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Sample records for wave piezoelectric motor

  1. 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.

  2. Transient Response Model of Standing Wave Piezoelectric Linear Ultrasonic Motor

    Institute of Scientific and Technical Information of China (English)

    SHI Yunlai; CHEN Chao; ZHAO Chunsheng

    2012-01-01

    A transient response model for describing the starting and stopping characteristics of the standing wave piezoelectric linear ultrasonic motor was presented.Based on the contact dynamic model,the kinetic equation of the motor was derived.The starting and stopping characteristics of the standing wave piezoelectric linear ultrasonic motor according to different loads,contact stiffness and inertia mass were described and analyzed,respectively.To validate the transient response model,a standing wave piezoelectric linear ultrasonic motor based on in-plane modes was used to carry out the simulation and experimental study.The corresponding results showed that the simulation of the motor performances based on the proposed model agreed well with the experimental results.This model will helpful to improve the stepping characteristics and the control flexibility of the standing wave piezoelectric linear ultrasonic motor.

  3. Comparison of Walking and Traveling-Wave Piezoelectric Motors as Actuators in Kinesthetic Haptic Devices.

    Science.gov (United States)

    Olsson, Pontus; Nysjo, Fredrik; Carlbom, Ingrid B; Johansson, Stefan

    2016-01-01

    Piezoelectric motors offer an attractive alternative to electromagnetic actuators in portable haptic interfaces: they are compact, have a high force-to-volume ratio, and can operate with limited or no gearing. However, the choice of a piezoelectric motor type is not obvious due to differences in performance characteristics. We present our evaluation of two commercial, operationally different, piezoelectric motors acting as actuators in two kinesthetic haptic grippers, a walking quasi-static motor and a traveling wave ultrasonic motor. We evaluate each gripper's ability to display common virtual objects including springs, dampers, and rigid walls, and conclude that the walking quasi-static motor is superior at low velocities. However, for applications where high velocity is required, traveling wave ultrasonic motors are a better option.

  4. Piezoelectric Motors, an Overview

    OpenAIRE

    Karl Spanner; Burhanettin Koc

    2016-01-01

    Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ult...

  5. Piezoelectric Motors, an Overview

    Directory of Open Access Journals (Sweden)

    Karl Spanner

    2016-02-01

    Full Text Available Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ultrasonic motors, inertia-drive, and piezo-walk-drive. In this review, a comprehensive summary of piezoelectric motors, with their classification from initial idea to recent progress, is presented. This review also includes some of the industrial and commercial applications of piezoelectric motors that are presently available in the market as actuators.

  6. A finite volume method and experimental study of a stator of a piezoelectric traveling wave rotary ultrasonic motor.

    Science.gov (United States)

    Bolborici, V; Dawson, F P; Pugh, M C

    2014-03-01

    Piezoelectric traveling wave rotary ultrasonic motors are motors that generate torque by using the friction force between a piezoelectric composite ring (or disk-shaped stator) and a metallic ring (or disk-shaped rotor) when a traveling wave is excited in the stator. The motor speed is proportional to the amplitude of the traveling wave and, in order to obtain large amplitudes, the stator is excited at frequencies close to its resonance frequency. This paper presents a non-empirical partial differential equations model for the stator, which is discretized using the finite volume method. The fundamental frequency of the discretized model is computed and compared to the experimentally-measured operating frequency of the stator of Shinsei USR60 piezoelectric motor.

  7. Piezoelectric Torsional Vibration Driven Motor

    Science.gov (United States)

    2000-10-29

    20 which can provide large amplitude rotational motion with a high torque. 21 Piezoelectric ultrasonic motors have been developed using traveling...Motor for High Torque", T. S. Glenn, W.G. Hagwood, SPIE Volume 3041, 4 1997. These piezoelectric ultrasonic motors are of limited application

  8. Piezoelectric Rotary Tube Motor

    Science.gov (United States)

    Fisher, Charles D.; Badescu, Mircea; Braun, David F.; Culhane, Robert

    2011-01-01

    A custom rotary SQUIGGLE(Registered TradeMark) motor has been developed that sets new benchmarks for small motor size, high position resolution, and high torque without gear reduction. Its capabilities cannot be achieved with conventional electromagnetic motors. It consists of piezoelectric plates mounted on a square flexible tube. The plates are actuated via voltage waveforms 90 out of phase at the resonant frequency of the device to create rotary motion. The motors were incorporated into a two-axis postioner that was designed for fiber-fed spectroscopy for ground-based and space-based projects. The positioner enables large-scale celestial object surveys to take place in a practical amount of time.

  9. Modelling of the travelling wave piezoelectric motor stator: an integrated review and new perspective

    Directory of Open Access Journals (Sweden)

    Rodríguez, H.

    2004-06-01

    Full Text Available Articles from different areas which are closely related to the modelling of the stator of travelling wave ultrasonic motors (TWUMs are reviewed in this work. Thus, important issues relevant to this problem are identified from the areas of vibration of annular plates, laminated plate theories, and modelling of piezoelectric transducers. From this integrated point of view, it becomes clear that there are some very important issues yet to be addressed in the modelling of TWUMs. Firstly, the influence of material properties and stator dimensions on output efficiency, electromechanical coupling coefficients (EMCC and maximum output energy is to be investigated in more detail. Secondly, the modelling of the electric potential field (by explicitly including the charge equation for TWUMs seems to be a must for better prediction of displacements and electric fields close to the resonance, as suggested by some recent works [1]. Moreover, the improvement of current models by using shear deformation (or higher order laminated plate theories (LPTs in conjunction with approximated methods of solution are discussed. In addition to analytical models, those works using Finite Element and Finite difference Methods (FEM and FDM for the modelling and simulation of the TWUM stator dynamics are reviewed.

    En este trabajo se realiza una revisión de los trabajos de investigación realizados en diversas áreas sobre el modelado del estátor de los motores ultrasónicos de onda viajera (TWUMs. Entre los problemas relevantes que se han estudiado podemos citar la vibración de placas anulares, las teorías de placas laminadas y el modelado de transductores piezoeléctricos. A raíz de este punto de vista integral se hace manifiesto que todavía quedan asuntos importantes que estudiar en el modelado de los TWUMs. En primer lugar, la influencia de las propiedades del material y las dimensiones del estátor en la eficiencia del motor, los coeficientes de acoplamiento

  10. Cryogenic Rotary Piezoelectric Motor Project

    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...

  11. Cryogenic Rotary Piezoelectric Motor Project

    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....

  12. Systematic modeling for free stators of rotary - Piezoelectric ultrasonic motors

    DEFF Research Database (Denmark)

    Mojallali, Hamed; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    An equivalent circuit model with complex elements is presented in this paper to describe the free stator model of traveling wave piezoelectric motors. The mechanical, dielectric and piezoelectric losses associated with the vibrator are considered by introducing the imaginary part to the equivalent...

  13. Bio-inspired piezoelectric linear motor driven by a single-phase harmonic wave with an asymmetric stator

    Science.gov (United States)

    Pan, Qiaosheng; Miao, Enming; Wu, Bingxuan; Chen, Weikang; Lei, Xiujun; He, Liangguo

    2017-07-01

    A novel, bio-inspired, single-phase driven piezoelectric linear motor (PLM) using an asymmetric stator was designed, fabricated, and tested to avoid mode degeneracy and to simplify the drive mechanism of a piezoelectric motor. A piezoelectric transducer composed of two piezoelectric stacks and a displacement amplifier was used as the driving element of the PLM. Two simple and specially designed claws performed elliptical motion. A numerical simulation was performed to design the stator and determine the feasibility of the design mechanism of the PLM. Moreover, an experimental setup was built to validate the working principles, as well as to evaluate the performance, of the PLM. The prototype motor outputs a no-load speed of 233.7 mm/s at a voltage of 180 Vp-p and a maximum thrust force of 2.3 N under a preload of 10 N. This study verified the feasibility of the proposed design and provided a method to simplify the driving harmonic signal and structure of PLMs.

  14. Equivalent Circuit Modeling of a Rotary Piezoelectric Motor

    DEFF Research Database (Denmark)

    El, Ghouti N.; Helbo, Jan

    2000-01-01

    In this paper, an enhanced equivalent circuit model of a rotary traveling wave piezoelectric ultrasonic motor "shinsei type USR60" is derived. The modeling is performed on the basis of an empirical approach combined with the electrical network method and some simplification assumptions about...

  15. Torque for an Inertial Piezoelectric Rotary Motor

    Directory of Open Access Journals (Sweden)

    Jichun Xing

    2013-01-01

    Full Text Available For a novel inertial piezoelectric rotary motor, the equation of the strain energy in the piezoceramic bimorph and the equations of the strain energy and the kinetic energy in the rotor are given. Based on them, the dynamic equation of the motor is obtained. Using these equations, the inertial driving torque of the motor is investigated. The results show that the impulsive driving torque changes with changing peak voltage of the excitation signal, the piezoelectric stress constant, the thickness of the piezoceramic bimorph, and the rotor radius obviously. Tests about the motor torque are completed which verifies the theory analysis here in. The results can be used to design the operating performance of the motor.

  16. Planar Rotary Piezoelectric Motor Using Ultrasonic Horns

    Science.gov (United States)

    Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph; Geiyer, Daniel; Ostlund, Patrick N.; Allen, Phillip

    2011-01-01

    A motor involves a simple design that can be embedded into a plate structure by incorporating ultrasonic horn actuators into the plate. The piezoelectric material that is integrated into the horns is pre-stressed with flexures. Piezoelectric actuators are attractive for their ability to generate precision high strokes, torques, and forces while operating under relatively harsh conditions (temperatures at single-digit K to as high as 1,273 K). Electromagnetic motors (EM) typically have high rotational speed and low torque. In order to produce a useful torque, these motors are geared down to reduce the speed and increase the torque. This gearing adds mass and reduces the efficiency of the EM. Piezoelectric motors can be designed with high torques and lower speeds directly without the need for gears. Designs were developed for producing rotary motion based on the Barth concept of an ultrasonic horn driving a rotor. This idea was extended to a linear motor design by having the horns drive a slider. The unique feature of these motors is that they can be designed in a monolithic planar structure. The design is a unidirectional motor, which is driven by eight horn actuators, that rotates in the clockwise direction. There are two sets of flexures. The flexures around the piezoelectric material are pre-stress flexures and they pre-load the piezoelectric disks to maintain their being operated under compression when electric field is applied. The other set of flexures is a mounting flexure that attaches to the horn at the nodal point and can be designed to generate a normal force between the horn tip and the rotor so that to first order it operates independently and compensates for the wear between the horn and the rotor.

  17. Model-Based Torque Control of Piezoelectric Ultrasonic Motors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Piezoelectric ultrasonic motors (PUMs) are ideal actuators for a variety of spaced-based robotics applications. These motors replace conventional drive systems...

  18. Linear Piezoelectric Stepping Motor with Broad Operating Frequency

    Institute of Scientific and Technical Information of China (English)

    Chen Xifu; Wang Yin; Sun Mengxin; Huang Weiqing

    2015-01-01

    The existing resonant linear piezoelectric motors must operate with high working voltage in resonant con-dition ,resulting in their narrow operating frequency range and poor running stability .Here ,with the large dis-placement output characteristics of piezoelectric stacks ,the trajectory at the drive foot of stator is firstly produced with two space quadrature piezoelectric actuators excited by sawtooth wave and square wave .Secondly ,the friction drive principle of motor is used to analyze the working mechanisms of the continuous stepping motion .Finally ,the motor prototype is designed and experiments are carried out .The experimental result shows that the motor can stably operate within the scope of 350 Hz to 750 Hz .When the excitation voltage is 30 V and pre-load is 3 N or 10 N ,the lateral amplitude of the drive foot is approximately 4 μm and the stable average interval ranges from 3 .1 μm to 3 .2 μm with the error rate of 5% -7 .5% .

  19. Ultrasonic motors using piezoelectric ceramic multimode vibrators.

    Science.gov (United States)

    Takano, T; Tomikawa, Y; Ogasawara, T; Sugawara, S; Konno, M

    1990-01-01

    The development is reported of an ultrasonic motor using piezoelectric ceramic multimode vibrators consisting of circular or annular plates in which degenerate horizontal vibration modes of the same or different form are used. Two orthogonal nonaxisymmetric vibration modes were used in the same-form case, and the combination of a nonaxisymmetric vibration mode and a radial vibration mode was used in the different-forms case. Some details of the motor design and its experimental characteristics are presented. The ultrasonic motor presented here has a special advantage in its thin construction.

  20. A piezoelectric motor using flexural vibration of a thin piezoelectric membrane.

    Science.gov (United States)

    Lamberti, N; Iula, A; Pappalardo, M

    1998-01-01

    This paper describes a new implementation of a disk-type piezoelectric motor, whose stator is a commercial available piezomembrane composed of a nickel alloy disk to which a piezoceramic disk is bonded. The two disks are concentric, and the total thickness is very small. Ultrasonic motors are based on the concept of driving a rotor by mechanical vibration excited on a stator, via the piezoelectric effect. The rotor is in contact with the stator, and the driving force is the frictional force between rotor and stator. To transform the mechanical vibration of the stator in the rotor rotation, a traveling wave must be excited on the stator surface. The proposed motor can be regarded as a disk-type, single wavelength motor in which the traveling wave is due to the natural flexural vibration of the piezomembrane at low frequency. The behavior of the stator is analyzed both theoretically, by using the theory of isotropic and homogeneous vibrating plates, and by means of a commercial finite element computer code, finding a good agreement with the experimental results. The main features of the motor are very small thickness, appreciable torque, and high speed, obtained with low input power at low voltage; the intended application is to substitute the moving-coil in analogic instrumentation.

  1. Guided wave propagation in multilayered piezoelectric structures

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A general formulation of the method of the reverberation-ray matrix (MRRM) based on the state space formalism and plane wave expansion technique is presented for the analysis of guided waves in multilayered piezoelectric structures. Each layer of the structure is made of an arbitrarily anisotropic piezoelectric material. Since the state equation of each layer is derived from the three-dimensional theory of linear piezoelectricity, all wave modes are included in the formulation. Within the framework of the MRRM, the phase relation is properly established by excluding exponentially growing functions, while the scattering relation is also appropriately set up by avoiding matrix inversion operation. Consequently, the present MRRM is unconditionally numerically stable and free from computational limitations to the total number of layers, the thickness of individual layers, and the frequency range. Numerical examples are given to illustrate the good performance of the proposed formulation for the analysis of the dispersion characteristic of waves in layered piezoelectric structures.

  2. Gap Waves in Piezoelectric layered Medium

    Directory of Open Access Journals (Sweden)

    Danoyan Z.N.

    2007-03-01

    Full Text Available In the present paper the conditions of existence of shear electroelastic gap waves in piezoelectric-vacuum-dielectric layered system are found. It is shown that in the discontact layered system the gap electroelastic waves can be propagated. It is considered the limiting case when the thickness of vacuuming layer tends to zero. It is proved that the statement of the problem is true when there is no acoustic contact between piezoelectric and dielectric grounded media.

  3. 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...

  4. 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 ...

  5. Coupled tangential-axial resonant modes of piezoelectric hollow cylinders and their application in ultrasonic motors.

    Science.gov (United States)

    Vyshnevskyy, Oleksiy; Kovalev, Sergej; Mehner, Jan

    2005-01-01

    This paper describes a tangential-axial eigen-mode of a piezoelectric hollow cylinder. A new type of piezoelectric ultrasonic motor using this oscillation mode has been developed. The motor is a traveling-wave-type motor. The stator of such a motor consists of a solid piezoelectric hollow cylinder, which, excited in the tangential-axial resonant mode by a three-phase electrical signal, will exhibit elliptical displacement and transfer rotation to the rotor. The behavior of the stator has been simulated with finite element method (FEM) software. The simulation results have been checked with single-point contact measurements on the surface of the ultrasonic motors. The paper closes with the introduction of new ultrasonic motors based on this oscillation mode.

  6. Equivalent Circuit Modeling of a Rotary Piezoelectric Motor

    DEFF Research Database (Denmark)

    El, Ghouti N.; Helbo, Jan

    2000-01-01

    In this paper, an enhanced equivalent circuit model of a rotary traveling wave piezoelectric ultrasonic motor "shinsei type USR60" is derived. The modeling is performed on the basis of an empirical approach combined with the electrical network method and some simplification assumptions about...... the physical behavior of the real system. This paper highlights the importance of the electromechanical coupling factor, which is responsible for the electrical to mechanical energy conversion. The emphasis is put on the difference between the effective coupling factor and the modal coupling factor. The effect...

  7. Survey of the present state of the art of piezoelectric linear motors

    Science.gov (United States)

    Hemsel; Wallaschek

    2000-03-01

    Piezoelectric ultrasonic motors have been investigated for several years and have already found their first practical applications. Their key feature is that they are able to produce a high thrust force related to their volume. Beside rotary drives like the travelling wave motor, linear drives have also been developed, but only a few are presently commercially available. In the present paper, we first describe the state of the art of linear piezoelectric motors. The motors are characterized with respect to their no-load velocity, maximum thrust force, efficiency and other technical properties. In the second part, we present a new motor, which is judged to be capable of surpassing the characteristics of other piezoelectric motors because of its unique design which allows the piezoelectric drive elements to be pre-stressed in the direction of their polarization. The piezoelectric elements convert energy using the longitudinal d33 effect which allows an improved reliability, large vibration amplitudes and excellent piezoelectric coupling. Energy loss by vibration damping is minimized, and the efficiency can be improved significantly. Experimental results show that the motor characteristics can be optimized for a particular task by choosing the appropriate operating parameters such as exciting voltage, exciting frequency and normal force.

  8. Fronts of Stress Wave in Anisotropic Piezoelectric Media

    Institute of Scientific and Technical Information of China (English)

    刘颖; 刘凯欣; 高凌天

    2004-01-01

    The characteristic of wave fronts in anisotropic piezoelectric media is analysed by adopting the generalized characteristic theory. Analytical expressions for wave velocities and wave fronts are formulated. Apart from the ordinary characteristics, a new phenomenon, energy velocity funnel, is formed on the wave fronts of quasitransverse waves in anisotropic piezoelectric materials. A three-dimensional representation of wave fronts in anisotropic piezoelectric materials is given for a better understanding of the new phenomena.

  9. Piezoelectric Film Waveguides for Surface Acoustic Waves

    Directory of Open Access Journals (Sweden)

    M.F. Zhovnir

    2016-11-01

    Full Text Available The paper presents results of mathematical modeling of piezoelectric film waveguide structures for surface acoustic waves (SAW. Piezoelectric ZnO film is supposed to be placed on a fused quartz substrate. The analytical ratios and numerical results allow to determine the design parameters of the waveguide structures to provide a single-mode SAW propagation mode. The results of amplitude and phase experimental studies of the SAW in the waveguide structures that were carried out on the laser optical sensing set up confirm the theoretical calculations.

  10. Flexural waves focusing through shunted piezoelectric patches

    Science.gov (United States)

    Yi, K.; Collet, M.; Ichchou, M.; Li, L.

    2016-07-01

    In this paper, we designed and analyzed a piezo-lens to focus flexural waves in thin plates. The piezo-lens is comprised of a host plate and piezoelectric arrays bonded on the surfaces of the plate. The piezoelectric patches are shunted with negative capacitance circuits. The effective refractive indexes inside the piezo-lens are designed to fit a hyperbolic secant distribution by tuning the negative capacitance values. A homogenized model of a piezo-mechanical system is adopted in the designing process of the piezo-lens. The wave focusing effect is studied by the finite element method. Numerical results show that the piezo-lens can focus flexural waves by bending their trajectories, and is effective in a large frequency band. The piezo-lens has the ability to focus flexural waves at different locations by tuning the shunting negative capacitance values. The piezo-lens is shown to be effective for flexural waves generated by different types of sources.

