on the laminated plate. The bending moment is derived by using the classical laminate theory and piezoelectricity. The analytical solution of the flexural displacement of the simply supported composite plate subjected to the bending moment is solved by using the plate theory. The analytical solution is compared with the finite element solution to show the validation of present approach. The effects of the size and location of the piezoelectric actuators on the response of the composite laminate are presented through a parametric study. A simple model incorporating the classical laminate theory and plate theory is presented to predict the deformed shape of the simply supported laminate plate.

Bending-induced electromechanical coupling and large piezoelectric response in a micromachined diaphragm

KAUST Repository

Wang, Zhihong

2013-11-04

We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr 0.52 Ti 0.48)O 3 (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC voltage. The curvature of the diaphragm was controlled by applying air pressure to its back. We found that a depolarized flat diaphragm does not initially exhibit electromechanical coupling or the piezoelectric response. However, upon the application of static air pressure to the diaphragm, both electromechanical coupling and the piezoelectric response can be induced in the originally depolarized diaphragm. The piezoelectric response increases as the curvature increases and a giant piezoelectric response can be obtained from a bent diaphragm. The obtained results clearly demonstrate that a high strain gradient in a diaphragm can polarize a PZT film through a flexoelectric effect, and that the induced piezoelectric response of the diaphragm can be controlled by adjusting its curvature.

Characterization of Direct Piezoelectric Properties for Vibration Energy Harvesting

Energy Technology Data Exchange (ETDEWEB)

Yoshimura, Takeshi; Miyabuchi, Hiroki; Ashida, Atsushi; Fujimura, Norifumi [Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531 (Japan); Murakami, Syuichi, E-mail: tyoshi@pe.osakafu-u.ac.jp [Technology Research Institute of Osaka Prefecture, 2-7-1 Ayumino, Izumi, Osaka, 594-1157 (Japan)

2011-10-29

Direct piezoelectric effect of Pb(Zr,Ti)O{sub 3} (PZT) thin films was investigated to discuss the application of ferroelectric films to vibration energy harvesting. From the model of the piezoelectric vibration energy harvester, it was found that the figure of merit (FOM) is proportional of the square of the effective transverse piezoelectric coefficient e{sub 31,f}. The e{sub 31,f} coefficient of PZT films were measured by substrate bending method. Furthermore, it was found that the e{sub 31,f} coefficient increases with increasing strain, which is favourable for the vibration energy harvesting.

Steel Bar corrosion monitoring based on encapsulated piezoelectric sensors

Science.gov (United States)

Xu, Ying; Tang, Tianyou

2018-05-01

The durability of reinforced concrete has a great impact on the structural bearing capacity, while the corrosion of steel bars is the main reason for the degradation of structural durability. In this paper, a new type of encapsulated cement based piezoelectric sensor is developed and its working performance is verified. The consistency of the finite element simulation and the experimental results shows the feasibility of monitoring the corrosion of steel bars using encapsulated piezoelectric sensors. The research results show that the corrosion conditions of the steel bars can be determined by the relative amplitude of the measured signal through the encapsulated piezoelectric sensor.

Noncontact inspection laser system for characterization of piezoelectric samples

International Nuclear Information System (INIS)

Jimenez, F.J.; Frutos, J. de

2004-01-01

In this work measurements on a piezoelectric sample in dynamic behavior were taken, in particular, around the frequencies of resonance for the sample where the nonlineal effects are accentuated. Dimension changes in the sample need to be studied as that will allow a more reliable characterization of the piezoelectric samples. The goal of this research is to develop an inspection system able to obtain measurements, using a noncontact laser displacement transducer, also able to visualize, in three-dimensional graphic environment, the displacement that takes place in a piezoelectric sample surface. In resonant mode, the vibration mode of the sample is visualized

Effect of water on piezoelectricity in bone and collagen.

Science.gov (United States)

Netto, T G; Zimmerman, R L

1975-01-01

Interferometric measurements of bovine bone and tendon show that the values of the piezoelectric strain constant d14 decrease with hydration from the dry values of 0.2 X 10(-14) and 2.0 X 10(-14) m/V, respectively. The decrease of piezoelectricity in tendon is exponential with a characteristic hydration of 7% by weight from which an upper limit of the average molecular weight of the responsible electric dipole moments is deduced. The piezoelectricity in bone decreases relatively slowly with hydration indicating that the electric dipoles in bone collagen are subject to a different cancelling mechanism. PMID:1148359

Cryogenic motion performances of a piezoelectric single crystal micromotor

Science.gov (United States)

Li, Xiaotian; Wu, Yuting; Chen, Zhijiang; Wei, Xiaoyong; Luo, Haosu; Dong, Shuxiang

2014-04-01

This study investigates the cryogenic performances of a millimeter-size piezoelectric ultrasonic linear micromotor. The piezoelectric vibrator of the micromotor is made of Pb(In1/2Nb1/2)O3 -Pb(Mg1/3Nb2/3)-PbTiO3 single crystal and operated in first-bending wobbling mode. Experiments show that the piezoelectric single crystal micromotor works effectively even at extremely low temperature of -175 °C, although its resonance peaks vary with temperature significantly. This work confirms the feasibility of cryogenic operation of the piezo-micromotor, which is meaningful for aerospace or superconducting microwave application.

Energy harvesting “3-D knitted spacer” based piezoelectric textiles

Science.gov (United States)

Anand, S.; Soin, N.; Shah, T. H.; Siores, E.

2016-07-01

The piezoelectric effect in Poly(vinylidene fluoride), PVDF, was discovered over four decades ago and since then, significant work has been carried out aiming at the production of high p-phase fibres and their integration into fabric structures for energy harvesting. However, little work has been done in the area of production of “true piezoelectric fabric structures” based on flexible polymeric materials such as PVDF. In this work, we demonstrate “3-D knitted spacer” technology based all-fibre piezoelectric fabrics as power generators and energy harvesters. The knitted single-structure piezoelectric generator consists of high p-phase (~80%) piezoelectric PVDF monofilaments as the spacer yarn interconnected between silver (Ag) coated polyamide multifilament yarn layers acting as the top and bottom electrodes. The novel and unique textile structure provides an output power density in the range of 1.105.10 gWcm-2 at applied impact pressures in the range of 0.02-0.10 MPa, thus providing significantly higher power outputs and efficiencies over the existing 2-D woven and nonwoven piezoelectric structures. The high energy efficiency, mechanical durability and comfort of the soft, flexible and all-fibre based power generator is highly attractive for a variety of potential applications such as wearable electronic systems and energy harvesters charged from ambient environment or by human movement.

Analysis of the transfer function for layered piezoelectric ultrasonic sensors

Directory of Open Access Journals (Sweden)

E. Gutiérrrez-Reyes

2017-06-01

Full Text Available We model theoretically the voltage response to an acoustic pulse of a multilayer system forming a low noise capacitive sensor including a Polyvinylidene Fluoride piezoelectric film. First we model a generic piezoelectric detector consisting of a piezoelectric film between two metallic electrodes that are the responsible to convert the acoustic signal into a voltage signal. Then we calculate the pressure-to-voltage transfer function for a N-layer piezo-electric capacitor detector, allowing to study the effects of the electrode and protective layers thickness in typical layered piezoelectric sensors. The derived transfer function, when multiplied by the Fourier transform of the incident acoustic pulse, gives the voltage electric response in the frequency domain. An important concern regarding the transfer function is that it may have zeros at specific frequencies, and thus inverting the voltage Fourier transform of the pulse to recover the pressure signal in the time domain is not always, in principle, possible. Our formulas can be used to predict the existence and locations of such zeroes. We illustrate the use of the transfer function by predicting the electric signal generated at a multilayer piezoelectric sensor to an ultrasonic pulse generated photoacoustically by a laser pulse at a three media system with impedance mismatch. This theoretical calculations are compared with our own experimental measurements.

Fabrication and Characterization of Aligned Flexible Lead-Free Piezoelectric Nanofibers for Wearable Device Applications

Directory of Open Access Journals (Sweden)

Sang Hyun Ji

2018-03-01

Full Text Available Flexible lead-free piezoelectric nanofibers, based on BNT-ST (0.78Bi0.5Na0.5TiO3-0.22SrTiO3 ceramic and poly(vinylidene fluoride-trifluoroethylene (PVDF-TrFE copolymers, were fabricated by an electrospinning method and the effects of the degree of alignment in the nanofibers on the piezoelectric characteristics were investigated. The microstructure of the lead-free piezoelectric nanofibers was observed by field emission scanning electron microscope (FE-SEM and the orientation was analyzed by fast Fourier transform (FFT images. X-ray diffraction (XRD analysis confirmed that the phase was not changed by the electrospinning process and maintained a perovskite phase. Polarization-electric field (P-E loops and piezoresponse force microscopy (PFM were used to investigate the piezoelectric properties of the piezoelectric nanofibers, according to the degree of alignment—the well aligned piezoelectric nanofibers had higher piezoelectric properties. Furthermore, the output voltage of the aligned lead-free piezoelectric nanofibers was measured according to the vibration frequency and the bending motion and the aligned piezoelectric nanofibers with a collector rotation speed of 1500 rpm performed the best.

Direct observation of shear piezoelectricity in poly-l-lactic acid nanowires

Directory of Open Access Journals (Sweden)

Michael Smith

2017-07-01

Full Text Available Piezoelectric polymers are capable of interconverting mechanical and electrical energy, and are therefore candidate materials for biomedical applications such as sensors, actuators, and energy harvesters. In particular, nanowires of these materials are attractive as they can be unclamped, flexible and sensitive to small vibrations. Poly-l-lactic acid (PLLA nanowires have been investigated for their use in biological applications, but their piezoelectric properties have never been fully characterised, even though macroscopic films and fibres have been shown to exhibit shear piezoelectricity. This piezoelectric mode is particularly interesting for in vivo applications where shear forces are especially relevant, and is similar to what has been observed in natural materials such as bone and DNA. Here, using piezo-response force microscopy (PFM, we report the first direct observation of shear piezoelectricity in highly crystalline and oriented PLLA nanowires grown by a novel template-wetting method. Our results are validated using finite-element simulations and numerical analysis, which importantly and more generally allow for accurate interpretation of PFM signals in soft nanostructured materials. Our work opens up the possibility for the development of biocompatible and sustainable piezoelectric nanogenerators and sensors based on polymer nanowires.

Direct observation of shear piezoelectricity in poly-l-lactic acid nanowires

Science.gov (United States)

Smith, Michael; Calahorra, Yonatan; Jing, Qingshen; Kar-Narayan, Sohini

2017-07-01

Piezoelectric polymers are capable of interconverting mechanical and electrical energy, and are therefore candidate materials for biomedical applications such as sensors, actuators, and energy harvesters. In particular, nanowires of these materials are attractive as they can be unclamped, flexible and sensitive to small vibrations. Poly-l-lactic acid (PLLA) nanowires have been investigated for their use in biological applications, but their piezoelectric properties have never been fully characterised, even though macroscopic films and fibres have been shown to exhibit shear piezoelectricity. This piezoelectric mode is particularly interesting for in vivo applications where shear forces are especially relevant, and is similar to what has been observed in natural materials such as bone and DNA. Here, using piezo-response force microscopy (PFM), we report the first direct observation of shear piezoelectricity in highly crystalline and oriented PLLA nanowires grown by a novel template-wetting method. Our results are validated using finite-element simulations and numerical analysis, which importantly and more generally allow for accurate interpretation of PFM signals in soft nanostructured materials. Our work opens up the possibility for the development of biocompatible and sustainable piezoelectric nanogenerators and sensors based on polymer nanowires.

The vibrational and buckling behaviors of piezoelectric nanobeams with surface effects

International Nuclear Information System (INIS)

Yan, Z; Jiang, L Y

2011-01-01

In this work, the influence of surface effects, including residual surface stress, surface elasticity and surface piezoelectricity, on the vibrational and buckling behaviors of piezoelectric nanobeams is investigated by using the Euler-Bernoulli beam theory. The surface effects are incorporated by applying the surface piezoelectricity model and the generalized Young-Laplace equations. The results demonstrate that surface effects play a significant role in predicting these behaviors. It is found that the influence of the residual surface stress and the surface piezoelectricity on the resonant frequencies and the critical electric potential for buckling is more prominent than the surface elasticity. The nanobeam boundary conditions are also found to influence the surface effects on these parameters. This study also shows that the resonant frequencies can be tuned by adjusting the applied electrical load. The present study is envisaged to provide useful insights for the design and applications of piezoelectric-beam-based nanodevices.

BaTiO3-based piezoelectrics: Fundamentals, current status, and perspectives

Science.gov (United States)

Acosta, M.; Novak, N.; Rojas, V.; Patel, S.; Vaish, R.; Koruza, J.; Rossetti, G. A.; Rödel, J.

2017-12-01

We present a critical review that encompasses the fundamentals and state-of-the-art knowledge of barium titanate-based piezoelectrics. First, the essential crystallography, thermodynamic relations, and concepts necessary to understand piezoelectricity and ferroelectricity in barium titanate are discussed. Strategies to optimize piezoelectric properties through microstructure control and chemical modification are also introduced. Thereafter, we systematically review the synthesis, microstructure, and phase diagrams of barium titanate-based piezoelectrics and provide a detailed compilation of their functional and mechanical properties. The most salient materials treated include the (Ba,Ca)(Zr,Ti)O3, (Ba,Ca)(Sn,Ti)O3, and (Ba,Ca)(Hf,Ti)O3 solid solution systems. The technological relevance of barium titanate-based piezoelectrics is also discussed and some potential market indicators are outlined. Finally, perspectives on productive lines of future research and promising areas for the applications of these materials are presented.

Piezoelectricity and absorption of water in biomaterials: bone and tendon

International Nuclear Information System (INIS)

Ghilardi Netto, T.

1973-01-01

A new application of the Fabry-Perot interferometer has been developed, capable of measuring variations in length with a precision of the order of one angstrom. The method has been applied to the determination of some of the inverse piezoelectric coefficients of bovine bone and tendon. The effect of water in these materials was carefully measured and shown to decrease the piezoelectricity. Correlations between the piezoelectricity and length, weight, and volume and surface resistivity were made during the absorption of water [pt

Piezoelectric energy harvesting for powering low power electronics

Energy Technology Data Exchange (ETDEWEB)

Leinonen, M.; Palosaari, J.; Hannu, J.; Juuti, J.; Jantunen, H. (Univ. of Oulu, Dept. of Electrical and Information Engineering (Finland)). email: jajuu@ee.oulu.fi

2009-07-01

Although wireless data transmission techniques are commonly used in electronic devices, they still suffer from wires for the power supply or from batteries which require charging, replacement and other maintenance. The vision for the portable electronics and industrial measurement systems of the future is that they are intelligent and independent on their energy supply. The major obstacle in this path is the energy source which enables all other functions and 'smartness' of the systems as the computing power is also restricted by the available energy. The development of long-life energy harvesters would reduce the need for batteries and wires thus enabling cost-effective and environment friendlier solutions for various applications such as autonomous wireless sensor networks, powering of portable electronics and other maintenance-free systems. One of the most promising techniques is mechanical energy harvesting e.g. by piezoelectric components where deformations produced by different means is directly converted to electrical charge via direct piezoelectric effect. Subsequently the electrical energy can be regulated or stored for further use. The total mechanical energy in vibration of machines can be very large and usually only a fraction of it can be transformed to electrical energy. Recently, piezoelectric vibration based energy harvesters have been developed widely for different energy consumption and application areas. As an example for low energy device an piezoelectric energy harvester based on impulse type excitations has been developed for active RFID identification. Moreover, piezoharvester with externally leveraged mechanism for force amplification was reported to be able to generate mean power of 0.4 mW from backpack movement. Significantly higher power levels are expected from larger scale testing in Israel, where piezoelectric material is embedded under active walking street, road, airport or railroad. The energy is harvested from human or

Switchable static friction of piezoelectric composite-silicon wafer contacts

NARCIS (Netherlands)

Ende, D.A. van den; Fischer, H.R.; Groen, W.A.; Zwaag, S. van der

2013-01-01

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and

Switchable static friction of piezoelectric composite—silicon wafer contacts

NARCIS (Netherlands)

Van den Ende, D.A.; Fischer, H.R.; Groen, W.A.; Van der Zwaag, S.

2013-01-01

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and

3D, wideband vibro-impacting-based piezoelectric energy harvester

Energy Technology Data Exchange (ETDEWEB)

Yu, Qiangmo; Yang, Jin, E-mail: yangjin@cqu.edu.cn; Yue, Xihai; Yang, Aichao; Zhao, Jiangxin; Zhao, Nian; Wen, Yumei; Li, Ping [Department of Optoelectronic Engineering, Research Center of Sensors and Instruments, Chongqing University, Chongqing 400044 (China)

2015-04-15

An impacting-based piezoelectric energy harvester was developed to address the limitations of the existing approaches in single-dimensional operation as well as a narrow working bandwidth. In the harvester, a spiral cylindrical spring rather than the conventional thin cantilever beam was utilized to extract the external vibration with arbitrary directions, which has the capability to impact the surrounding piezoelectric beams to generate electricity. And the introduced vibro-impacting between the spiral cylindrical spring and multi-piezoelectric-beams resulted in not only a three-dimensional response to external vibration, but also a bandwidth-broadening behavior. The experimental results showed that each piezoelectric beam exhibited a maximum bandwidth of 8 Hz and power of 41 μW with acceleration of 1 g (with g=9.8 ms{sup −2}) along the z-axis, and corresponding average values of 5 Hz and 45 μW with acceleration of 0.6 g in the x-y plane. .

3D, wideband vibro-impacting-based piezoelectric energy harvester

International Nuclear Information System (INIS)

Yu, Qiangmo; Yang, Jin; Yue, Xihai; Yang, Aichao; Zhao, Jiangxin; Zhao, Nian; Wen, Yumei; Li, Ping

2015-01-01

An impacting-based piezoelectric energy harvester was developed to address the limitations of the existing approaches in single-dimensional operation as well as a narrow working bandwidth. In the harvester, a spiral cylindrical spring rather than the conventional thin cantilever beam was utilized to extract the external vibration with arbitrary directions, which has the capability to impact the surrounding piezoelectric beams to generate electricity. And the introduced vibro-impacting between the spiral cylindrical spring and multi-piezoelectric-beams resulted in not only a three-dimensional response to external vibration, but also a bandwidth-broadening behavior. The experimental results showed that each piezoelectric beam exhibited a maximum bandwidth of 8 Hz and power of 41 μW with acceleration of 1 g (with g=9.8 ms −2 ) along the z-axis, and corresponding average values of 5 Hz and 45 μW with acceleration of 0.6 g in the x-y plane. 

Integration of bulk piezoelectric materials into microsystems

Science.gov (United States)

Aktakka, Ethem Erkan

Bulk piezoelectric ceramics, compared to deposited piezoelectric thin-films, provide greater electromechanical coupling and charge capacity, which are highly desirable in many MEMS applications. In this thesis, a technology platform is developed for wafer-level integration of bulk piezoelectric substrates on silicon, with a final film thickness of 5-100microm. The characterized processes include reliable low-temperature (200°C) AuIn diffusion bonding and parylene bonding of bulk-PZT on silicon, wafer-level lapping of bulk-PZT with high-uniformity (+/-0.5microm), and low-damage micro-machining of PZT films via dicing-saw patterning, laser ablation, and wet-etching. Preservation of ferroelectric and piezoelectric properties is confirmed with hysteresis and piezo-response measurements. The introduced technology offers higher material quality and unique advantages in fabrication flexibility over existing piezoelectric film deposition methods. In order to confirm the preserved bulk properties in the final film, diaphragm and cantilever beam actuators operating in the transverse-mode are designed, fabricated and tested. The diaphragm structure and electrode shapes/sizes are optimized for maximum deflection through finite-element simulations. During tests of fabricated devices, greater than 12microm PP displacement is obtained by actuation of a 1mm2 diaphragm at 111kHz with integration of a 50-80% efficient power management IC, which incorporates a supply-independent bias circuitry, an active diode for low-dropout rectification, a bias-flip system for higher efficiency, and a trickle battery charger. The overall system does not require a pre-charged battery, and has power consumption of <1microW in active-mode (measured) and <5pA in sleep-mode (simulated). Under lg vibration at 155Hz, a 70mF ultra-capacitor is charged from OV to 1.85V in 50 minutes.

Piezoelectric array elements for sound reconstruction with a digital input

KAUST Repository

Carreno, Armando Arpys Arevalo

2016-10-13

Various examples are provided for digital sound reconstruction using piezoelectric array elements. In one example, a digital loudspeaker includes a fixed frame and an array of transducers disposed on the fixed frame. Individual transducers of the array of transducers can include a flexible membrane disposed on a piezoelectric actuation element positioned over a corresponding opening that extends through the fixed frame. In another example, a method includes forming a flexible membrane structure on a substrate and backetching the substrate opposite the flexible membrane structure. The flexible membrane structure can be formed by disposing a first electrode layer on a substrate, disposing a piezoelectric layer on the first electrode layer and disposing a second electrode layer on the piezoelectric layer. A flexible membrane layer (e.g., polyimide) can be disposed on the second electrode layer.

Design, Manufacturing and Characterization of Functionally Graded Flextensional Piezoelectric Actuators

International Nuclear Information System (INIS)

Amigo, R C R; Vatanabe, S L; Silva, E C N

2013-01-01

Previous works have been shown several advantages in using Functionally Graded Materials (FGMs) for the performance of flextensional devices, such as reduction of stress concentrations and gains in reliability. In this work, the FGM concept is explored in the design of graded devices by using the Topology Optimization Method (TOM), in order to determine optimal topologies and gradations of the coupled structures of piezoactuators. The graded pieces are manufactured by using the Spark Plasma Sintering (SPS) technique and are bonded to piezoelectric ceramics. The graded actuators are then tested by using a modular vibrometer system for measuring output displacements, in order to validate the numerical simulations. The technological path developed here represents the initial step toward the manufacturing of an integral piezoelectric device, constituted by piezoelectric and non-piezoelectric materials without bonding layers.

Advances in Lead-Free Piezoelectric Materials for Sensors and Actuators

Directory of Open Access Journals (Sweden)

Jacob L. Jones

2010-03-01

Full Text Available Piezoelectrics have widespread use in today’s sensor and actuator technologies. However, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1-x] O3 (PZT,are comprised of more than 60 weight percent lead (Pb. Dueto its harmful effects, there is a strong impetus to identify new lead-free replacement materials with comparable properties to those of PZT. This review highlights recent developments in several lead-free piezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3, and their solid solutions. The factors that contribute to strong piezoelectric behavior are described and a summary of the properties for the various systems is provided.

Piezoelectric Actuator with Frequency Characteristics for a Middle-Ear Implant.