  11. Flextensional ultrasonic motor using the contour mode of a square piezoelectric plate.

    Science.gov (United States)

    Leinvuo, Joni T; Wilson, Stephen A; Whatmore, Roger W

    2004-08-01

    This paper presents the design, fabrication, and characterization of a new type of standing wave piezoelectric ultrasonic motor. The motor uses a metallic flextensional amplifier, or cymbal, to convert the contour mode vibrations of a square piezoelectric ceramic plate into flexural oscillations, which are further converted to produce rotary actuation by means of an elastic-fin friction drive. The motor operates on a single-phase electrical supply. A beryllium copper rotor design with three-fin configuration was adopted, and the geometry was varied to include different material thicknesses, fin lengths, and inclinations. The best stall torque and no load speed for a 25-mm square motor were 0.72 Nmm and 895 r/minute, respectively. The behavior of the stator structure was analyzed by ANSYS finite element software using harmonic and modal analyses. The vibration mode estimated by finite element modeling (FEM) was confirmed by laser Doppler vibration measurements.

  12. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  13. High-Temperature Piezoelectric Crystals for Acoustic Wave Sensor Applications.

    Science.gov (United States)

    Zu, Hongfei; Wu, Huiyan; Wang, Qing-Ming

    2016-03-01

    In this review paper, nine different types of high-temperature piezoelectric crystals and their sensor applications are overviewed. The important materials' properties of these piezoelectric crystals including dielectric constant, elastic coefficients, piezoelectric coefficients, electromechanical coupling coefficients, and mechanical quality factor are discussed in detail. The determination methods of these physical properties are also presented. Moreover, the growth methods, structures, and properties of these piezoelectric crystals are summarized and compared. Of particular interest are langasite and oxyborate crystals, which exhibit no phase transitions prior to their melting points ∼ 1500 °C and possess high electrical resistivity, piezoelectric coefficients, and mechanical quality factor at ultrahigh temperature ( ∼ 1000 °C). Finally, some research results on surface acoustic wave (SAW) and bulk acoustic wave (BAW) sensors developed using this high-temperature piezoelectric crystals are discussed.

  14. WAVE LOCALIZATION IN RANDOMLY DISORDERED PERIODIC PIEZOELECTRIC RODS

    Institute of Scientific and Technical Information of China (English)

    Li Fengming; Wang Yuesheng; Chen Ali

    2006-01-01

    The wave propagation in periodic and disordered periodic piezoelectric rods is studied in this paper. The transfer matrix between two consecutive unit cells is obtained according to the continuity conditions. The electromechanical coupling of piezoelectric materials is considered.According to the theory of matrix eigenvalues, the frequency bands in periodic structures are studied. Moreover, by introducing disorder in both the dimensionless length and elastic constants of the piezoelectric ceramics, the wave localization in disordered periodic structures is also studied by using the matrix eigenvalue method and Lyapunov exponent method. It is found that tuned periodic structures have the frequency passbands and stopbands and localization phenomenon can occur in mistuned periodic structures. Furthermore, owing to the effect of piezoelectricity, the frequency regions for waves that cannot propagate through the structures are slightly increased with the increase of the piezoelectric constant.

  15. Amplification of acoustic waves in laminated piezoelectric semiconductor plates

    Energy Technology Data Exchange (ETDEWEB)

    Yang, J.S.; Yang, X.M.; Turner, J.A. [University of Nebraska, Department of Engineering Mechanics, Lincoln, NE (United States)

    2004-12-01

    Two-dimensional equations for coupled extensional, flexural and thickness-shear motions of laminated plates of piezoelectric semiconductors are obtained systematically from the three-dimensional equations by retaining lower order terms in power series expansions in the plate thickness coordinate. The equations are used to analyze extensional waves in a composite plate of piezoelectric ceramics and semiconductors. Dispersion and dissipation due to semiconduction as well as wave amplification by a dc electric field are discussed. (orig.)

  16. Piezoelectric Generation and Damping of Extensional Waves in Bars

    OpenAIRE

    Jansson, Anders

    2007-01-01

    This thesis focuses on the electromechanical processes of generation and damping of transient waves in bars with attached piezoelectric members. In particular, the influence of amplifier and electrical circuitry on the mechanical waves is of interest. A straight bar element containing piezoelectric members is viewed as a linear system with one electrical and two mechanical ports where it interacts with external electrical and mechanical devices through voltage, current, forces and velocities....

  17. Love wave propagation in piezoelectric layered structure with dissipation.

    Science.gov (United States)

    Du, Jianke; Xian, Kai; Wang, Ji; Yong, Yook-Kong

    2009-02-01

    We investigate analytically the effect of the viscous dissipation of piezoelectric material on the dispersive and attenuated characteristics of Love wave propagation in a layered structure, which involves a thin piezoelectric layer bonded perfectly to an unbounded elastic substrate. The effects of the viscous coefficient on the phase velocity of Love waves and attenuation are presented and discussed in detail. The analytical method and the results can be useful for the design of the resonators and sensors.

  18. WAVE PROPAGATION IN TWO-DIMENSIONAL DISORDERED PIEZOELECTRIC PHONONIC CRYSTALS

    Institute of Scientific and Technical Information of China (English)

    Jinqiang Li; Fengming Li; Yuesheng Wang; Kikuo Kishimoto

    2008-01-01

    The wave propagation is studied in two-dimensional disordered piezoelectric phononie crystals using the finite-difference time-domain (FDTD) method. For different eases of disorder,the transmission coefficients are calculated. The influences of disorders on band gaps are investigated. The results show that the disorder in the piezoelectric phononic crystals has more significant influences on the band gap in the low frequency regions than in the high frequency ones. The relation between the width of band gap and the direction of position disorder is also discussed. When the position disorder is along the direction perpendicular to the wave transmission, the piezoelectric phononic crystals have wider band gaps at low frequency regions than the case of position disorder being along the wave transmission direction. It can also be found that the effect of. size disorder on band gaps is analogous to that of location disorder. When the perturbation coefficient is big, it has more pronounced effects on the pass bands in the piezoelectric phononic crystals with both size and location disorders than in the piezoelectric phononic crystals with single disorder.In higher frequency regions the piezoelectric effect reduces the transmission coefficients. But for larger disorder degree, the effects of the piezoelectricity will be reduced.

  19. Modeling and Simulation of Miniature Piezoelectric Motors

    Energy Technology Data Exchange (ETDEWEB)

    Mahoney, J.F.

    1998-06-01

    The use of piezo materials is becoming common in both commercial and retail products. Motors designed using piezo materials as actuators are also being utilized where either space or magnetic materials are limited. This paper discusses the use of ABAQUS/Standard and ABAQUS/Explicit toward the development and production of small piezo motors. Analytical techniques are the only methods possible to determine motor design parameters and performance issues prior to prototype production and testing. The use of ABAQUS/Standard to solve baseline Eigenvalue extractions and transient dynamics for stator motion has made it possible to evaluate motor designs much quicker than physical evaluations. The use of the ''VUMAT'' subroutine in ABAQUS/Explicit has been used to create strains driven by the piezo effects, thus allowing for many thousands of cyclic loads to be applied to contacting 3D continuum structures. The use of viscous pressure techniques for near-perfect static loading under explicit dynamics will also be presented and discussed.

  20. Integration of a piezoelectric transformer and an ultrasonic motor.

    Science.gov (United States)

    Manuspiya, Suwan; Laoratanakul, Pitak; Uchino, Kenji

    2003-03-01

    Ultrasonic motors are usually operated at an AC voltage higher than a regular battery. This implies the need of a voltage step-up transformer. In this paper, we report the integration of a piezoelectric transformer (PT) with an ultrasonic motor and a simple drive circuit. The stator of the ultrasonic motor and the PT were operated in the same radial vibration mode. Their dimensions were very close to each other yielding nearly matching resonance frequencies. Consequently, they could be combined together without inductor. The drive circuit was designed by using a 555 timer as an astable multivibrator, and high-speed dual MOSFET drivers as a class D half-bridge switching amplifier. This integrated PT-ultrasonic motor performed reasonably without the use of electromagnetic transformer or inductor.

  1. SH-guided waves in layered piezoelectric/piezomagnetic plates

    Institute of Scientific and Technical Information of China (English)

    Guoquan Nie; Zijun An; Jinxi Liu

    2009-01-01

    The propagation of shear horizontal (SH) guided waves in a coupled plate consisting of a piezoelectric layer and a piezomagnetic layer is studied. Both the layers are transversely isotropic and perfectly bonded along the interface. The upper and the lower surfaces of the plate are assumed to be mechanically free, electrically open and magnetically dosed. Two different cases are considered. One is that the bulk shear wave velocity of piezoelectric material is larger than that of piezomagnetic material. The other is that the bulk shear wave velocity of piezomagnetic material is larger than that of piezoelectric material. The dispersion relation is obtained while the phase velocity is among the bulk shear wave velocity of two different layers. The numerical results show that the phase velocity approaches the smaller bulk shear wave velocity of the material in the system with the increase in the wave number for different modes. The thickness ratio and the properties of the piezoelectric material have great effect on the dispersion behaviors. The results of this paper can offer some funda-mental theory to the application of piezoelectric/piezomagnetic composites or structures.

  2. A T-shape linear piezoelectric motor with single foot.

    Science.gov (United States)

    Liu, Yingxiang; Chen, Weishan; Yang, Xiaohui; Liu, Junkao

    2015-02-01

    A new T-shape piezoelectric motor using the hybrid of two orthogonal longitudinal vibrations is proposed in this work. Six pieces of PZT ceramic plates are bonded on the upside and downside surfaces of a T-shape duralumin alloy base respectively to form the proposed motor. Elliptical movement can be generated on the driving tip by applying sine and cosine voltages to the PZT elements. The horizontal displacement of the driving tip will push the runner while the vertical displacement can overcome the preload. Finite element method is used to accomplish the design and analysis process. The resonance frequencies of the two vibration modes are tuned to be close by modal analysis, while the motion trajectory of the driving tip is observed by transient analysis. After the fabrication of a prototype, the vibration characteristics and mechanical output ability are measured. The no-load speed and the maximum output thrust force of the proposed motor are tested to be 718 mm/s and 3.5 N under an exciting frequency of 53.1 kHz. The proposed T-shape piezoelectric motor exhibits merits of simple structure, easy to realize miniaturization, easy to be fabricated, and high power-to-weight ratio.

  3. Analysis of a disk-type piezoelectric ultrasonic motor using impedance matrices.

    Science.gov (United States)

    Kim, Young H; Ha, Sung K

    2003-12-01

    The dynamic behavior and the performance characteristics of the disk-type traveling wave piezoelectric ultrasonic motors (USM) are analyzed using impedance matrices. The stator is divided into three coupled subsystems: an inner metal disk, a piezoelectric annular actuator with segmented electrodes, and an outer metal disk with teeth. The effects of both shear deformation and rotary inertia are taken into account in deriving an impedance matrix for the piezoelectric actuator. The impedance matrices for each subsystem then are combined into a global impedance matrix using continuity conditions at the interfaces. A comparison is made between the impedance matrix model and the three-dimensional finite element model of the piezoelectric stator, obtaining the resonance and antiresonance frequencies and the effective electromechanical coupling factors versus circumferential mode numbers. Using the calculated resonance frequency and the vibration modes for the stator and a brush model with the Coulomb friction for the stator and rotor contact, stall torque, and no-load speed versus excitation frequencies are calculated at different preloads. Performance characteristics such as speed-torque curve and the output efficiency of the USM also are estimated using the current impedance matrix and the contact model. The present impedance model can be shown to be very effective in the design of the USM.

  4. A Novel Rotary Piezoelectric Motor Using First Bending Hybrid Transducers

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    2015-08-01

    Full Text Available We report a novel rotary piezoelectric motor using bending transducers in this work. Three transducers are used to drive a disk-shaped rotor together by the elliptical movements of their driving tips; these motions are produced by the hybrid of two first bending vibration modes. The proposed piezoelectric transducer has a simple structure as it only contains an aluminum alloy beam and four pieces of PZT plates. Symmetrical structure is the only necessary condition in the design process as it will ensure the resonance frequencies of the two orthogonal first bending modes are equal. Transducers with first bending resonance frequency of about 53 kHz were fabricated and assembled into a rotary motor. The proposed motor exhibits good performance on speed and torque control. Under a working frequency of 53.2 kHz, the maximum no-load speed and the maximum torque of the prototype are tested to be 53.3 rpm and of 27 mN·m.

  5. Systematic experimental based modeling of a rotary piezoelectric ultrasonic motor

    DEFF Research Database (Denmark)

    Mojallali, Hamed; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    In this paper, a new method for equivalent circuit modeling of a traveling wave ultrasonic motor is presented. The free stator of the motor is modeled by an equivalent circuit containing complex circuit elements. A systematic approach for identifying the elements of the equivalent circuit...

  6. Analysis of shaking beam actuator for piezoelectric linear ultrasonic motor.

    Science.gov (United States)

    Lee, Kyongjai; Lee, Dong-Kyun; Borodinas, Sergejus; Vasiljev, Piotr; Nahm, Sahn; Yoon, Seok-Jin

    2004-11-01

    In this paper, piezoelectric linear ultrasonic motors (PLUM) have been investigated on the elliptic trajectory of a contact point in shaking beam, which has been accomplished by two resonance vibration modes of the actuators. The actuators have generated the vibration modes, longitudinal and flexural, by two longitudinal mechanical vibrations with phase difference of pi/2. Modal and harmonic analysis of the shaking beam actuator were performed by the finite element method (FEM) to calculate a resonance frequency and a modal shape and to perform harmonic response. Experimental results proved that a contact point of the PLUM tends to move with an elliptic trajectory.

  7. WAVE PROPAGATION IN PIEZOELECTRIC/PIEZOMAGNETIC LAYERED PERIODIC COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Yu Pang; Jinxi Liu; Yuesheng Wang; Daining Fang

    2008-01-01

    This paper is concerned with the dynamic behaviors of wave propagation in layered periodic composites consisting of piezoelectric and piezomagnetic phases. The dispersion relations of Lamb waves are derived. Dispersion curves and displacement fields are calculated with different piezoelectric volume fractions. Numerical results for BaTiOa/CoFe204 composites show that the dispersion curves resemble the symmetric Lamb waves in a plate. Exchange between the longitudinal (i.e. thickness) mode and coupled mode takes place at the crossover point between dispersion curves of the first two branches. With the increase of BaTiO3 volume fraction, the crossover point appears at a lower wave number and wave velocity is higher. These findings are useful for magnetoelectric transducer applications.

  8. 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.

  9. Long-Stroke Nanopositioning Stage Driven by Piezoelectric Motor

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2014-01-01

    Full Text Available This paper reported a biaxial nanopositioning stage single-driven by piezoelectric motor. The employed piezoelectric motor can perform two different driving modes, namely, AC drive mode to drive in long-stroke and at high-speed and DC scanning mode with the high-resolution of several nanometers, which satisfies the requirements of both long-stroke and nanoresolution. To compensate for the effects of the variable friction force and some unpredictable disturbances, a novel backward error compensation (BEC positioning control method integrated of the two driving modes and a double closed-loop PID controller system are proposed to obtain a high-accuracy positional motion. The experiment results demonstrate that the nanopositioning stage with large travel range of 300 mm × 300 mm has a fine speed characteristic and resolution is 5 nm. In the experiments of different travels up to 15 mm, calibrated by a commercial laser vibrometer, the positioning accuracy is proved within 55 nm in x-axis and 40 nm in y-axis with standard deviation less than 40 nm in x-axis and 30 nm in y-axis and the final position locking can be limited to 10 nm, meeting the requirements of micromanipulation technology.

  10. A new hybrid piezoelectric ultrasonic motor with two stators

    Institute of Scientific and Technical Information of China (English)

    YI You-ping; Wolfgang Seemann; Rainer Gausmann; ZHONG Jue

    2005-01-01

    A new hybrid piezoelectric ultrasonic motor, which consists of one rotor and two stators, was proposed in this paper. In order to match the resonance frequencies of longitudinal vibration and torsional vibration excited in the stators, a symmetrical structure was adopted in design of the motor. A so-called mass matching method, namely adding two rings to the outside circumference of the two stators respe ctively, was used to adjust the resonance frequencies of these two vibrations. A finite element model was developed using ANSYS software for the purpose of analyzing the resonance frequencies of longitudinal vibration and torsional vibration as well as the function of the adjusting rings. The results show that the resonance frequency of torsional vibration varies with the position of the ring, but the resonance frequency of longitudinal vibration changes little. By means of adjusting the mass and the position of the rings, the first order resonance frequency of longitudinal vibration is coincided with that of torsional vibration and the value is 20.75 kHz. An experimental prototype motor was fabricated according to the analytical results and its performance is in agreement with the theoretical predictions. The speed of motor reaches the maximum 92 r/min at the working frequency 19.0 kHz.

  11. High-temperature piezoelectric materials for elements of linear piezo motors

    Science.gov (United States)

    Khramtsov, A. M.; Spitsin, A. I.; Segalla, A. G.; Ponomarev, S. V.; Rikkonen, S. V.

    2016-11-01

    This paper discusses technological and construction ways to achieve a high working temperature with a high displacement in linear piezo motors. The first part reviews the results of the piezoelectric material development, its temperature stability testing and basic parameters for piezo motors. The second part focuses on the multilayer structure of piezoelectric elements, which are based on high-temperature piezoelectric materials (HTPM). Also analyzed are working temperatures of multilayer piezoelectric elements (MPE) and their hysteresis. Finally, the third part shows a comparison of three recent prototypes of high-temperature MPEs that were in our lab using different materials.

  12. Piezoelectric motor development at AlliedSignal Inc., Kansas City Division

    Energy Technology Data Exchange (ETDEWEB)

    Pressly, R.B.; Mentesana, C.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.

  13. Wave localization in randomly disordered periodic layered piezoelectric structures

    Institute of Scientific and Technical Information of China (English)

    Fengming Li; Yuesheng Wang; Chao Hu; Wenhu Huang

    2006-01-01

    Considering the mechnoelectrical coupling,the localization of SH-waves in disordered periodic layered piezoelectric structures is studied.The waves propagating in directions normal and tangential to the layers are considered.The transfer matrices between two consecutive unit cells are obtained according to the continuity conditions.The expressions of localization factor and localization length in the disordered periodic structures are presented.For the disordered periodic piezoelectric structures,the numerical results of localization factor and localization length are presented and discussed.It can be seen from the results that the fequency passbands and stopbands appear for the ordered periodic structures and the wave localization phenomenon occurs in the disordered periodic ones,and the larger the coefficient of variation is,the greater the degree of wave localization is.The widths of stopbands in the ordered periodic structures are very narrow when the properties of the consecutive piezoelectric materials are similar and the intervals of stopbands become broader when a certain material parameter has large changes.For the wave propagating in the direction normal to the layers the localization length has less dependence on the frequency,but for the wave propagating in the direction tangential to the layers the localization length is strongly dependent on the frequency.

  14. A Traveling Wave Type of Piezoelectric Ultrasonic Bidirectional Linear Microactuator

    Science.gov (United States)

    Sun, Dongming; Wang, Sheng; Sakurai, Junpei; Hata, Seiichi; Choi, Kee-Bong; Shimokohbe, Akira

    2009-04-01

    A piezoelectric ultrasonic microactuator is presented, with a cylindrical stator and slider structure. The length and diameter of the microactuator are about 10 and 1.5 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a thin film metallic glass (TFMG) pipe, which is fabricated using the rotating magnetron sputtering technique. Traveling wave propagation is generated on the TFMG pipe in finite element method (FEM) simulations and also observed in the measurement. Bi-directional motion of the slider was observed around 600 kHz, and the maximum velocity was about 40 mm/s at 25 V.

  15. Love wave propagation in functionally graded piezoelectric material layer.

    Science.gov (United States)

    Du, Jianke; Jin, Xiaoying; Wang, Ji; Xian, Kai

    2007-03-01

    An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along the x-axis direction. The analytical solutions of dispersion relations are obtained for electrically open or short circuit conditions. The effects of the gradient variation of material constants on the phase velocity, the group velocity, and the coupled electromechanical factor are discussed in detail. The displacement, electric potential, and stress distributions along thickness of the graded layer are calculated and plotted. Numerical examples indicate that appropriate gradient distributing of the material properties make Love waves to propagate along the surface of the piezoelectric layer, or a bigger electromechanical coupling factor can be obtained, which is in favor of acquiring a better performance in surface acoustic wave (SAW) devices.

  16. Lamb waves dispersion curves for diamond based piezoelectric layered structure

    Science.gov (United States)

    Sorokin, B. P.; Kvashnin, G. M.; Telichko, A. V.; Novoselov, A. S.; Burkov, S. I.

    2016-03-01

    The presence of spurious peaks in the amplitude-frequency response of diamond based piezoelectric layered structure was shown. Excitation of such peaks results in deterioration of an useful acoustical signal. It was shown that such spurious peaks should be associated with Lamb waves in a layered structure. By means of FEM analysis, the propagation of acoustic waves of different types in the piezoelectric layered structure "Al/AlN/Mo/(100) diamond" has been investigated in detail. By analyzing the elastic displacement patterns at frequencies from 0 up to 250 MHz, a set of all the possible acoustic waves, especially Lamb modes, have been studied, and dispersive curves of phase velocity have been plotted. A revised classification of Lamb modes has been introduced.

  17. A piezoelectric linear ultrasonic motor with the structure of a circular cylindrical stator and slider

    Science.gov (United States)

    Sun, Dongming; Wang, Sheng; Sakurai, Junpei; Choi, Kee-Bong; Shimokohbe, Akira; Hata, Seiichi

    2010-04-01

    A piezoelectric linear ultrasonic motor is proposed, with a cylindrical stator and slider structure. The length and diameter of the motor are about 10 and 1.5 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a thin film metallic glass (TFMG) pipe. The stator is designed based on theoretical analyses and finite element method (FEM) simulation. The traveling wave propagation is obtained in the FEM simulation under the proper geometrical sizes, suitable boundary conditions and driving voltage signals. The trajectories of particles on the TFMG pipe are elliptical motion. In the experiment, a 25 µm thick TFMG pipe is fabricated using the rotating magnetron sputtering technique and the vibration characteristics of the stator are measured by a laser Doppler vibrometer (LDV) system. Bidirectional motion of the slider is observed around 600 kHz, the maximum velocity is near to 40 mm s - 1 at 50 Vp-p for the loose slider and the maximum output force is 6 mN at 70 Vp-p for the tight slider.

  18. Finite element modelling of a rotating piezoelectric ultrasonic motor.

    Science.gov (United States)

    Frangi, A; Corigliano, A; Binci, M; Faure, P

    2005-10-01

    The evaluation of the performance of ultrasonic motors as a function of input parameters such as the driving frequency, voltage input and pre-load on the rotor is of key importance to their development and is here addressed by means of a finite element three-dimensional model. First the stator is simulated as a fully deformable elastic body and the travelling wave dynamics is accurately reproduced; secondly the interaction through contact between the stator and the rotor is accounted for by assuming that the rotor behaves as a rigid surface. Numerical results for the whole motor are finally compared to available experimental data.

  19. Millipede-inspired locomotion through novel U-shaped piezoelectric motors

    Science.gov (United States)

    Avirovik, Dragan; Butenhoff, Bryan; Priya, Shashank

    2014-03-01

    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 Vrms, 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.

  20. TECHNICAL NOTE: Multi-DOF and sub-micrometer piezoelectric-electrorheological stepper motor

    Science.gov (United States)

    Chu, Xiangcheng; Qiu, Hongyun; Li, Longtu; Gui, Zhilun

    2004-08-01

    A new type of piezoelectric-electrorheological plane stepper motor combining the piezoelectric effect with the electrorheological effect is proposed in this paper. Four electrorheological clampers and four multilayer piezoelectric actuators are designed in the prototype motor. Based on a bionic inchworm movement mechanism, when these electrorheological clampers are combined with piezoelectric actuators in different ways, the movements in the x-direction, the y-direction and z-rotation with a long travel stroke of 100 and 0.36 µm resolution can be completed. The maximum moving speed and driving force of the prototype motor are 1.8 mm min-1 and 100 gf, respectively. The steady stepper velocity and instant motion image are measured by a CCD optical measuring system from 0.2 to 23 µm s-1. The motor may be applied in fields such as MEMs, optical manipulator, manipulator in SEM or STM, laser adjustor, micromachining, etc.

  1. SHEAR WAVE SCATTERING FROM A PARTIALLY DEBONDED PIEZOELECTRIC CYLINDRICAL INCLUSION

    Institute of Scientific and Technical Information of China (English)

    FengWenjie; WangLiqun; JiangZhiqing; ZhaoYongmao

    2004-01-01

    The scattering of SH wave by a cylindrical piezoelectric inclusion partially debonded from its surrounding piezoelectric material is investigated using the wave function expansion method and singular integral equation technique. The debonding regions are modeled as multiple arc-shaped interface cracks with non-contacting faces. By expressing the scattered fields as wave function expansions with unknown coefficients, the mixed boundary value problem is firstly reduced to a set of simultaneous dual series equations. Then dislocation density functions are introduced as unknowns to transform these dual series equations into Cauchy singular integral equations of the first type, which can be numerically solved easily. The solution is valid for arbitrary number and size of the debonds. Finally, numerical results of the dynamic stress intensity factors are presented for the cases of one debond and two debonds. The effects of incidence direction, crack configuration and various material parameters on the dynamic stress intensity factors are respectively discussed. The solution of this problem is expected to find applications in the investigation of dynamic fracture properties of piezoelectric materials with cracks.

  2. Lamb waves propagation in layered piezoelectric/piezomagnetic plates.

    Science.gov (United States)

    Ezzin, Hamdi; Ben Amor, Morched; Ben Ghozlen, Mohamed Hédi

    2017-04-01

    A dynamic solution is presented for the propagation of harmonic waves in magneto-electro-elastic plates composed of piezoelectric BaTiO3(B) and magnetostrictive CoFe2O4(F) material. The state-vector approach is employed to derive the propagator matrix which connects the field variables at the upper interface to those at the lower interface of each layer. The ordinary differential approach is employed to determine the wave propagating characteristics in the plate by imposing the traction-free boundary condition on the top and bottom surfaces of the layered plate. The dispersion curves of the piezoelectric-piezomagnetic plate are shown for different thickness ratios. The numerical results show clearly the influence of different stacking sequences as well as thickness ratio on dispersion curves and on magneto-electromechanical coupling factor. These findings could be relevant to the analysis and design of high-performance surface acoustic wave (SAW) devices constructed from piezoelectric and piezomagnetic materials.

  3. Modeling Piezoelectric Interfacial Wave Near an Imperfect Interface

    Institute of Scientific and Technical Information of China (English)

    XU Li-mei; FAN Hui; CHEN Min; LI Hui

    2006-01-01

    The interface wave propagating along an imperfect interface between two piezoelectric half spaces is derived firstly. The wave equations based on the interface modeled, called "spring model", are presented. The micro-scale structures of the interface for connecting the spring constant with the interface micro-structures are examined. For some simple interface micro-structure, exact dynamic solution is available, and the spring constant is obtained by comparing solutions. For the complex micro structures, it remains as a challenge of micro-mechanics modeling to connect the "spring constant" and micro-structure.

  4. Ultrasonic wave's interaction at fluid-porous piezoelectric layered interface.

    Science.gov (United States)

    Vashishth, Anil K; Gupta, Vishakha

    2013-02-01

    The complete description of acoustic propagation in a multilayered system is of great interest in a variety of applications such as non-destructive evaluation and acoustic design and there is need for a flexible model that can describe the reflection and transmission of ultrasonic waves in these media. The reflection and transmission of ultrasonic waves from a fluid loaded porous piezoelectric layered structure is studied analytically. The layered structure is considered to be consisting of n number of layers of porous piezoelectric materials. Transfer matrix technique is used to study the layered materials. The analytical expressions for the reflected, transmitted, interaction energy ratios and surface impedance are obtained. The effects of frequency, porosity, angle of incidence, layer thickness and number of layers on the energy ratios and surface impedance are studied for different configurations of the layered materials. The results obtained are deduced for the poro-elastic and fluid loaded porous piezoelectric half space case, which are in agreement with earlier established results. A comparison of the results, obtained by alternate numerical techniques, is made.

  5. Lamb wave characteristics of thickness-graded piezoelectric IDT.

    Science.gov (United States)

    Roy Mahapatra, D; Singhal, A; Gopalakrishnan, S

    2005-10-01

    An equivalent single layer model of Lamb wave generation by thickness-graded piezoelectric IDT on host structure is developed. Various additional complexities, such as the coupling between the Lamb wave modes, complicated nature of the electro-mechanical excitation are considered. The model of infinite IDT is extended to deal with the finite IDT with edge discontinuities. The effects of electromechanical coupling and thickness gradation on the wavelength shifts are investigated. The problem of electrically driven instability within the IDT is analyzed. Numerical results are reported by considering Al2O3/PZT IDT as integral part of the host structure, which show that there are significant changes and improvements in the Lamb wave characteristics due to the graded configuration. Most important among these is the reduced dispersiveness of the Lamb wave modes, which is useful in launching a SAW that propagates with narrower pulse width and less attenuation.

  6. Focusing of Surface Acoustic Wave on a Piezoelectric Crystal

    Institute of Scientific and Technical Information of China (English)

    QIAO Dong-Hai; WANG Cheng-Hao; WANG Zuo-Qing

    2006-01-01

    @@ We investigate the focusing phenomena of a surface acoustic wave (SAW) field generated by a circular-arc interdigital transducer (IDT) on a piezoelectric crystal. A rigorous vector field theory of surface excitation on the crystal we developed previously is used to evaluate the convergent SAW field instead of the prevalent scalar angular spectrum used in optics. The theoretical results show that the anisotropy of a medium has great impact on the focusing properties of the acoustic beams, such as focal length and symmetrical distributions near the focus. A dark field method is used in experiment to observe the focusing of the SAW field optically. Although the convergent phenomena of SAW field on the anisotropic media or piezoelectric crystals are very complicated,the experimental data are in agreement with those from the rigorous theory.

  7. Nonlinear dynamic analysis of traveling wave-type ultrasonic motors.

    Science.gov (United States)

    Nakagawa, Yosuke; Saito, Akira; Maeno, Takashi

    2008-03-01

    In this paper, nonlinear dynamic response of a traveling wave-type ultrasonic motor was investigated. In particular, understanding the transient dynamics of a bar-type ultrasonic motor, such as starting up and stopping, is of primary interest. First, the transient response of the bar-type ultrasonic motor at starting up and stopping was measured using a laser Doppler velocimeter, and its driving characteristics are discussed in detail. The motor is shown to possess amplitude-dependent nonlinearity that greatly influences the transient dynamics of the motor. Second, a dynamical model of the motor was constructed as a second-order nonlinear oscillator, which represents the dynamics of the piezoelectric ceramic, stator, and rotor. The model features nonlinearities caused by the frictional interface between the stator and the rotor, and cubic nonlinearity in the dynamics of the stator. Coulomb's friction model was employed for the interface model, and a stick-slip phenomenon is considered. Lastly, it was shown that the model is capable of representing the transient dynamics of the motor accurately. The critical parameters in the model were identified from measured results, and numerical simulations were conducted using the model with the identified parameters. Good agreement between the results of measurements and numerical simulations is observed.

  8. Actuating Mechanism and Design of a Cylindrical Traveling Wave Ultrasonic Motor Using Cantilever Type Composite Transducer

    OpenAIRE

    Yingxiang Liu; Weishan Chen; Junkao Liu; Shengjun Shi

    2010-01-01

    BACKGROUND: Ultrasonic motors (USM) are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS: A cylindrical type traveling wave ultrasonic motor using cantilever type composite transducer was proposed in this paper. There are two cantilevers on the ...

  9. Application of Piezoelectric Materials in a Novel Linear Ultrasonic Motor based on Shear-induced Vibration Mode

    Institute of Scientific and Technical Information of China (English)

    CHEN Chao; SHI Yunlai; CHEN Haipeng; ZHAO Chunsheng

    2014-01-01

    A novel linear ultrasonic motor based on d15 effect of piezoelectric materials was presented. The design idea aimed at the direct utilization of the shear-induced vibration modes of piezoelectric material. Firstly, the inherent electromechanical coupling mechanism of piezoelectric material was investigated, and shear vibration modes of a piezoelectric shear block was specially designed. A driving point’s elliptical trajectory induced by shear vibration modes was discussed. Then a dynamic model for the piezoelectric shear stator was established with finite element (FE) method to conduct the parametric optimal design. Finally, a prototype based on d15 converse piezoelectric effect is manufactured, and the modal experiment of piezoelectric stator was conducted with laser doppler vibrometer. The experimental results show that the calculated shear-induced vibration modes can be excited completely, and the new linear ultrasonic motor reaches a speed 118 mm/s at no-load, and maximal thrust 12.8 N.

  10. Calculation of surface acoustic waves in a multilayered piezoelectric structure

    Institute of Scientific and Technical Information of China (English)

    Zhang Zuwei; Wen Zhiyu; Hu Jing

    2013-01-01

    The propagation properties of the surface acoustic waves (SAWs) in a ZnO-SiO2-Si multilayered piezoelectric structure are calculated by using the recursive asymptotic method.The phase velocities and the electromechanical coupling coefficients for the Rayleigh wave and the Love wave in the different ZnO-SiO2-Si structures are calculated and analyzed.The Love mode wave is found to be predominantly generated since the c-axis of the ZnO film is generally perpendicular to the substrate.In order to prove the calculated results,a Love mode SAW device based on the ZnO-SiO2-Si multilayered structure is fabricated by micromachining,and its frequency responses are detected.The experimental results are found to be mainly consistent with the calculated ones,except for the slightly larger velocities induced by the residual stresses produced in the fabrication process of the films.The deviation of the experimental results from the calculated ones is reduced by thermal annealing.

  11. Actuation Using Piezoelectric Materials: Application in Augmenters, Energy Harvesters, and Motors

    Science.gov (United States)

    Hasenoehrl, Jennifer

    2012-01-01

    Piezoelectric actuators are used in many manipulation, movement, and mobility applications as well as transducers and sensors. When used at the resonance frequencies of the piezoelectric stack, the actuator performs at its maximum actuation capability. In this Space Grant internship, three applications of piezoelectric actuators were investigated including hammering augmenters of rotary drills, energy harvesters, and piezo-motors. The augmenter shows improved drill performance over rotation only. The energy harvesters rely on moving fluid to convert mechanical energy into electrical power. Specific designs allow the harvesters more freedom to move, which creates more power. The motor uses the linear movement of the actuator with a horn applied to the side of a rotor to create rotational motion. Friction inhibits this motion and is to be minimized for best performance. Tests and measurements were made during this internship to determine the requirements for optimal performance of the studied mechanisms and devices.

  12. 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.

  13. Plated-designed structures: new possibility of obtaining resonance enhancement of piezoelectric properties using Lamb waves

    Energy Technology Data Exchange (ETDEWEB)

    Radchenko, G S [Institute of Physics, South Federal University, Rostov-on-Don 344090 (Russian Federation); Pedagogical Institute of South Federal University, Rostov-on-Don 344022 (Russian Federation)], E-mail: grig1980@mail.ru

    2008-08-07

    In this paper we propose a novel theoretical approach to the description of acoustic oscillations in plated piezoelectric structures. The expansion of acoustic Lamb and longitudinal waves in such structures and the fundamental effective properties of them are described. A considerable enhancement of piezoelectric properties in such objects under an applied alternating electric field has been found.

  14. Study on the electromechanical coupling coefficient of Rayleigh-type surface acoustic waves in semi-infinite piezoelectrics/non-piezoelectrics superlattices.

    Science.gov (United States)

    Chen, Shi; Zhang, Yinhong; Lin, Shuyu; Fu, Zhiqiang

    2014-02-01

    The electromechanical coupling coefficient of Rayleigh-type surface acoustic waves in semi-infinite piezoelectrics/non-piezoelectrics superlattices is investigated by the transfer matrix method. Research results show the high electromechanical coupling coefficient can be obtained in these systems. The optimization design of it is also discussed fully. It is significantly influenced by electrical boundary conditions on interfaces, thickness ratios of piezoelectric and non-piezoelectric layers, and material parameters (such as velocities of pure longitudinal and transversal bulk waves in non-piezoelectric layers). In order to obtain higher electromechanical coupling coefficient, shorted interfaces, non-piezoelectric materials with large velocities of longitudinal and transversal bulk waves, and proper thickness ratios should be chosen.

  15. Free Stator Modeling of a Traveling Wave Ultrasonic Motor

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Helbo, Jan; Mojallali, Hamed

    2005-01-01

    An equivalent circuit method describing the free stator of piezoelectric motor is presented in this paper, while the circuit elements have complex values. The mechanical, dielectric and piezoelectric losses associated with the vibrator are accounted for by the imaginary components of the circuit ...

  16. Piezoelectric theory for finite element analysis of ultrasonic motors

    Energy Technology Data Exchange (ETDEWEB)

    Emery, J.D.; Mentesana, C.P.

    1997-06-01

    The authors present the fundamental equations of piezoelectricity and references. They show how a second form of the equations and a second set of coefficients can be found, through inversions involving the elasticity tensor. They show how to compute the clamped permittivity matrix from the unclamped matrix. The authors list the program pzansys.ftn and present examples of its use. This program does the conversions and calculations needed by the finite element program ANSYS.

  17. Parametric dispersion and amplification of acoustohelicon waves in piezoelectric semiconductors

    Science.gov (United States)

    Neogi, A.; Ghosh, S.

    1991-01-01

    Assuming that the origin of the nonlinear interaction lies in the second-order optical susceptibility arising from the nonlinear induced current density and using the coupled-mode theory, the parametric dispersion and amplification of acoustohelicon waves is analytically investigated in a longitudinally magnetized piezoelectric semiconductor of noncentrosymmetric nature. The relevant experiments have not been reported. The threshold value of the pump electric field E0th and its corresponding excitation intensity is obtained. The longitudinal magnetic field decreases the required magnitude of E0th for the excitation of parametric amplification. The phenomenon of self-defocusing of the signal in the prevailing case is found to be a consequence of the negative dispersive characteristics exhibited by the acoustohelicon waves. Numerical analyses are performed for an InSb crystal at 77 K, duly irradiated by frequency-doubled pulsed 10.6-μm CO2 lasers. The parametric gain constant is observed to be maximum when the cyclotron frequency ωc attains the magnitude equal to that of ω0, the incident laser frequency (=1.78×1014 s-1 ).