Science.gov (United States)

Shin, Dong Ho; Cho, Jin-Ho

2018-05-24

The design and implementation of a novel piezoelectric-based actuator for an implantable middle-ear hearing aid is described in this paper. The proposed actuator has excellent low-frequency output characteristics, and can generate high output in a specific frequency band by adjusting the mechanical resonance. The actuator consists of a piezoelectric element, a miniature bellows, a cantilever membrane, a metal ring support, a ceramic tip, and titanium housing. The optimal structure of the cantilever-membrane design, which determines the frequency characteristics of the piezoelectric actuator, was derived through finite element analysis. Based on the results, the piezoelectric actuator was implemented, and its performance was verified through a cadaveric experiment. It was confirmed that the proposed actuator provides better performance than currently used actuators, in terms of frequency characteristics.

Lead-free piezoelectric transducers for vibration-based energy harvesting devices

Energy Technology Data Exchange (ETDEWEB)

Roescher, Mark

2011-11-15

Future applications like piezoelectric energy harvesters in addition with increasing environmental awareness ultimately demand novel sophisticated material systems in the field of piezoelectrics as an alternative to the long-established system lead-zirconate-titanate. In this publication state-of-the-art microgenerators have been designed to possess nonlinear Duffing oscillator characteristics. It is shown by measurement and simulation that lead-zirconate-titanate may hence no longer be the first choice in material selection for a piezoelectric microgenerator. Polyvinylidene fluoride has been integrated in a piezoelectric microgenerator and identified as an extraordinarily promising material system for transducer applications being highly insusceptible to stretching induced material failure. Finally, a fundamentally new chemical synthesis approach has been developed for the fabrication of potassium-sodium-niobate films that may also be suitable for other complex oxides.

Piezoelectric Materials Synthesized by the Hydrothermal Method and Their Applications

Directory of Open Access Journals (Sweden)

Takeshi Morita

2010-12-01

Full Text Available Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate (PZT thin film was applied to a micro ultrasonic motor, and an epitaxial lead titanate (PbTiO3 thin film was estimated as a ferroelectric data storage medium. Ferroelectric and piezoelectric properties were successfully obtained for epitaxial PbTiO3 films. As lead-free piezoelectric powders, KNbO3 and NaNbO3 powders were synthesized by the hydrothermal method and sintered together to form (K,NaNbO3 ceramics, from which reasonable piezoelectric performance was achieved.

Piezoelectric array elements for sound reconstruction with a digital input

KAUST Repository

Carreno, Armando Arpys Arevalo; Gonzalez, David Conchouso; Signoret, David Castro; Foulds, Ian G.

2016-01-01

Various examples are provided for digital sound reconstruction using piezoelectric array elements. In one example, a digital loudspeaker includes a fixed frame and an array of transducers disposed on the fixed frame. Individual transducers of the array of transducers can include a flexible membrane disposed on a piezoelectric actuation element positioned over a corresponding opening that extends through the fixed frame. In another example, a method includes forming a flexible membrane structure on a substrate and backetching the substrate opposite the flexible membrane structure. The flexible membrane structure can be formed by disposing a first electrode layer on a substrate, disposing a piezoelectric layer on the first electrode layer and disposing a second electrode layer on the piezoelectric layer. A flexible membrane layer (e.g., polyimide) can be disposed on the second electrode layer.

Characterization of piezoelectric materials for simultaneous strain and temperature sensing for ultra-low frequency applications

International Nuclear Information System (INIS)

Islam, Mohammad Nouroz; Seethaler, Rudolf; Alam, M Shahria

2015-01-01

Piezoelectric materials are used extensively in a number of sensing applications ranging from aerospace industries to medical diagnostics. Piezoelectric materials generate charge when they are subjected to strain. However, since measuring charge is difficult at low frequencies, traditional piezoelectric sensors are limited to dynamic applications. In this research an alternative technique is proposed to determine static strain that relies upon the measurement of piezoelectric capacitance and resistance using piezoelectric sensors. To demonstrate the validity of this approach, the capacitance and resistance of a piezoelectric patch sensor was characterized for a wide range of strain and temperature. The study shows that the piezoelectric capacitance is sensitive to both strain and temperature while the resistance is mostly dependent on the temperature variation. The findings can be implemented to obtain thermally compensated static strain from piezoelectric sensors, which does not require an additional temperature sensor. (paper)

Microstructure Control of Barium Titanate Grain-oriented Ceramics and Their Piezoelectric Properties

International Nuclear Information System (INIS)

Mori, Rintaro; Nakashima, Koichi; Fujii, Ichiro; Wada, Satoshi; Hayashi, Hiroshi; Nagamori, Yoshitaka; Yamamoto, Yuichi

2011-01-01

The Barium titanate (BaTiO 3 , BT) [110] grain-oriented ceramics along [110] direction were prepared by a templated grain growth (TGG) method. The [110] oriented BT platelike particles (t-BT) were used as template particles. The relationship between poling treatment program and piezoelectric constant was investigated. The change in the poling conditions did not greatly influence domain size and the piezoelectric constant. The relationship between piezoelectric properties and domain size in BT grain-oriented ceramics was investigated. The smaller domain size was required to increase the piezoelectric constant.

Development and Research of Peristaltic Multiphase Piezoelectric Micro-Pump

Science.gov (United States)

Vinogradov, Alexander N.; Ivanikin, Igor A.; Lubchenco, Roman V.; Matveev, Yegor V.; Titov, Pavel A.

2016-01-01

The paper presents the results of a study of existing models and mathematical representations of a range of truly peristaltic multiphase micro-pumps with a piezoelectric actuator (piezo drive). Piezo drives with different types of substrates use vertical movements at deformation of individual piezoelectric elements, which define device…

Development of a commercially viable piezoelectric force sensor system for static force measurement

Science.gov (United States)

Liu, Jun; Luo, Xinwei; Liu, Jingcheng; Li, Min; Qin, Lan

2017-09-01

A compensation method for measuring static force with a commercial piezoelectric force sensor is proposed to disprove the theory that piezoelectric sensors and generators can only operate under dynamic force. After studying the model of the piezoelectric force sensor measurement system, the principle of static force measurement using a piezoelectric material or piezoelectric force sensor is analyzed. Then, the distribution law of the decay time constant of the measurement system and the variation law of the measurement system’s output are studied, and a compensation method based on the time interval threshold Δ t and attenuation threshold Δ {{u}th} is proposed. By calibrating the system and considering the influences of the environment and the hardware, a suitable Δ {{u}th} value is determined, and the system’s output attenuation is compensated based on the Δ {{u}th} value to realize the measurement. Finally, a static force measurement system with a piezoelectric force sensor is developed based on the compensation method. The experimental results confirm the successful development of a simple compensation method for static force measurement with a commercial piezoelectric force sensor. In addition, it is established that, contrary to the current perception, a piezoelectric force sensor system can be used to measure static force through further calibration.

Distributed parameter modeling to prevent charge cancellation for discrete thickness piezoelectric energy harvester

Science.gov (United States)

Krishnasamy, M.; Qian, Feng; Zuo, Lei; Lenka, T. R.

2018-03-01

The charge cancellation due to the change of strain along single continuous piezoelectric layer can remarkably affect the performance of a cantilever based harvester. In this paper, analytical models using distributed parameters are developed with some extent of averting the charge cancellation in cantilever piezoelectric transducer where the piezoelectric layers are segmented at strain nodes of concerned vibration mode. The electrode of piezoelectric segments are parallelly connected with a single external resistive load in the 1st model (Model 1). While each bimorph piezoelectric layers are connected in parallel to a resistor to form an independent circuit in the 2nd model (Model 2). The analytical expressions of the closed-form electromechanical coupling responses in frequency domain under harmonic base excitation are derived based on the Euler-Bernoulli beam assumption for both models. The developed analytical models are validated by COMSOL and experimental results. The results demonstrate that the energy harvesting performance of the developed segmented piezoelectric layer models is better than the traditional model of continuous piezoelectric layer.

Micromechanics approach to the magnetoelectric properties of laminate and fibrous piezoelectric/magnetostrictive composites

International Nuclear Information System (INIS)

Huang Haitao; Zhou, L.M.

2004-01-01

We use a micromechanics approach to study the magnetoelectric (ME) properties of the piezoelectric/magnetostrictive composite with a 2-2 laminate structure and a 3-1 fibrous structure. It is found that the 3-1 composite has a higher ME coefficient than the 2-2 one, if the volume ratio of piezoelectric material is the same. The reason is that the 3-1 fibrous composite makes use of the longitudinal piezoelectric response and the piezoelectric voltage constant g 33 is 2-3 times that of g 31 . Generally, a smaller volume ratio of the piezoelectric material will generate a higher ME response. The tensile stress at the piezoelectric/magnetostrictive interface of the 3-1 fibrous composite, however, could be high enough to induce plastic deformation or microcracks, which leads to a ME coefficient lower than the theoretically predicted one

Vibration control for precision manufacturing using piezoelectric actuators

Energy Technology Data Exchange (ETDEWEB)

Martinez, D.R.; Hinnerichs, T.D.; Redmond, J.M.

1995-12-31

Piezoelectric actuators provide high frequency, force, and stiffness capabilities along with reasonable Stroke limits, all of which can be used to increase performance levels in precision manufacturing systems. This paper describes two examples of embedding piezoelectric actuators in structural components for vibration control. One example involves suppressing the self excited chatter phenomenon in the metal cutting process of a milling machine and the other involves damping vibrations induced by rigid body stepping of a photolithography platen. Finite element modeling and analyses are essential for locating and sizing the actuators and permit further simulation studies of the response of the dynamic system. Experimental results are given for embedding piezoelectric actuators in a cantilevered bar configuration, which was used as a surrogate machine tool structure. These results are incorporated into a previously developed milling process simulation and the effect of the control on the cutting process stability diagram is quantified. Experimental results are also given for embedding three piezoelectric actuators in a surrogate photolithography platen to suppress vibrations. These results demonstrate the potential benefit that can be realized by applying advances from the field of adaptive structures to problems in precision manufacturing.

An Assessment of New Applications for Single-Crystal Piezoelectric Materials

National Research Council Canada - National Science Library

Veitch, Lisa

1998-01-01

Piezoelectricity was first discovered by the Curie brothers in 1880. During the 1940s, piezoelectric ceramic materials were first used in commercial devices, and new materials and other applications have continued to develop over the years...

Electromechanical response of (2–2) layered piezoelectric composites

International Nuclear Information System (INIS)

Kar-Gupta, Ronit; Venkatesh, T A

2013-01-01

Analytical and finite element models are developed to systematically characterize the effects of phase volume fraction and the relative orientations of the poling directions in two phases on the effective elastic, dielectric and piezoelectric properties of layered piezoelectric composites. Four classes of layered piezoelectric composites are identified based on the relative orientation of the poling directions in the two piezoelectric phases. Upon verifying that the results of the finite model compare well with that of analytical models for select layered composite systems, the finite element model is extended to characterize the electromechanical response of all four classes of piezoelectric composites. It is generally observed that the electromechanical properties of the layered composite along a direction perpendicular to the layer interface is largely influenced by the properties of the ‘softer’ phase whereas the in-plane response is modulated more by the ‘rule-of-mixtures’ theory. It is also observed that variations in the poling directions of the constituents can significantly influence the symmetry of the composite with composites that belong to Classes II and III (where the poling directions of the two phases are orthogonal to each other) exhibiting a relatively lower degree of material symmetry while the composites that belong to Classes I and IV (where the poling directions of the two phases are parallel to each other) exhibit a higher order symmetry. Furthermore, the best combination of figures of merit, i.e., enhanced coupling constant and reduced acoustic impedance, in a direction parallel to the layer interface is exhibited by Class I and Class II types of composite (where the piezoelectrically stiffer phase is poled along the layer interface). (paper)

Use of piezoelectric multicomponent force measuring devices in fluid mechanics

Science.gov (United States)

Richter, A.; Stefan, K.

1979-01-01

The characterisitics of piezoelectric multicomponent transducers are discussed, giving attention to the advantages of quartz over other materials. The main advantage of piezoelectric devices in aerodynamic studies is their ability to indicate rapid changes in the values of physical parameters. Problems in the accuracy of measurments by piezoelectric devices can be overcome by suitable design approaches. A practical example is given of how such can be utilized to measure rapid fluctuations of fluid forces exerted on a circular cylinder mounted in a water channel.

The origin of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals

Energy Technology Data Exchange (ETDEWEB)

Li, Fei; Zhang, Shujun; Yang, Tiannan; Xu, Zhuo; Zhang, Nan; Liu, Gang; Wang, Jianjun; Wang, Jianli; Cheng, Zhenxiang; Ye, Zuo-Guang; Luo, Jun; Shrout, Thomas R.; Chen, Long-Qing (Penn); (Xian Jiaotong); (CIW); (Simon); (TRS Techn); (Wollongong)

2016-12-19

The discovery of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution single crystals is a breakthrough in ferroelectric materials. A key signature of relaxor-ferroelectric solid solutions is the existence of polar nanoregions, a nanoscale inhomogeneity, that coexist with normal ferroelectric domains. Despite two decades of extensive studies, the contribution of polar nanoregions to the underlying piezoelectric properties of relaxor ferroelectrics has yet to be established. Here we quantitatively characterize the contribution of polar nanoregions to the dielectric/piezoelectric responses of relaxor-ferroelectric crystals using a combination of cryogenic experiments and phase-field simulations. The contribution of polar nanoregions to the room-temperature dielectric and piezoelectric properties is in the range of 50–80%. A mesoscale mechanism is proposed to reveal the origin of the high piezoelectricity in relaxor ferroelectrics, where the polar nanoregions aligned in a ferroelectric matrix can facilitate polarization rotation. This mechanism emphasizes the critical role of local structure on the macroscopic properties of ferroelectric materials.

The origin of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution crystals.

Science.gov (United States)

Li, Fei; Zhang, Shujun; Yang, Tiannan; Xu, Zhuo; Zhang, Nan; Liu, Gang; Wang, Jianjun; Wang, Jianli; Cheng, Zhenxiang; Ye, Zuo-Guang; Luo, Jun; Shrout, Thomas R; Chen, Long-Qing

2016-12-19

The discovery of ultrahigh piezoelectricity in relaxor-ferroelectric solid solution single crystals is a breakthrough in ferroelectric materials. A key signature of relaxor-ferroelectric solid solutions is the existence of polar nanoregions, a nanoscale inhomogeneity, that coexist with normal ferroelectric domains. Despite two decades of extensive studies, the contribution of polar nanoregions to the underlying piezoelectric properties of relaxor ferroelectrics has yet to be established. Here we quantitatively characterize the contribution of polar nanoregions to the dielectric/piezoelectric responses of relaxor-ferroelectric crystals using a combination of cryogenic experiments and phase-field simulations. The contribution of polar nanoregions to the room-temperature dielectric and piezoelectric properties is in the range of 50-80%. A mesoscale mechanism is proposed to reveal the origin of the high piezoelectricity in relaxor ferroelectrics, where the polar nanoregions aligned in a ferroelectric matrix can facilitate polarization rotation. This mechanism emphasizes the critical role of local structure on the macroscopic properties of ferroelectric materials.

Unified treatment of coupled optical and acoustic phonons in piezoelectric cubic materials

DEFF Research Database (Denmark)

Willatzen, Morten; Wang, Zhong Lin

2015-01-01

A unified treatment of coupled optical and acoustic phonons in piezoelectric cubic materials is presented whereby the lattice displacement vector and the internal ionic displacement vector are found simultaneously. It is shown that phonon couplings exist in pairs only; either between the electric...... piezoelectricity in a cubic structured material slab. First, it is shown that isolated optical phonon modes generally cannot exist in piezoelectric cubic slabs. Second, we prove that confined acousto-optical phonon modes only exist for a discrete set of in-plane wave numbers in piezoelectric cubic slabs. Third...... potential and the lattice displacement coordinate perpendicular to the phonon wave vector or between the two other lattice displacement components. The former leads to coupled acousto-optical phonons by virtue of the piezoelectric effect. We then establish three new conjectures that entirely stem from...

Feasibility of Energy Harvesting Using a Piezoelectric Tire

Science.gov (United States)

Malotte, Christopher

While the piezoelectric effect has been around for some time, it has only recently caught interest as a potential sustainable energy harvesting device. Piezoelectric energy harvesting has been developed for shoes and panels, but has yet to be integrated into a marketable bicycle tire. For this thesis, the development and feasibility of a piezoelectric tire was done. This includes the development of a circuit that incorporates piezoceramic elements, energy harvesting circuitry, and an energy storage device. A single phase circuit was designed using an ac-dc diode rectifier. An electrolytic capacitor was used as the energy storage device. A financial feasibility was also done to determine targets for manufacturing cost and sales price. These models take into account market trends for high performance tires, economies of scale, and the possibility of government subsidies. This research will help understand the potential for the marketability of a piezoelectric energy harvesting tire that can create electricity for remote use. This study found that there are many obstacles that must be addressed before a piezoelectric tire can be marketed to the general public. The power output of this device is minuscule compared to an alkaline battery. In order for this device to approach the power output of an alkaline battery the weight of the device would also become an issue. Additionally this device is very costly compared to the average bicycle tire. Lastly, this device is extreme fragile and easily broken. In order for this device to become marketable the issues of power output, cost, weight, and durability must all be successfully overcome.

Energy harvesting from radio frequency propagation using piezoelectric cantilevers

KAUST Repository

Al Ahmad, Mahmoud

2012-02-01

This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates in the line it sets an alternating current in the actuator electrodes. This flowing current drives the piezoelectric cantilever to mechanical movement, especially when the frequency of the RF signal matches the mechanical resonant frequency of the cantilever. Output voltage signals versus frequency for both mechanical vibrational and RF signal excitations have been measured using different loads.© 2011 Elsevier Ltd. All rights reserved.

Modeling Bistable Composite Laminates for Piezoelectric Morphing Structures

OpenAIRE

Darryl V. Murray; Oliver J. Myers

2013-01-01

A sequential modeling effort for bistable composite laminates for piezoelectric morphing structures is presented. Thin unsymmetric carbon fiber composite laminates are examined for use of morphing structures using piezoelectric actuation. When cooling from the elevated cure temperature to room temperature, these unsymmetric composite laminates will deform. These postcure room temperature deformation shapes can be used as morphing structures. Applying a force to these deformed laminates will c...

Piezoelectricity of chiral polymeric fiber and its application in biomedical engineering.

Science.gov (United States)

Tajitsu, Y

2008-05-01

Poly-L-lactic acid (PLLA), which is a type of chiral polymer, exhibits a high shear piezoelectric constant. To realize a higher shear piezoelectric constant, we spun PLLA resin into fibers. We succeeded in controlling the piezoelectric motion of a PLLA fiber by applying a dc voltage and ac voltage, similar to the control of a piezoelectric actuator. On the basis of this experimental result, we designed a catheter using a PLLA fiber (PLLA fiber catheter) and tweezers using a pair of PLLA fibers (PLLA fiber tweezers), controlled by adjusting the applied voltage. Then, using the PLLA fiber tweezers or catheter, we successfully picked up and removed small samples, such as a thrombosis in a blood vessel.

Enhanced piezoelectric properties of vertically aligned single-crystalline NKN nano-rod arrays.

Science.gov (United States)

Kang, Min-Gyu; Oh, Seung-Min; Jung, Woo-Suk; Moon, Hi Gyu; Baek, Seung-Hyub; Nahm, Sahn; Yoon, Seok-Jin; Kang, Chong-Yun

2015-05-08

Piezoelectric materials capable of converting between mechanical and electrical energy have a great range of potential applications in micro- and nano-scale smart devices; however, their performance tends to be greatly degraded when reduced to a thin film due to the large clamping force by the substrate and surrounding materials. Herein, we report an effective method for synthesizing isolated piezoelectric nano-materials as means to relax the clamping force and recover original piezoelectric properties of the materials. Using this, environmentally friendly single-crystalline NaxK1-xNbO3 (NKN) piezoelectric nano-rod arrays were successfully synthesized by conventional pulsed-laser deposition and demonstrated to have a remarkably enhanced piezoelectric performance. The shape of the nano-structure was also found to be easily manipulated by varying the energy conditions of the physical vapor. We anticipate that this work will provide a way to produce piezoelectric micro- and nano-devices suitable for practical application, and in doing so, open a new path for the development of complex metal-oxide nano-structures.

Individual GaN nanowires exhibit strong piezoelectricity in 3D.

Science.gov (United States)

Minary-Jolandan, Majid; Bernal, Rodrigo A; Kuljanishvili, Irma; Parpoil, Victor; Espinosa, Horacio D

2012-02-08

Semiconductor GaN NWs are promising components in next generation nano- and optoelectronic systems. In addition to their direct band gap, they exhibit piezoelectricity, which renders them particularly attractive in energy harvesting applications for self-powered devices. Nanowires are often considered as one-dimensional nanostructures; however, the electromechanical coupling leads to a third rank tensor that for wurtzite crystals (GaN NWs) possesses three independent coefficients, d(33), d(13), and d(15). Therefore, the full piezoelectric characterization of individual GaN NWs requires application of electric fields in different directions and measurements of associated displacements on the order of several picometers. In this Letter, we present an experimental approach based on scanning probe microscopy to directly quantify the three-dimensional piezoelectric response of individual GaN NWs. Experimental results reveal that GaN NWs exhibit strong piezoelectricity in three dimensions, with up to six times the effect in bulk. Based on finite element modeling, this finding has major implication on the design of energy harvesting systems exhibiting unprecedented levels of power density production. The presented method is applicable to other piezoelectric NW materials as well as wires manufactured along different crystallographic orientations. © 2011 American Chemical Society

A study on impact monitoring using a piezoelectric paint sensor

International Nuclear Information System (INIS)

Choi, Kyung Woo; Kang, Dong Hoon; Park, Seung Bok; Kang, Lae Hyong

2015-01-01

The piezoelectric paint sensor is a paint type sensor comprising of an epoxy and piezoelectric powder, which is the main component of a piezoelectric material. This sensor can be easily attached to any type of structure as compared to other sensors because it is viable to directly apply it on structures, as in the case with a typical paint. In this study, the capability of piezoelectric paint sensor for impact detection was evaluated. In Particular, the applications of the piezoelectric paint sensor for railroad vehicles were considered. There have been various cases reported about the damages caused by flying gravel to the under-cover of the railroad vehicle during operation. In order to prevent this, real-time monitoring of the large under-cover surface of the railroad vehicle is unavoidable. Under the assumption of vehicle application, sensor sensitivities were measured after multiple and prolonged exposure to thermal cycle environment -20⁓60 degrees Celsius). Sensitivity evaluation of paint sensor under environmental conditions was conducted in an aluminum specimen. In results, despite the small variations in sensitivity, we could confirm the applicability of this paint sensor for impact detection even after a severe environmental exposure test

Identification of elastic, dielectric, and piezoelectric constants in piezoceramic disks.