  18. Resonance reflection of acoustic waves in piezoelectric bi-crystalline structures.

    Science.gov (United States)

    Darinskii, Alexander N; Weihnacht, Manfred

    2005-05-01

    The paper studies the bulk wave reflection from internal interfaces in piezoelectric media. The interfaces of two types have been considered. Infinitesimally thin metallic layer inserted into homogeneous piezoelectric crystal of arbitrary symmetry. Rigidly bonded crystals whose piezoelectric coefficients differ by sign but the other material constants are identical. Analytic expressions for the coefficients of mode conversion have been derived. An analysis has been carried out of specific singularities arising when the angle of incidence is such that the resonance excitation of leaky interface acoustic waves occurs. The conditions for the resonance total reflection have been established. The computations performed for lithium niobate (LiNbO3) illustrate general conclusions.

  19. PROPAGATION OF LOVE WAVES IN PRESTRESSED PIEZOELECTRIC LAYERED STRUCTURES LOADED WITH VISCOUS LIQUID

    Institute of Scientific and Technical Information of China (English)

    Jianke Du; Kai Xian; Ji Wang; Yook-Kong Yong

    2008-01-01

    We investigate analytically the effect of initial stress in piezoelectric layered structures loaded with viscous liquid on the dispersive and attenuated characteristics of Love waves,which involves a thin piezoelectric layer bonded perfectly to an unbounded elastic substrate. The effects of initial stress in the piezoelectric layer and the viscous coefficient of the liquid on the phase velocity of Love waves are analyzed. Numerical results are presented and discussed. The analytical method and the results can be useful for the design of chemical and bioseusing liquid sensors.

  20. A Novel Traveling Wave Ultrasonic Motor Using a Bar Shaped Transducer

    Institute of Scientific and Technical Information of China (English)

    JIN Jiamei; ZHAO Chunsheng

    2008-01-01

    A novel traveling wave ultrasonic motor was proposed.The structure of the motor is rather simple and different from the conventional traveling wave ultra.sonic motors.Its production processes are very convenient.It is composed of a stator constituted with a ring and a bar shaped transducer and two cone shaped rotors.The rotors were pressed on inner surface of the ring by means of a pre-pressure system.The bar shaped transducer has a sandwich-like configuration,where two sets of piezoelectric element are bolted.One set excites a longitudinal vibration of the bar,and the other set excites a flexural vibration of the bar.The ring's traveling wave excited with the longitudinal vibration and the bending vibration of the bar transducer was simulated with FEM (finite element method).The prototype of the motor was made and investigated experimentally for its performance.Its maximum torque and ro

  1. Wave propagation in layered piezoelectric rectangular bar: an extended orthogonal polynomial approach.

    Science.gov (United States)

    Yu, J G; Zhang, Ch; Lefebvre, J E

    2014-08-01

    Wave propagation in multilayered piezoelectric structures has received much attention in past forty years. But the research objects of previous research works are only for semi-infinite structures and one-dimensional structures, i.e., structures with a finite dimension in only one direction, such as horizontally infinite flat plates and axially infinite hollow cylinders. This paper proposes an extension of the orthogonal polynomial series approach to solve the wave propagation problem in a two-dimensional (2-D) piezoelectric structure, namely, a multilayered piezoelectric bar with a rectangular cross-section. Through numerical comparison with the available reference results for a purely elastic multilayered rectangular bar, the validity of the extended polynomial series approach is illustrated. The dispersion curves and electric potential distributions of various multilayered piezoelectric rectangular bars are calculated to reveal their wave propagation characteristics.

  2. 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.

  3. Traveling wave ultrasonic motor using polymer-based vibrator

    Science.gov (United States)

    Wu, Jiang; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

    2016-01-01

    With the characteristics of low density, low elastic modulus, and low mechanical loss, poly(phenylene sulfide) (PPS) is a promising material for fabricating lightweight ultrasonic motors (USMs). For the first time, we used PPS to fabricate an annular elastomer with teeth and glued a piece of piezoelectric-ceramic annular disk to the bottom of the elastomer to form a vibrator. To explore for a material suitable for the rotor surface coming in contact with the PPS-based vibrator, several disk-shaped rotors made of different materials were fabricated to form traveling wave USMs. The polymer-based USM rotates successfully as the conventional metal-based USMs. The experimental results show that the USM with the aluminum rotor has the largest torque, which indicates that aluminum is the most suitable for the rotor surface among the tested materials.

  4. Design and simulation of a novel impact piezoelectric linear-rotary motor

    Science.gov (United States)

    Han, Liling; Zhao, Yahui; Pan, Chengliang; Yu, Liandong

    2016-01-01

    This paper presents a novel impact piezoelectric linear-rotary motor which is driven by a single piezoceramic tube with two parts of electrodes. From the inner and outer electrodes, longitudinal displacement of the tube is generated and used to actuate the shaft with linear motion ability. From the grooved helical interdigitated electrodes, torsional displacement is generated and used to actuate the shaft with rotary motion ability. Working principle and structural design of the motor are introduced and quasi-static longitudinal and torsional displacements of the tube are estimated. With established kinematics model of the motor, the working behaviors of the motor are investigated numerically with MATLAB/Simulink software. The stepping characteristics of the linear and rotary motions are analyzed, compared, and discussed. With optimized material selection, structural design, and driving parameters, the proposed linear-rotary motor will provide remarkable performances as a miniaturized multi-degree driving device for complex positioning and manipulation applications.

  5. Speed Estimation of Adaptive Fuzzy-Controlled Piezo-Electric Motor using MLP-Neural Network

    Directory of Open Access Journals (Sweden)

    Shebel ALSABBAH

    2008-01-01

    Full Text Available The speed of ultrasonic motor of piezo-electric type is usually measured using mechanical sensors such as pulse encoders. However, these sensors are costly and bulky. In this paper, a numerical speed estimation approach of a piezo-electric motor (PEM is implemented using multi-layer perception neural network (MLP-NN. The proposed model evaluates rotational speed and load torque based on the amplitude and driving frequency of the terminal voltage, considering the temperature variation. The estimated speed is employed to enhance the performance of the adaptive-fuzzy based speed control system. The model is validated and examined to achieve a minimized relative error in speed estimation approaches.

  6. Functionally graded piezoelectric materials for modal transducers for exciting bulk and surface acoustic waves.

    Science.gov (United States)

    Yang, Jiashi; Jin, Zhihe; Li, Jiangyu

    2008-07-01

    We show that functionally graded piezoelectric materials can be used to make modal actuators through theoretical analyses of the excitation of extensional motion in an elastic rod and Rayleigh surface waves over an elastic half-plane. The results suggest alternatives with certain advantages for the excitation of bulk and surface acoustic waves.

  7. 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.

  8. Three-degree-of-freedom ultrasonic motor using a 5-mm-diameter piezoelectric ceramic tube.

    Science.gov (United States)

    Mingsen Guo; Junhui Hu; Hua Zhu; Chunsheng Zhao; Shuxiang Dong

    2013-07-01

    A small three-degree-of-freedom ultrasonic motor has been developed using a simple piezoelectric lead zirconate titanate (PZT)-tube stator (OD 5 mm, ID 3 mm, length 15 mm). The stator drives a ball-rotor into rotational motion around one of three orthogonal (x-, y-, and z-) axes by combing the first longitudinal and second bending vibration modes. A motor prototype was fabricated and characterized; its performance was superior to those of previous motors made with a PZT ceramic/metal composite stator of comparable size. The method for further improving the performance was discussed. The motor can be further miniaturized and it has potential to be applied to medical microrobots, endoscopes or micro laparoscopic devices, and cell manipulation devices.

  9. Recession in a linear stepper motor based on piezoelectric actuator and electrorheological clampers

    Science.gov (United States)

    Li, Cuihong; Meng, Yonggang; Tian, Yu

    2012-12-01

    A linear inchworm-type stepper motor based on piezoelectric actuator and comb shape electrorheological (ER) clampers was developed and tested. A recession phenomenon in the movement of the motor was found and was significantly affected by the driving voltage of the piezoelectric actuator and ER fluids. A dynamic model to analyze the mechanism of the recession was established. The force ratio of the viscoelastic clamping force (applied high electric field) to the viscous damping force (zero field) of ER fluids is the critical factor which determines the recession. The ratio is also affected by the extension or contraction rate of the actuator during movement, which is affected by the charging and discharging processes. With a relatively large distance between the clamper electrodes and a small displacement activated by the extension of the piezoelectric actuator, the instantaneous shear rate might not be sufficiently high, preventing ER fluids from attaining a shear-thickened and high-strength state. The ratio of yield strength to the viscous strength of ER fluids during movement should be as large as possible to reduce the recession displacement.

  10. Effect of an imperfect interface on the SH wave propagating in a cylindrical piezoelectric sensor.

    Science.gov (United States)

    Li, Yong-Dong; Yong Lee, Kang

    2010-04-01

    Under harsh in situ conditions, the interface in piezoelectric sensors may be damaged mechanically and/or electrically. The damaged interface would in turn affect the electromechanical behaviors of the sensors. The purpose of the present work is to study the effect of the imperfect interface on SH wave propagating in a cylindrical piezoelectric sensor. The dispersion relations of SH wave are derived analytically and the phase velocity are obtained numerically. Parametric studies on the phase velocity indicate that the mechanical imperfection may reduce the phase velocity under certain circumstances; however, the electrical imperfection has no obvious effect on the phase velocity in any cases; with the thickness of the piezoelectric layer increasing, the phase velocity may increase, decrease or keep unchanged, depending on the combination of the values of the wave number and the mechanical imperfection parameter.

  11. Numerical simulation of ultrasonic waves in an isotropic elastic layer with a piezoelectric actuator

    Directory of Open Access Journals (Sweden)

    Andrey V. Pivkov

    2016-12-01

    Full Text Available This paper is dedicated to finite-element modeling (FEM of elastic waves caused by the work of a piezoactuator. For this purpose, a mathematical model of the ‘elastic layer—piezoelectric element’ system has been developed. In the terms of the model, the simultaneous solution of the piezoelectricity and the solid-mechanics equations was employed. This model allowed us to describe the propagation process of high-frequency mechanical vibrations caused by the application of the probing electrical pulse to the electrodes of the piezoelectric element (the vibrations occur in the elastic layer and to reproduce the potential difference arising in the reception of the reflected wave. The influence of t-parameters of the FEM and numerical integration scheme on the calculation results was investigated. The essential sensitivity of the reflected-wave's delay-time to the integrating time-step was found.

  12. Radiation and scattering analysis of piezoelectric transducers using finite and infinite wave envelope elements

    Science.gov (United States)

    Kim, Jaehwan; Jung, Eunmi; Choi, Seung-Bok

    2002-07-01

    This paper presents a numerical modeling technique of piezoelectric transducers by taking into account wave radiation and scattering. It is based on the finite element modeling. Coupling problems between piezoelectric and elastic materials as well as fluid and structure systems associated with the modeling of piezoelectric underwater acoustic sensors are formulated. In the finite element modeling of unbounded acoustic fluid, IWEE (Infinite Wave Envelop Element) is adopted to take into account the infinite domain. The IWEE code is added to an in-house finite element program, and commercial pre and post-processor are used for mesh generation and to see the output. The validation of the numerical modeling is proved through an example, and scattering and radiation analysis of Tonpilz transducer is performed. The scattered wave on the sensor is calculated, and the sensor response, so called RVS (Receiving Voltage Sensitivity) is predicted.

  13. Design and experiments of a linear piezoelectric motor driven by a single mode

    Science.gov (United States)

    Liu, Zhen; Yao, Zhiyuan; Li, Xiang; Fu, Qianwei

    2016-11-01

    In this contribution, we propose a novel linear piezoelectric motor with a compact stator that is driven by a single mode. The linear piezoelectric motor can realize bidirectional motion by changing the vibration modes of the stator. Finite element analysis is performed to determine the required vibration mode of the stator and obtain the optimal stator structure and dimensions. Furthermore, the trajectories of the driving foot are analyzed with and without consideration of the mechanical contact with the slider. It is shown that the trajectory of the driving foot is an oblique line when disregarding the contact, and the trajectory becomes an oblique ellipse while taking into account the contact. Finally, a prototype of the motor is fabricated based on the results of finite element analysis. The optimization results show that the motor reaches its maximum thrust force of 4.0 kg, maximum thrust-weight ratio of 33.3, maximum unloaded velocity of 385 mm/s under the excitation of Mode-B, and maximum unloaded velocity of 315 mm/s under the excitation of Mode-L.

  14. The surface effect on axisymmetric wave propagation in piezoelectric cylindrical shells

    Directory of Open Access Journals (Sweden)

    Yunying Zhou

    2015-02-01

    Full Text Available Based on the surface piezoelectricity theory and first-order shear deformation theory, the surface effect on the axisymmetric wave propagating in piezoelectric cylindrical shells is analyzed. The Gurtin–Murdoch theory is utilized to get the nontraditional boundary conditions and constitutive equations of the surface, in company with classical governing equations of the bulk, from which the basic formulations are obtained. Numerical results show that the surface layer has a profound effect on wave characteristics in nanostructure at a higher mode.

  15. Study of a stator of a piezoelectric rotary ultrasonic motor

    OpenAIRE

    Rebollo Sancho, Gonzalo

    2015-01-01

    En este estudio es presentado un modelo matemático y los resultados de simulación numérica que son parte del estudio acerca de la dinámica del estator de un motor ultrasónico de onda viajera. El estator está dividido principalmente en tres partes; Un anillo de material piezoeléctrico, un adhesivo y un anillo metálico que transmite las ondas vibratorias al rotor. El momento giratorio es producido por la excitación del estator con una onda de flexión transmitida al rotor a través de la fricción...

  16. Amplification and absorption of acousto-electric waves in the system of piezoelectric rhombic crystal of 222 class and semiconductor

    Directory of Open Access Journals (Sweden)

    Danoyan Z.N.

    2008-03-01

    Full Text Available The reflection, amplification and absorption of plane electro-elastic shear wave from the boundary of piezoelectric rhombic crystal of 222 class and semiconductor in the absence of acoustic contact is considered. The wave fields' in the piezoelectric crystal and semiconductor are found. The amplitude ratios of arising waves are determined. It is shown, that in the crystal the attendant surface waves are occurred, in consequence of which, the amplification is took place.

  17. Bleustein-Gulyaev waves in a functionally graded piezoelectric material layered structure

    Institute of Scientific and Technical Information of China (English)

    CAO Xiaoshan; JIN Feng; WANG ZiKun; LU TianJian

    2009-01-01

    This work presents a theoretical study of the propagation behavior of Bleustein-Gulyaev waves in a layered structure consisting of a functionally graded piezoelectric material (FGPM) layer and a trans-versely isotropic piezoelectric substrate. The influence of the graded variation of FGPM coefficients on the dispersion relations of Bleustein-Gulyaev waves in the layered structure is investigated. It is dem-onstrated that, for a certain frequency range of Bleustein-Gulyaev waves, the mechanical perturbations of the particles are restricted in the FPGM layer and the phase velocity is independent of the electrical boundary conditions at the free surface. Results presented in this study can not only provide further Insight on the electromechanical coupling behavior of surface waves in FGPM layered structures, but also lend a theoretical basis for the design of high-performance surface acoustic wave (SAW) devices.

  18. Bleustein-Gulyaev waves in a functionally graded piezoelectric material layered structure

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This work presents a theoretical study of the propagation behavior of Bleustein-Gulyaev waves in a layered structure consisting of a functionally graded piezoelectric material(FGPM) layer and a transversely isotropic piezoelectric substrate. The influence of the graded variation of FGPM coefficients on the dispersion relations of Bleustein-Gulyaev waves in the layered structure is investigated. It is demonstrated that,for a certain frequency range of Bleustein-Gulyaev waves,the mechanical perturbations of the particles are restricted in the FPGM layer and the phase velocity is independent of the electrical boundary conditions at the free surface. Results presented in this study can not only provide further insight on the electromechanical coupling behavior of surface waves in FGPM layered structures,but also lend a theoretical basis for the design of high-performance surface acoustic wave(SAW) devices.

  19. Spatial bandwidth enlargement and field enhancement of shear horizontal waves in finite graded piezoelectric layered media

    KAUST Repository

    Xu, Yanlong

    2015-09-01

    Shear horizontal (SH) wave propagation in finite graded piezoelectric layered media is investigated by transfer matrix method. Different from the previous studies on SH wave propagation in completely periodic layered media, calculations on band structure and transmission in this paper show that the graded layered media possess very large band gaps. Harmonic wave simulation by finite element method (FEM) confirms that the reason of bandwidth enlargement is that waves within the band gap ranges are spatially enhanced and stopped by the corresponding graded units. The study suggests that the graded structure possesses the property of manipulating elastic waves spatially, which shows potential applications in strengthening energy trapping and harvesting. © 2015.

  20. Wave propagation through an inhomogeneous slab sandwiched by the piezoelectric and the piezomagnetic half spaces.

    Science.gov (United States)

    Jiao, Fengyu; Wei, Peijun; Li, Li

    2017-01-01

    Wave propagation through a gradient slab sandwiched by the piezoelectric and the piezomagnetic half spaces are studied in this paper. First, the secular equations in the transverse isotropic piezoelectric/piezomagnetic half spaces are derived from the general dynamic equation. Then, the state vectors at piezoelectric and piezomagnetic half spaces are related to the amplitudes of various possible waves. The state transfer equation of the functionally graded slab is derived from the equations of motion by the reduction of order, and the transfer matrix of the functionally gradient slab is obtained by solving the state transfer equation with the spatial-varying coefficient. Finally, the continuous interface conditions are used to lead to the resultant algebraic equations. The algebraic equations are solved to obtain the amplitude ratios of various waves which are further used to obtain the energy reflection and transmission coefficients of various waves. The numerical results are shown graphically and are validated by the energy conservation law. Based on the numerical results on the fives of gradient profiles, the influences of the graded slab on the wave propagation are discussed. It is found that the reflection and transmission coefficients are obviously dependent upon the gradient profile. The various surface waves are more sensitive to the gradient profile than the bulk waves.

  1. Numerical comparison of patch and sandwich piezoelectric transducers for transmitting ultrasonic waves

    Science.gov (United States)

    Loveday, Philip W.

    2006-03-01

    Guided wave ultrasonic inspection is becoming an important method of non-destructive testing for long, slender structures such as pipes and rails. Often it is desirable to use transducers that can strongly excite a specific mode of wave propagation in the waveguide. Piezoelectric patch transducers are frequently employed, by researchers, for exciting waves in beam like structures. Sonar systems frequently make use of resonant transducers, such as sandwich transducers, for acoustic wave generation and this principle has been used to excite waves in a rail. This paper compares the two transduction approaches, for launching bending waves in rectangular waveguides, with numerical modeling. The numerical modeling combined a waveguide finite element model, of the waveguide, with conventional three-dimensional piezoelectric finite element models of the transducers. The waveguide finite elements were formulated using a complex exponential to describe the wave propagation along the structure and conventional finite element interpolation over the area of the element. Consequently, only a two-dimensional finite element mesh covering the cross-section of the waveguide is required. The harmonic forced response of the waveguide was used to compute a complex dynamic stiffness matrix which represented the waveguide in the transducer model. The effects of geometrical parameters of patch and sandwich transducers were considered before the comparison was made. It appears that piezoelectric patch transducers offer advantages at low frequencies while sandwich transducers are superior at high frequencies, where resonance can be exploited, at the cost of more complex design.

  2. The effect of initial stress on the propagation behavior of SH waves in piezoelectric coupled plates.

    Science.gov (United States)

    Son, Myung Seob; Kang, Yeon June

    2011-05-01

    This study analytically investigates the propagation of shear waves (SH waves) in a coupled plate consisting of a piezoelectric layer and an elastic layer with initial stress. The piezoelectric material is polarized in z-axis direction and perfectly bonded to an elastic layer. The mechanical displacement and electrical potential function are derived for the piezoelectric coupled plates by solving the electromechanical field equations. The effects of the thickness ratio and the initial stress on the dispersion relations and the phase and group velocities are obtained for electrically open and mechanically free situations. The numerical examples are provided to illustrate graphically the variations of the phase and group velocities versus the wave number for the different layers comparatively. It is seen that the phase velocity of SH waves decreases with the increase of the magnitude of the initial compression stress, while it increases with the increase of the magnitude of the initial tensile stress. The initial stress has a great effect on the propagation of SH waves with the decrease of the thickness ratio. This research is theoretically useful for the design of surface acoustic wave (SAW) devices with high performance.

  3. Evaluation of polarization of embedded piezoelectrics by the thermal wave method.

    Science.gov (United States)

    Suchaneck, Gunnar; Eydam, Agnes; Hu, Wenguo; Kranz, Burkhart; Drossel, Welf-Guntram; Gerlach, Gerald

    2012-09-01

    This work demonstrates the benefit of the thermal wave method for the evaluation of the polarization state of embedded piezoelectrics. Two types of samples were investigated: A low-temperature co-fired ceramics (LTCC)/lead zirconate titanate (PZT) sensor-actuator and a macro-fiber composite (MFC) actuator. At modulation frequencies below 10 Hz, the pyroelectric response was governed by thermal losses to the embedding layers. Here, the sample behavior was described by a harmonically heated piezoelectric plate exhibiting heat losses to the environment characterized by a single thermal relaxation time.

  4. Excitation of fundamental shear horizontal wave by using face-shear (d36) piezoelectric ceramics

    Science.gov (United States)

    Miao, Hongchen; Dong, Shuxiang; Li, Faxin

    2016-05-01

    The fundamental shear horizontal (SH0) wave in plate-like structures is extremely useful for non-destructive testing (NDT) and structural health monitoring (SHM) as it is non-dispersive. However, currently, the SH0 wave is usually excited by electromagnetic acoustic transducers (EMAT) whose energy conversion efficiency is fairly low. The face-shear ( d 36 ) mode piezoelectrics is more promising for SH0 wave excitation, but this mode cannot appear in conventional piezoelectric ceramics. Recently, by modifying the symmetry of poled PbZr1-xTixO3 (PZT) ceramics via ferroelastic domain engineering, we realized the face-shear d 36 mode in both soft and hard PZT ceramics. In this work, we further improved the face-shear properties of PZT-4 and PZT-5H ceramics via lateral compression under elevated temperature. It was found that when bonded on a 1 mm-thick aluminum plate, the d 36 type PZT-4 exhibited better face-shear performance than PZT-5H. We then successfully excite SH0 wave in the aluminum plate using a face-shear PZT-4 square patch and receive the wave using a face-shear 0.72[Pb(Mg1/3Nb2/3)O3]-0.28[PbTiO3] (PMN-PT) patch. The frequency response and directionality of the excited SH0 wave were also investigated. The SH0 wave can be dominated over the Lamb waves (S0 and A0 waves) from 160 kHz to 280 kHz. The wave amplitude reaches its maxima along the two main directions (0° and 90°). The amplitude can keep over 80% of the maxima when the deviate angle is less than 30°, while it vanishes quickly at the 45° direction. The excited SH0 wave using piezoelectric ceramics could be very promising in the fields of NDT and SHM.

  5. Novel modeling technique for the stator of traveling wave ultrasonic motors.

    Science.gov (United States)

    Pons, José L; Rodríguez, Humberto; Ceres, Ramón; Calderón, Leopoldo

    2003-11-01

    Traveling wave ultrasonic motors (TWUM) are a promising type of piezoelectric transducers, which are based on the friction transmission of mechanical propagating waves. These waves are excited on the stator by using high Q piezoelectric ceramics. This article presents a modeling strategy, which allows for a quick and precise modal and forced analysis of the stator of TWUM. First-order shear deformation laminated plate theory is applied to annular subdomains (super-elements) of the stator. In addition to shear deformations, the model takes into account the effect of rotary inertia, the stiffness contribution of the teeth, and the linear varying thickness of the stator. Moreover, the formulation considers a more realistic function for the electric field inside the piezoelectric ceramic, i.e., a linear function, instead of the generally assumed constant electric field. The Ritz method is used to find an approximated solution for the dynamic equations. Finally, the modal response is obtained and compared against the results from classical simplified models and the finite element method. Thus, the high accuracy and short computation times of the novel strategy were demonstrated.

  6. Analyses of axisymmetric waves in layered piezoelectric rods and their composites.

    Science.gov (United States)

    Nayfeh, A H; Abdelrahman, W G; Nagy, P B

    2000-10-01

    An exact treatment of the propagation of axisymmetric waves in coaxial anisotropic assembly of piezoelectric rod systems is presented. The rod system consists of an arbitrary number of coaxial layers, each possessing transversely isotropic symmetry properties. The treatment, which is based on the transfer matrix technique, is capable of deriving the dispersion relations for a variety of situations. These include the case of a single rod system that is either embedded in an infinitely extended solid or fluid host or kept free. The procedure is also adapted to derive approximate solutions for the cases of a periodic fiber distribution in a matrix material, which model unidirectional fiber-reinforced composites. The results are numerically illustrated for a widely used piezoelectric-polymer composite. It is seen that piezoelectric coupling can significantly change the morphology of the dispersive behavior of the composite.

  7. A Methodological Review of Piezoelectric Based Acoustic Wave Generation and Detection Techniques for Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Zhigang Sun

    2013-01-01

    Full Text Available Piezoelectric transducers have a long history of applications in nondestructive evaluation of material and structure integrity owing to their ability of transforming mechanical energy to electrical energy and vice versa. As condition based maintenance has emerged as a valuable approach to enhancing continued aircraft airworthiness while reducing the life cycle cost, its enabling structural health monitoring (SHM technologies capable of providing on-demand diagnosis of the structure without interrupting the aircraft operation are attracting increasing R&D efforts. Piezoelectric transducers play an essential role in these endeavors. This paper is set forth to review a variety of ingenious ways in which piezoelectric transducers are used in today’s SHM technologies as a means of generation and/or detection of diagnostic acoustic waves.

  8. Piezoelectric responses of brittle rock mass containing quartz to static stress and exploding stress wave respectively

    Institute of Scientific and Technical Information of China (English)

    WAN Guo-xiang; LI Xi-bing; HONG Liang

    2008-01-01

    The electromagnetic emission (EME) induced from the rock containing piezoelectric materials was investigated under both static stress and exploding stress wave in the view of piezoelectric effect. The results show that the intensity of the EME induced from the rock under static stress increases with increasing stress level and loading rate; the relationship between the amplitude of theme from the rock under different modes of stress wave and elastic parameters and propagation distance was presented. The intensity of the EME relates not only to the strength and elastic moduli of rock masses, but also to the initial damage of the rock. The intensity of EME induced by stress wave reaches the highest at the explosion-center and attenuates with the propagation distance. The intensity of EME increases with increasing the elastic modulus and decreases with increasing initial damage. The results are in good agreement with the experimental results.

  9. Love waves propagation in a transversely isotropic piezoelectric layer on a piezomagnetic half-space.

    Science.gov (United States)

    Ezzin, Hamdi; Ben Amor, Morched; Ben Ghozlen, Mohamed Hédi

    2016-07-01

    A theoretical approach is taken into consideration to investigate Love wave propagation in a transversely isotropic piezoelectric layer on a piezomagnetic half-space. The magneto-electrically open and short conditions are applied to solve the problem. The phase and group velocity of the Love wave is numerically calculated for the magneto-electrically open and short cases, respectively. The variations of magneto-electromechanical coupling factor, mechanical displacements, electric and magnetic potentials along the thickness direction of the layers are obtained and discussed. The numerical results clearly show the influence of different stacking sequences on dispersion curves and on magneto-electromechanical coupling factor. This work may be relevant to analysis and design of various acoustic surface wave devices constructed from piezoelectric and piezomagnetic materials.

  10. A smooth impact rotation motor using a multi-layered torsional piezoelectric actuator.

    Science.gov (United States)

    Morita, T; Yoshida, R; Okamoto, Y; Kurosawa, M K; Higuchi, T

    1999-01-01

    A smooth impact rotation motor was fabricated and successfully operated using a torsional piezo actuator. Yoshida et al. reported a linear type smooth impact motor in 1997. This linear motor demonstrated a high output force and a long stroke. A superior feature of the smooth impact drive is a high positioning resolution compared with an impact drive. The positioning resolution of SIDM (smooth impact drive mechanism) is equal to the piezo displacement. The reported positioning resolution of the linear type was 5 nm. Our rotation motor utilized a torsional actuator containing multi-layered piezoelectric material. The torsional actuator was cylindrical in shape with an outer diameter of 15 mm, an inner diameter of 10 mm, and a length of 11 mm. Torsional vibration performance was measured with a laser Doppler vibrometer. The obtained torsional displacement agreed with the calculated values and was sufficient to drive a rotor. The rotor was operated with a saw-shaped input voltage (180 V; 8 kHz). The revolution direction was reversible. The maximum revolution speed was 27 rpm, and the maximum output torque was 56 gfcm. In general, smooth-impact drives do not show high efficiency; however, the level of efficiency of our results (max., 0.045%) could be increased by improving the contact surface material. In addition, we are studying quantitative consideration, for example, about the optimum pre-load or frictional force.

  11. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  12. A wave-based design of semi-active piezoelectric composites for broadband vibration control

    Science.gov (United States)

    Fan, Y.; Collet, M.; Ichchou, M.; Li, L.; Bareille, O.; Dimitrijevic, Z.

    2016-05-01

    This paper deals with the design of periodic piezoelectric structures for broadband vibration control. By shunting identical negative capacitances to the periodically distributed piezoelectric patches, a wide and continuous band gap is created so as to cover the frequency range of interest. This way the modal density of the structure is reduced and the modal shapes are localized at the boundaries. A large proportion of the energy can then be removed or dissipated by a small number of dampers or energy harvesters integrated within the negative capacitance circuits. A design process is proposed to achieve the wide band gap. The overall amount of piezoelectric materials is constrained in order to keep mass of structures low. The wave electromechanical coupling factor is proposed and used as a criterion. This allows to reach the largest width of the band gap by using a stable value of negative capacitance. The control of multiple high-order modes of a cantilever beam is considered as an example. The vibration reduction performance of the designed piezoelectric structures is presented and the influences of band gap resonance, resistor and the boundary condition are discussed. The proposed approach is fully based on wave characteristics and it does not rely on any modal information. It is therefore promising for applications at mid- and high frequencies where the access to the exact modal information is difficult.

  13. Amplification of surface acoustic waves by transverse electric current in piezoelectric semiconductors

    DEFF Research Database (Denmark)

    Gulyaev, Yuri V.

    1974-01-01

    It is shown that the principal characteristic feature of the surface acoustic waves in piezoelectrics—the presence of an alternating electric field transverse to the surface, which can be of the same order of magnitude as the longitudinal field—may not only give rise to the known transverse...... acoustoelectric effect but also lead to amplification of surface acoustic waves by electron drift perpendicular to the surface. For Love waves in a piezoelectric semiconductor film on a highly conducting substrate, the amplification coefficient is found and the conditions necessary for amplification...

  14. Hybrid Modelling of a Traveling Wave Piezoelectric Motor

    DEFF Research Database (Denmark)

    El, Ghouti N.

    torque at low speed, quiet operation (ultrasonic), simple structure, compactness in size and no electromagnetic interferences. However, the mathematical model of the PEM is complex and difficult to derive due to its driving principle based on high-frequency mechanical vibrations and frictional force...... the performance characteristics of the PEM under various working conditions. The main objective of this PhD project is to derive a suitable model for investigating some nonlinear control strategies in a simulated environment. Most of the existing modeling approaches are inappropriate for the control community due......) and finally the basic laws of dynamics. In order to overcome some of the drawbacks of the existing methods, and thereby meet the needs of the control community, three main approaches are considered in this modeling task. First, the equivalent circuit method is investigated in order to derive a lumped model...

  15. Guided wave structural health monitoring with an array of novel piezoelectric transducers

    Science.gov (United States)

    Lesky, A.; Lissenden, C. J.

    2014-02-01

    Multi-element, conformable piezoelectric strip transducers have been designed and fabricated for structural health monitoring using ultrasonic guided waves. The piezoelectric fiber composite elements function as a strip transducer to activate a planar wave. A mockup of a storage tank or pressure vessel has been constructed from a steel shell and a hexagonal array of strip transducers. A hot spot to which artificial damage has been induced is monitored with the strip transducers. In addition, conventional piezoelectric disks have also been affixed to the shell in a circular pattern for the purpose of comparison. Different operating conditions are represented by the presence of water inside the shell and temperature variations between 20 and 35°C. The strip transducers have been designed to excite the S1 Lamb wave mode at the dilatational wave speed, which is oblivious to the presence of liquid loaded boundary conditions. An artificial defect simulated a surface breaking fatigue crack. Preliminary results are presented for baseline and damaged conditions using transmission and reflection coefficients as a damage-sensitive feature. At the request of the Proceedings Editor, and all authors of the paper, an updated version of this article was published on 8 April 2014. The Corrigendum attached to the corrected article PDF file explains the changes made to the original paper.

  16. Love waves in functionally graded piezoelectric materials by stiffness matrix method.

    Science.gov (United States)

    Ben Salah, Issam; Wali, Yassine; Ben Ghozlen, Mohamed Hédi

    2011-04-01

    A numerical matrix method relative to the propagation of ultrasonic guided waves in functionally graded piezoelectric heterostructure is given in order to make a comparative study with the respective performances of analytical methods proposed in literature. The preliminary obtained results show a good agreement, however numerical approach has the advantage of conceptual simplicity and flexibility brought about by the stiffness matrix method. The propagation behaviour of Love waves in a functionally graded piezoelectric material (FGPM) is investigated in this article. It involves a thin FGPM layer bonded perfectly to an elastic substrate. The inhomogeneous FGPM heterostructure has been stratified along the depth direction, hence each state can be considered as homogeneous and the ordinary differential equation method is applied. The obtained solutions are used to study the effect of an exponential gradient applied to physical properties. Such numerical approach allows applying different gradient variation for mechanical and electrical properties. For this case, the obtained results reveal opposite effects. The dispersive curves and phase velocities of the Love wave propagation in the layered piezoelectric film are obtained for electrical open and short cases on the free surface, respectively. The effect of gradient coefficients on coupled electromechanical factor, on the stress fields, the electrical potential and the mechanical displacement are discussed, respectively. Illustration is achieved on the well known heterostructure PZT-5H/SiO(2), the obtained results are especially useful in the design of high-performance acoustic surface devices and accurately prediction of the Love wave propagation behaviour.

  17. Auto-Gopher: A Wireline Deep Sampler Driven by Piezoelectric Percussive Actuator and EM Rotary Motor

    Science.gov (United States)

    Badescu, Mircea; Ressa, Aaron; Jae Lee, Hyeong; Bar-Cohen, Yoseph; Sherrit, Stewart; Zacny, Kris; Paulsen, Gale L.; Beegle, Luther; Bao, Xiaoqi

    2013-01-01

    The ability to penetrate subsurfaces and perform sample acquisition at depth of meters may be critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars and Europa. A corer/sampler was developed with the goal of enabling acquisition of samples from depths of several meters where if used on Mars would be beyond the oxidized and sterilized zone. For this purpose, we developed a rotary-hammering coring drill, called Auto-Gopher, which employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor that rotates the bit to remove the powdered cuttings. This sampler is a wireline mechanism that can be fed into and retrieved from the drilled hole using a winch and a cable. It includes an inchworm anchoring mechanism allowing the drill advancement and weight on bit control without twisting the reeling and power cables. The penetration rate is being optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism that is driven by piezoelectric stack and that was demonstrated to require low axial preload. The design and fabrication of this device were presented in previous publications. This paper presents the results of laboratory and field tests and lessons learned from this development.

  18. Auto-Gopher: a wireline deep sampler driven by piezoelectric percussive actuator and EM rotary motor

    Science.gov (United States)

    Badescu, Mircea; Ressa, Aaron; Lee, Hyeong Jae; Bar-Cohen, Yoseph; Sherrit, Stewart; Zacny, Kris; Paulsen, Gale L.; Beegle, Luther; Bao, Xiaoqi

    2013-04-01

    The ability to penetrate subsurfaces and perform sample acquisition at depth of meters may be critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars and Europa. A corer/sampler was developed with the goal of enabling acquisition of samples from depths of several meters where if used on Mars would be beyond the oxidized and sterilized zone. For this purpose, we developed a rotary-hammering coring drill, called Auto-Gopher, which employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor that rotates the bit to remove the powdered cuttings. This sampler is a wireline mechanism that can be fed into and retrieved from the drilled hole using a winch and a cable. It includes an inchworm anchoring mechanism allowing the drill advancement and weight on bit control without twisting the reeling and power cables. The penetration rate is being optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism that is driven by piezoelectric stack and that was demonstrated to require low axial preload. The design and fabrication of this device were presented in previous publications. This paper presents the results of laboratory and field tests and lessons learned from this development.

  19. Nonmagnetic driver for piezoelectric actuators

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh

    2014-01-01

    Piezoelectric actuator drive aims to enable reliable motor performance in strong magnetic fields for magnetic res- onance imaging and computed tomography treatment tables. There are technical limitations in operation of these motors and drive systems related to magnetic interference. Piezoelectric...... actuators. Therefore, piezoelectric transformer-based power converters are used for driving piezoelectric actuator drive motor in the presence of high electromagnetic field....

  20. Piezoelectric transducer parameter selection for exciting a single mode from multiple modes of Lamb waves

    Institute of Scientific and Technical Information of China (English)

    Rang Hai-Yan; Yu Jian-Bo

    2011-01-01

    Excitation and propagation of Lamb waves by using rectangular and circular piezoelectric transducers surfacebonded to an isotropic plate are investigated in this work. Analytical stain wave solutions are derived for the two transducer shapes,giving the responses of these transducers in Lamb wave fields. The analytical study is supported by a numerical simulation using the finite element method. Symmetric and antisymmetric components in the wave propagation responses are inspected in detail with respect to test parameters such as the transducer geometry,the length and the excitation frequency. By placing only one piezoelectric transducer on the top or the bottom surface of the plate and weakening the strength of one mode while enhancing the strength of the other modes to find the centre frequency,with which the peak wave amplitude ratio between the S0 and A0 modes is maximum,a single mode excitation from the multiple modes of the Lamb waves can be achieved approximately. Experimental data are presented to show the validity of the analyses. The results are used to optimize the Lamb wave detection system.