Science.gov (United States)

Perez, Nicolas; Andrade, Marco A B; Buiochi, Flavio; Adamowski, Julio C

2010-12-01

Three-dimensional modeling of piezoelectric devices requires a precise knowledge of piezoelectric material parameters. The commonly used piezoelectric materials belong to the 6mm symmetry class, which have ten independent constants. In this work, a methodology to obtain precise material constants over a wide frequency band through finite element analysis of a piezoceramic disk is presented. Given an experimental electrical impedance curve and a first estimate for the piezoelectric material properties, the objective is to find the material properties that minimize the difference between the electrical impedance calculated by the finite element method and that obtained experimentally by an electrical impedance analyzer. The methodology consists of four basic steps: experimental measurement, identification of vibration modes and their sensitivity to material constants, a preliminary identification algorithm, and final refinement of the material constants using an optimization algorithm. The application of the methodology is exemplified using a hard lead zirconate titanate piezoceramic. The same methodology is applied to a soft piezoceramic. The errors in the identification of each parameter are statistically estimated in both cases, and are less than 0.6% for elastic constants, and less than 6.3% for dielectric and piezoelectric constants.

Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

Science.gov (United States)

Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

2012-01-01

Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

Electrical properties of a piezoelectric transformer for an AC-DC converter

International Nuclear Information System (INIS)

Park, Yong-Wook

2010-01-01

The electrical properties of a ring/dot piezoelectric transformer were analyzed for applications as an AC-DC converter using the step-down behavior of a piezoelectric transformer. The ring/dot piezoelectric transformer was prepared using Pb(Mn 1/3 Nb 2/3 )O 3 and Pb(Zn 1/3 Nb 2/3 )O 3 modified Pb(Zr,Ti)O 3 ceramics sintered at a relatively low temperature of 930 .deg. C for 90 min. When the transformer was matched with a load resistance of 1000 Ω, it transferred a maximum power of 27 W. The maximum power was produced at a dc output voltage of 30 V and a matching load resistance of 1000 Ω. While the manufactured ring/dot piezoelectric transformer released the maximum power at a resonance frequency of 71 kHz, the available frequency bandwidth was about 1 kHz at most due to strong frequency dependence of the piezoelectric transformer. The output dc current was highly improved up to 905 mA because no anisotropy of poling direction existed in the ring/dot piezoelectric transformer. Under a commercial input of 220 V ac , AC-DC converter successfully produced 27 W at 30 V dc and 905 mA.

Piezoelectric Lead Zirconium Titanate Composite Touch Sensors for Integration with Flexible OLED Technology

NARCIS (Netherlands)

Deutz, D.B.; Tempelman, E.; Zwaag, S. van der; Groen, W.A.

2015-01-01

To enable the design of more intuitive product user interfaces, the prospects of matching piezoelectric touch sensors with flexible organic light emitting diode (OLED) technology are investigated. Low stiffness piezoelectric composite sensors, combining piezoelectric Pb(Zr,Ti)O3 powder with a

Piezoelectric surgery in implant dentistry: clinical applications

Directory of Open Access Journals (Sweden)

Lydia Masako Ferreira

2009-01-01

Full Text Available Pizosurgery has therapeutic characteristics in osteotomies, such as extremely precise, selective and millimetric cuts and a clear operating field. Piezoelectricity uses ultrasonic frequencies, which cause the points specially designed for osteotomy to vibrate. The points of the instrument oscillate, allowing effective osteotomy with minimal or no injury to the adjacent soft tissues, membranes and nerve tissues. This article presents the various applications of piezoelectricity in oral implant surgery such as: removal of autogenous bone; bone window during elevation of the sinus membrane and removal of fractured implants. The cavitational effect caused by the vibration of the point and the spray of physiological solution, provided a field free of bleeding and easy to visualize. The study showed that the piezoelectric surgery is a new surgical procedurethat presents advantages for bone cutting in many situations in implant dentistry, with great advantages in comparison with conventional instrumentation. Operating time is longer when compared with that of conventional cutters.

Cantilever piezoelectric energy harvester with multiple cavities

International Nuclear Information System (INIS)

S Srinivasulu Raju; M Umapathy; G Uma

2015-01-01

Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity. (paper)

Impedance-based damage assessment using piezoelectric sensors

Science.gov (United States)

Rim, Mi-Sun; Yoo, Seung-Jae; Lee, In; Song, Jae-Hoon; Yang, Jae-Won

2011-04-01

Recently structural health monitoring (SHM) systems are being focused because they make it possible to assess the health of structures at real-time in many application fields such as aircraft, aerospace, civil and so on. Piezoelectric materials are widely used for sensors of SHM system to monitor damage of critical parts such as bolted joints. Bolted joints could be loosened by vibration, thermal cycling, shock, corrosion, and they cause serious mechanical failures. In this paper, impedance-based method using piezoelectric sensors was applied for real-time SHM. A steel beam specimen fastened by bolts was tested, and polymer type piezoelectric materials, PVDFs were used for sensors to monitor the condition of bolted joint connections. When structure has some damage, for example loose bolts, the impedance of PVDF sensors showed different tendency with normal structure which has no loose bolts. In the case of loose bolts, impedance values are decreased and admittance values are increased.

Modeling the power output of piezoelectric energy harvesters

KAUST Repository

Al Ahmad, Mahmoud

2011-04-30

Design of experiments and multiphysics analyses were used to develop a parametric model for a d 33-based cantilever. The analysis revealed that the most significant parameters influencing the resonant frequency are the supporting layer thickness, piezoelectric layer thickness, and cantilever length. On the other hand, the most important factors affecting the charge output arethe piezoelectric thickness and the interdigitated electrode dimensions. The accuracy of the developed model was confirmed and showed less than 1% estimation error compared with a commercial simulation package. To estimate the power delivered to a load, the electric current output from the piezoelectric generator was calculated. A circuit model was built and used to estimate the power delivered to a load, which compared favorably to experimentally published power data on actual cantilevers of similar dimensions. © 2011 TMS.

Analytical model for nonlinear piezoelectric energy harvesting devices

International Nuclear Information System (INIS)

Neiss, S; Goldschmidtboeing, F; M Kroener; Woias, P

2014-01-01

In this work we propose analytical expressions for the jump-up and jump-down point of a nonlinear piezoelectric energy harvester. In addition, analytical expressions for the maximum power output at optimal resistive load and the 3 dB-bandwidth are derived. So far, only numerical models have been used to describe the physics of a piezoelectric energy harvester. However, this approach is not suitable to quickly evaluate different geometrical designs or piezoelectric materials in the harvester design process. In addition, the analytical expressions could be used to predict the jump-frequencies of a harvester during operation. In combination with a tuning mechanism, this would allow the design of an efficient control algorithm to ensure that the harvester is always working on the oscillator's high energy attractor. (paper)

Modeling and analysis on ring-type piezoelectric transformers.

Science.gov (United States)

Ho, Shine-Tzong

2007-11-01

This paper presents an electromechanical model for a ring-type piezoelectric transformer (PT). To establish this model, vibration characteristics of the piezoelectric ring with free boundary conditions are analyzed in advance. Based on the vibration analysis of the piezoelectric ring, the operating frequency and vibration mode of the PT are chosen. Then, electromechanical equations of motion for the PT are derived based on Hamilton's principle, which can be used to simulate the coupled electromechanical system for the transformer. Such as voltage stepup ratio, input impedance, output impedance, input power, output power, and efficiency are calculated by the equations. The optimal load resistance and the maximum efficiency for the PT will be presented in this paper. Experiments also were conducted to verify the theoretical analysis, and a good agreement was obtained.

Modeling the power output of piezoelectric energy harvesters

KAUST Repository

Al Ahmad, Mahmoud; Alshareef, Husam N.

2011-01-01

Design of experiments and multiphysics analyses were used to develop a parametric model for a d 33-based cantilever. The analysis revealed that the most significant parameters influencing the resonant frequency are the supporting layer thickness, piezoelectric layer thickness, and cantilever length. On the other hand, the most important factors affecting the charge output arethe piezoelectric thickness and the interdigitated electrode dimensions. The accuracy of the developed model was confirmed and showed less than 1% estimation error compared with a commercial simulation package. To estimate the power delivered to a load, the electric current output from the piezoelectric generator was calculated. A circuit model was built and used to estimate the power delivered to a load, which compared favorably to experimentally published power data on actual cantilevers of similar dimensions. © 2011 TMS.

On the buckling behavior of piezoelectric nanobeams: An exact solution

International Nuclear Information System (INIS)

Jandaghian, Ali Akbar; Rahmaini, Omid

2015-01-01

In this paper, thermoelectric-mechanical buckling behavior of the piezoelectric nanobeams is investigated based on the nonlocal theory and Euler-Bernoulli beam theory. The electric potential is assumed linear through the thickness of the nanobeam and the governing equations are derived by Hamilton's principle. The governing equations are solved analytically for different boundary conditions. The effects of the nonlocal parameter, temperature change, and external electric voltage on the critical buckling load of the piezoelectric nanobeams are discussed in detail. This study should be useful for the design of piezoelectric nanodevices.

Modeling and Experimental Analysis of Piezoelectric Shakers for High-Frequency Calibration of Accelerometers

International Nuclear Information System (INIS)

Vogl, Gregory W.; Harper, Kari K.; Payne, Bev

2010-01-01

Piezoelectric shakers have been developed and used at the National Institute of Standards and Technology (NIST) for decades for high-frequency calibration of accelerometers. Recently, NIST researchers built new piezoelectric shakers in the hopes of reducing the uncertainties in the calibrations of accelerometers while extending the calibration frequency range beyond 20 kHz. The ability to build and measure piezoelectric shakers invites modeling of these systems in order to improve their design for increased performance, which includes a sinusoidal motion with lower distortion, lower cross-axial motion, and an increased frequency range. In this paper, we present a model of piezoelectric shakers and match it to experimental data. The equations of motion for all masses are solved along with the coupled state equations for the piezoelectric actuator. Finally, additional electrical elements like inductors, capacitors, and resistors are added to the piezoelectric actuator for matching of experimental and theoretical frequency responses.

Piezoelectric transducer array microspeaker

KAUST Repository

Carreno, Armando Arpys Arevalo; Conchouso Gonzalez, David; Castro, David; Kosel, Jü rgen; Foulds, Ian G.

2016-01-01

contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT

Piezoelectric Response Evaluation of ZnO Thin Film Prepared by RF Magnetron Sputtering

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Cheng Da-Long

2017-01-01

Full Text Available The most important parameter of piezoelectric materials is piezoelectric coefficient (d33. In this study, the piezoelectric ZnO thin films were deposited on the SiNx/Si substrate. The 4 inches substrate is diced into 8 cm× 8 cm piece. During the deposition process, a zinc target (99.999 wt% of 2 inches diameter was used. The vertical distance between the target and the substrate holder was fixed at 5 cm. The piezoelectric response of zinc oxide (ZnO thin films were obtained by using a direct measurement system. The system adopts a mini impact tip to generate an impulsive force and read out the piezoelectric signals immediately. Experimentally, a servo motor is used to produce a fixed quantity of force, for giving an impact against to the piezoelectric film. The ZnO thin films were deposited using the reactive radio frequency (RF magnetron sputtering method. The electric charges should be generated because of the material’s extrusion. This phenomenon was investigated through the oscilloscope by one shot trigger. It was apparent that all ZnO films exhibit piezoelectric responses evaluated by our measurement system, however, its exhibit a significant discrepancy. The piezoelectric responses of ZnO thin film at various deposition positions were measured and the crystal structures of the sputtering pressure were also discussed. The crystalline characteristics of ZnO thin films are investigated through the XRD and SEM. The results show the ZnO thin film exhibits good crystalline pattern and surface morphology with controlled sputtering condition. The ZnO thin films sputtered using 2 inches target present various piezoelectric responses. With the exactly related position, a best piezoelectric response of ZnO thin film can be achieved.

Ultrahigh Piezoelectric Properties in Textured (K,Na)NbO3 -Based Lead-Free Ceramics.

Science.gov (United States)

Li, Peng; Zhai, Jiwei; Shen, Bo; Zhang, Shujun; Li, Xiaolong; Zhu, Fangyuan; Zhang, Xingmin

2018-02-01

High-performance lead-free piezoelectric materials are in great demand for next-generation electronic devices to meet the requirement of environmentally sustainable society. Here, ultrahigh piezoelectric properties with piezoelectric coefficients (d 33 ≈700 pC N -1 , d 33 * ≈980 pm V -1 ) and planar electromechanical coupling factor (k p ≈76%) are achieved in highly textured (K,Na)NbO 3 (KNN)-based ceramics. The excellent piezoelectric properties can be explained by the strong anisotropic feature, optimized engineered domain configuration in the textured ceramics, and facilitated polarization rotation induced by the intermediate phase. In addition, the nanodomain structures with decreased domain wall energy and increased domain wall mobility also contribute to the ultrahigh piezoelectric properties. This work not only demonstrates the tremendous potential of KNN-based ceramics to replace lead-based piezoelectrics but also provides a good strategy to design high-performance piezoelectrics by controlling appropriate phase and crystallographic orientation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Piezoelectric and dielectric properties of polymer-ceramic composites for sensors

NARCIS (Netherlands)

James, N.K.

2015-01-01

The main objective of this PhD thesis is to develop new routes and concepts for manufacturing piezoelectric ceramic-polymer composites with adequate piezoelectric properties while retaining ease of manufacturing and mechanical flexibility and explore new possibilities to maximize especially the

Design, Simulation and Experimental Evaluation of Tri-Phasic Piezoelectric Composite Transducers

Science.gov (United States)

Tamez, Juan Pedro

Piezoelectric ceramics exhibit excellent piezoelectric and dielectric properties that is the basis of practically all transducers and piezoelectric devices, but their inherent properties, such as brittleness, non-ductility and poor shapeability may limit their applications in areas such as vibration sensing, impact detection, structural health monitoring and other reinforced structures and energy harvesting. To compensate for such limitations, the 1-3 piezoelectric composites transducers have become the material of choice for many high performance ultrasound transducers since it was invented in the late 1970's [ref. Newnham/Cross]. Extensive studies on 1-3 composites have been performed since then to improve the performance of a transducer by modifying their electromechanical coupling, bandwidth, quality factor, and flexibility and by reducing or eliminating the cross talk, i.e., induced noise between the active piezoelectric elements, especially in high power and low frequency applications. These fundamental issues, their possible solutions and their wide impact underline the motivation of the current work in this dissertation report. The motivation for this dissertation was to study and provide a foundation to designing multiphasic piezoelectric transducers that could be useful for multitude of applications. The goal was to improve the 1-3 diphasic composite transducer by eliminating the cross talk between the active piezoelectric elements while maintaining and improving the figures of merit of the design. To achieve the ultimate goal, the steps outlined below were followed: i. Understanding the theoretical and mathematical modeling for tri-phasic piezoelectric composite. ii. Implement Finite Element Analysis (FEA) and simulations of tri-phasic piezoelectric composites where the different active piezoelectric material PZT-5H and PMN-30%PT is surrounded by a vacuum phase that is enclosed by a hexagonal polymer walls. iii. Propose a redesign of the tri

Calculations for piezoelectric ultrasonic transducers

International Nuclear Information System (INIS)

Jensen, H.

1986-05-01

Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a body which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation losses as well as internal losses may be important. Due to the complexity of the problem, a closed form solution is the exception rather than the rule. For this reason, it is necessary to use approximate methods for the analysis. Equivalent circuits, the Rayleigh-Ritz method, Mindlin plate theory and in particular the finite element method are considered. The finite element method is utilized for analysis of axisymmetric transducers. An explicit, fully piezoelectric, triangular ring element, with linear variations in displacement and electric potential is given. The influence of a fluid half-space is also given, in the form of a complex stiffness matrix. A special stacking procedure, for analysis of the backing has been developed. This procedure gives a saving, which is similar to that of the fast fourier transform algorithm, and is also wellsuited for analysis of finite and infinite waveguides. Results obtained by the finite element method are shown and compared with measurements and exact solutions. Good agreement is obtained. It is concluded that the finite element method can be a valueable tool in analysis and design of ultrasonic transducers. (author)

Telescoping cylindrical piezoelectric fiber composite actuator assemblies

Science.gov (United States)

Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

2010-01-01

A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

Hydrogen and fluorine co-decorated silicene: A first principles study of piezoelectric properties

International Nuclear Information System (INIS)

Noor-A-Alam, Mohammad; Kim, Hye Jung; Shin, Young-Han

2015-01-01

A low-buckled silicene monolayer being centrosymmetric like graphene, in contrast to a piezoelectric hexagonal boron nitride (h-BN), is not intrinsically piezoelectric. However, based on first principles calculations, we show that chemical co-decoration of hydrogen (H) and fluorine (F) on opposite sides of silicene (i.e., one side is decorated with H, while the other one is with F) breaks the centrosymmetry. Redistributing the charge density due to the electronegativity difference between the atoms, non-centrosymmetric co-decoration induces an out-of-plane dipolar polarization and concomitant piezoelectricity into non-piezoelectric silicene monolayer. Our piezoelectric coefficients are comparable with other known two-dimensional piezoelectric materials (e.g., hydrofluorinated graphene/h-BN) and some bulk semiconductors, such as wurtzite GaN and wurtzite BN. Moreover, because of silicene's lower elastic constants compared to graphene or h-BN, piezoelectric strain constants are found significantly larger than those of hydrofluorinated graphene/h-BN. We also predict that a wide range of band gaps with an average of 2.52 eV can be opened in a low-buckled gapless semi-metallic silicene monolayer by co-decoration of H and F atoms on the surface

Electromechanical response of a curved piezoelectric nanobeam with the consideration of surface effects

International Nuclear Information System (INIS)

Yan Zhi; Jiang Liying

2011-01-01

This work investigates the electromechanical response of a curved piezoelectric nanobeam with the consideration of surface effects through the surface-layer-based model and the generalized Young-Laplace equations. For nanoscale piezoelectric structures, the surface effects also include surface piezoelectricity in addition to the residual surface stress and surface elasticity for elastic nanomaterials. A Euler-Bernoulli curved beam theory is used to get the explicit solutions for the electroelastic fields of a curved cantilever beam when subjected to mechanical and electrical loads. In order to apply the appropriate boundary conditions on the beam, effective axial force, shear force and moment are derived. The results indicate that the surface effects play a significant role in the electroelastic fields and the piezoelectric response of the curved piezoelectric nanobeam. It is also found that the coupling of the residual surface stress, the surface elasticity and the surface piezoelectricity may be dramatic despite that the influence of the individual one is small under some circumstances. This study is expected to be useful for design and applications of curved beam based piezoelectric nanodevices, such as the curved nanowires/nanobelts or nanorings as nanoswitches or nanoactuators for displacement control purpose.

Piezoelectric ceramic implants: in vivo results.

Science.gov (United States)

Park, J B; Kelly, B J; Kenner, G H; von Recum, A F; Grether, M F; Coffeen, W W

1981-01-01

The suitability of barium titanate (BaTiO3) ceramic for direct substitution of hard tissues was evaluated using both electrically stimulated (piezoelectric) and inactive (nonpolarized) test implants. Textured cylindrical specimens, half of them made piezoelectric by polarization in a high electric field, were implanted into the cortex of the midshaft region of the femora of dogs for various periods of time. Interfacial healing and bio-compatibility of the implant material were studied using mechanical, microradiographical, and histological techniques. Our results indicate that barium titanate ceramic shows a very high degree of biocompatibility as evidenced by the absence of inflammatory or foreign body reactions at the implant-tissue interface. Furthermore, the material and its surface porosity allowed a high degree of bone ingrowth as evidenced by microradiography and a high degree of interfacial tensile strength. No difference was found between the piezoelectric and the electrically neutral implant-tissue interfaces. Possible reasons for this are discussed. The excellent mechanical properties of barium titanate, its superior biocompatibility, and the ability of bone to form a strong mechanical interfacial bond with it, makes this material a new candidate for further tests for hard tissue replacement.

Piezoelectric energy harvester under parquet floor

Science.gov (United States)

Bischur, E.; Schwesinger, N.

2011-03-01

The design, fabrication and testing of piezoelectric energy harvesting modules for floors is described. These modules are used beneath a parquet floor to harvest the energy of people walking over it. The harvesting modules consist of monoaxial stretched PVDF-foils. Multilayer modules are built up as roller-type capacitors. The fabrication process of the harvesting modules is simple and very suitable for mass production. Due to the use of organic polymers, the modules are characterized by a great flexibility and the possibility to create them in almost any geometrical size. The energy yield was determined depending on the dynamic loading force, the thickness of piezoelectric active material, the size of the piezoelectric modules, their alignment in the walking direction and their position on the floor. An increase of the energy yield at higher loading forces and higher thicknesses of the modules was observed. It was possible to generate up to 2.1mWs of electric energy with dynamic loads of 70kg using a specific module design. Furthermore a test floor was assembled to determine the influence of the size, alignment and position of the modules on the energy yield.

Piezoelectric effect in polarized and electrically depolarized ferrotextures

International Nuclear Information System (INIS)

Luchaninov, A.G.; Shil'nikov, A.V.; Shuvalov, L.A.

1999-01-01

Piezoelectric moduli were calculated for ferroelectric textures in the states with the greatest possible (in terms of symmetry) polarization and the zero polarization (obtained from the former by electrical depolarization). The calculations were performed for the textures of crystals of the classes 2, 3, 4, 6, mm2, 3m, 4mm,and 6mm. The experimental results for lead zirconate-titanate- and barium-titanate-based piezoelectric ceramic are reported

Finite element analysis of vibration energy harvesting using lead-free piezoelectric materials: A comparative study

Directory of Open Access Journals (Sweden)

Anuruddh Kumar

2014-06-01

Full Text Available In this article, the performance of various piezoelectric materials is simulated for the unimorph cantilever-type piezoelectric energy harvester. The finite element method (FEM is used to model the piezolaminated unimorph cantilever structure. The first-order shear deformation theory (FSDT and linear piezoelectric theory are implemented in finite element simulations. The genetic algorithm (GA optimization approach is carried out to optimize the structural parameters of mechanical energy-based energy harvester for maximum power density and power output. The numerical simulation demonstrates the performance of lead-free piezoelectric materials in unimorph cantilever-based energy harvester. The lead-free piezoelectric material K0.5Na0.5NbO3-LiSbO3-CaTiO3 (2 wt.% has demonstrated maximum mean power and maximum mean power density for piezoelectric energy harvester in the ambient frequency range of 90–110 Hz. Overall, the lead-free piezoelectric materials of K0.5Na0.5NbO3-LiSbO3 (KNN-LS family have shown better performance than the conventional lead-based piezoelectric material lead zirconate titanate (PZT in the context of piezoelectric energy harvesting devices.