  1. Imaging mechanical shear waves induced by piezoelectric ceramics in magnetic resonance elastography

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Magnetic Resonance Elastography (MRE) is a noninvasive technique to measure elasticity of tissues in vivo. In this paper, a mechanical shear wave MR imaging system experiment is set for MRE. A novel actuator is proposed to generate mechanical shear waves propagating inside a gel phantom. The actuator is made of piezoelectric ceramics, and fixed on a plexiglass bracket. Both of the gel phantom and the actuator are put into a head coil inside the MR scanner's bore. The actuator works synchronously with an MR imaging sequence running on the MR scanner. The sequence is modified from a FLASH sequence into a motion-sensitizing phase- contrast sequence for shear wave MR imaging. Shear wave images are presented, and these effects on the shear wave MR imaging system, including the stiffness of phantoms, the frequency of the actuator, the parameters of the motion-sensitizing gradient, and the oscillation of the patient bed, are discussed.

  2. Surface Electroelastic Love Waves in Layered System with a Piezoelectric Substrate and Two Isotropic Layers of Any Thickness

    Directory of Open Access Journals (Sweden)

    Danoyan Z.N.

    2009-09-01

    Full Text Available In the article the existence and behaviour of electroelastic Love waves in three-layered system of a piezoelectric substrate of classes 6, 4, 6mm, 4mm and attached to her two isotropic layers (conductor-dielectric, conductor-conductor of any thickness is investigated, depending on the physicomechanical characteristics of layered system and relative thicknesses of layers. The characteristic equation of a required surface wave is investigated in case of a basic soft layer. The research is based on properties of the electromechanical factor of surface wave given in the work [1-5]. Existence of a Love wave of a gap type caused by extremely piezoelectric effect in particular is shown. The structure and behavior of modes of Love waves are investigated. The qualitative diagrams of “dispersive” curves of modes of Love waves are given . The relation between electroelastic Love waves, pure-elastic Love waves, and Bleustein-Gulyaev waves is discussed.

  3. Analysis of Longitudinal Waves in Rod-Type Piezoelectric Phononic Crystals

    Directory of Open Access Journals (Sweden)

    Longfei Li

    2016-04-01

    Full Text Available Phononic crystals can be used to control elastic waves due to their frequency bands. This paper analyzes the passive and active control as well as the dispersion properties of longitudinal waves in rod-type piezoelectric phononic crystals over large frequency ranges. Based on the Love rod theory for modeling the longitudinal wave motions in the constituent rods and the method of reverberation-ray matrix (MRRM for deriving the member transfer matrices of the constituent rods, a modified transfer matrix method (MTMM is proposed for the analysis of dispersion curves by combining with the Floquet–Bloch principle and for the calculation of transmission spectra. Numerical examples are provided to validate the proposed MTMM for analyzing the band structures in both low and high frequency ranges. The passive control of longitudinal-wave band structures is studied by discussing the influences of the electrode’s thickness, the Poisson’s effect and the elastic rod inserts in the unit cell. The influences of electrical boundaries (including electric-open, applied electric capacity, electric-short and applied feedback control conditions on the band structures are investigated to illustrate the active control scheme. From the calculated comprehensive frequency spectra over a large frequency range, the dispersion properties of the characteristic longitudinal waves in rod-type piezoelectric phononic crystals are summarized.

  4. Excitation of waves in elastic waveguides by piezoelectric patch actuators

    CSIR Research Space (South Africa)

    Loveday, PW

    2006-01-01

    Full Text Available to be an infinite waveguide. The excitation of waves in waveguides may be analysed in the time domain using conventional finite element methods. This analysis is computationally very demanding as the model must be a number of wavelengths long to avoid the influence...

  5. Science Letters: New solutions of shear waves in piezoelectric cubic crystals

    Institute of Scientific and Technical Information of China (English)

    ZAKHARENKO A.A.

    2007-01-01

    Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 (-43m) of the Chalcogenide family and the crystal Bi12TiO20 (23) possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves (SH-SAWs) are found in the monocrystals using different electrical boundary conditions such as electrically "short" and "open" free-surfaces for the unique [ 101] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling (CEMC) Ke2=e2/(C×g)~1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula: Vph=(Va+Vt)/2, where Vt is the speed of bulk SH-wave, Vt=Vt4(1+Ke2)1/2, Va=aKVt4, aK=2[Ke(1+Ke2)1/2-Ke2]1/2,and Vt4=(C44/ρ)1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K2=2(Vf-Vm)/Vf~O.047 (~4.7%),where Vf~848 m/s and Vm~828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of K2(Tl3TaSe4) is significantly greater than K2(Tl3VS4)~3% and about five times that of K2(Bi12TiO20).

  6. A flexible, wave-shaped P(VDF-TrFE)/metglas piezoelectric composite for wearable applications

    Science.gov (United States)

    You, Sujian; Shi, Huaduo; Wu, Jingen; Shan, Liang; Guo, Shishang; Dong, Shuxiang

    2016-12-01

    In this work, a wave-shaped piezoelectric composite (WSPC) made of fine β-phase vinylidene fluoride trifluoroethylene copolymer (P(VDF-TrFE)) polymer and high-elastic FeSiB amorphous alloy (metglas) ribbon has been successfully fabricated for wearable device applications. X-ray diffraction and the Fourier Transform Infrared Spectrum studies reveal P(VDF-TrFE) exhibiting the fine β-phase. Both theoretical analysis and experimental results show that unique wave-shaped structure enhances the electromechanical coupling significantly, because of the combination piezoelectric effects of d33 and d31 modes in P(VDF-TrFE) polymer, as well as the enhanced effective piezoelectric coefficient caused by the pre-stretch in P(VDF-TrFE) film. Two application examples of WSPC, (i) mechanical force sensor or energy harvester, and (ii) the medical blood-pressure pulse sensor, have been investigated, which show that the WSPC is a promising candidate for future wearable device applications.

  7. High-fidelity simulation of a standing-wave thermoacoustic-piezoelectric engine

    CERN Document Server

    Lin, Jeffrey; Hesselink, Lambertus

    2015-01-01

    We have carried out wall-resolved fully unstructured Navier--Stokes simulations of a complete standing-wave thermoacoustic piezoelectric (TAP) engine model inspired by the experimental work of Smoker et al. (2012). The computational model is axisymmetric and comprises a 51 cm long cylindrical resonator divided into two sections: one of 19.5 mm in diameter, enclosing a thermoacoustic stack where a linear temperature distribution is imposed via isothermal boundary conditions; the other of 71 mm in diameter, capped by a piezoelectric diaphragm modelled via multi-oscillator broadband time-domain impedance boundary conditions (TDIBCs) matching the measured electromechanical impedance of a PZT-5A diaphragm tuned to the thermoacoustically amplified mode (388 Hz) for maximization of acoustic energy extraction. Simulations were first carried out without energy extraction from quiescent conditions to a limit cycle, for hot-to-cold temperature differences in the range $\\Delta T = 340 - 490\\textrm{ K}$, achieving acousti...

  8. Resonance Effects of Bilayered Piezoelectric Films Used for Bulk Acoustic Wave Sensors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; ZHANG Shu-Yi; FAN Li

    2011-01-01

    The resonance vibrations of acoustic sensors with two layers of (1120) textured hexagonal piezoelectric films are studied.When the acoustic and electric fields satisfy a special match condition,i.e.the phase variation of thickness shear mode (TSM) at each film equals π,both piezoelectric layers with opposite polarization directions reduce the first TSM and generate the second TSM with higher frequency and a higher quality factor.The excited second TSM can increase the product of the operating frequency and the quality factor,which is useful for improving the mass sensitivity and resolution of acoustic sensors.Additionally,both of the piezoelectric films have larger thickness and decrease the risk of mechanical damage in device production processes.Thin film bulk acoustic sensors have attracted great attention due to their small sizes,low power consumption and high sensitivity,etc.[1] The thickness shear mode (TSM) is more suitable for liquid sensing applications since much less acoustic energy is transferred into the liquid medium than that of longitudinal acoustic waves,due to the fact that ideal liquids cannot support propagations of shear waves.By using a TSM with a high resonance frequency,sensorsbased on thin film bulk acoustic resonator structures can be fabricated by the fixing of a sensitive coating on the surface of the device.[2] The binding events at the sensitive coating can cause a shift of the resonance frequency.[3]%The resonance vibrations of acoustic sensors with two layers of (1120) textured hexagonal piezoelectric films are studied. When the acoustic and electric fields satisfy a special match condition, I.e. The phase variation of thickness shear mode (TSM) at each film equals it, both piezoelectric layers with opposite polarization directions reduce the first TSM and generate the second TSM with higher frequency and a higher quality factor. The excited second TSM can increase the product of the operating frequency and the quality factor, which

  9. Study of the Impact of Non-linear Piezoelectric Constants on the Acoustic Wave Propagation on Lithium Niobate

    Directory of Open Access Journals (Sweden)

    C. Soumali

    2016-06-01

    Full Text Available Impact of nonlinear piezoelectric constants on surface acoustic wave propagation on a piezoelectric substrate is investigated in this work. Propagation of acoustic wave propagation under uniform stress is analyzed; the wave equation is obtained by incorporating the applied uniform stress in the equation of motion and taking account of the set of linear and nonlinear piezoelectric constants. A new method of separation between the different modes of propagation is proposed regarding the attenuation coefficients and not to the displacement vectors. Detail calculations and simulations have made for Lithium Niobate (LiNbO3; transformations between modes of propagation, under uniform stress, have been found. These results leads to conclusion that nonlinear terms affect the acoustic wave propagation and also we can make controllable acoustic devices.

  10. Pressure Distribution for Piezoelectric Extracorporeal Shock Wave Lithotripsy

    Science.gov (United States)

    Yanagida, Yuji; Iwama, Nobuyuki; Okazaki, Kiyoshi

    1993-05-01

    The objective of this study is to develop a safer and more effective extracorporeal shock wave lithotripter. The first stage of the study shows the sound pressure field of the shock wave made by an ECHOLITH ESL-500A. The sound pressure distribution is in a ring configuration on a 60 mm plane in front of the focal plane. As the plane approaches the focal plane, the sound pressure relatively increases at the cross point with the axis of the transducer and decreases at the ring. The focal zone is 2.5 mm × 16.1 mm at 60 V driving voltage and 1.8 mm × 14.2 mm at “INTENSITY 2.” In the next stage we propose a method for changing the field by electronic driving control of each piezoceramic element for effective therapy. The focal zone can be changed from 3.1 mm × 19.1 mm to 3.9 mm × 32.4 mm at 60 V driving voltage with this method. These focal zones are calculated by means of computer simulation.

  11. Method for generation of THz frequency radiation and sensing of large amplitude material strain waves in piezoelectric materials

    Science.gov (United States)

    Reed, Evan J.; Armstrong, Michael R.

    2010-09-07

    Strain waves of THz frequencies can coherently generate radiation when they propagate past an interface between materials with different piezoelectric coefficients. Such radiation is of detectable amplitude and contains sufficient information to determine the time-dependence of the strain wave with unprecedented subpicosecond, nearly atomic time and space resolution.

  12. Modeling of composite piezoelectric structures with the finite volume method.

    Science.gov (United States)

    Bolborici, Valentin; Dawson, Francis P; Pugh, Mary C

    2012-01-01

    Piezoelectric devices, such as piezoelectric traveling- wave rotary ultrasonic motors, have composite piezoelectric structures. A composite piezoelectric structure consists of a combination of two or more bonded materials, at least one of which is a piezoelectric transducer. Piezoelectric structures have mainly been numerically modeled using the finite element method. An alternative approach based on the finite volume method offers the following advantages: 1) the ordinary differential equations resulting from the discretization process can be interpreted directly as corresponding circuits; and 2) phenomena occurring at boundaries can be treated exactly. This paper presents a method for implementing the boundary conditions between the bonded materials in composite piezoelectric structures modeled with the finite volume method. The paper concludes with a modeling example of a unimorph structure.

  13. The Evaluation of Piezoelectric Contact Target Sensor Taking Account of the Wave Processes

    Directory of Open Access Journals (Sweden)

    A. K. Efremov

    2014-01-01

    Full Text Available Mechanical fuses usually do not provide high performance in the process of destruction of such objects as the armored vehicles. Shaped and armor-piercing high-explosive shells have a heading part of low strength. This prevents from achieving a required level of contact force (reaction or inertia, which is necessary for reliable operation of the target sensor. At the same time, electromechanical fuses have higher sensitivity and operating speed rates being capable of adaptive response to the conditions of shell encountering with the target. A generalized block diagram of the fuse is analysed, and a mathematical model of the piezoelectric transducer (PT as a sensing element of the fuse contact sensor target (CST is proposed. The model takes into account the empirical dependence of the relative permittivity of piezoelectric ceramics on the electric field. An approximate method of calculating the response of PT is presented. It is oriented at evaluating the propagation of a short stress pulse of high intensity, the geometric length of which is commensurate with the length of the piezoelectric element (PE. In this case significantly increases the role of wave processes in the ammunition shell and the PT itself. The calculation is based on the use of the concept of equivalent stress, which is obtained by averaging its diagrams at each time point along the PE. The method allows to analyze the sequence of loading phases passing through the PE body, which depends on the ratio of said geometrical parameters and quantitative characteristics of the output electrical signal of the transducer. An example of estimating the performance of a real piezoelectric CTS is presented. The experimentally obtained force characteristic of the head of piezoelectric fuse is taken into account as well as the encountering speed of the shell and the threshold operating level of the firing train actuator. Calculation results are in good agreement with the results of field tests

  14. Actuating mechanism and design of a cylindrical traveling wave ultrasonic motor using cantilever type composite transducer.

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    Full Text Available BACKGROUND: Ultrasonic motors (USM are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. PRINCIPAL FINDINGS: A cylindrical type traveling wave ultrasonic motor using cantilever type composite transducer was proposed in this paper. There are two cantilevers on the outside surface of cylinder, four longitudinal PZT ceramics are set between the cantilevers, and four bending PZT ceramics are set on each outside surface of cantilevers. Two degenerate flexural vibration modes spatially and temporally orthogonal to each other in the cylinder are excited by the composite transducer. In this new design, a single transducer can excite a flexural traveling wave in the cylinder. Thus, elliptical motions are achieved on the teeth. The actuating mechanism of proposed motor was analyzed. The stator was designed with FEM. The two vibration modes of stator were degenerated. Transient analysis was developed to gain the vibration characteristic of stator, and results indicate the motion trajectories of nodes on the teeth are nearly ellipses. CONCLUSIONS: The study results verify the feasibility of the proposed design. The wave excited in the cylinder isn't an ideal traveling wave, and the vibration amplitudes are inconsistent. The distortion of traveling wave is generated by the deformation of bending vibration mode of cylinder, which is caused by the coupling effect between the cylinder and transducer. Analysis results also prove that the objective motions of nodes on the teeth are three-dimensional vibrations. But, the vibration in axial direction is minute compared with the vibrations in circumferential and radial direction. The results of this paper can guide the development of this new type of motor.

  15. Frequency Dispersion of Love Waves in a Piezoelectric Nanofilm Bonded on a Semi-infinite Elastic Substrate

    Institute of Scientific and Technical Information of China (English)

    ZHANG Sijia; GU Bin; ZHANG Hongbin; PAN Rongying; Alamusi; FENG Xiqiao

    2015-01-01

    Research on the propagation of elastic waves in piezoelectric nanostructures is very limited. The frequency dispersion of Love waves in layered piezoelectric nanostructures has not yet been reported when surface effects are taken into account. Based on the surface elasticity theory, the propagation of Love waves with surface effects in a structure consisting of a nanosized piezoelectric film and a semi-infinite elastic substrate is investigated focusing on the frequency dispersion curves of different modes. The results show that under the electrically-open conditions, surface effects give rise to the dependence of Love wave dispersion on the film thickness when the thickness of the piezoelectric film reduces to nanometers. For a given wave frequency, phase velocity of Love waves in all dispersion modes exhibit obvious toward shift as the film thickness decreases or the surface parameters increase. Moreover, there may exist a cut-off frequency in the first mode dispersion below which Love waves will be evanescent in the structure due to surface effects. The cut-off frequency depends on the film thickness, the surface parameters and the bulk material properties.

  16. Lamb wave generation with piezoelectric wafer active sensors for structural health monitoring

    Science.gov (United States)

    Giurgiutiu, Victor

    2003-08-01

    The capability of embedded piezoelectric wafer active sensors (PWAS) to perform in-situ nondestructive evaluation (NDE) is explored. Theoretical developments and laboratory tests are used to prove that PWAS transducers can satisfactorily perform Lamb wave transmission and reception, pulse-echo, pitch-catch, and phased array functions of conventional ultrasonics thus opening the road for embedded ultrasonics. Subsequently, crack detection in an aircraft panel with the pulse-echo method is illustrated. For large area scanning, a PWAS phased array is used to create the embedded ultrasonics structural radar (EUSR). For quality assurance, PWAS self-tests with the electromechanical impedance method are discussed.

  17. SAFE-3D analysis of a piezoelectric transducer to excite guided waves in a rail web

    CSIR Research Space (South Africa)

    Ramatlo, DA

    2016-10-01

    Full Text Available stream_source_info Ramatlo_2016_ABSTRACT.pdf.txt stream_content_type text/plain stream_size 2038 Content-Encoding ISO-8859-1 stream_name Ramatlo_2016_ABSTRACT.pdf.txt Content-Type text/plain; charset=ISO-8859-1 AIP... Conference Proceedings, 1706, 020005, 26-31 July 2015, Minneapolis, Minnesota SAFE-3D Analysis of a Piezoelectric Transducer to Excite Guided Waves in a Rail Web Dineo A. Ramatlo1, 2, Craig S. Long2 , Philip W. Loveday2 and Daniel N. Wilke1 1...

  18. The Peano-series solution for modeling shear horizontal waves in piezoelectric plates

    Directory of Open Access Journals (Sweden)

    Ben Ghozlen M.H.

    2012-06-01

    Full Text Available The shear horizontal (SH wave devices have been widely used in electroacoustic. To improve their performance, the phase velocity dispersion and the electromechanical coupling coefficient of the Lamb wave should be calculated exactly in the design. Therefore, this work is to analyze exactly the Lamb waves polarized in the SH direction in homogeneous plate pie.zoelectric material (PZT-5H. An alternative method is proposed to solve the wave equation in such a structure without using the standard method based on the electromechanical partial waves. This method is based on an analytical solution, the matricant explicitly expressed under the Peano series expansion form. Two types of configuration have been addressed, namely the open circuited and the short circuited. Results confirm that the SH wave provides a number of attractive properties for use in sensing and signal processing applications. It has been found that the phase velocity remains nearly constant for all values of h/λ (h is the plate thickness, λ the acoustic wavelength. Secondly the SH0 wave mode can provide very high electromechanical coupling. Graphical representations of electrical and mechanical amounts function of depth are made, they are in agreement with the continuity rules. The developed Peano technique is in agreement with the classical approach, and can be suitable with cylindrical geometry.

  19. Excitation and reception of pure shear horizontal waves by using face-shear d24 mode piezoelectric wafers

    Science.gov (United States)

    Miao, Hongchen; Huan, Qiang; Li, Faxin

    2016-11-01

    The fundamental shear horizontal (SH0) wave in plate-like structures is of great importance in non-destructive testing (NDT) and structural health monitoring (SHM) as it is non-dispersive, while excitation or reception of SH0 waves using piezoelectrics is always a challenge. In this work, we firstly demonstrate via finite element simulations that face-shear piezoelectrics is superior to thickness-shear piezoelectrics in driving SH waves. Next, by using a newly defined face-shear d24 PZT wafer as an actuator and face-shear d36 PMN-PT wafers as sensors, pure SH0 wave was successfully excited in an aluminum plate from 130 to 180 kHz. Then, it was shown that the face-shear d24 PZT wafer could receive the SH0 wave only and filter the Lamb waves over a wide frequency range (120-230 kHz). The directionality of the excited SH0 wave was also investigated using face-shear d24 PZT wafers as both actuators and sensors. Results show that pure SH0 wave can be excited symmetrically along two orthogonal directions (0° and 90°) and the amplitude of the excited SH0 wave can keep over 90% of the maximum amplitude when the deviate angle is within 30°. This work could greatly promote the applications of SH0 wave in NDT and SHM.

  20. A new omnidirectional shear horizontal wave transducer using face-shear (d24) piezoelectric ring array.

    Science.gov (United States)

    Miao, Hongchen; Huan, Qiang; Wang, Qiangzhong; Li, Faxin

    2017-02-01

    The non-dispersive fundamental shear horizontal (SH0) wave in plate-like structures is of practical importance in non-destructive testing (NDT) and structural health monitoring (SHM). Theoretically, an omnidirectional SH0 transducer phased array system can be used to inspect defects in a large plate in the similar manner to the phased array transducers used in medical B-scan ultrasonics. However, very few omnidirectional SH0 transducers have been proposed so far. In this work, an omnidirectional SH0 wave piezoelectric transducer (OSH-PT) was proposed, which consists of a ring array of twelve face-shear (d24) trapezoidal PZT elements. Each PZT element can produce face-shear deformation under applied voltage, resulting in circumferential shear deformation in the OSH-PT and omnidirectional SH0 waves in the hosting plate. Both finite element simulations and experiments were conducted to examine the performance of the proposed OSH-PT. Experimental testing shows that the OSH-PT exhibits good omnidirectional properties, no matter it is used as a SH0 wave transmitter or a SH0 wave receiver. This work may greatly promote the applications of SH0 waves in NDT and SHM.

  1. Piezoelectric Love waves on rotated Y-cut mm2 substrates.

    Science.gov (United States)

    Collet, Bernard; Destrade, Michel

    2006-11-01

    Consider a layer consisting of a m3m dielectric crystal, with faces cut parallel to a symmetry plane. Then bond it onto a semi-infinite mm2 piezoelectric substrate. For a X- or Y-cut of the substrate, a Love wave can propagate in the resulting structure and the corresponding dispersion equation is derived analytically. It turns out that when the upper (free) face of the layer is metalized, a fully explicit treatment can also be conducted in the case of a Y-cut rotated about Z. In the case of a germanium layer over a potassium niobate substrate, the wave exists at any wavelength for X-and Y-cuts but this ceases to be the case for rotated cuts, with the appearance of forbidden ranges. By playing on the cut angle, the Love wave can be made to travel faster than, or slower than, or at the same speed as, the shear bulk wave of the layer. A by-product of the analysis is the derivation of the explicit secular equation for the Bleustein-Gulyaev wave in the substrate alone, which corresponds to an asymptotic behavior of the Love wave. The results are valid for other choices for the layer and for the substrate, provided they have the same, or more, symmetries.

  2. Propagation characteristics of SH wave in an mm2 piezoelectric layer on an elastic substrate

    Directory of Open Access Journals (Sweden)

    Yanping Kong

    2015-09-01

    Full Text Available We investigate the propagation characteristics of shear horizontal (SH waves in a structure consisting of an elastic substrate and an mm2 piezoelectric layer with different cut orientations. The dispersion equations are derived for electrically open and shorted conditions on the free surface of the piezoelectric layer. The phase velocity and electromechanical coupling coefficient are calculated for a layered structure with a KNbO3 layer perfectly bonded to a diamond substrate. The dispersion curves for the electrically shorted boundary condition indicate that for a given cut orientation, the phase velocity of the first mode approaches the B-G wave velocity of the KNbO3 layer, while the phase velocities of the higher modes tend towards the limit velocity of the KNbO3 layer. For the electrically open boundary condition, the asymptotic phase velocities of all modes are the limit velocity of the KNbO3 layer. In addition, it is found that the electromechanical coupling coefficient strongly depends on the cut orientation of the KNbO3 crystal. The obtained results are useful in device applications.

  3. Shear Bloch waves and coupled phonon-polariton in periodic piezoelectric waveguides.

    Science.gov (United States)

    Piliposyan, D G; Ghazaryan, K B; Piliposian, G T

    2014-02-01

    Coupled electro-elastic SH waves propagating in a periodic piezoelectric finite-width waveguide are considered in the framework of the full system of Maxwell's electrodynamic equations. We investigate Bloch-Floquet waves under homogeneous or alternating boundary conditions for the elastic and electromagnetic fields along the guide walls. Zero frequency stop bands, trapped modes as well as some anomalous features due to piezoelectricity are identified. For mixed boundary conditions, by modulating the ratio of the length of the unit cell to the width of the waveguide, the minimum widths of the stop bands can be moved to the middle of the Brillouin zone. The dispersion equation has been investigated also for phonon-polariton band gaps. It is shown that for waveguides at acoustic frequencies, acousto-optic coupling gives rise to polariton behavior at wavelengths much larger than the length of the unit cell but at optical frequencies polariton resonance occurs at wavelengths comparable with the period of the waveguide. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. A theoretical study of the propagation of Rayleigh waves in a functionally graded piezoelectric material (FGPM).

    Science.gov (United States)

    Ben Salah, Issam; Njeh, Anouar; Ben Ghozlen, Mohamed Hédi

    2012-02-01

    An exact approach is used to investigate Rayleigh waves in a functionally graded piezoelectric material (FGPM) layer bonded to a semi infinite homogenous solid. The piezoelectric material is polarized when the six fold symmetry axis is put along the propagation direction x(1). The FGPM character imposes that the material properties change gradually with the thickness of the layer. Contrary to the analytical approach, the adopted numerical methods, including the ordinary differential equation (ODE) and the stiffness matrix method (SMM), treat separately the electrical and mechanical gradients. The influences of graded variations applied to FGPM film coefficients on the dispersion curves of Rayleigh waves are discussed. The effects of gradient coefficients on electromechanical coupling factor, displacement fields, stress distributions and electrical potential, are reported. The obtained deviations in comparison with the ungraded homogenous film are plotted with respect to the dimensionless wavenumber. Opposite effects are observed on the coupling factor when graded variations are applied separately. A particular attention has been devoted to the maximum of the coupling factor and it dependence on the stratification rate and the gradient coefficient. This work provides with a theoretical foundation for the design and practical applications of SAW devices with high performance.

  5. Active tuning of vibration and wave propagation in elastic beams with periodically placed piezoelectric actuator/sensor pairs

    Science.gov (United States)

    Li, Fengming; Zhang, Chuanzeng; Liu, Chunchuan

    2017-04-01

    A novel strategy is proposed to actively tune the vibration and wave propagation properties in elastic beams. By periodically placing the piezoelectric actuator/sensor pairs along the beam axis, an active periodic beam structure which exhibits special vibration and wave propagation properties such as the frequency pass-bands and stop-bands (or band-gaps) is developed. Hamilton's principle is applied to establish the equations of motion of the sub-beam elements i.e. the unit-cells, bonded by the piezoelectric patches. A negative proportional feedback control strategy is employed to design the controllers which can provide a positive active stiffness to the beam for a positive feedback control gain, which can increase the stability of the structural system. By means of the added positive active stiffness, the periodicity or the band-gap property of the beam with periodically placed piezoelectric patches can be actively tuned. From the investigation, it is shown that better band-gap characteristics can be achieved by using the negative proportional feedback control. The band-gaps can be obviously broadened by properly increasing the control gain, and they can also be greatly enlarged by appropriately designing the structural sizes of the controllers. The control voltages applied on the piezoelectric actuators are in reasonable and controllable ranges, especially, they are very low in the band-gaps. Thus, the vibration and wave propagation behaviors of the elastic beam can be actively controlled by the periodically placed piezoelectric patches.

  6. A finite element method for modelling electromechanical wave propagation in anisotropic piezoelectric media

    CERN Document Server

    Rahman, S; Barnes, C H W

    2005-01-01

    We describe and evaluate a numerical solution strategy for simulating surface acoustic waves through semiconductor devices with complex geometries. This multi-physics problem is of particular relevance to the design of quantum electronic devices. The mathematical model consists of two coupled partial differential equations for the elastic wave propagation and the electric field, respectively, in anisotropic piezoelectric media. These equations are discretized by the finite element method in space and by a finite difference method in time. The latter method yields a convenient numerical decoupling of the governing equations. We describe how a computer implementation can utilize the decoupling and via object-oriented programming techniques reuse independent codes for the Poisson equation and the linear time-dependent elasticity equation. First we apply the simulator to a simplified model problem for verifying the implementation, and thereafter we show that the methodology is capable of simulating a real-world c...

  7. Modeling and Control Of Surface Acoustic Wave Motors

    NARCIS (Netherlands)

    Feenstra, P.J.

    2005-01-01

    This thesis introduces Rayleigh waves and describes the generation of Rayleigh waves. Furthermore, the principle of operation of a SAW motor is analyzed. The analysis is based on a contact model, which describes the behavior between slider and stator. Due to the contact model, the microscopic and

  8. Transformation of acoustic waves in periodic metal grating sandwiched between piezoelectric and dielectric.

    Science.gov (United States)

    Naumenko, Natalya F; Abbott, Benjamin P

    2011-10-01

    The mechanism of SAW transformation with variation of film thickness is investigated in a piezoelectric substrate with a metal grating overlaid by a dielectric film, via simulation and visualization of the acoustic fields. By way of example, two orientations of lithium niobate substrates are analyzed, YX-LN and 128°YX-LN, with a Cu grating and an isotropic silica glass overlay. The motions, which follow the wave propagation in the sagittal plane, are visualized within two periods of the grating, with added contour plots showing the shear horizontal displacements. The continuous transformation of the wave's nature is investigated for each wave propagating in the analyzed material structures when the film thickness is increased from zero to a few wavelengths. The examples of the SAW transformation into boundary waves and into plate modes of different polarization have been found and investigated. The behavior of the SAW characteristics in the grating is correlated with transformation of the wave structure with increasing overlay thickness.

  9. Calculations of Lamb wave band gaps and dispersions for piezoelectric phononic plates using mindlin's theory-based plane wave expansion method.

    Science.gov (United States)

    Hsu, Jin-Chen; Wu, Tsung-Tsong

    2008-02-01

    Based on Mindlin's piezoelectric plate theory and the plane wave expansion method, a formulation is proposed to study the frequency band gaps and dispersion relations of the lower-order Lamb waves in two-dimensional piezoelectric phononic plates. The method is applied to analyze the phononic plates composed of solid-solid and airsolid constituents with square and triangular lattices, respectively. Factors that influence the opening and width of the complete Lamb wave gaps are identified and discussed. For solid/solid phononic plates, it is suggested that the filling material be chosen with larger mass density, proper stiffness, and weak anisotropic factor embedded in a soft matrix in order to obtain wider complete band gaps of the lower-order Lamb waves. By comparing to the calculated results without considering the piezoelectricity, the influences of piezoelectric effect on Lamb waves are analyzed as well. On the other hand, for air/solid phononic plates, a background material itself with proper anisotropy and a high filling fraction of air may favor the opening of the complete Lamb wave gaps.

  10. Propagation of SH waves in an infinite/semi-infinite piezoelectric/piezomagnetic periodically layered structure.

    Science.gov (United States)

    Pang, Yu; Liu, Yu-Shan; Liu, Jin-Xi; Feng, Wen-Jie

    2016-04-01

    In this paper, SH bulk/surface waves propagating in the corresponding infinite/semi-infinite piezoelectric (PE)/piezomagnetic (PM) and PM/PE periodically layered composites are investigated by two methods, the stiffness matrix method and the transfer matrix method. For a semi-infinite PE/PM or PM/PE medium, the free surface is parallel to the layer interface. Both PE and PM materials are assumed to be transversely isotropic solids. Dispersion equations are derived by the stiffness/transfer matrix methods, respectively. The effects of electric-magnetic (ME) boundary conditions at the free surface and the layer thickness ratios on dispersion curves are considered in detail. Numerical examples show that the results calculated by the two methods are the same. The dispersion curves of SH surface waves are below the bulk bands or inside the frequency gaps. The ratio of the layer thickness has an important effect not only on the bulk bands but also on the dispersion curves of SH surface waves. Electric and magnetic boundary conditions, respectively, determine the dispersion curves of SH surface waves for the PE/PM and PM/PE semi-infinite structures. The band structures of SH bulk waves are consistent for the PE/PM and PM/PE structures, however, the dispersive behaviors of SH surface waves are indeed different for the two composites. The realization of the above-mentioned characteristics of SH waves will make it possible to design PE/PM acoustic wave devices with periodical structures and achieve the better performance.

  11. Active Vibration Suppression of a Motor-Driven Piezoelectric Smart Structure Using Adaptive Fuzzy Sliding Mode Control and Repetitive Control

    Directory of Open Access Journals (Sweden)

    Chi-Ying Lin

    2017-03-01

    Full Text Available In this paper, we report on the use of piezoelectric sensors and actuators for the active suppression of vibrations associated with the motor-driven rotation of thin flexible plate held vertically. Motor-driven flexible structures are multi-input multi-output systems. The design of active vibration-suppression controllers for these systems is far more challenging than for flexible structures with a fixed end, due to the effects of coupling and nonlinear vibration behavior generated in structures with poor damping. To simplify the design of the controller and achieve satisfactory vibration suppression, we treated the coupling of vibrations caused by the rotary motion of the thin flexible plate as external disturbances and system uncertainties. We employed an adaptive fuzzy sliding mode control algorithm in the design of a single-input–single-output controller for the suppression of vibrations using piezoelectric sensors and actuators. We also used a repetitive control system to reduce periodic vibrations associated with the repetitive motions induced by the motor. Experimental results demonstrate that the hybrid intelligent control approach proposed in this study can suppress complex vibrations caused by modal excitation, coupling effects, and periodic external disturbances.

  12. Acoustic Energy Harvesting Using Piezoelectric Generator for Low Frequency Sound Waves Energy Conversion

    Directory of Open Access Journals (Sweden)

    Haris Fazilah Hassan

    2014-01-01

    Full Text Available The applications of electronic devices with low power consumption, such as wireless sensor network and electronic communication devices, are rapidly increasing. Thus, utilizing environmental energy as an alternative to electrochemical battery, which has a finite lifespan, can be a great advantage to these electronic devices. Harvesting environmental energy, such as solar, thermal, wind flow, water current, and raindrops, has attracted increasing research interest in the field of energy harvesting. In this paper, harvesting sound energy in the form of pressure waves is investigated as an alternative to existing energy harvesting methods. In the experimental work, a piezoelectric generator lead zirconate titanate (PZT-5A cantilever type is used to extract sound energy from the loudspeaker from various distances and then to convert this energy into electrical energy. A direct piezoelectric effect operating in 31 coupling mode is used. The maximum voltage generated by the piezoelectric generator occurs when its resonant frequency is operating near the frequency of sound. An analytical method with an appropriate equation is used to determine the resonant frequency and is then validated using the experimental result. The result shows that the maximum output voltage of 26.7 mVrms was obtained with the sound intensity of 78.6 dB at resonant frequency of 62 Hz at 1 cm distance in the first mode. In the second mode, the maximum output voltage of 91 mVrms was obtained with the sound intensity of 102.6 dB at resonant frequency of 374 Hz at 1 cm distance which is larger than that of the first mode. However, for both modes, voltage decreases as distance increases.

  13. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Serhane, Rafik, E-mail: rserhane@cdta.dz [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Abdelli-Messaci, Samira; Lafane, Slimane; Khales, Hammouche; Aouimeur, Walid [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Hassein-Bey, Abdelkadder [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Micro and Nano Physics Group, Faculty of Sciences, University Saad Dahlab of Blida (USDB), BP. 270, DZ-09000 Blida (Algeria); Boutkedjirt, Tarek [Equipe de Recherche Physique des Ultrasons, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32, El-Alia, Bab-Ezzouar, DZ-16111 Algiers (Algeria)

    2014-01-01

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO{sub 2}/Si and Al (1 1 1)/SiO{sub 2}/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as K{sub eff}{sup 2}=5.09%, with a quality factor Q{sub r} = 1001.4.

  14. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    Science.gov (United States)

    Serhane, Rafik; Abdelli-Messaci, Samira; Lafane, Slimane; Khales, Hammouche; Aouimeur, Walid; Hassein-Bey, Abdelkadder; Boutkedjirt, Tarek

    2014-01-01

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO2/Si and Al (1 1 1)/SiO2/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as Keff2    =    5 .0 9 %, with a quality factor Qr = 1001.4.

  15. Three phase full wave dc motor decoder

    Science.gov (United States)

    Studer, P. A. (Inventor)

    1977-01-01

    A three phase decoder for dc motors is disclosed which employs an extremely simple six transistor circuit to derive six properly phased output signals for fullwave operation of dc motors. Six decoding transistors are coupled at their base-emitter junctions across a resistor network arranged in a delta configuration. Each point of the delta configuration is coupled to one of three position sensors which sense the rotational position of the motor. A second embodiment of the invention is disclosed in which photo-optical isolators are used in place of the decoding transistors.

  16. Analysis of axisymmetric and non-axisymmetric wave propagation in a homogeneous piezoelectric solid circular cylinder of transversely isotropic material

    CSIR Research Space (South Africa)

    Shatalov, MY

    2010-01-01

    Full Text Available for PZT-4 and PZT-7A piezoelectric ceramics for circumferential wave numbers m = 1, 2, and 3. It is observed that the dispersion curves are sensitive to the type of the imposed boundary conditions as well as to the measure of the electromechanical coupling...

  17. Analysis of non-axisymmetric wave propagation in a homogeneous piezoelectric solid circular cylinder of transversely isotropic material

    CSIR Research Space (South Africa)

    Shatalov, MY

    2009-01-01

    Full Text Available for PZT-4 and PZT-7A piezoelectric ceramics for circumferential wave numbers m = 1, 2, and 3. It is observed that the dispersion curves are sensitive to the type of the imposed boundary conditions as well as to the measure of the electromechanical coupling...

  18. Damping Enhancement of Composite Panels by Inclusion of Shunted Piezoelectric Patches: A Wave-Based Modelling Approach

    Directory of Open Access Journals (Sweden)

    Dimitrios Chronopoulos

    2015-02-01

    Full Text Available The waves propagating within complex smart structures are hereby computed by employing a wave and finite element method. The structures can be of arbitrary layering and of complex geometric characteristics as long as they exhibit two-dimensional periodicity. The piezoelectric coupling phenomena are considered within the finite element formulation. The mass, stiffness and piezoelectric stiffness matrices of the modelled segment can be extracted using a conventional finite element code. The post-processing of these matrices involves the formulation of an eigenproblem whose solutions provide the phase velocities for each wave propagating within the structure and for any chosen direction of propagation. The model is then modified in order to account for a shunted piezoelectric patch connected to the composite structure. The impact of the energy dissipation induced by the shunted circuit on the total damping loss factor of the composite panel is then computed. The influence of the additional mass and stiffness provided by the attached piezoelectric devices on the wave propagation characteristics of the structure is also investigated.