Development of optical phase shifter based on piezoelectric ceramic

Science.gov (United States)

Yu, Fusheng; Shen, Xiaoqin; Yao, Chunjuan; Leng, Changlin

2005-02-01

The phase shifter is necessary in the optical phase-shifting measurement. At present the phase shifter commonly used is approximately divided into the penetrance-type and the reflection-type. In this paper, a reflection-type phase shifter made of piezoelectric ceramic stackup assemble is developed. The assemble are constituted of the flat piezoelectric ceramic with parallel connection circuit and inline structure. The communication between the computer and MCU is by RS232. The D/A converter controlled by the MCU outputs 0~10V voltage. Then the voltage is amplified to 0~400V DC voltage by the designed linear DC amplifier. When this voltage loads on the piezoelectric ceramic stackup assemble, the assemble will axially extend 0~5mm. In this paper, the connecting types for the mechanical construction and circuit of the piezoelectric ceramic stackup assemble, the driving power and the DC amplifier with high linearity are all introduced. The whole system developed is standardized by using phase-interfering Michelson. The standardization and the practical application indicates that this system has excellent linearity and precision repeatability.

Atomic-scale origin of piezoelectricity in wurtzite ZnO.

Science.gov (United States)

Lee, Jung-Hoon; Lee, Woo-Jin; Lee, Sung-Hoon; Kim, Seong Min; Kim, Sungjin; Jang, Hyun Myung

2015-03-28

ZnO has been extensively studied by virtue of its remarkably high piezoelectric responses, especially in nanowire forms. Currently, the high piezoelectricity of wurtzite ZnO is understood in terms of the covalent-bonding interaction between Zn 3d and O 2p orbitals. However, the Zn 3d orbitals are not capable of forming hybridized orbitals with the O 2pz orbitals since the Zn ion is characterized by fully filled non-interacting 3d orbitals. To resolve this puzzling problem, we have investigated the atomic-scale origin of piezoelectricity by exploiting density-functional theory calculations. On the basis of the computed orbital-resolved density of states and the band structure over the Γ-M first Brillouin zone, we propose an intriguing bonding mechanism that accounts for the observed high piezoelectricity - intra-atomic 3dz(2)-4pz orbital self-mixing of Zn, followed by asymmetric hybridization between the Zn 3dz(2)-4pz self-mixed orbital and the O 2pz orbital along the polar c-axis of the wurtzite ZnO.

Structural control by the use of piezoelectric active members

Science.gov (United States)

Fanson, J. L.; Chen, J.-C.

1987-01-01

Large Space Structures (LSS) exhibit characteristics which make the LSS control problem different form other control problems. LSS will most likely exhibit low frequency, densely spaced and lightly damped modes. In theory, the number of these modes is infinite. Because these structures are flexible, Vibration Suppression (VS) is an important aspect of LSS operation. In terms of VS, the control actuators should be as low mass as possible, have infinite bandwidth, and be electrically powered. It is proposed that actuators be built into the structure as dual purpose structural elements. A piezoelectric active member is proposed for the control of LSS. Such a device would consist of a piezoelectric actuator and sensor for measuring strain, and screwjack actuator in series for use in quasi-static shape control. An experiment simulates an active member using piezoelectric ceramic thin sheet material on a thin, uniform cantilever beam. The feasibility of using the piezoelectric materials for VS on LSS was demonstrated. Positive positive feedback as a VS control strategy was implemented. Multi-mode VS was achieved with dramatic reduction in dynamic response.

Capacitance-based frequency adjustment of micro piezoelectric vibration generator.

Science.gov (United States)

Mao, Xinhua; He, Qing; Li, Hong; Chu, Dongliang

2014-01-01

Micro piezoelectric vibration generator has a wide application in the field of microelectronics. Its natural frequency is unchanged after being manufactured. However, resonance cannot occur when the natural frequencies of a piezoelectric generator and the source of vibration frequency are not consistent. Output voltage of the piezoelectric generator will sharply decline. It cannot normally supply power for electronic devices. In order to make the natural frequency of the generator approach the frequency of vibration source, the capacitance FM technology is adopted in this paper. Different capacitance FM schemes are designed by different locations of the adjustment layer. The corresponding capacitance FM models have been established. Characteristic and effect of the capacitance FM have been simulated by the FM model. Experimental results show that the natural frequency of the generator could vary from 46.5 Hz to 42.4 Hz when the bypass capacitance value increases from 0 nF to 30 nF. The natural frequency of a piezoelectric vibration generator could be continuously adjusted by this method.

Capacitance-Based Frequency Adjustment of Micro Piezoelectric Vibration Generator

Directory of Open Access Journals (Sweden)

Xinhua Mao

2014-01-01

Full Text Available Micro piezoelectric vibration generator has a wide application in the field of microelectronics. Its natural frequency is unchanged after being manufactured. However, resonance cannot occur when the natural frequencies of a piezoelectric generator and the source of vibration frequency are not consistent. Output voltage of the piezoelectric generator will sharply decline. It cannot normally supply power for electronic devices. In order to make the natural frequency of the generator approach the frequency of vibration source, the capacitance FM technology is adopted in this paper. Different capacitance FM schemes are designed by different locations of the adjustment layer. The corresponding capacitance FM models have been established. Characteristic and effect of the capacitance FM have been simulated by the FM model. Experimental results show that the natural frequency of the generator could vary from 46.5 Hz to 42.4 Hz when the bypass capacitance value increases from 0 nF to 30 nF. The natural frequency of a piezoelectric vibration generator could be continuously adjusted by this method.

Use of piezoelectric actuators in active vibration control of rotating machinery

Science.gov (United States)

Lin, Reng Rong; Palazzolo, Alan B.; Kascak, Albert F.; Montague, Gerald

1990-01-01

Theoretical and test results for the development of piezoelectric-actuator-based active vibration control (AVC) are presented. The evolution of this technology starts with an ideal model of the actuator and progresses to a more sophisticated model where the pushers force the squirrel cage ball bearing supports of a rotating shaft. The piezoelectric pushers consist of a stack of piezoelectric ceramic disks that are arranged on top of one another and connected in parallel electrically. This model consists of a prescribed displacement that is proportional to the input voltage and a spring that represents the stiffness of the stack of piezoelectric disks. System tests were carried out to stabilize the AVC system, verify its effectiveness in controlling vibration, and confirm the theory presented.

Design and performance testing of an ultrasonic linear motor with dual piezoelectric actuators.

Science.gov (United States)

Smithmaitrie, Pruittikorn; Suybangdum, Panumas; Laoratanakul, Pitak; Muensit, Nantakan

2012-05-01

In this work, design and performance testing of an ultrasonic linear motor with dual piezoelectric actuator patches are studied. The motor system consists of a linear stator, a pre-load weight, and two piezoelectric actuator patches. The piezoelectric actuators are bonded with the linear elastic stator at specific locations. The stator generates propagating waves when the piezoelectric actuators are subjected to harmonic excitations. Vibration characteristics of the linear stator are analyzed and compared with finite element and experimental results. The analytical, finite element, and experimental results show agreement. In the experiments, performance of the ultrasonic linear motor is tested. Relationships between velocity and pre-load weight, velocity and applied voltage, driving force and applied voltage, and velocity and driving force are reported. The design of the dual piezoelectric actuators yields a simpler structure with a smaller number of actuators and lower stator stiffness compared with a conventional design of an ultrasonic linear motor with fully laminated piezoelectric actuators.

Homotopy analysis approach for nonlinear piezoelectric vibration energy harvesting

Directory of Open Access Journals (Sweden)

Shahlaei-Far Shahram

2016-01-01

Full Text Available Piezoelectric energy harvesting from a vertical geometrically nonlinear cantilever beam with a tip mass subject to transverse harmonic base excitations is analyzed. One piezoelectric patch is placed on the slender beam to convert the tension and compression into electrical voltage. Applying the homotopy analysis method to the coupled electromechanical governing equations, we derive analytical solutions for the horizontal displacement of the tip mass and consequently the output voltage from the piezoelectric patch. Analytical approximation for the frequency response and phase of the geometrically forced nonlinear vibration system are also obtained. The research aims at a rigorous analytical perspective on a nonlinear problem which has previously been solely investigated by numerical and experimental methods.

High Temperature Piezoelectric Drill

Science.gov (United States)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom

2012-01-01

Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is 460 deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts. Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials (such as piezoelectric and electrostrictive) have enabled potential actuation capabilities that can be used to support such missions. Taking advantage of these materials, we developed a piezoelectric actuated drill that operates at the temperature range up to 500 deg C and the mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) configuration. The detailed results of our study are presented in this paper

Magnetoelectric effect in structures which consist from ferrimagnetic and piezoelectric components

International Nuclear Information System (INIS)

Koronovs'kij, V.Je.

2007-01-01

Magnetoelectric (ME) properties of the structure which consists from mechanically connected magnetostriction and piezoelectric plates were investigated on example of the yttrium-ferrite-garnet (YIG) - piezoelectric. The laser polarimeter is using

Effects of Proof Mass Geometry on Piezoelectric Vibration Energy Harvesters

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Abdul Hafiz Alameh

2018-05-01

Full Text Available Piezoelectric energy harvesters have proven to have the potential to be a power source in a wide range of applications. As the harvester dimensions scale down, the resonance frequencies of these devices increase drastically. Proof masses are essential in micro-scale devices in order to decrease the resonance frequency and increase the strain along the beam to increase the output power. In this work, the effects of proof mass geometry on piezoelectric energy harvesters are studied. Different geometrical dimension ratios have significant impact on the resonance frequency, e.g., beam to mass lengths, and beam to mass widths. A piezoelectric energy harvester has been fabricated and tested operating at a frequency of about 4 kHz within the audible range. The responses of various prototypes were studied, and an optimized T-shaped piezoelectric vibration energy harvester design is presented for improved performance.

Piezoelectric Zinc Oxide Based MEMS Acoustic Sensor

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Aarti Arora

2008-04-01

Full Text Available An acoustic sensors exhibiting good sensitivity was fabricated using MEMS technology having piezoelectric zinc oxide as a dielectric between two plates of capacitor. Thin film zinc oxide has structural, piezoelectric and optical properties for surface acoustic wave (SAW and bulk acoustic wave (BAW devices. Oxygen effficient films are transparent and insulating having wide applications for sensors and transducers. A rf sputtered piezoelectric ZnO layer transforms the mechanical deflection of a thin etched silicon diaphragm into a piezoelectric charge. For 25-micron thin diaphragm Si was etched in tetramethylammonium hydroxide solution using bulk micromachining. This was followed by deposition of sandwiched structure composed of bottom aluminum electrode, sputtered 3 micron ZnO film and top aluminum electrode. A glass having 1 mm diameter hole was bonded on backside of device to compensate sound pressure in side the cavity. The measured value of central capacitance and dissipation factor of the fabricated MEMS acoustic sensor was found to be 82.4pF and 0.115 respectively, where as the value of ~176 pF was obtained for the rim capacitance with a dissipation factor of 0.138. The response of the acoustic sensors was reproducible for the devices prepared under similar processing conditions under different batches. The acoustic sensor was found to be working from 30Hz to 8KHz with a sensitivity of 139µV/Pa under varying acoustic pressure.

Wave propagations of curvilinear motors driven by partially laminated piezoelectric actuators

International Nuclear Information System (INIS)

Smithmaitrie, Pruittikorn; Suybangdum, Panumas; Muensit, Supasarote; Tzou, Horn-Sen

2008-01-01

A piezoelectric arc stator is the key component delivering driving actions to an ultrasonic curvilinear motor. The arc stator drives the rotor along the arc structure to any specific angular position. Usually conventional stators in ultrasonic motors are fully bounded with piezoelectric patch actuators. To reduce production costs while maintaining similar driving characteristics, an arc stator partially bonded with piezoelectric actuators is proposed and its dynamic characteristics are analyzed in this study. The effect of actuator locations on the wave propagation is investigated. Both analytical and finite element results demonstrate similar dynamic responses. That is, the response of the wave propagation depends on specific locations of piezoelectric actuators. One of the two configurations investigated shows that the partially laminated piezoelectric actuator pattern can also generate rather steady traveling waves on the stator with consistent wave amplitude. This implies that the partially laminated actuator technique could be an alternative actuator pattern to the fully laminated actuators in the design of ultrasonic curvilinear motors or other finite-length ultrasonic motors

Piezoelectric Flexible LCP-PZT Composites for Sensor Applications at Elevated Temperatures

Science.gov (United States)

Tolvanen, Jarkko; Hannu, Jari; Juuti, Jari; Jantunen, Heli

2018-03-01

In this paper fabrication of piezoelectric ceramic-polymer composites is demonstrated via filament extrusion enabling cost-efficient large-scale production of highly bendable pressure sensors feasible for elevated temperatures. These composites are fabricated by utilizing environmentally resistant and stable liquid crystal polymer matrix with addition of lead zirconate titanate at loading levels of 30 vol%. These composites, of approximately 0.99 mm thick and length of > 50 cm, achieved excellent bendability with minimum bending radius of 6.6 cm. The maximum piezoelectric coefficients d33 and g33 of the composites were > 14 pC/N and > 108 mVm/N at pressure < 10 kPa. In all cases, the piezoelectric charge coefficient (d33) of the composites decreased as a function of pressure. Also, piezoelectric coefficient (d33) further decreased in the case of increased frequency press-release cycle sand pre-stress levels by approximately 37-50%. However, the obtained results provide tools for fabricating novel piezoelectric sensors in highly efficient way for environments with elevated temperatures.

Optimization of piezoelectric cantilever energy harvesters including non-linear effects

International Nuclear Information System (INIS)

Patel, R; McWilliam, S; Popov, A A

2014-01-01

This paper proposes a versatile non-linear model for predicting piezoelectric energy harvester performance. The presented model includes (i) material non-linearity, for both substrate and piezoelectric layers, and (ii) geometric non-linearity incorporated by assuming inextensibility and accurately representing beam curvature. The addition of a sub-model, which utilizes the transfer matrix method to predict eigenfrequencies and eigenvectors for segmented beams, allows for accurate optimization of piezoelectric layer coverage. A validation of the overall theoretical model is performed through experimental testing on both uniform and non-uniform samples manufactured in-house. For the harvester composition used in this work, the magnitude of material non-linearity exhibited by the piezoelectric layer is 35 times greater than that of the substrate layer. It is also observed that material non-linearity, responsible for reductions in resonant frequency with increases in base acceleration, is dominant over geometric non-linearity for standard piezoelectric harvesting devices. Finally, over the tested range, energy loss due to damping is found to increase in a quasi-linear fashion with base acceleration. During an optimization study on piezoelectric layer coverage, results from the developed model were compared with those from a linear model. Unbiased comparisons between harvesters were realized by using devices with identical natural frequencies—created by adjusting the device substrate thickness. Results from three studies, each with a different assumption on mechanical damping variations, are presented. Findings showed that, depending on damping variation, a non-linear model is essential for such optimization studies with each model predicting vastly differing optimum configurations. (paper)

A novel traveling wave piezoelectric actuated tracked mobile robot utilizing friction effect

Science.gov (United States)

Wang, Liang; Shu, Chengyou; Jin, Jiamei; Zhang, Jianhui

2017-03-01

A novel traveling wave piezoelectric-actuated tracked mobile robot with potential application to robotic rovers was proposed and investigated in this study. The proposed tracked mobile robot is composed of a parallelogram-frame-structure piezoelectric transducer with four rings and a metal track. Utilizing the converse piezoelectric and friction effects, traveling waves were propagated in the rings and then the metal track was actuated by the piezoelectric transducer. Compared with traditional tracked mechanisms, the proposed tracked mobile robot has a simpler and more compact structure without lubricant, which eliminates the problem of lubricant volatilization and deflation, thus, it could be operated in the vacuum environment. Dynamic characteristics were simulated and measured to reveal the mechanism of actuating track of the piezoelectric transducer. Experimental investigations of the traveling wave piezoelectric-actuated tracked mobile robot were then carried out, and the results indicated that the robot prototype with a pair of exciting voltages of 460 Vpp is able to achieve a maximum velocity of 57 mm s-1 moving on the foam plate and possesses the obstacle crossing capability with a maximum height of 27 mm. The proposed tracked mobile robot exhibits potential to be the driving system of robotic rovers.

RELEVANCE OF COLLAGEN PIEZOELECTRICITY TO “WOLFF’S LAW”: A CRITICAL REVIEW

Science.gov (United States)

Ahn, Andrew C.; Grodzinsky, Alan J.

2009-01-01

According to “Wolff’s Law”, bone is deposited and reinforced at areas of greatest stress. From a clinical perspective, this “law” is supported by the strong association between bone density and physical activity. From a mechanistic standpoint, however, the law presents a challenge to scientists seeking to understand how osteocytes and osteoblasts sense the mechanical load. In the 1960’s, collagen piezoelectricity was invoked as a potential mechanism by which osteocytes could detect areas of greater stress but piezoelectricity diminished in importance as more compelling mechanisms, such as streaming potential, were identified. In addition, accumulating evidence for the role of fluid-related shear stress in osteocyte’s mechanosensory function has made piezoelectricity seemingly more obsolete in bone physiology. This review critically evaluates the role of collagen piezoelectricity (if any) in Wolff’s Law – specifically, the evidence regarding its involvement in strain-generated potentials, existing alternate mechanisms, the present understanding of bone mechanosensation, and whether piezoelectricity serves an influential role within the context of this newly proposed mechanism. In addition to reviewing the literature, this review generates several hypotheses and proposes future research to fully address the relevance of piezoelectricity in bone physiology. PMID:19286413

An Equivalent Circuit of Longitudinal Vibration for a Piezoelectric Structure with Losses.

Science.gov (United States)

Yuan, Tao; Li, Chaodong; Fan, Pingqing

2018-03-22

Equivalent circuits of piezoelectric structures such as bimorphs and unimorphs conventionally focus on the bending vibration modes. However, the longitudinal vibration modes are rarely considered even though they also play a remarkable role in piezoelectric devices. Losses, especially elastic loss in the metal substrate, are also generally neglected, which leads to discrepancies compared with experiments. In this paper, a novel equivalent circuit with four kinds of losses is proposed for a beamlike piezoelectric structure under the longitudinal vibration mode. This structure consists of a slender beam as the metal substrate, and a piezoelectric patch which covers a partial length of the beam. In this approach, first, complex numbers are used to deal with four kinds of losses-elastic loss in the metal substrate, and piezoelectric, dielectric, and elastic losses in the piezoelectric patch. Next in this approach, based on Mason's model, a new equivalent circuit is developed. Using MATLAB, impedance curves of this structure are simulated by the equivalent circuit method. Experiments are conducted and good agreements are revealed between experiments and equivalent circuit results. It is indicated that the introduction of four losses in an equivalent circuit can increase the result accuracy considerably.

Stress in piezoelectric hollow sphere with thermal gradient

International Nuclear Information System (INIS)

Saadatfar, M.; Rastgoo, A.

2008-01-01

The piezoelectric phenomenon has been exploited in science and engineering for decades. Recent advances in smart structures technology have led to a resurgence of interest in piezoelectricity, and in particular, in the solution of fundamental boundary value problems. In this paper, we develop an analytic solution to the axisymmetric problem of a radially polarized, spherically isotropic piezoelectric hollow sphere. The sphere is subjected to uniform internal pressure, or uniform external pressure, or both and thermal gradient. There is a constant thermal difference between its inner and outer surfaces. An analytic solution to the governing equilibrium equations (a coupled system of second-order ordinary differential equations) is obtained. On application of the boundary conditions, the problem is reduced to solving a system of linear algebraic equations. Finally, the stress distributions in the sphere are obtained numerically for two piezoceramics

Fundamental solutions in piezoelectricity. Penny-shaped crack solution

International Nuclear Information System (INIS)

Dyka, Ewa; Rogowski, Bogdan

2006-01-01

The problem of electroelasticity for piezoelectric materials is considered. For axially symmetric states three potentials are introduced, which determine the displacements, the electric potentials, the stresses, the components of the electric field vector and the electric displacements in a piezoelectric body. These fundamental solutions are utilized to solve the penny-shaped crack problem. Two cases of boundary-value problems are considered, namely the permeable and impermeable crack boundary conditions. Exact solutions are obtained for elastic and electric fields. The main results are the stress intensity factor for singular stress and the electric displacement intensity factor. The numerical results are presented graphically to show the influence of applied mechanical and electrical loading on the analyzed quantities and to clarify the effect of anisotropy of piezoelectric materials. It is show that the influence of anisotropy of the materials on these fields is significant

Dynamic characteristics of a cyclic-periodic structure with a piezoelectric network

Directory of Open Access Journals (Sweden)

Li Lin

2015-10-01

Full Text Available This paper deals with a cyclic-periodic structure with a piezoelectric network. In such a system, there is not only mechanical connection but also electrical connection between adjacent periodic sectors. The objective is to learn whether the presence of a piezoelectric network would change the dynamic characteristics of the system. The background of the research is about vibration reduction of a bladed disk in an aero-engine, and the system is simulated by a lumped parameter model. The dynamic equations of the system are derived, and then the analytical solution corresponding to the eigenvalue problem is given. The vibration responses to single traveling wave excitations (EO excitations and multiple traveling wave excitations (NEO excitations are studied. The results show that the presence of a piezoelectric network would change the natural frequencies of the system compared with those of the system with the piezoelectric shunt circuit. The forced response is sensitive to the connection type and the elements of the network. An energy analysis of the electro-mechanical coupling system has been performed to understand its dynamic behavior, and the following conclusion is obtained: a vibration reduction to excitations whose primary harmonic component is not zero can be achieved by a parallel piezoelectric network, while a reduction to other excitations should be based on a series piezoelectric network.

Experimental measurements and finite element models of High Displacement Piezoelectric Actuators.

Science.gov (United States)

Camargo, Gilberto; Ashford, Gevale; Naco, Eris; Usher, Tim

2004-03-01

Piezoelectric actuators have many applications including morphable wing technology and piezoelectric transformers. A Piezoelectric ceramic is a material that will move when a voltage is applied and conversely produces a charge when a pressure is applied. In our study, we examine THUNDER (Thin Layer Unimorph Ferroelectric Driver and Sensor) actuators (Thunder TM is a trademark of FACE International Corporation.) Thunder actuators are constructed by bonding thin PZT piezoelectric ceramics to metal sheets. We will present physical measurements of piezoelectric actuators, as well as measurements of the displacements due to applied voltages. In our studies we used a laser micrometer to measure the dimensional characteristics of four sizes of THUNDER actuators including TH-8R, TH-9R, TH-10R, and finally the TH-11R. We also developed computer models using a commercial fine element modeling package (FEM) known as ANSYS6.0®. This software enables us to construct our models controlling such attributes as exact dimensions of the three layers of the piezoelectric actuator, the material properties of each element, the type of load that is to be applied as well as the manner in which the layers are bonded together. The computer model compares favorably with the experimental results. Acknowledgements: NASA Grant No. 0051-0078 Department of Defense (DoD) Control No.ISP02-EUG15

Energy harvesting with piezoelectric and pyroelectric materials

CERN Document Server

Muensit, Nantakan

2011-01-01

The purpose of this book is to present the current state of knowledge in the field of energy harvesting using piezoelectric and pyroelectric materials. The book is addressed to students and academics engaged in research in the fields of energy harvesting, material sciences and engineering. Scientists and engineers who are working in the area of energy conservation and renewable energy resources should find it useful as well. Explanations of fundamental physical properties such as piezoelectricity and pyroelectricity are included to aid the understanding of the non-specialist. Specific technolo

Sm/Ti co-substituted bismuth ferrite multiferroics: reciprocity between tetragonality and piezoelectricity.

Science.gov (United States)

Jha, Pardeep K; Jha, Priyanka A; Singh, Prabhakar; Ranjan, Rajeev; Dwivedi, R K

2017-10-04

BiFeO 3 (BFO) systems co-modified with Ti, Sm and Sm-Ti have been investigated for piezoelectricity together with dielectric and multiferroic properties. Structural studies revealed the coexistence of orthorhombic and rhombohedral (R3c) phases for x > 0.12. Impurity phases were shown to have hardly any effect on the remanent magnetization, which rather depends on the Fe-O-Fe bond angle. The dielectric loss was reduced considerably by substitution. A correlation between the piezoelectric coefficient and tetragonality was observed in these samples. BFO co-substituted with Sm-Ti exhibited a high piezoelectric coefficient with better ferroic properties, which revealed a unique combination of green piezoelectricity and multiferroicity.

Piezoelectricity in Two-Dimensional Materials

KAUST Repository

Wu, Tao; Zhang, Hua

2015-01-01

Powering up 2D materials: Recent experimental studies confirmed the existence of piezoelectricity - the conversion of mechanical stress into electricity - in two-dimensional single-layer MoS2 nanosheets. The results represent a milestone towards

Vertical comb drive actuator for the measurement of piezoelectric coefficients in small-scale systems

International Nuclear Information System (INIS)

Wooldridge, J; Muniz-Piniella, A; Stewart, M; Shean, T A V; Weaver, P M; Cain, M G

2013-01-01

A micro-electro-mechanical systems (MEMS) vertical levitation comb drive actuator has been created for the measurement of piezoelectric coefficients in thin/thick films or piezoelectrically active micro-scale components of other MEMS devices. The device exerts a dynamic force of 33 μN at an applied voltage of 100 V. The charge developed on the piezoelectric test device is measured using a charge sensitive pre-amplifier and lock-in technique, enabling measurements down to 1×10 −5 pC. The system was tested with ten different piezoelectric samples with coefficients in the range 70–1375 pC N −1 and showed a good correlation (r = 0.9997) to measurements performed with macroscopic applied stresses, and piezoelectric impedance resonance techniques. The measurement of the direct piezoelectric effect in micro- and nano-scale piezo-materials has been made possible using MEMS processing technology. This new application of a MEMS metrology device has been developed and fully characterized in order to accurately evaluate the functional properties of piezoelectric materials at the scale required in micro- to nano-scale applications. (paper)

Determination of maximum power transfer conditions of bimorph piezoelectric energy harvesters

KAUST Repository

Ahmad, Mahmoud Al; Alshareef, Husam N.; Elshurafa, Amro M.; Salama, Khaled N.

2012-01-01

the bimorph based on the electromechanical, single degree of freedom, analogy. Further, by taking into account the intrinsic capacitance of the piezoelectric harvester, a more descriptive expression of the resonant frequency in piezoelectric bimorphs

Applications of Piezoelectric Materials in Structural Health Monitoring and Repair: Selected Research Examples.

Science.gov (United States)

Duan, Wen Hui; Wang, Quan; Quek, Ser Tong

2010-12-06

The paper reviews the recent applications of piezoelectric materials in structural health monitoring and repair conducted by the authors. First, commonly used piezoelectric materials in structural health monitoring and structure repair are introduced. The analysis of plain piezoelectric sensors and actuators and interdigital transducer and their applications in beam, plate and pipe structures for damage detection are reviewed in detail. Second, an overview is presented on the recent advances in the applications of piezoelectric materials in structural repair. In addition, the basic principle and the current development of the technique are examined.

Applications of Piezoelectric Materials in Structural Health Monitoring and Repair: Selected Research Examples

Directory of Open Access Journals (Sweden)

Ser Tong Quek

2010-12-01

Full Text Available The paper reviews the recent applications of piezoelectric materials in structural health monitoring and repair conducted by the authors. First, commonly used piezoelectric materials in structural health monitoring and structure repair are introduced. The analysis of plain piezoelectric sensors and actuators and interdigital transducer and their applications in beam, plate and pipe structures for damage detection are reviewed in detail. Second, an overview is presented on the recent advances in the applications of piezoelectric materials in structural repair. In addition, the basic principle and the current development of the technique are examined.

Finite Element Study on Acoustic Energy Harvesting Using Lead-Free Piezoelectric Ceramics

Science.gov (United States)

Kumar, Anuruddh; Sharma, Anshul; Kumar, Rajeev; Vaish, Rahul

2018-02-01

In this article, a numerical investigation is performed for ambient acoustic energy harvesting at a low-frequency acoustic signal. A model of a quarter-wavelength resonator with a rectangular cross section is constructed, and piezoelectric-laminated bimorph plates are placed inside the system. Finite element modeling is implemented to numerically formulate the piezoelectric energy harvester. With the application of acoustic pressure at the open end of the resonator, amplified acoustic pressure inside the tube vibrates the piezolaminated bimorphs inside the tube, thus generating electric potential on the piezoelectric layers. To generate higher voltage and power in the acoustic harvester, multiple piezolaminated plates are positioned inside the resonator. The lead-free piezoelectric material K0.475Na0.475Li0.05 (Nb0.92Ta0.05Sb0.03)O3 (KNLNTS) is laminated on the host structure as a layer of piezoelectric material for the acoustic energy harvester. With the application of an acoustic sound pressure of 1 dB at the opening of the tube, a maximum output voltage of 16.3 V is measured at the first natural frequency, while the maximum power calculated is 0.033 mW. Maximum voltage is obtained when five piezoelectric bimorphs are place inside the resonator. At the second natural frequency, the maximum voltage measured is 8.40 V, obtained when eight piezoelectric bimorphs are placed inside the resonator, and the maximum power calculated is 0.020 mW.

Atomistic configurational effects on piezoelectric properties of La3Ta0.5Ga5.5O14 and a new piezoelectric crystal design

International Nuclear Information System (INIS)

Chung, Chan-Yeup; Yaokawa, Ritsuko; Mizuseki, Hiroshi; Kawazoe, Yoshiyuki

2011-01-01

Single crystalline langatate (LTG, La 3 Ta 0.5 Ga 5.5 O 14 ) has been widely used as a sensor material in high temperature applications because of its thermally stable piezoelectric properties. In this research, to elucidate the relationship between piezoelectric tensors and local ionic configurations, first-principles calculations based on density functional perturbation theory (DFPT) were performed on various local ionic structures. The results indicate that two independent relaxed-ion piezoelectric coefficients, e 11 and e 14 , increased with increases in La (3e) -O and Ta (1a) -O distances or decreases in Ga (3f,2d) -O distances. Thus, to obtain high piezoelectric constants in this crystal, ions larger than La 3+ should be incorporated at 3e sites to open the distance between 3e ions and oxygen ions, and ions smaller than Ga 3+ should be introduced at 2d and 3f sites to reduce the distance between Ga and O ions. Finally, from this design rule, a new crystal, BTAS (Ba 3 TaAl 3 Si 2 O 14 ), which belongs to the same P321 group, is proposed. The calculated relaxed-ion piezoelectric coefficient e 11 of BTAS was 17.7% higher than the coefficient of a LTG crystal. This significant increase confirms BTAS as a useful new piezo-material, especially in applications where there is also a need to reduce the use of more expensive elements.

Effect of porosity on the ferroelectric and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 piezoelectric ceramics

DEFF Research Database (Denmark)

Yap, Emily W.; Glaum, Julia; Oddershede, Jette

2018-01-01

The ferroelectric and piezoelectric properties of (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) ceramics were measured as a function of porosity. Porous BCZT ceramics were fabricated using the sacrificial fugitive technique. Two different pore morphologies were induced by adding polymeric microspheres...... and fibres as the pore-forming agents. Increasing porosity led to decreasing ferroelectric and piezoelectric properties due to a reduction of polarisable BCZT ceramic available. With the benefit of being a lead-free piezoelectric material, porous BCZT ceramics may be considered for acoustic impedance...

Static aeroelastic behavior of an adaptive laminated piezoelectric composite wing

Science.gov (United States)

Weisshaar, T. A.; Ehlers, S. M.

1990-01-01

The effect of using an adaptive material to modify the static aeroelastic behavior of a uniform wing is examined. The wing structure is idealized as a laminated sandwich structure with piezoelectric layers in the upper and lower skins. A feedback system that senses the wing root loads applies a constant electric field to the piezoelectric actuator. Modification of pure torsional deformaton behavior and pure bending deformation are investigated, as is the case of an anisotropic composite swept wing. The use of piezoelectric actuators to create an adaptive structure is found to alter static aeroelastic behavior in that the proper choice of the feedback gain can increase or decrease the aeroelastic divergence speed. This concept also may be used to actively change the lift effectiveness of a wing. The ability to modify static aeroelastic behavior is limited by physical limitations of the piezoelectric material and the manner in which it is integrated into the parent structure.

Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion

Science.gov (United States)

Khan, Farid Ullah; Izhar

2016-02-01

This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester.

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT–ionomer composites

International Nuclear Information System (INIS)

James, N K; Lafont, U; Van der Zwaag, S; Groen, W A

2014-01-01

Piezoelectric ceramic–polymer composites with 0–3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT–Zn ionomer and PZT–EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT–Zn ionomer composites have better piezoelectric properties compared to PZT–EMAA composites. The static and fatigue properties of the composites were investigated. The PZT–Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing. (paper)

Piezoelectric and mechanical properties of fatigue resistant, self-healing PZT-ionomer composites

Science.gov (United States)

James, N. K.; Lafont, U.; van der Zwaag, S.; Groen, W. A.

2014-05-01

Piezoelectric ceramic-polymer composites with 0-3 connectivity were fabricated using lead zirconium titanate (PZT) powder dispersed in an ionomer (Zn ionomer) and its reference ethylene methacrylic acid copolymer (EMAA) polymer matrix. The PZT-Zn ionomer and PZT-EMAA composites were prepared by melt extrusion followed by hot pressing. The effects of poling conditions such as temperature, time and electric field on the piezoelectric properties of the composites were investigated. The experimentally observed piezoelectric charge coefficient and dielectric constant of the composites were compared with theoretical models. The results show that PZT-Zn ionomer composites have better piezoelectric properties compared to PZT-EMAA composites. The static and fatigue properties of the composites were investigated. The PZT-Zn ionomer composites were found to have excellent fatigue resistance even at strain levels of 4%. Due to the self-healing capabilities of the ionomer matrix, the loss of piezoelectric properties after high strain tensile cyclic loading could be partially recovered by thermal healing.

r-Shaped hybrid nanogenerator with enhanced piezoelectricity.

Science.gov (United States)

Han, Mengdi; Zhang, Xiao-Sheng; Meng, Bo; Liu, Wen; Tang, Wei; Sun, Xuming; Wang, Wei; Zhang, Haixia

2013-10-22

Piezoelectric and triboelectric nanogenerators (NGs) have been proposed in the past few years to effectively harvest mechanical energy from the environment. Here, a polydimethylsiloxane (PDMS) layer is placed under the aluminum electrode of polyvinylidene fluoride (PVDF), thus forming an r-shaped hybrid NG. Micro/nanostructures have been fabricated on the PDMS surface and the aluminum electrodes of PVDF to enhance the output performance. Power densities of the piezoelectric part and the triboelectric part are 10.95 and 2.04 mW/cm(3), respectively. Moreover, influence of the triboelectric charges on the piezoelectric output voltage is investigated. Both finite element method simulations and experimental measurements are conducted to verify this phenomenon. The novel hybrid NG is also demonstrated as a power source for consumer electronics. Through one cycle of electric generation, 10 light-emitting diodes are lighted up instantaneously, and a 4-bit liquid crystal display can display continuously for more than 15 s. Besides, the device is integrated into a keyboard to harvest energy in the typing process.

Ultrasonic Guided Waves in Piezoelectric Layered Composite with Different Interfacial Properties

Directory of Open Access Journals (Sweden)

Xiao Chen

2011-01-01

Full Text Available Combining the propagation model of guided waves in a multilayered piezoelectric composite with the interfacial model of rigid, slip, and weak interfaces, the generalized dispersion characteristic equations of guided waves propagating in a piezoelectric layered composite with different interfacial properties are derived. The effects of the slip, weak, and delamination interfaces in different depths on the dispersion properties of the lowest-order mode ultrasonic guided wave are analyzed. The theory would be used to characterize the interfacial properties of piezoelectric layered composite nondestructively.

Effect of B-site substitution of complex ions on dielectric and piezoelectric properties in (Bi1/2Na1/2)TiO3 piezoelectric ceramics

International Nuclear Information System (INIS)

Zhou Changrong; Liu Xinyu

2008-01-01

The effect of B-site substitution of complex ions on dielectric and piezoelectric properties in (Bi 1/2 Na 1/2 )Ti 1-x (Zn 1/3 Nb 2/3 ) x O 3 (BNTZN-100x) lead-free piezoelectric ceramics was investigated. X-ray diffraction analysis shows that the materials are mono-perovskite phase. The morphotropic phase boundary (MPB) of BNTZN-100x ceramics between rhombohedral and tetragonal locates in the range of 0.5% ≤ x ≤ 2.0%. Temperature dependence of dielectric constant shows that these compounds are relaxor ferroelectrics. The compositions near the MPB exhibit relatively high piezoelectric properties. The piezoelectric constant (d 33 ) and the electromechanical coupling factor (k t ) show the maximum values of d 33 = 97 pC N -1 and k t = 0.46 at x = 2.0% and x = 1.0%, respectively. The BNTZN-100x ceramics are good candidate for use as ultrasonic transducer ceramics for high anisotropic with high k t value and low k p value

Integration of Geometrical and Material Nonlinear Energy Sink with Piezoelectric Material Energy Harvester

Directory of Open Access Journals (Sweden)

Ye-Wei Zhang

2017-01-01

Full Text Available This paper presents a novel design by integrating geometrical and material nonlinear energy sink (NES with a piezoelectric-based vibration energy harvester under shock excitation, which can realize vibration control and energy harvesting. The nonlinear spring and hysteresis behavior of the NES could reflect geometrical and material nonlinearity, respectively. Two configurations of the piezoelectric device, including the piezoelectric element embedded between the NES mass and the single-degree-of-freedom system or ground, are utilised to examine the energy dissipated by damper and hysteresis behavior of NES and the energy harvested by the piezoelectric element. Similar numerical research methods of Runge-Kutta algorithm are used to investigate the two configurations. The energy transaction measure (ETM is adopted to examine the instantaneous energy transaction between the primary and the NES-piezoelectricity system. And it demonstrates that the dissipated and harvested energy transaction is transferred from the primary system to the NES-piezoelectricity system and the instantaneous transaction of mechanical energy occupies a major part of the energy of transaction. Both figurations could realize vibration control efficiently.

Optimization of the piezoelectric response of 0–3 composites: a modeling approach

International Nuclear Information System (INIS)

Chambion, B; Goujon, L; Badie, L; Mugnier, Y; Barthod, C; Galez, C; Wiebel, S; Venet, C

2011-01-01

Finite element modeling is used in this study to optimize the electromechanical behavior of 0–3 composites according to the material properties of their constituents. Our modeling approach considers an 'extended' 2D representative volume element (RVE) with randomly dispersed piezoelectric particles. A variable distribution of their polarization axes is also implemented because a full periodic arrangement of fillers and a unique poling orientation are unrealistic in practice. Comparisons with a simpler RVE and with an analytical model based on the Mori–Tanaka approach are performed as a function of the particle concentration for the elastic, dielectric and piezoelectric homogenized properties. An optimization of the piezoelectric response of 0–3 composites according to material considerations is then computed, allowing it to be shown that the piezoelectric strain coefficient is not the only relevant parameter and that lead-free piezoelectric fillers such as LiNbO 3 and ZnO are competitive alternatives. Finally, the piezoelectric responses of 0–3 composites with different filler arrangements are quantitatively compared to 1–3 composites and to the corresponding bulk material

Giant piezoelectric voltage coefficient in grain-oriented modified PbTiO3 material.

Science.gov (United States)

Yan, Yongke; Zhou, Jie E; Maurya, Deepam; Wang, Yu U; Priya, Shashank

2016-10-11

A rapid surge in the research on piezoelectric sensors is occurring with the arrival of the Internet of Things. Single-phase oxide piezoelectric materials with giant piezoelectric voltage coefficient (g, induced voltage under applied stress) and high Curie temperature (T c ) are crucial towards providing desired performance for sensing, especially under harsh environmental conditions. Here, we report a grain-oriented (with 95% texture) modified PbTiO 3 ceramic that has a high T c (364 °C) and an extremely large g 33 (115 × 10 -3  Vm N -1 ) in comparison with other known single-phase oxide materials. Our results reveal that self-polarization due to grain orientation along the spontaneous polarization direction plays an important role in achieving large piezoelectric response in a domain motion-confined material. The phase field simulations confirm that the large piezoelectric voltage coefficient g 33 originates from maximized piezoelectric strain coefficient d 33 and minimized dielectric permittivity ɛ 33 in [001]-textured PbTiO 3 ceramics where domain wall motions are absent.

Piezoelectric Actuator Modeling Using MSC/NASTRAN and MATLAB

Science.gov (United States)

Reaves, Mercedes C.; Horta, Lucas G.

2003-01-01

This paper presents a procedure for modeling structures containing piezoelectric actuators using MSCMASTRAN and MATLAB. The paper describes the utility and functionality of one set of validated modeling tools. The tools described herein use MSCMASTRAN to model the structure with piezoelectric actuators and a thermally induced strain to model straining of the actuators due to an applied voltage field. MATLAB scripts are used to assemble the dynamic equations and to generate frequency response functions. The application of these tools is discussed using a cantilever aluminum beam with a surface mounted piezoelectric actuator as a sample problem. Software in the form of MSCINASTRAN DMAP input commands, MATLAB scripts, and a step-by-step procedure to solve the example problem are provided. Analysis results are generated in terms of frequency response functions from deflection and strain data as a function of input voltage to the actuator.

Smart helicopter rotors optimization and piezoelectric vibration control

CERN Document Server

Ganguli, Ranjan; Viswamurthy, Sathyamangalam Ramanarayanan

2016-01-01

Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibra...

A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

International Nuclear Information System (INIS)

Yoon, Sunghyun; Cho, Young-Ho

2014-01-01

We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm 2 . Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

Development of multilayer piezoelectric actuator valve for JT-60

International Nuclear Information System (INIS)

Miyo, Yasuhiko; Hiratsuka, Hajime; Masui, Hiroshi; Hosogane, Nobuyuki; Miya, Naoyuki

2001-11-01

In order to improve the gas injection valve used for the operation of JT-60, a new type of valve (multilayer piezoelectric actuator valve) was developed. The conventional valve (bimorph piezoelectric valve) has been used for 15 years since the beginning of experimental operation in April, 1985. However, it came to be hard to keep the performance of the valve because of the deterioration of the driving source, i.e. piezoelectric element. Developments of the new valve were carried out based on experiences through experimental operations in JT-60. Requirements for the design are: (1) to be hard structure for making a sheet leak, (2) to allow a repair work at atmosphere side without an air vent of the vacuum vessel, (3) to be more smaller and lighter compared with the conventional one, and (4) to have a high maintenance efficiency by utilizing of the commercial piezoelectric elements and power supplies. The newly developed valve was examined with various tests such as gas flow characteristic test, high magnetic field proof test, high temperature proof test and gas flow rate test for aged deterioration. Results, confirm that the performance of the valve is applicable for JT-60 operations. (author)

Obstructive Sleep Apnea Screening Using a Piezo-Electric Sensor.

Science.gov (United States)

Erdenebayar, Urtnasan; Park, Jong Uk; Jeong, Pilsoo; Lee, Kyoung Joung

2017-06-01

In this study, we propose a novel method for obstructive sleep apnea (OSA) detection using a piezo-electric sensor. OSA is a relatively common sleep disorder. However, more than 80% of OSA patients remain undiagnosed. We investigated the feasibility of OSA assessment using a single-channel physiological signal to simplify the OSA screening. We detected both snoring and heartbeat information by using a piezo-electric sensor, and snoring index (SI) and features based on pulse rate variability (PRV) analysis were extracted from the filtered piezo-electric sensor signal. A support vector machine (SVM) was used as a classifier to detect OSA events. The performance of the proposed method was evaluated on 45 patients from mild, moderate, and severe OSA groups. The method achieved a mean sensitivity, specificity, and accuracy of 72.5%, 74.2%, and 71.5%; 85.8%, 80.5%, and 80.0%; and 70.3%, 77.1%, and 71.9% for the mild, moderate, and severe groups, respectively. Finally, these results not only show the feasibility of OSA detection using a piezo-electric sensor, but also illustrate its usefulness for monitoring sleep and diagnosing OSA. © 2017 The Korean Academy of Medical Sciences.

Hybrid Piezoelectric/Fiber-Optic Sensor Sheets

Science.gov (United States)

Lin, Mark; Qing, Xinlin

2004-01-01

Hybrid piezoelectric/fiber-optic (HyPFO) sensor sheets are undergoing development. They are intended for use in nondestructive evaluation and long-term monitoring of the integrity of diverse structures, including aerospace, aeronautical, automotive, and large stationary ones. It is anticipated that the further development and subsequent commercialization of the HyPFO sensor systems will lead to economic benefits in the form of increased safety, reduction of life-cycle costs through real-time structural monitoring, increased structural reliability, reduction of maintenance costs, and increased readiness for service. The concept of a HyPFO sensor sheet is a generalization of the concept of a SMART Layer(TradeMark), which is a patented device that comprises a thin dielectric film containing an embedded network of distributed piezoelectric actuator/sensors. Such a device can be mounted on the surface of a metallic structure or embedded inside a composite-material structure during fabrication of the structure. There is has been substantial interest in incorporating sensors other than piezoelectric ones into SMART Layer(TradeMark) networks: in particular, because of the popularity of the use of fiber-optic sensors for monitoring the "health" of structures in recent years, it was decided to incorporate fiber-optic sensors, giving rise to the concept of HyPFO devices.

Hydrothermal crystal growth, piezoelectricity, and triboluminescence of KNaNbOF5

International Nuclear Information System (INIS)

Chang, Kelvin B.; Edwards, Bryce W.; Frazer, Laszlo; Lenferink, Erik J.; Stanev, Teodor K.; Stern, Nathaniel P.; Nino, Juan C.; Poeppelmeier, Kenneth R.

2016-01-01

Single crystals of the noncentrosymmetric KNaNbOF 5 polymorph were grown for piezoelectric and triboluminescent measurements. Piezoelectric measurements yielded a d 33 value of ±6.3 pCN −1 and an effective electromechanical coupling coefficient of up to 0.1565 in the frequency range 1960–2080 kHz. Crystals of KNaNbOF 5 were found to exhibit a strong triboluminscence effect visible to the naked eye as blue sparks when crystals are crushed. This triboluminescence effect is uncommon in that it is likely independent from both the piezoelectric effect and atmospheric electrical discharge. Instead, triboluminescence may originate from crystal defects or be related to an electroluminescence effect. - Graphical abstract: An optical emission visible to the naked eye as blue sparks is observed when KNaNbOF 5 single crystals are fractured. - Highlights: • Single crystals of KNaNbOF 5 were grown under hydrothermal conditions. • Piezoelectric and triboluminescent properties were characterized. • Piezoelectric measurements yielded a d 33 value of ±pCN −1 . • KNaNbOF 5 exhibits strong triboluminscence visible to the naked eye as blue sparks.

Cryogenic Rotary Piezoelectric Motor, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Piezoelectric motors operate on the principal of converting the high-frequency oscillation of high-force, precision ceramic elements into useful continuous motion....

Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

Energy Technology Data Exchange (ETDEWEB)

Xu, J.; Tang, J., E-mail: jtang@engr.uconn.edu [Department of Mechanical Engineering, The University of Connecticut, Storrs, Connecticut 06269 (United States)

2015-11-23

This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

International Nuclear Information System (INIS)

Xu, J.; Tang, J.

2015-01-01

This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined

Role of Reversible Phase Transformation for Strong Piezoelectric Performance at the Morphotropic Phase Boundary

Science.gov (United States)

Liu, Hui; Chen, Jun; Huang, Houbing; Fan, Longlong; Ren, Yang; Pan, Zhao; Deng, Jinxia; Chen, Long-Qing; Xing, Xianran

2018-01-01

A functional material with coexisting energetically equivalent phases often exhibits extraordinary properties such as piezoelectricity, ferromagnetism, and ferroelasticity, which is simultaneously accompanied by field-driven reversible phase transformation. The study on the interplay between such phase transformation and the performance is of great importance. Here, we have experimentally revealed the important role of field-driven reversible phase transformation in achieving enhanced electromechanical properties using in situ high-energy synchrotron x-ray diffraction combined with 2D geometry scattering technology, which can establish a comprehensive picture of piezoelectric-related microstructural evolution. High-throughput experiments on various Pb /Bi -based perovskite piezoelectric systems suggest that reversible phase transformation can be triggered by an electric field at the morphotropic phase boundary and the piezoelectric performance is highly related to the tendency of electric-field-driven phase transformation. A strong tendency of phase transformation driven by an electric field generates peak piezoelectric response. Further, phase-field modeling reveals that the polarization alignment and the piezoelectric response can be much enhanced by the electric-field-driven phase transformation. The proposed mechanism will be helpful to design and optimize the new piezoelectrics, ferromagnetics, or other related functional materials.

Subperiosteal preparation using a new piezoelectric device: a histological examination

Directory of Open Access Journals (Sweden)

Stoetzer, Marcus

2014-12-01

Full Text Available Introduction: Subperiosteal preparation using a periosteal elevator leads to disturbances of local immunohistochemistry and periosteal histology due to a microtrauma. Usually soft-tissue damage can be considerably reduced by using piezoelectric technology. For this reason, the effects of a novel piezoelectric device on immunohistochemistry and periosteal histology were examined and compared to conventional preparation of the periosteum using a periosteal elevator.Material and methods: Lewis rats were randomly assigned to one of five groups (n=50. Subperiosteal preparation was performed using either a piezoelectric device or a periosteal elevator. Immunohistochemical and histological analyses were performed immediately after preparation as well as three and eight days postoperatively. A statistical analysis of the histological colouring was performed offline using analysis of variance (ANOVA on ranks (p<0.05. Results: At all times, immunohistochemical and histological analysis demonstrated a significantly more homogenous tissue structure in the group of rats that underwent piezosurgery than in the group of rats that underwent treatment with a periosteal elevator.Conclusion: The use of a piezoelectric device for subperiosteal preparation is associated with more harmonious immunohistochemical and histological results for the periosteum than the use of a conventional periosteal elevator. As a result, piezoelectric devices can be expected to have a positive effect primarily on soft tissue, in particular of the periosteal as well as on surrounding tissues.

Various aspects of the placement of a piezoelectric material in composite actuators, motors, and transducers

International Nuclear Information System (INIS)

Lierke, Ernst Gunter; Littmann, Walter; Morita, Takeshi; Hemsel, Tobias

2010-01-01

Piezoelectric materials have found wide applications in technical systems. Most often, a combination of piezoelectric and other materials is advantageous. The position and the amount of the piezoelectric material within the overall system depends on various aspects, such as the maximum mechanical output to the load, the maximum electromechanical efficiency of the system, the maximum utilization of the piezoelectric material, the minimum self-heating of the piezoelectric material, and the controllability of the system, which might be key aspects for the optimization of the system design. For a composite longitudinal vibrator (bolted Langevin transducer), which is a base for many technical applications, this contribution shows in detail, how the above-mentioned aspects depend on the position and the volume of the piezoelectric material related to the mode shape.

Piezoelectric Resonance Defined High Performance Sensors and Modulators

Science.gov (United States)

2016-05-30

19.00 20.00 30.00 Received Paper 3.00 Juan P. Tamez, Amar Bhalla, Ruyan Guo. Design and Simulation of 100 kHz and 200 kHz Tri-Phasic PZT Piezoelectric...electrooptic coefficient r_51 of tetragonal potassium lithium tantalate niobate K_095Li_005Ta_040Nb_060O_3 single crystal, Optical Materials Express, (11...Experimental Studies on Tri- Phasic PZT Piezoelectric Transducer, Ferroelectrics, (12 2014): 0. doi: 10.1080/00150193.2014.974472 Jun Li, Yang Li

Critical electrode size in measurement of d33 coefficient of films via spatial distribution of piezoelectric displacement

International Nuclear Information System (INIS)

Wang Zhihong; Miao Jianmin

2008-01-01

Spatial distributions of piezoelectric displacement response across the top electrode have been used in this paper to measure the piezoelectric coefficient d 33 of films based on the converse piezoelectric effect. The technical details and features of a scanning laser Doppler vibrometer have been summarized and discussed for accurately obtaining the spatial displacement distributions. Three definitions, including the apparent, the effective and the constrained piezoelectric coefficient d 33 of films, have been clarified and used to better understand the fundamental phenomenon behind the measured displacement distributions. Finite element analysis reveals that both the apparent and the effective piezoelectric coefficients depend on the electrode radius of test capacitor as well as film thickness. However, there exists a critical electrode size for apparent piezoelectric coefficients and a critical test capacitor aspect ratio for effective piezoelectric coefficient. Beyond their respective critical values, both coefficients converge to the constrained piezoelectric coefficient irrespective of film thickness. The finding of the critical electric size makes it possible to consistently measure the constrained piezoelectric coefficient of films by using the spatial distributions of the piezoelectric displacement response and becomes the fundamental criterion of this measurement method

Cryogenic Rotary Piezoelectric Motor, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Piezoelectric motors operate on the principal of high frequency oscillation of high force precision ceramic elements. The high power oscillations are converted to...

Validation of High Displacement Piezoelectric Actuator Finite Element Models

Science.gov (United States)

Taleghani, B. K.

2000-01-01

The paper presents the results obtained by using NASTRAN(Registered Trademark) and ANSYS(Regitered Trademark) finite element codes to predict doming of the THUNDER piezoelectric actuators during the manufacturing process and subsequent straining due to an applied input voltage. To effectively use such devices in engineering applications, modeling and characterization are essential. Length, width, dome height, and thickness are important parameters for users of such devices. Therefore, finite element models were used to assess the effects of these parameters. NASTRAN(Registered Trademark) and ANSYS(Registered Trademark) used different methods for modeling piezoelectric effects. In NASTRAN(Registered Trademark), a thermal analogy was used to represent voltage at nodes as equivalent temperatures, while ANSYS(Registered Trademark) processed the voltage directly using piezoelectric finite elements. The results of finite element models were validated by using the experimental results.

Piezoelectric displacement in ceramics

International Nuclear Information System (INIS)

Stewart, M.; Cain, M.; Gee, M.

1999-01-01

This Good Practice Guide is intended to aid a user to perform displacement measurements on piezoelectric ceramic materials such as PZT (lead zirconium titanate) in either monolithic or multilayer form. The various measurement issues that the user must consider are addressed, and good measurement practise is described for the four most suitable methods. (author)

Comparative analysis of the planar capacitor and IDT piezoelectric thin-film micro-actuator models

International Nuclear Information System (INIS)

Myers, Oliver J; Anjanappa, M; Freidhoff, Carl B

2011-01-01

A comparison of the analysis of similarly developed microactuators is presented. Accurate modeling and simulation techniques are vital for piezoelectrically actuated microactuators. Coupling analytical and numerical modeling techniques with variational design parameters, accurate performance predictions can be realized. Axi-symmetric two-dimensional and three-dimensional static deflection and harmonic models of a planar capacitor actuator are presented. Planar capacitor samples were modeled as unimorph diaphragms with sandwiched piezoelectric material. The harmonic frequencies were calculated numerically and compared well to predicted values and deformations. The finite element modeling reflects the impact of the d 31 piezoelectric constant. Two-dimensional axi-symmetric models of circularly interdigitated piezoelectrically membranes are also presented. The models include the piezoelectric material and properties, the membrane materials and properties, and incorporates various design considerations of the model. These models also include the electro-mechanical coupling for piezoelectric actuation and highlight a novel approach to take advantage of the higher d 33 piezoelectric coupling coefficient. Performance is evaluated for varying parameters such as electrode pitch, electrode width, and piezoelectric material thickness. The models also showed that several of the design parameters were naturally coupled. The static numerical models correlate well with the maximum static deflection of the experimental devices. Finally, this paper deals with the development of numerical harmonic models of piezoelectrically actuated planar capacitor and interdigitated diaphragms. The models were able to closely predict the first two harmonics, conservatively predict the third through sixth harmonics and predict the estimated values of center deflection using plate theory. Harmonic frequency and deflection simulations need further correlation by conducting extensive iterative

Enhancing the piezoelectric properties of flexible hybrid AlN materials using semi-crystalline parylene

Science.gov (United States)

Jackson, Nathan; Mathewson, Alan

2017-04-01

Flexible piezoelectric materials are desired for numerous applications including biomedical, wearable, and flexible electronics. However, most flexible piezoelectric materials are not compatible with CMOS fabrication technology, which is desired for most MEMS applications. This paper reports on the development of a hybrid flexible piezoelectric material consisting of aluminium nitride (AlN) and a semi-crystalline polymer substrate. Various types of semi-crystalline parylene and polyimide materials were investigated as the polymer substrate. The crystallinity and surfaces of the polymer substrates were modified by micro-roughening and annealing in order to determine the effects on the AlN quality. The AlN crystallinity and piezoelectric properties decreased when the polymer surfaces were treated with O2 plasma. However, increasing the crystallinity of the parylene substrate prior to deposition of AlN caused enhanced c-axis (002) AlN crystallinity and piezoelectric response of the AlN. Piezoelectric properties of 200 °C annealed parylene-N substrate resulted in an AlN d 33 value of 4.87 pm V-1 compared to 2.17 pm V-1 for AlN on polyimide and 4.0 pm V-1 for unannealed AlN/parylene-N. The electrical response measurements to an applied force demonstrated that the parylene/AlN hybrid material had higher V pp (0.918 V) than commercial flexible piezoelectric material (PVDF) (V pp 0.36 V). The results in this paper demonstrate that the piezoelectric properties of a flexible AlN hybrid material can be enhanced by increasing the crystallinity of the polymer substrate, and the enhanced properties can function better than previous flexible piezoelectrics.

Wafer-scale integration of piezoelectric actuation capabilities in nanoelectromechanical systems resonators

OpenAIRE

DEZEST, Denis; MATHIEU, Fabrice; MAZENQ, Laurent; SOYER, Caroline; COSTECALDE, Jean; REMIENS, Denis; THOMAS, Olivier; DEÜ, Jean-François; NICU, Liviu

2013-01-01

In this work, we demonstrate the integration of piezoelectric actuation means on arrays of nanocantilevers at the wafer scale. We use lead titanate zirconate (PZT) as piezoelectric material mainly because of its excellent actuation properties even when geometrically constrained at extreme scale

One-Step Solvent Evaporation-Assisted 3D Printing of Piezoelectric PVDF Nanocomposite Structures.

Science.gov (United States)

Bodkhe, Sampada; Turcot, Gabrielle; Gosselin, Frederick P; Therriault, Daniel

2017-06-21

Development of a 3D printable material system possessing inherent piezoelectric properties to fabricate integrable sensors in a single-step printing process without poling is of importance to the creation of a wide variety of smart structures. Here, we study the effect of addition of barium titanate nanoparticles in nucleating piezoelectric β-polymorph in 3D printable polyvinylidene fluoride (PVDF) and fabrication of the layer-by-layer and self-supporting piezoelectric structures on a micro- to millimeter scale by solvent evaporation-assisted 3D printing at room temperature. The nanocomposite formulation obtained after a comprehensive investigation of composition and processing techniques possesses a piezoelectric coefficient, d 31 , of 18 pC N -1 , which is comparable to that of typical poled and stretched commercial PVDF film sensors. A 3D contact sensor that generates up to 4 V upon gentle finger taps demonstrates the efficacy of the fabrication technique. Our one-step 3D printing of piezoelectric nanocomposites can form ready-to-use, complex-shaped, flexible, and lightweight piezoelectric devices. When combined with other 3D printable materials, they could serve as stand-alone or embedded sensors in aerospace, biomedicine, and robotic applications.

Piezoelectric constants for ZnO calculated using classical polarizable core-shell potentials

International Nuclear Information System (INIS)

Dai Shuangxing; Dunn, Martin L; Park, Harold S

2010-01-01

We demonstrate the feasibility of using classical atomistic simulations, i.e. molecular dynamics and molecular statics, to study the piezoelectric properties of ZnO using core-shell interatomic potentials. We accomplish this by reporting the piezoelectric constants for ZnO as calculated using two different classical interatomic core-shell potentials: that originally proposed by Binks and Grimes (1994 Solid State Commun. 89 921-4), and that proposed by Nyberg et al (1996 J. Phys. Chem. 100 9054-63). We demonstrate that the classical core-shell potentials are able to qualitatively reproduce the piezoelectric constants as compared to benchmark ab initio calculations. We further demonstrate that while the presence of the shell is required to capture the electron polarization effects that control the clamped ion part of the piezoelectric constant, the major shortcoming of the classical potentials is a significant underprediction of the clamped ion term as compared to previous ab initio results. However, the present results suggest that overall, these classical core-shell potentials are sufficiently accurate to be utilized for large scale atomistic simulations of the piezoelectric response of ZnO nanostructures.

Direct strain energy harvesting in automobile tires using piezoelectric PZT–polymer composites

International Nuclear Information System (INIS)

Van den Ende, D A; Van de Wiel, H J; Groen, W A; Van der Zwaag, S

2012-01-01

Direct piezoelectric strain energy harvesting can be used to power wireless autonomous sensors in environments where low frequency, high strains are present, such as in automobile tires during operation. However, these high strains place stringent demands on the materials with respect to mechanical failure or depolarization, especially at elevated temperatures. In this work, three kinds of ceramic–polymer composite piezoelectric materials were evaluated and compared against state-of-the-art piezoelectric materials. The new composites are unstructured and structured composites containing granular lead zirconate titanate (PZT) particles or PZT fibers in a polyurethane matrix. The composites were used to build energy harvesting patches which were attached to a tire and tested under simulated rolling conditions. The energy density of the piezoelectric ceramic–polymer composite materials is initially not as high as that of the reference materials (a macro-fiber composite and a polyvinylidene fluoride polymer). However, the area normalized power output of the composites after temperature and strain cycling is comparable to that of the reference devices because the piezoelectric ceramic–polymer composites did not degrade during operation. (paper)

TOPICAL REVIEW: Progress in engineering high strain lead-free piezoelectric ceramics

Science.gov (United States)

Leontsev, Serhiy O.; Eitel, Richard E.

2010-08-01

Environmental concerns are strongly driving the need to replace the lead-based piezoelectric materials currently employed as multilayer actuators. The current review describes both compositional and structural engineering approaches to achieve enhanced piezoelectric properties in lead-free materials. The review of the compositional engineering approach focuses on compositional tuning of the properties and phase behavior in three promising families of lead-free perovskite ferroelectrics: the titanate, alkaline niobate and bismuth perovskites and their solid solutions. The 'structural engineering' approaches focus instead on optimization of microstructural features including grain size, grain orientation or texture, ferroelectric domain size and electrical bias field as potential paths to induce large piezoelectric properties in lead-free piezoceramics. It is suggested that a combination of both compositional and novel structural engineering approaches will be required in order to realize viable lead-free alternatives to current lead-based materials for piezoelectric actuator applications.

On the Nonlinear Behavior of the Piezoelectric Coupling on Vibration-Based Energy Harvesters

Directory of Open Access Journals (Sweden)

Luciana L. Silva

2015-01-01

Full Text Available Vibration-based energy harvesting with piezoelectric elements has an increasing importance nowadays being related to numerous potential applications. A wide range of nonlinear effects is observed in energy harvesting devices and the analysis of the power generated suggests that they have considerable influence on the results. Linear constitutive models for piezoelectric materials can provide inconsistencies on the prediction of the power output of the energy harvester, mainly close to resonant conditions. This paper investigates the effect of the nonlinear behavior of the piezoelectric coupling. A one-degree of freedom mechanical system is coupled to an electrical circuit by a piezoelectric element and different coupling models are investigated. Experimental tests available in the literature are employed as a reference establishing the best matches of the models. Subsequently, numerical simulations are carried out showing different responses of the system indicating that nonlinear piezoelectric couplings can strongly modify the system dynamics.

Design of a bimorph piezoelectric energy harvester for railway monitoring

Energy Technology Data Exchange (ETDEWEB)

Li, Jingcheng; Jang, Shinae; Tang, Jiong [Univ. of Connecticut, Connecticut (United States)

2012-12-15

Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s{sup 2} base excitation compared to stand alone piezoelectric energy harvester without tip mass.

Design of a bimorph piezoelectric energy harvester for railway monitoring

International Nuclear Information System (INIS)

Li, Jingcheng; Jang, Shinae; Tang, Jiong

2012-01-01

Wireless sensor network is one of prospective methods for railway monitoring due to the long term operation and low maintenance performances. How to supply power to the wireless sensor nodes has drawn much attention recently. In railway monitoring, the idea of converting ambient vibration energy from vibration of railway track induced by passing trains to electric energy has made it a potential way for powering the wireless sensor nodes. In this paper, a bimorph cantilever piezoelectric energy harvester was designed based on a single degree of freedom model. Experimental test was also performed to validate the design. The first natural frequency of the bimorph piezoelectric energy harvester was decreased from 117.1 Hz to 65.2 Hz by adding 4 gram tip mass to the free end of the 8.6 gram energy harvester. In addition, the power generation of the piezoelectric energy harvester with 4 gram tip mass at resonant frequency was increased from 0.14 mW to 0.74 mW from 2.06 m/s 2 base excitation compared to stand alone piezoelectric energy harvester without tip mass

Best voltage bias-flipping strategy towards maximum piezoelectric power generation

International Nuclear Information System (INIS)

Liang, Junrui; Chung, Henry Shu-Hung

2013-01-01

In piezoelectric energy harvesting (PEH) systems, energy extracted from piezoelectric structure can be increased by making piezoelectric voltage in phase with vibration velocity and raising the voltage amplitude. Such voltage manipulations can be realized by synchronously flipping the piezoelectric voltage with respect to a bias dc source at every displacement extremum. Given that net harvested energy is obtained by deducting dissipated energy from total extracted energy, a sophisticated voltage bias-flipping scheme, which can maximize extracted energy at low dissipative cost, is required towards harvested energy optimization. This paper extends the state of the art by proposing the best bias-flip strategy, which is delivered on conceptual synchronized multiple bias-flip (SMBF) interface circuits. The proposed strategy coordinates both requirements on larger voltage change in synchronized instant for more extracted energy and smaller voltage change in each bias-flip action for less dissipated energy. It not only leads to further enhancement of harvesting capability beyond existing solutions, but also provides an unprecedented physical insight on maximum achievable harvesting capability of PEH interface circuit

INFLUENCE OF PIEZOELECTRIC TRANSDUCER TO GLASS FIBER REINFORCED COMPOSITE STIFFNESS

Directory of Open Access Journals (Sweden)

Witold Rządkowski

2015-08-01

Full Text Available The main goal was to determine if transducers based on piezoelectric materials are suitable for strain calculations in thin GFRP specimens. Numerous experimental studies, both physical and numerical, performed by the authors, have shown that there is a huge influence of bonded piezoelectric transducer on the overall stiffness of the measured object. The paper presents tensile test performed on strength machine with Digital Image Correlation strain and deflection observations. Test were compared with FEM models for detailed investigation. The main conclusion is piezoelectric transducers has huge influence on local stiffness of measured object. That is critical especially when they are used as strain sensors, when presence of sensor is influencing to measured results.

Analysis on and Optimization of a Circular Piezoelectric Composite Laminate for a Micro-Pump Driver

International Nuclear Information System (INIS)

Jia, Jianyuan; Wang, Weidong; Huang, Xinbo

2002-01-01

Among the various micro-pump actuation devices, piezoelectric composite laminate actuation has become an effective method. Due to lacking of analysis treatments, the design of this type micro-pump is in a great limitation. In this paper, an electromechanical-coupled mechanics model is established for the circle-flake micro-actuator. A kind of analysis and design method is presented that piezoelectric plate's radial strain induced by inverse piezoelectric effect is equivalently substituted with transverse stress on piezoelectric composite laminates. It is pointed out that the equivalent transverse load depends on the edge electric field distribution of parallel plate capacitor. The question has been solved that where the neutral plane in the piezoelectric composite laminates lies. Finally, an optimization design is developed on the radius ratio of piezoelectric-to-silicon plate radius by utilizing of FEA modeling

Piezoelectric and electromechanical properties of ultrahigh temperature CaBi2Nb2O9 ceramics

International Nuclear Information System (INIS)

Wang, Jin-Feng; Zhang, Shujun; Shrout, Thomas R.; Wang, Chun-Ming

2009-01-01

The piezoelectric, dielectric, and electromechanical properties of the (KCe) co-substituted calcium bismuth niobate (CaBi 2 Nb 2 O 9 , CBN) were investigated. The piezoelectric activities of CBN ceramics were significantly enhanced and the dielectric loss tan δ decreased by (KCe) substitution. The Ca 0.9 (KCe) 0.05 Bi 2 Nb 2 O 9 ceramics possess the optimal piezoelectric properties, and the piezoelectric coefficient (d 33 ), Curie temperature (T C ), and electromechanical coupling factors (k p and k t ) were found to be 16 pC/N, 868 C, 8.6%, and 23.8%, respectively. The excellent dielectric and electromechanical spectra, together with the high piezoelectric activities and ultrahigh Curie temperature, make CBN ceramics promising candidates for high temperature piezoelectric applications. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

A classical mechanics model for the interpretation of piezoelectric property data

International Nuclear Information System (INIS)

Bell, Andrew J.

2015-01-01

In order to provide a means of understanding, the relationship between the primary electromechanical coefficients and simple crystal chemistry parameters for piezoelectric materials, a static analysis of a 3 atom, dipolar molecule has been undertaken to derive relationships for elastic compliance s E , dielectric permittivity ε X , and piezoelectric charge coefficient d in terms of an effective ionic charge and two inter-atomic force constants. The relationships demonstrate the mutual interdependence of the three coefficients, in keeping with experimental evidence from a large dataset of commercial piezoelectric materials. It is shown that the electromechanical coupling coefficient k is purely an expression of the asymmetry in the two force constants or bond compliances. The treatment is extended to show that the quadratic electrostriction relation between strain and polarization, in both centrosymmetric and non-centrosymmetric systems, is due to the presence of a non-zero 2nd order term in the bond compliance. Comparison with experimental data explains the counter-intuitive, positive correlation of k with s E and ε X and supports the proposition that high piezoelectric activity in single crystals is dominated by large compliance coupled with asymmetry in the sub-cell force constants. However, the analysis also shows that in polycrystalline materials, the dielectric anisotropy of the constituent crystals can be more important for attaining large charge coefficients. The model provides a completely new methodology for the interpretation of piezoelectric and electrostrictive property data and suggests methods for rapid screening for high activity in candidate piezoelectric materials, both experimentally and by novel interrogation of ab initio calculations

A classical mechanics model for the interpretation of piezoelectric property data

Energy Technology Data Exchange (ETDEWEB)

Bell, Andrew J., E-mail: a.j.bell@leeds.ac.uk [Institute for Materials Research, School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)

2015-12-14

In order to provide a means of understanding, the relationship between the primary electromechanical coefficients and simple crystal chemistry parameters for piezoelectric materials, a static analysis of a 3 atom, dipolar molecule has been undertaken to derive relationships for elastic compliance s{sup E}, dielectric permittivity ε{sup X}, and piezoelectric charge coefficient d in terms of an effective ionic charge and two inter-atomic force constants. The relationships demonstrate the mutual interdependence of the three coefficients, in keeping with experimental evidence from a large dataset of commercial piezoelectric materials. It is shown that the electromechanical coupling coefficient k is purely an expression of the asymmetry in the two force constants or bond compliances. The treatment is extended to show that the quadratic electrostriction relation between strain and polarization, in both centrosymmetric and non-centrosymmetric systems, is due to the presence of a non-zero 2nd order term in the bond compliance. Comparison with experimental data explains the counter-intuitive, positive correlation of k with s{sup E} and ε{sup X} and supports the proposition that high piezoelectric activity in single crystals is dominated by large compliance coupled with asymmetry in the sub-cell force constants. However, the analysis also shows that in polycrystalline materials, the dielectric anisotropy of the constituent crystals can be more important for attaining large charge coefficients. The model provides a completely new methodology for the interpretation of piezoelectric and electrostrictive property data and suggests methods for rapid screening for high activity in candidate piezoelectric materials, both experimentally and by novel interrogation of ab initio calculations.

High precision optical measurement of displacement and simultaneous determinations of piezoelectric coefficients

Science.gov (United States)

Gamboa, Bryan M.; Malladi, Madhuri; Vadlamani, Ramya; Guo, Ruyan; Bhalla, Amar

2016-09-01

PZT are also well known for their applications in Micro Electrical Mechanical Systems (MEMS). It is necessary to study the piezoelectric coefficients of the materials accurately in order to design a sensor as an example, which defines their strain dependent applications. Systematic study of the electro mechanic displacement measurement was conducted and compared using a white light fiber optic sensor, a heterodyne laser Doppler vibrometer, and a homodyne laser interferometry setup. Frequency dependent measurement is conducted to evaluate displacement values well below and near the piezoelectric resonances. UHF-120 ultra-high frequency Vibrometer is used to measure the longitudinal piezoelectric displacement or x33 and the MTI 2000 FotonicTM Sensor is used to measure the transverse piezoelectric displacement or x11 over 100Hz to 2MHz. A Multiphysics Finite Element Analysis method, COMSOL, is also adopted in the study to generate a three dimensional electromechanical coupled model based on experimentally determined strains x33 and x11 as a function of frequency of the electric field applied. The full family of piezoelectric coefficients of the poled electronic ceramic PZT, d33, d31, and d15, can be then derived, upon satisfactory simulation of the COMSOL. This is achieved without the usual need of preparation of piezoelectric resonators of fundamental longitudinal, transversal, and shear modes respectively.

Exact analysis of two kinds of piezoelectric actuator

International Nuclear Information System (INIS)

Han Rong; Shi Zhifei

2008-01-01

Two kinds of piezoelectric hollow cylinder actuator are studied in this paper. One is the expansion actuator and the other is the contraction actuator. Using the Airy stress function method, the analytical solutions of these two kinds of actuators are obtained based on the theory of piezo-elasticity. The solutions are compared with numerical results and good agreement is found. Inherent properties of these two kinds of piezoelectric cylinder actuator are presented and discussed. Findings have applications in the field of micromechanics and microengineering

A piezoelectric-based infinite stiffness generation method for strain-type load sensors

International Nuclear Information System (INIS)

Zhang, Shuwen; Shao, Shubao; Xu, Minglong; Chen, Jie

2015-01-01

Under certain application conditions like nanoindentation technology and the mechanical property measurement of soft materials, the elastic deformation of strain-type load sensors affects their displacement measurement accuracy. In this work, a piezoelectric-based infinite stiffness generation method for strain-type load sensors that compensates for this elastic deformation is presented. The piezoelectric material-based deformation compensation method is proposed. An Hottinger Baldwin Messtechnik GmbH (HBM) Z30A/50N load sensor acts as the foundation of the method presented in this work. The piezoelectric stack is selected based on its size, maximum deformation value, blocking force and stiffness. Then, a clamping and fixing structure is designed to integrate the HBM sensor with the piezoelectric stack. The clamping and fixing structure, piezoelectric stack and HBM load sensor comprise the sensing part of the enhanced load sensor. The load-deformation curve and the voltage-deformation curve of the enhanced load sensor are then investigated experimentally. Because a hysteresis effect exists in the piezoelectric structure, the relationship between the control signal and the deformation value of the piezoelectric material is nonlinear. The hysteresis characteristic in a quasi-static condition is studied and fitted using a quadratic polynomial, and its coefficients are analyzed to enable control signal prediction. Applied arithmetic based on current theory and the fitted data is developed to predict the control signal. Finally, the experimental effects of the proposed method are presented. It is shown that when a quasi-static load is exerted on this enhanced strain-type load sensor, the deformation is reduced and the equivalent stiffness appears to be almost infinite. (paper)

Tuning piezoelectric properties through epitaxy of La2Ti2O7 and related thin films

Energy Technology Data Exchange (ETDEWEB)

Kaspar, Tiffany C.; Hong, Seungbum; Bowden, Mark E.; Varga, Tamas; Yan, Pengfei; Wang, Chongmin; Spurgeon, Steven R.; Comes, Ryan B.; Ramuhalli, Pradeep; Henager, Charles H.

2018-02-14

Current piezoelectric sensors and actuators are limited to operating temperatures less than ~200°C due to the low Curie temperature of the piezoelectric material. High temperature piezoelectric materials such as La2Ti2O7 (LTO) would facilitate the development of high-temperature sensors if the piezoelectric coupling coefficient could be maximized. We have deposited epitaxial LTO films on SrTiO3(001), SrTiO3(110), and rutile TiO2(110) substrates by pulsed laser deposition, and show that the crystalline orientation of the LTO film, and thus its piezoelectric coupling direction, can be controlled by epitaxial matching to the substrate. The structure and phase purity of the films were investigated by x-ray diffraction and scanning transmission electron microscopy. To characterize the piezoelectric properties, piezoresponse force microscopy was used to measure the in-plane and out-of-plane piezoelectric coupling in the films. We find that the strength of the out-of-plane piezoelectric coupling can be increased when the piezoelectric crystalline direction is rotated partially out-of-plane via epitaxy. The strongest out-of-plane coupling is observed for LTO/STO(001). Deposition on TiO2(110) results in epitaxial La2/3TiO3, an orthorhombic perovskite of interest as a microwave dielectric material. La2/3TiO3 can be difficult to stabilize in bulk form, and epitaxial deposition has not been previously reported. These results confirm that control of the crystalline orientation of LTO-based materials can increase the out-of-plane strength of its piezoelectric coupling, which can be exploited in piezoelectric devices.

Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

Energy Technology Data Exchange (ETDEWEB)

Wada, S; Mase, Y; Shimizu, S; Maeda, K; Fujii, I; Nakashima, K; Pulpan, P; Miyajima, N, E-mail: swada@yamanashi.ac.jp [Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi, 4-4-37 Takeda, Kofu, Yamanashi 400-8510 (Japan)

2011-10-29

Porous potassium niobate (KNbO{sub 3}, KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

Forecast of Piezoelectric Properties of Crystalline Materials from First Principles Calculation

International Nuclear Information System (INIS)

Zheng Yanqing; Shi Erwei; Chen Jianjun; Zhang Tao; Song Lixin

2006-01-01

In this paper, forecast of piezoelectric tensors are presented. Piezo crystals including quartz, quartz-like crystals, known and novel crystals of langasite-type structure are treated with density-functional perturb theory (DFPT) using plane-wave pseudopotentials method, within the local density approximation (LDA) to the exchange-correlation functional. Compared with experimental results, the ab initio calculation results have quantitative or semi-quantitative accuracy. It is shown that first principles calculation opens a door to the search and design of new piezoelectric material. Further application of first principles calculation to forecast the whole piezoelectric properties are also discussed

Porosity Dependence of Piezoelectric Properties for Porous Potassium Niobate System Ceramics

International Nuclear Information System (INIS)

Wada, S; Mase, Y; Shimizu, S; Maeda, K; Fujii, I; Nakashima, K; Pulpan, P; Miyajima, N

2011-01-01

Porous potassium niobate (KNbO 3 , KN) system ceramics were prepared by a conventional sintering method using carbon black (CB) nanoparticles. First, KN nanoparticles with a size of 100 nm was mixed with CB nanoparticles and binder using ball milling with ethanol. The mixture was dried, and pressed into pellets using uniaxial pressing. After binder burnout, these ceramics was sintered in air. Their piezoelectric properties were measured and discussed a relationship between porosity and piezoelectric properties. As the results, with increasing porosity, piezoelectric g33 constant increased significantly, which suggested that porous ceramics were effective for stress sensor application.

Flexible-CMOS and biocompatible piezoelectric AlN material for MEMS applications

International Nuclear Information System (INIS)

Jackson, Nathan; Keeney, Lynette; Mathewson, Alan

2013-01-01

The development of a CMOS compatible flexible piezoelectric material is desired for numerous applications and in particular for biomedical MEMS devices. Aluminum nitride (AlN) is the most commonly used CMOS compatible piezoelectric material, which is typically deposited on Si in order to enhance the c-axis (002) crystal orientation which gives AlN its high piezoelectric properties. This paper reports on the successful deposition of AlN on polyimide (PI-2611) material. The AlN deposited has a FWHM (002) value of 5.1° and a piezoelectric d 33 value of 1.12 pm V −1 , and SEM images show high quality columnar grains. The highly crystalline AlN material is due to the semi-crystalline properties of the polyimide film used. Cytotoxicity testing showed the AlN/polyimide material to be non-toxic to 3T3 cells and primary neurons. Surface properties of the AlN/polyimide film were evaluated as they have a significant effect on the adhesion of cells to the film. The results show neurons adhering to the AlN surface. The results of this paper show the characterization of a new flexible-CMOS and biocompatible AlN/polyimide material for MEMS devices with improved crystallinity and piezoelectric properties. (paper)

Vibration piezoelectric energy harvester with multi-beam

Energy Technology Data Exchange (ETDEWEB)

Cui, Yan, E-mail: yanc@dlut.edu.cn; Zhang, Qunying, E-mail: zhangqunying89@126.com; Yao, Minglei, E-mail: yaomingleiok@126.com [Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Dong, Weijie, E-mail: dongwj@dlut.edu.cn [School of Electronic and Information Engineering, Dalian University of Technology, 116024, Dalian, Liaoning Province (China); Gao, Shiqiao, E-mail: gaoshq@bit.edu.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, 100081, Beijing Province (China)

2015-04-15

This work presents a novel vibration piezoelectric energy harvester, which is a micro piezoelectric cantilever with multi-beam. The characteristics of the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film were measured; XRD (X-ray diffraction) pattern and AFM (Atomic Force Microscope) image of the PZT thin film were measured, and show that the PZT (Pb(Zr{sub 0.53}Ti{sub 0.47})O{sub 3}) thin film is highly (110) crystal oriented; the leakage current is maintained in nA magnitude, the residual polarisation Pr is 37.037 μC/cm{sup 2}, the coercive field voltage Ec is 27.083 kV/cm, and the piezoelectric constant d{sub 33} is 28 pC/N. In order to test the dynamic performance of the energy harvester, a new measuring system was set up. The maximum output voltage of the single beam of the multi-beam can achieve 80.78 mV under an acceleration of 1 g at 260 Hz of frequency; the maximum output voltage of the single beam of the multi-beam is almost 20 mV at 1400 Hz frequency. .

Ultrahigh piezoelectricity in ferroelectric ceramics by design

Science.gov (United States)

Li, Fei; Lin, Dabin; Chen, Zibin; Cheng, Zhenxiang; Wang, Jianli; Li, ChunChun; Xu, Zhuo; Huang, Qianwei; Liao, Xiaozhou; Chen, Long-Qing; Shrout, Thomas R.; Zhang, Shujun

2018-03-01

Piezoelectric materials, which respond mechanically to applied electric field and vice versa, are essential for electromechanical transducers. Previous theoretical analyses have shown that high piezoelectricity in perovskite oxides is associated with a flat thermodynamic energy landscape connecting two or more ferroelectric phases. Here, guided by phenomenological theories and phase-field simulations, we propose an alternative design strategy to commonly used morphotropic phase boundaries to further flatten the energy landscape, by judiciously introducing local structural heterogeneity to manipulate interfacial energies (that is, extra interaction energies, such as electrostatic and elastic energies associated with the interfaces). To validate this, we synthesize rare-earth-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT), as rare-earth dopants tend to change the local structure of Pb-based perovskite ferroelectrics. We achieve ultrahigh piezoelectric coefficients d33 of up to 1,500 pC N-1 and dielectric permittivity ɛ33/ɛ0 above 13,000 in a Sm-doped PMN-PT ceramic with a Curie temperature of 89 °C. Our research provides a new paradigm for designing material properties through engineering local structural heterogeneity, expected to benefit a wide range of functional materials.

A Piezoelectric PZT Ceramic Mulitlayer Stack for Energy Harvesting Under Dynamic Forces

Science.gov (United States)

Xu, Tian-Bing; Siochi, Emilie J.; Kang, Jin Ho; Zuo, Lei; Zhou, Wanlu; Tang, Xiudong; Jiang, Xiaoning

2011-01-01

Piezoelectric energy harvesting transducers (PEHTs) are commonly used in motion/vibration energy scavenging devices. To date, most researchers have focused on energy harvesting at narrow bandwidths around the mechanical resonance frequency, and most piezoelectric harvesting devices reported in the literature have very low effective piezoelectric coefficient (d(sub eff)) (coefficients of about 100 pC/N. The level of harvested electrical power for CBPEHTs is on the order of microW even at resonance mode. In order to harvest more electrical energy across broader bandwidth, high effective piezoelectric coefficient structures are needed. In this study, we investigate a "33" longitudinal mode, piezoelectric PZT ceramic multilayer stack (PZT-Stack) with high effective piezoelectric coefficient for high-performance PEHTs. The PZT-Stack is composed of 300 layers of 0.1 mm thick PZT plates, with overall dimensions of 32.4 mm X 7.0 mm X 7.0 mm. Experiments were carried out with dynamic forces in a broad bandwidth ranging from 0.5 Hz to 25 kHz. The measured results show that the effective piezoelectric coefficient of the PZT-stack is about 1 X 10(exp 5) pC/N at off-resonance frequencies and 1.39 X 10(exp 6) pC/N at resonance, which is order of magnitude larger than that of traditional PEHTs. The effective piezoelectric coefficients (d(sub eff)) do not change significantly with applied dynamic forces having root mean square (RMS) values ranging from 1 N to 40 N. In resonance mode, 231 mW of electrical power was harvested at 2479 Hz with a dynamic force of 11.6 N(sub rms), and 7.6 mW of electrical power was generated at a frequency of 2114 Hz with 1 N(sub rms) dynamic force. In off-resonance mode, an electrical power of 18.7 mW was obtained at 680 Hz with a 40 N(sub rms) dynamic force. A theoretical model of energy harvesting for the PZT-Stack is established. The modeled results matched well with experimental measurements. This study demonstrated that high effective

The concept of a novel hybrid smart composite reinforced with radially aligned zigzag carbon nanotubes on piezoelectric fibers

International Nuclear Information System (INIS)

Ray, M C

2010-01-01

A new hybrid piezoelectric composite (HPZC) reinforced with zigzag single-walled carbon nanotubes (CNTs) and piezoelectric fibers is proposed. The novel constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of piezoelectric fibers. A micromechanics model is derived to estimate the effective piezoelectric and elastic properties. It is found that the effective piezoelectric coefficient e 31 of the proposed HPZC, which accounts for the in-plane actuation, is significantly higher than that of the existing 1-3 piezoelectric composite without reinforcement with carbon nanotubes and the previously reported hybrid piezoelectric composite (Ray and Batra 2009 ASME J. Appl. Mech. 76 034503)

Reducing the capacitance of piezoelectric film sensors

Energy Technology Data Exchange (ETDEWEB)

González, Martín G., E-mail: mggonza@fi.uba.ar [Grupo de Láser, Óptica de Materiales y Aplicaciones Electromagnéticas (GLOMAE), Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1425FQB Buenos Aires (Argentina); Sorichetti, Patricio A.; Santiago, Guillermo D. [Grupo de Láser, Óptica de Materiales y Aplicaciones Electromagnéticas (GLOMAE), Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV Buenos Aires (Argentina)

2016-04-15

We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N{sup 2}, whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

Reducing the capacitance of piezoelectric film sensors

International Nuclear Information System (INIS)

González, Martín G.; Sorichetti, Patricio A.; Santiago, Guillermo D.

2016-01-01

We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N"2, whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

A digital output piezoelectric accelerometer using a Pb(Zr, Ti)O3 thin film array electrically connected in series

International Nuclear Information System (INIS)

Kobayashi, T; Okada, H; Maeda, R; Itoh, T; Masuda, T

2010-01-01

A digital output piezoelectric accelerometer is proposed to realize an ultra-low power consumption wireless sensor node. The accelerometer has patterned piezoelectric thin films (piezoelectric plates) electrically connected in series accompanied by CMOS switches at the end of some of the piezoelectric plates. The connected piezoelectric plates amplify the output voltage without the use of amplifiers. The CMOS switches turn on when the output voltage of the piezoelectric plates is higher than the CMOS threshold voltage. The piezoelectric accelerometer converts the acceleration into a number of on-state CMOS switches, which can be called the digital output. The proposed digital output piezoelectric accelerometer, using Pb(Zr, Ti)O 3 (PZT) thin films as the piezoelectric material, was fabricated through a microelectromechanical system (MEMS) microfabrication process. The output voltage was found to be amplified by the number of connected piezoelectric plates. The DC output voltage obtained by using an AC to DC conversion circuit is proportional to the number of connections. The results show the potential for realizing the proposed digital output piezoelectric accelerometer

Piezoelectricity enhancement and bandstructure modification of atomic defect-mediated MoS2 monolayer.

Science.gov (United States)

Yu, Sheng; Rice, Quinton; Neupane, Tikaram; Tabibi, Bagher; Li, Qiliang; Seo, Felix Jaetae

2017-09-13

Piezoelectricity appears in the inversion asymmetric crystal that converts mechanical deformation to electricity. Two-dimensional transition metal dichalcolgenide (TMDC) monolayers exhibit the piezoelectric effect due to inversion asymmetry. The intrinsic piezoelectric coefficient (e 11 ) of MoS 2 is ∼298 pC m -1 . For the single atomic shift of Mo of 20% along the armchair direction, the piezoelectric coefficient (e 11 ) of MoS 2 with 5 × 5 unit cells was enhanced up to 18%, and significantly modified the band structure. The single atomic shift in the MoS 2 monolayer also induced new energy levels inside the forbidden bandgap. The defect-induced energy levels for a Mo atom shift along the armchair direction are relatively deeper than that for a S atom shift along the same direction. This indicates that the piezoelectricity and band structure of MoS 2 can be engineered by a single atomic shift in the monolayer with multi unit cells for piezo- and opto-electric applications.

The effect of particle aspect ratio on the electroelastic properties of piezoelectric nanocomposites

International Nuclear Information System (INIS)

Andrews, C; Lin, Y; Sodano, H A

2010-01-01

Piezoelectric materials offer exceptional sensing and actuation properties; however, they are prone to breakage and difficult to apply on curved surfaces in their monolithic form. One method of alleviating these issues is through the use of 0–3 nanocomposites, which are formed by embedding piezoelectric particles into a polymer matrix. Material of this class offers certain advantages over monolithic materials; however, it has seen little use due to its low coupling. Here we develop micromechanics and finite element models to study the electroelastic properties of an active nanocomposite, as a function of the aspect ratio and alignment of the piezoelectric filler. Our results show that the aspect ratio is critical for achieving high electromechanical coupling, and with an increase from 1 to 10 at 30% volume fraction of piezoelectric filler the coupling can increase to 60 times its initial value and achieve a bulk composite coupling as high as 90% for a pure PZT-7A piezoelectric constituent

Analysis on Coupled Vibration of a Radially Polarized Piezoelectric Cylindrical Transducer

Directory of Open Access Journals (Sweden)

Jie Xu

2017-12-01

Full Text Available Coupled vibration of a radially polarized piezoelectric cylindrical transducer is analyzed with the mechanical coupling coefficient method. The method has been utilized to analyze the metal cylindrical transducer and the axially polarized piezoelectric cylindrical transducer. In this method, the mechanical coupling coefficient is introduced and defined as the stress ratio in different directions. Coupled vibration of the cylindrical transducer is regarded as the interaction of the plane radial vibration of a ring and the longitudinal vibration of a tube. For the radially polarized piezoelectric cylindrical transducer, the radial and longitudinal electric admittances as functions of mechanical coupling coefficients and angular frequencies are derived, respectively. The resonance frequency equations are obtained. The dependence of resonance frequency and mechanical coupling coefficient on aspect ratio is studied. Vibrational distributions on the surfaces of the cylindrical transducer are presented with experimental measurement. On the support of experiments, this work is verified and provides a theoretical foundation for the analysis and design of the radially polarized piezoelectric cylindrical transducer.

Anomalous piezoelectric properties of poly(vinylidene fluoride-trifluoroethylene)/ionic liquid gels

Science.gov (United States)

Fukagawa, Miki; Koshiba, Yasuko; Fukushima, Tatsuya; Morimoto, Masahiro; Ishida, Kenji

2018-04-01

Piezoelectric gels were prepared from low-volatile ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) gels, and their structural, ferroelectric, and piezoelectric properties were investigated. Poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE)/IL gels were formed using thermally reversible physical gels. The structural characterization indicated that the P(VDF-TrFE) molecules in the gels predominantly formed a ferroelectric phase (Form I) of P(VDF-TrFE). Polarization switching peaks were clearly observed using a three-layer stacked device structure. The coercive field of the P(VDF-TrFE)/IL gels substantially decreased to 4-9 MV/m, and their remnant polarizations were maintained at 63-71 mC/m2, which is similar to that for typical solid-state P(VDF-TrFE). Finally, the P(VDF-TrFE)/IL gel films exhibited a piezoelectric response, and the highest piezoelectric coefficient was ˜300 pm/V at an applied voltage frequency of 4 kHz.

Combined Pyroelectric, Piezoelectric and Shape Memory Effects for Thermal Energy Harvesting

International Nuclear Information System (INIS)

Zakharov, D; Gusarov, B; Cugat, O; Delamare, J; Gimeno, L; Gusarova, E; Viala, B

2013-01-01

This work proposes an enhanced method for thermal energy harvesting exploiting combined pyroelectric, piezoelectric and shape memory (SME) effects, and presents its experimental validation. A material which is pyroelectric is also piezoelectric. If it is combined with a material with SME, which generates large strain and stress in a rather narrow temperature range, the resulting composite material would generate voltage from temperature variations using two different energy conversion principles at once: (1) pyroelectric effect, (2) piezoelectric effect driven by SME. A Macro Fiber Composite piezoelectric was shown here to exhibit significant pyroelectric effect (∼4 V/°C). When combining it with a SME Ti-Ni-Cu alloy into a laminated structure, this effect increased by 50%. This increase may be an order of magnitude higher for an optimized system. Such composites open an opportunity to harvest thermal energy from natural sources, since this method can increase the rather low efficiency of current pyroelectric materials especially for small temperature variations

Broadband transmission noise reduction of smart panels featuring piezoelectric shunt circuits and sound-absorbing material.

Science.gov (United States)

Kim, Jaehwan; Lee, Joong-Kuen

2002-09-01

The possibility of a broadband noise reduction of piezoelectric smart panels is experimentally studied. A piezoelectric smart panel is basically a plate structure on which piezoelectric patches with electrical shunt circuits are mounted and sound-absorbing material is bonded on the surface of the structure. Sound-absorbing material can absorb the sound transmitted at the midfrequency region effectively while the use of piezoelectric shunt damping can reduce the transmission at resonance frequencies of the panel structure. To be able to reduce the sound transmission at low panel resonance frequencies, piezoelectric damping using the measured electrical impedance model is adopted. A resonant shunt circuit for piezoelectric shunt damping is composed of resistor and inductor in series, and they are determined by maximizing the dissipated energy through the circuit. The transmitted noise-reduction performance of smart panels is tested in an acoustic tunnel. The tunnel is a square cross-sectional tube and a loudspeaker is mounted at one side of the tube as a sound source. Panels are mounted in the middle of the tunnel and the transmitted sound pressure across panels is measured. When an absorbing material is bonded on a single plate, a remarkable transmitted noise reduction in the midfrequency region is observed except for the fundamental resonance frequency of the plate. By enabling the piezoelectric shunt damping, noise reduction is achieved at the resonance frequency as well. Piezoelectric smart panels incorporating passive absorbing material and piezoelectric shunt damping is a promising technology for noise reduction over a broadband of frequencies.

Degenerated shell element for geometrically nonlinear analysis of thin-walled piezoelectric active structures

International Nuclear Information System (INIS)

Marinković, D; Köppe, H; Gabbert, U

2008-01-01

Active piezoelectric thin-walled structures, especially those with a notably higher membrane than bending stiffness, are susceptible to large rotations and transverse deflections. Recent investigations conducted by a number of researchers have shown that the predicted behavior of piezoelectric structures can be significantly influenced by the assumption of large displacements and rotations of the structure, thus demanding a geometrically nonlinear formulation in order to investigate it. This paper offers a degenerated shell element and a simplified formulation that relies on small incremental steps for the geometrically nonlinear analysis of piezoelectric composite structures. A set of purely mechanical static cases is followed by a set of piezoelectric coupled static cases, both demonstrating the applicability of the proposed formulation

Harvesting energy from airflow with a michromachined piezoelectric harvester inside a Helmholtz resonator

International Nuclear Information System (INIS)

Matova, S P; Elfrink, R; Vullers, R J M; Van Schaijk, R

2011-01-01

In this paper we report an airflow energy harvester that combines a piezoelectric energy harvester with a Helmholtz resonator. The resonator converts airflow energy to air oscillations which in turn are converted into electrical energy by a piezoelectric harvester. Two Helmholtz resonators with adjustable resonance frequencies have been designed—one with a solid bottom and one with membrane on the bottom. The resonance frequencies of the resonators were matched to the complementing piezoelectric harvesters during harvesting. The aim of the presented work is a feasibility study on using packaged piezoelectric energy harvesters with Helmholtz resonators for airflow energy harvesting. The maximum energy we were able to obtain was 42.2 µW at 20 m s −1

Dynamic optimum dead time in piezoelectric transformer-based switch-mode power supplies

DEFF Research Database (Denmark)

Ekhtiari, Marzieh; Andersen, Thomas; Andersen, Michael A. E.

2016-01-01

to charge and discharge the input capacitance of piezoelectric transformers in order to achieve zero-voltage switching. This paper proposes a method for detecting the optimum dead time in piezoelectric transformer-based switch-mode power supplies. The provision of sufficient dead time in every cycle......Soft switching is required to attain high efficiency in high-frequency power converters. Piezoelectric transformerbased converters can benefit from soft switching in terms of significantly diminished switching losses and stresses. Adequate dead time is needed in order to deliver sufficient energy...

Piezoelectric evaluation of ion beam etched Pb(Zr,Ti)O3 thin films by piezoresponse force microscopy

International Nuclear Information System (INIS)

Legrand, C.; Da Costa, A.; Desfeux, R.; Soyer, C.; Remiens, D.

2007-01-01

The evolution of piezoelectric properties of Pb(Zr,Ti)O 3 (PZT) thin films after ion beam etching have been investigated at the nanoscale level by piezoelectric force microscopy. A comparison of the piezoelectric properties on etched and unetched films is realized. Piezoelectric contrasts imaging evidences a modification of the domain architecture at the film surface. Local piezoelectric hysteresis loops measurements on grains indicate that the coercive voltage for switching is much higher for the etched films (2.3 V) compared to the unetched ones (1.0 V) while the average piezoelectric activity is slightly lower. The results are explained in terms of grain-damaging during etching and domain-wall pinning

Modified Continuum Mechanics Modeling on Size-Dependent Properties of Piezoelectric Nanomaterials: A Review

Directory of Open Access Journals (Sweden)

Zhi Yan

2017-01-01

Full Text Available Piezoelectric nanomaterials (PNs are attractive for applications including sensing, actuating, energy harvesting, among others in nano-electro-mechanical-systems (NEMS because of their excellent electromechanical coupling, mechanical and physical properties. However, the properties of PNs do not coincide with their bulk counterparts and depend on the particular size. A large amount of efforts have been devoted to studying the size-dependent properties of PNs by using experimental characterization, atomistic simulation and continuum mechanics modeling with the consideration of the scale features of the nanomaterials. This paper reviews the recent progresses and achievements in the research on the continuum mechanics modeling of the size-dependent mechanical and physical properties of PNs. We start from the fundamentals of the modified continuum mechanics models for PNs, including the theories of surface piezoelectricity, flexoelectricity and non-local piezoelectricity, with the introduction of the modified piezoelectric beam and plate models particularly for nanostructured piezoelectric materials with certain configurations. Then, we give a review on the investigation of the size-dependent properties of PNs by using the modified continuum mechanics models, such as the electromechanical coupling, bending, vibration, buckling, wave propagation and dynamic characteristics. Finally, analytical modeling and analysis of nanoscale actuators and energy harvesters based on piezoelectric nanostructures are presented.

Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers

Directory of Open Access Journals (Sweden)

Shuyu Lin

2017-02-01

Full Text Available The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

Effect of the Matching Circuit on the Electromechanical Characteristics of Sandwiched Piezoelectric Transducers.

Science.gov (United States)

Lin, Shuyu; Xu, Jie

2017-02-10

The input electrical impedance behaves as a capacitive when a piezoelectric transducer is excited near its resonance frequency. In order to increase the energy transmission efficiency, a series or parallel inductor should be used to compensate the capacitive impedance of the piezoelectric transducer. In this paper, the effect of the series matching inductor on the electromechanical characteristics of the piezoelectric transducer is analyzed. The dependency of the resonance/anti-resonance frequency, the effective electromechanical coupling coefficient, the electrical quality factor and the electro-acoustical efficiency on the matching inductor is obtained. It is shown that apart from compensating the capacitive impedance of the piezoelectric transducer, the series matching inductor can also change the electromechanical characteristics of the piezoelectric transducer. When series matching inductor is increased, the resonance frequency is decreased and the anti-resonance unchanged; the effective electromechanical coupling coefficient is increased. For the electrical quality factor and the electroacoustic efficiency, the dependency on the matching inductor is different when the transducer is operated at the resonance and the anti-resonance frequency. The electromechanical characteristics of the piezoelectric transducer with series matching inductor are measured. It is shown that the theoretically predicted relationship between the electromechanical characteristics and the series matching inductor is in good agreement with the experimental results.

Modified Continuum Mechanics Modeling on Size-Dependent Properties of Piezoelectric Nanomaterials: A Review.

Science.gov (United States)

Yan, Zhi; Jiang, Liying

2017-01-26

Piezoelectric nanomaterials (PNs) are attractive for applications including sensing, actuating, energy harvesting, among others in nano-electro-mechanical-systems (NEMS) because of their excellent electromechanical coupling, mechanical and physical properties. However, the properties of PNs do not coincide with their bulk counterparts and depend on the particular size. A large amount of efforts have been devoted to studying the size-dependent properties of PNs by using experimental characterization, atomistic simulation and continuum mechanics modeling with the consideration of the scale features of the nanomaterials. This paper reviews the recent progresses and achievements in the research on the continuum mechanics modeling of the size-dependent mechanical and physical properties of PNs. We start from the fundamentals of the modified continuum mechanics models for PNs, including the theories of surface piezoelectricity, flexoelectricity and non-local piezoelectricity, with the introduction of the modified piezoelectric beam and plate models particularly for nanostructured piezoelectric materials with certain configurations. Then, we give a review on the investigation of the size-dependent properties of PNs by using the modified continuum mechanics models, such as the electromechanical coupling, bending, vibration, buckling, wave propagation and dynamic characteristics. Finally, analytical modeling and analysis of nanoscale actuators and energy harvesters based on piezoelectric nanostructures are presented.

Thermoelastic expansion vs. piezoelectricity for high-frequency, 2-D arrays.

Science.gov (United States)

Buma, Takashi; Spisar, Monica; O'Donnell, Matthew

2003-08-01

Optical generation using the thermoelastic effect has traditionally suffered from low conversion efficiency. We previously demonstrated increased efficiency of nearly 20 dB with an optical absorbing layer consisting of a mixture of polydimethylsiloxane (PDMS) and carbon black spin coated onto a glass microscope slide. In this paper we show that the radiated power from a black PDMS film is comparable to a 20 MHz piezoelectric two-dimensional (2-D) array element. Furthermore, we predict that a thermoelastic array element can produce similar acoustic power levels compared to ideal piezoelectric 2-D array elements at frequencies in the 100 MHz regime. We believe these results show that thermoelastic generation of ultrasound is a promising alternative to piezoelectricity for high-frequency, 2-D arrays.

Shape-Memory PVDF Exhibiting Switchable Piezoelectricity.

Science.gov (United States)

Hoeher, Robin; Raidt, Thomas; Novak, Nikola; Katzenberg, Frank; Tiller, Joerg C

2015-12-01

In this study, a material is designed which combines the properties of shape-memory and electroactive polymers. This is achieved by covalent cross-linking of polyvinylidene fluoride. The resulting polymer network exhibits excellent shape-memory properties with a storable strain of 200%, and fixity as well as recovery values of 100%. Programming upon rolling induces the transformation from the nonelectroactive α-phase to the piezoelectric β-phase. The highest β-phase content is found to be 83% for a programming strain of 200% affording a d33 value of -30 pm V(-1). This is in good accordance with literature known values for piezoelectric properties. Thermal triggering this material does not only result in a shape change but also renders the material nonelectroactive. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A 3D scanning laser endoscope architecture utilizing a circular piezoelectric membrane

Science.gov (United States)

Khayatzadeh, Ramin; Çivitci, Fehmi; Ferhanoğlu, Onur

2017-12-01

A piezo-scanning fiber endoscopic device architecture is proposed for 3D imaging or ablation. The endoscopic device consists of a piezoelectric membrane that is placed perpendicular to the optical axis, a fiber optic cable that extends out from and actuated by the piezoelectric membrane, and one or multiple lenses for beam delivery and collection. Unlike its counterparts that utilize piezoelectric cylinders for fiber actuation, the proposed architecture offers quasi-static actuation in the axial direction along with resonant actuation in the lateral directions forming a 3D scanning pattern, allowing adjustment of the focus plane. The actuation of the four-quadrant piezoelectric membrane involves driving of two orthogonal electrodes with AC signals for lateral scanning, while simultaneously driving all electrodes for axial scanning and focus adjustment. We have characterized piezoelectric membranes (5 -15mm diameter) with varying sizes to monitor axial displacement behavior with respect to applied DC voltage. We also demonstrate simultaneous lateral and axial actuation on a resolution target, and observe the change of lateral resolution on a selected plane through performing 1D cross-sectional images, as an indicator of focal shift through axial actuation. Based on experimental results, we identify the optical and geometrical parameters for optimal 3D imaging of tissue samples. Our findings reveal that a simple piezoelectric membrane, having comparable dimensions and drive voltage requirement with off-the-shelf MEMS scanner chips, offers tissue epithelial imaging with sub-cellular resolution.

Fatigue and retention properties of shape memory piezoelectric actuator with non-180° domain switching

International Nuclear Information System (INIS)

Kadota, Y; Morita, T

2012-01-01

A shape memory piezoelectric actuator can maintain a piezoelectric displacement without an operating voltage. It has two stable strain states at zero voltage: a poled state and a depoled state. The driving principle of the shape memory piezoelectric actuator is based on reorientation of the non-180° domains in the ferroelectric materials. In this study, a unimorph shape memory piezoelectric actuator with a soft lead zirconate titanate was fabricated. The fatigue and retention properties of this shape memory piezoelectric actuator were investigated. The fatigue behavior of the actuator in the early stages is considered to be closely related to the domain stabilization process. Continuous cycle fatigue tests revealed that the shape memory piezoelectric actuator continues to operate even after 10 6 cycles. Retention measurements revealed that the depoled state of the actuator was more stable than the poled state. The drift in the actuator displacement over one year was estimated to be less than 10% of the initial shape memory displacement. (paper)

Theoretical analysis of piezoelectric energy harvesting from traffic induced deformation of pavements

International Nuclear Information System (INIS)

Xiang, H J; Wang, J J; Shi, Z F; Zhang, Z W

2013-01-01

The problem of energy harvesting using piezoelectric transducers for pavement system applications is formulated with a focus on moving vehicle excitations. The pavement behavior is described by an infinite Bernoulli–Euler beam subjected to a moving line load and resting on a Winkler foundation. A closed-form dynamic response of the pavement is determined by a Fourier transform and the residue theorem. The voltage and power outputs of the piezoelectric harvester embedded in the pavements are then obtained by the direct piezoelectric effect. A comprehensive parametric study is conducted to show the effect of damping, the Winkler modulus, and the velocity of moving vehicles on the voltage and power output of the piezoelectric harvester. It is found that the output increases sharply when the velocity of the vehicle is close to the so-called critical velocity. (paper)

Development of a Piezoelectric Vacuum Sensing Component for a Wide Pressure Range

Directory of Open Access Journals (Sweden)

Bing-Yu Wang

2014-11-01

Full Text Available In this study, we develop a clamped–clamped beam-type piezoelectric vacuum pressure sensing element. The clamped–clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous forces on the piezoelectric beam vary at different air pressures, the vibration of the beam depends on the vacuum pressure. The developed pressure sensor can sense a wide range of pressure, from 6.5 × 10−6 to 760 Torr. The experimental results showed that the output voltage is inversely proportional to the gas damping ratio, and thus, the vacuum pressure was estimated from the output voltage.

High power Co3O4/ZnO p–n type piezoelectric transducer

International Nuclear Information System (INIS)

Hu, Yuh-Chung; Lee, Tsung-Han; Chang, Pei-Zen; Su, Pei-Chen

2015-01-01

Enhancing the output power of piezoelectric transducer is essential in order to supply sufficient and sustainable power to wireless sensor nodes or electronic devices. In this work, a Co 3 O 4 /ZnO p–n type power piezoelectric transducer which can be operated at low frequencies has been developed by utilizing n-type semiconducting zinc oxide (ZnO) and p-type semiconducting tricobalt tetroxide (Co 3 O 4 ). We utilize ZnO to be the piezoelectric transducer and build a multi-layer (Au/Co 3 O 4 /ZnO/Ti) thin film structure. The ZnO thin film with preferred orientation along the (002) plane was deposited under optimized deposition conditions on the flexible titanium (Ti) foil with thickness of 80 μm. The Co 3 O 4 /ZnO interface forms a p–n junction and increases the difference in Fermi levels between the two electrodes, resulting in the great enhancement of output power. The measured output power of the p–n type piezoelectric transducer with optimal resistance of 100 kΩ is 10.4 μW at low operating frequency of 37 Hz, which is 10.9 times of output power of ZnO piezoelectric transducers. - Highlights: • Deposited zinc oxide performed good piezoelectric coefficient. • ZnO thin film with preferred orientation along the (002) plane was deposited. • A p–n type piezoelectric transducer with enhanced output power was fabricated. • 10.9 times increment in output power was obtained. • Increase of difference in Fermi level and p–n junction formation was explained

Design and fabrication of a double-sided piezoelectric transducer for harvesting vibration power

Energy Technology Data Exchange (ETDEWEB)

Chang, Wei-Tsai; Chen, Ying-Chung [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Kao, Kuo-Sheng [Department of Computer and Communication, Shu-Te University, Kaohsiung, Taiwan, ROC (China); Chu, Yu-Hsien [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, ROC (China); Cheng, Chien-Chuan, E-mail: chengccc@dlit.edu.tw [Department of Electronic Engineering, De Lin Institute of Technology, Taipei, Taiwan, ROC (China)

2013-02-01

This investigation examines a means of integrating high-performance ZnO piezoelectric thin films with a flexible stainless steel substrate (SUS304) to fabricate a double-sided piezoelectric transducer for vibration-energy harvesting applications. The double-sided piezoelectric transducer is constructed by depositing ZnO piezoelectric thin films on both the front and the back sides of the SUS304 substrate. The titanium and platinum layers were deposited using a dual-gun DC sputtering system between the ZnO piezoelectric thin film and the back side of the SUS304 substrate. The scanning electron microscopy and X-ray diffraction of ZnO piezoelectric films reveal a rigid surface structure and a highly c-axis-preferring orientation. To fabricate a transducer with a low resonant frequency, a tip-mass of 0.5 g and a vibration-area of 1 cm{sup 2} are designed, based on the cantilever vibration theory. The maximum open circuit voltage of the power transducer is approximately 18 V. After rectification and filtering through a 33 nF capacitor, a specific power output of 1.31 μW/cm{sup 2} is obtained from the transducers with a load resistance of 6 MΩ. The variation of the power output of ± 0.001% is obtained after 24-hour continuous test. - Highlights: ► A double-sided piezoelectric transducer is fabricated with the ZnO thin films. ► Vibrated frequency of a double-sided transducer is designed and presented. ► A maximum output power of 3.23 μW/cm{sup 2} is obtained under turbulent vibration.

Estimation of Back-Surface Flaw Depth by Laminated Piezoelectric Highpolymer Film

Directory of Open Access Journals (Sweden)

Akinobu YAMAMOTO

2009-08-01

Full Text Available Piezoelectric thin films have been used to visualize back surface flaws in plates. If the plate with a surface flaw is deformed, the strain distribution appears on the other surface reflecting the location and the shape of the flaw. Such surface strain distribution can be transformed into the electric potential distribution on the piezoelectric film mounted on the plate surface. This paper deals with a NDE technique to estimate the depth of a back-surface flaw from the electric potential distribution on a laminated piezoelectric thin film. It is experimentally verified that the flaw depth can be exactly estimated by the peak height of the electric potential distribution.

Local piezoelectric response of ZnO nanoparticles embedded in a photosensitive polymer