  19. A wave-shaped hybrid piezoelectric and triboelectric nanogenerator based on P(VDF-TrFE) nanofibers.

    Science.gov (United States)

    Chen, Xuexian; Han, Mengdi; Chen, Haotian; Cheng, Xiaoliang; Song, Yu; Su, Zongming; Jiang, Yonggang; Zhang, Haixia

    2017-01-19

    A wave-shaped hybrid nanogenerator (NG) with mutually enhanced piezoelectric and triboelectric output is presented in this work. By sandwiching piezoelectric P(VDF-TrFE) nanofibers between wave-shaped Kapton films, the device forms a three-layer structure, which can generate piezoelectric and triboelectric outputs simultaneously in one press and release cycle. Through systematic situational analysis and experimental validation, the three-layer structure can achieve obvious improvement of the output performance for both parts. When triggered with 4 Hz external force, the piezoelectric part generates a peak output and current of 96 V and 3.8 μA, which is ∼2 times higher than its initial output. Meanwhile, the performance of triboelectric parts also increases 8 V and 16 V with the assistance of piezoelectric potential. The enhanced high output enables the hybrid nanogenerator to instantaneously light up LEDs and charges capacitors quickly, which shows extensive application prospects in the field of self-powered systems or sensor networks.

  20. Effect of initial stress on Love waves in a piezoelectric structure carrying a functionally graded material layer.

    Science.gov (United States)

    Qian, Zheng-Hua; Jin, Feng; Lu, Tianjian; Kishimoto, Kikuo; Hirose, Sohichi

    2010-01-01

    The effect of initial stress on the propagation behavior of Love waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance.

  1. Novel two-stage piezoelectric-based ocean wave energy harvesters for moored or unmoored buoys

    Science.gov (United States)

    Murray, R.; Rastegar, J.

    2009-03-01

    Harvesting mechanical energy from ocean wave oscillations for conversion to electrical energy has long been pursued as an alternative or self-contained power source. The attraction to harvesting energy from ocean waves stems from the sheer power of the wave motion, which can easily exceed 50 kW per meter of wave front. The principal barrier to harvesting this power is the very low and varying frequency of ocean waves, which generally vary from 0.1Hz to 0.5Hz. In this paper the application of a novel class of two-stage electrical energy generators to buoyant structures is presented. The generators use the buoy's interaction with the ocean waves as a low-speed input to a primary system, which, in turn, successively excites an array of vibratory elements (secondary system) into resonance - like a musician strumming a guitar. The key advantage of the present system is that by having two decoupled systems, the low frequency and highly varying buoy motion is converted into constant and much higher frequency mechanical vibrations. Electrical energy may then be harvested from the vibrating elements of the secondary system with high efficiency using piezoelectric elements. The operating principles of the novel two-stage technique are presented, including analytical formulations describing the transfer of energy between the two systems. Also, prototypical design examples are offered, as well as an in-depth computer simulation of a prototypical heaving-based wave energy harvester which generates electrical energy from the up-and-down motion of a buoy riding on the ocean's surface.

  2. Phonon-electron interactions in piezoelectric semiconductor bulk acoustic wave resonators.

    Science.gov (United States)

    Gokhale, Vikrant J; Rais-Zadeh, Mina

    2014-07-08

    This work presents the first comprehensive investigation of phonon-electron interactions in bulk acoustic standing wave (BAW) resonators made from piezoelectric semiconductor (PS) materials. We show that these interactions constitute a significant energy loss mechanism and can set practical loss limits lower than anharmonic phonon scattering limits or thermoelastic damping limits. Secondly, we theoretically and experimentally demonstrate that phonon-electron interactions, under appropriate conditions, can result in a significant acoustic gain manifested as an improved quality factor (Q). Measurements on GaN resonators are consistent with the presented interaction model and demonstrate up to 35% dynamic improvement in Q. The strong dependencies of electron-mediated acoustic loss/gain on resonance frequency and material properties are investigated. Piezoelectric semiconductors are an extremely important class of electromechanical materials, and this work provides crucial insights for material choice, material properties, and device design to achieve low-loss PS-BAW resonators along with the unprecedented ability to dynamically tune resonator Q.

  3. Effect of initial stress on propagation behaviors of shear horizontal waves in piezoelectric/piezomagnetic layered cylinders.

    Science.gov (United States)

    Zhao, X; Qian, Z H; Zhang, S; Liu, J X

    2015-12-01

    An analytical approach is taken to investigate shear horizontal wave (SH wave) propagation in layered cylinder with initial stress, where a piezomagnetic (PM) material thin layer is bonded to a piezoelectric (PE) cylinder. Two different material combinations are taken into account, and the phase velocities of the SH waves are numerically calculated for the magnetically open and short cases, respectively. It is found that the initial stress, the thickness ratio and the material performance have a great influence on the phase velocity. The results obtained in this paper can offer fundamental significance to the application of PE/PM composite media or structure for the acoustic wave and microwave technologies.

  4. Numerical investigation of a piezoelectric surface acoustic wave interaction with a one-dimensional channel

    Science.gov (United States)

    Rahman, S.; Kataoka, M.; Barnes, C. H. W.; Langtangen, H. P.

    2006-07-01

    We investigate the propagation of a piezoelectric surface acoustic wave (SAW) across a GaAs/AlxGa1-xAs heterostructure surface, on which there is a fixed metallic split gate. Our method is based on a finite element formulation of the underlying equations of motion, and is performed in three dimensions fully incorporating the geometry and material composition of the substrate and gates. We demonstrate attenuation of the SAW amplitude as a result of the presence of both mechanical and electrical gates on the surface. We show that the incorporation of a simple model for the screening by the two-dimensional electron gas (2DEG), results in a total electric potential modulation that suggests a mechanism for the capture and release of electrons by the SAW. Our simulations suggest the absence of any significant turbulence in the SAW motion which could hamper the operation of SAW based quantum devices of a more complex geometry.

  5. SCATTERING OF THE HARMONIC STRESS WAVE BY CRACKS IN FUNCTIONALLY GRADED PIEZOELECTRIC MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Ma Li; Nie Wu; Wu Linzhi; Zhou Zhengong

    2005-01-01

    The present paper considers the scattering of the time harmonic stress wave by a single crack and two collinear cracks in functionally graded piezoelectric material (FGPM).It is assumed that the properties of the FGPM vary continuously as an exponential function.By using the Fourier transform and defining the jumps of displacements and electric potential components across the crack surface as the unknown functions, two pairs of dual integral equations are derived. To solve the dual integral equations, the jumps of the displacement and electric potential components across the crack surface are expanded in a series of Jacobi polynomials.Numerical examples are provided to show the influences of material properties on the dynamic stress and the electric displacement intensity factors.

  6. A novel sandwich-type traveling wave piezoelectric tracked mobile system.

    Science.gov (United States)

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

    2017-03-01

    In this paper, a novel sandwich-type traveling wave piezoelectric tracked mobile system was proposed, designed, fabricated and experimentally investigated. The proposed system exhibits the advantages of simple structure, high mechanical integration, lack of electromagnetic interference, and lack of lubrication requirement, and hence shows potential application to robotic rovers for planetary exploration. The tracked mobile system is comprised of a sandwich actuating mechanism and a metal track. The actuating mechanism includes a sandwich piezoelectric transducer and two annular parts symmetrically placed at either end of the transducer, while the metal track is tensioned along the outer surfaces of the annular parts. Traveling waves with the same rotational direction are generated in the two annular parts, producing the microscopic elliptical motions of the surface particles on the annular parts. In this situation, if the pre-load is applied properly, the metal track can be driven by friction force to achieve bidirectional movement. At first, the finite element method was adopted to conduct the modal analysis and harmonic response analysis of the actuating mechanism, and the vibration characteristics were measured to confirm the operating principle. Then the optimal driving frequency of the system prototype, namely 35.1kHz, was measured by frequency sensitivity experiments. At last, the mechanical motion characteristics of the prototype were investigated experimentally. The results show that the average motion speeds of the prototype in dual directions were as 72mm/s and 61.5mm/s under the excitation voltage of 500VRMS, respectively. The optimal loading weights of the prototype in bi-directions were 0.32kg and 0.24kg with a maximum speed of 59.5mm/s and 61.67mm/s at the driving voltage of 300VRMS, respectively.

  7. Optimal design of a piezoelectric transducer for exciting guided wave ultrasound in rails

    Science.gov (United States)

    Ramatlo, Dineo A.; Wilke, Daniel N.; Loveday, Philip W.

    2017-02-01

    An existing Ultrasonic Broken Rail Detection System installed in South Africa on a heavy duty railway line is currently being upgraded to include defect detection and location. To accomplish this, an ultrasonic piezoelectric transducer to strongly excite a guided wave mode with energy concentrated in the web (web mode) of a rail is required. A previous study demonstrated that the recently developed SAFE-3D (Semi-Analytical Finite Element - 3 Dimensional) method can effectively predict the guided waves excited by a resonant piezoelectric transducer. In this study, the SAFE-3D model is used in the design optimization of a rail web transducer. A bound-constrained optimization problem was formulated to maximize the energy transmitted by the transducer in the web mode when driven by a pre-defined excitation signal. Dimensions of the transducer components were selected as the three design variables. A Latin hypercube sampled design of experiments that required a total of 500 SAFE-3D analyses in the design space was employed in a response surface-based optimization approach. The Nelder-Mead optimization algorithm was then used to find an optimal transducer design on the constructed response surface. The radial basis function response surface was first verified by comparing a number of predicted responses against the computed SAFE-3D responses. The performance of the optimal transducer predicted by the optimization algorithm on the response surface was also verified to be sufficiently accurate using SAFE-3D. The computational advantages of SAFE-3D in optimal transducer design are noteworthy as more than 500 analyses were performed. The optimal design was then manufactured and experimental measurements were used to validate the predicted performance. The adopted design method has demonstrated the capability to automate the design of transducers for a particular rail cross-section and frequency range.

  8. Research on novel inertial linear ultrasonic piezoelectric motor%新型惯性式直线超声压电电机的运动机理及实验研究

    Institute of Scientific and Technical Information of China (English)

    金家楣; 时运来; 李玉宝; 赵淳生

    2008-01-01

    A novel inertial linear ultrasonic piezoelectric motor is developed,which can transfer motion through friction in the form of inertial displacement by combining the converse piezoelectric effect and the principle of inertial displacement of piezoelectrical crystal.This motor is composed of a stator and a mobile element.The stator contains a displacement enlargement element,a multilayer piezoelectric actuator and a shaft and the mobile element is a ring with a gap and an annular flute.In this paper,the running principle of the motor is investigated in detail and the effects of two exciting modes on the performance of the motor is analyzed by the simulation and the experiment synchronously.ExPeri-mental results show that the excited effect of square wave signal on this motor is better than that of saw-tooth wave signal.The no-load speed of a prototype achieves 11 mm/s and the largest thrust achieves 0.5 N in operation voltage of 50 V and driving frequency of 80 kHz.%提出了一种新型惯性式直线超声压电电机.该电机利用压电晶体的逆压电效应和惯性位移原理,由定子的轴向变形,通过摩擦力的作用,以惯性位移的形式传递运动.它由两部分组成,定子由具有位移放大功能的压电复合换能器和轴组成,动子为一带有缺口和环形凹槽的环.分析了该电机的工作原理,并通过仿真和实验相结合的方法分析了两种激励方式对电机性能的影响.实验结果表明:样机采用方波驱动比采用锯齿波驱动的效果好;在采用方波驱动信号驱动时,样机的最大空载速度可达到11 mm/s,最大输出力达到0.5 N.

  9. Standard practice for guided wave testing of above ground steel pipework using piezoelectric effect transduction

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This practice provides a procedure for the use of guided wave testing (GWT), also previously known as long range ultrasonic testing (LRUT) or guided wave ultrasonic testing (GWUT). 1.2 GWT utilizes ultrasonic guided waves, sent in the axial direction of the pipe, to non-destructively test pipes for defects or other features by detecting changes in the cross-section and/or stiffness of the pipe. 1.3 GWT is a screening tool. The method does not provide a direct measurement of wall thickness or the exact dimensions of defects/defected area; an estimate of the defect severity however can be provided. 1.4 This practice is intended for use with tubular carbon steel or low-alloy steel products having Nominal Pipe size (NPS) 2 to 48 corresponding to 60.3 to 1219.2 mm (2.375 to 48 in.) outer diameter, and wall thickness between 3.81 and 25.4 mm (0.15 and 1 in.). 1.5 This practice covers GWT using piezoelectric transduction technology. 1.6 This practice only applies to GWT of basic pipe configuration. This inc...

  10. Effect of a functionally graded soft middle layer on Love waves propagating in layered piezoelectric systems.

    Science.gov (United States)

    Ben Salah, Issam; Ben Amor, Morched; Ben Ghozlen, Mohamed Hédi

    2015-08-01

    Numerical examples for wave propagation in a three-layer structure have been investigated for both electrically open and shorted cases. The first order differential equations are solved by both methods ODE and Stiffness matrix. The solutions are used to study the effects of thickness and gradient coefficient of soft middle layer on the phase velocity and on the electromechanical coupling factor. We demonstrate that the electromechanical coupling factor is substantially increased when the equivalent thickness is in the order of the wavelength. The effects of gradient coefficients are plotted for the first mode when electrical and mechanical gradient variations are applied separately and altogether. The obtained deviations in comparison with the ungraded homogenous film are plotted with respect to the dimensionless wavenumber. The impact related to the gradient coefficient of the soft middle layer, on the mechanical displacement and the Poynting vector, is carried out. The numericals results are illustrated by a set of appropriate curves related to various profiles. The obtained results set guidelines not only for the design of high-performance surface acoustic wave (SAW) devices, but also for the measurement of material properties in a functionally graded piezoelectric layered system using Love waves.

  11. Characteristics of ring type traveling wave ultrasonic motor in vacuum.

    Science.gov (United States)

    Qu, Jianjun; Zhou, Ningning; Tian, Xiu; Jin, Long; Xu, Zhike

    2009-03-01

    The characteristics of ultrasonic motor strongly depend on the properties of stator/rotor contact interface which are affected by ambient environment. With the developed apparatus, load properties of two ring type traveling wave ultrasonic motors in atmosphere, low vacuum and high vacuum were studied, respectively. Wear of friction material, variations of vacuum degree and the temperature of motor during the experiment were also measured. The results show that load properties of motor A in vacuum were poorer than those in atmosphere, when load torque M(f) was less than 0.55 N m. Compared to motor A, load properties of motor B were affected a little by environmental pressure. Wear of friction material in vacuum was more severe than wear in atmosphere. The temperature of motor in vacuum rose more quickly than it in atmosphere and had not reached equilibrium in 2 h experiment. However, the temperature of motor in atmosphere had reached equilibrium in about forth minutes. Furthermore, outgas was also observed during experiment under vacuum conditions.

  12. Lamb waves propagation in functionally graded piezoelectric materials by Peano-series method.

    Science.gov (United States)

    Ben Amor, Morched; Ben Ghozlen, Mohamed Hédi

    2015-01-01

    The Peano-series expansion is used to investigate the propagation of the lowest-order symmetric (S0) and antisymmetric (A0) Lamb wave modes in a functionally graded piezoelectric material (FGPM) plate. Aluminum nitride has been retained for illustration, it is polarized along the thickness axis, and at the same time the material properties change gradually perpendicularly to the plate with an exponential variation. The effects of the gradient variation on the phase velocity and the coupling electromechanical factor are obtained. Appropriate curves are given to reflect their behavior with respect to frequency. The highest value of the electromechanical coupling factor has been observed for S0 mode, it is close to six percent, conversely for A0 mode it does not exceed 1.5%. The coupling factor maxima undergo a shift toward the high frequency area when the corresponding gradient coefficient increases. The Peano-series method computed under Matlab software, gives rapid convergence and accurate phase velocity when analysing Lamb waves in FGPM plate. The obtained numerical results can be used to design different sensors with high performance working at different frequency ranges by adjusting the extent of the gradient property.

  13. Contact Analysis and Modeling of Standing Wave Linear Ultrasonic Motor

    Institute of Scientific and Technical Information of China (English)

    SHI Yunlai; ZHAO Chunsheng; ZHANG Jianhui

    2011-01-01

    A contact model for describing the contact mechanics between the stator and slider of the standing wave linear ultrasonic motor was presented.The proposed model starts from the assumption that the vibration characteristics of the stator is not affected by the contact process.A modified friction models was used to analyze the contact problems.Firstly,the dynamic normal contact force,interface friction force,and steady-state characteristics were analyzed.Secondly,the influences of the contact layer material,the dynamic characteristics of the stator,and the pre-load on motor performance were simulated.Finally,to validate the contact model,a linear ultrasonic motor based on in-plane modes was used as an example.The corresponding results show that a set of simulation of motor performances based on the proposed contact mechanism is in good agreement with experimental results.This model is helpful to understanding the operation principle of the standing wave linear motor and thus contributes to the design of these tvpes of motor.

  14. Technical Report: Modeling of Composite Piezoelectric Structures with the Finite Volume Method

    CERN Document Server

    Bolborici, Valentin; Pugh, Mary C

    2011-01-01

    Piezoelectric devices, such as piezoelectric traveling wave rotary ultrasonic motors, have composite piezoelectric structures. A composite piezoelectric structure consists of a combination of two or more bonded materials, where at least one of them is a piezoelectric transducer. Numerical modeling of piezoelectric structures has been done in the past mainly with the finite element method. Alternatively, a finite volume based approach offers the following advantages: (a) the ordinary differential equations resulting from the discretization process can be interpreted directly as corresponding circuits and (b) phenomena occurring at boundaries can be treated exactly. This report extends the work of IEEE Transactions on UFFC 57(2010)7:1673-1691 by presenting a method for implementing the boundary conditions between the bonded materials in composite piezoelectric structures. The report concludes with one modeling example of a unimorph structure.

  15. Influence of acoustoelastic coefficient on wave time of flight in stress measurement in piezoelectric self-excited system

    Science.gov (United States)

    Kwaśniewki, Janusz; Dominik, Ireneusz; Lalik, Krzysztof; Holewa, Karolina

    2016-10-01

    This paper presents the Self-excited Acoustical System (SAS) in elastic construction stress change measurement. The system is based on the acoustical autoresonance phenomena and enables an indirect measurement of the construction effort level. The essence of the SAS system is to use a piezoelectric vibration emitter and a piezoelectric vibration receiver placed at a distance, which are coupled with a proper power amplifier, and which are operating in a closed loop with a positive feedback. This causes the excitation of the system. The change of the velocity of wave propagation, which is associated with the change of the resonance frequency in the system is caused by the stress change in the examined material. A variable, which determines the change of the acoustic wave velocity, is called an acoustoelastic coefficient β. Such a coefficient allows to determine the absolute stress value in the tested material.

  16. Some constructions and characteristics of rod-type piezoelectric ultrasonic motors using longitudinal and torsional vibrations.

    Science.gov (United States)

    Tomikawa, Y; Adachi, K; Aoyagi, M; Sagae, T; Takano, T

    1992-01-01

    Ultrasonic motors using longitudinal and torsional motions of rod vibrators have previously been proposed. Several motor constructions, whose forms are different from the previous ones, are proposed and their characteristics are experimentally examined in order to develop the ultrasonic motors of this type; that is, they are expected to have much different uses, according to how their forms are modified. Two groups of motor are dealt with: one contains motors basically suited to the relatively high torque of 2-3 kgf-cm and the other contains motors for small or medium torque below about 1.0 kgf-cm. As the result, operational characteristics of motors are totally revealed. These are useful in developing the rod type ultrasonic motors and in their practical applications.

  17. Simulation of surface acoustic wave motor with spherical slider.

    Science.gov (United States)

    Morita, T; Kurosawa, M K; Higuchi, T

    1999-01-01

    The operation of a surface acoustic wave (SAW) motor using spherical-shaped sliders was demonstrated by Kurosawa et al. (1994). It was necessary to modify the previous simulation models for usual ultrasonic motors because of this slider shape and the high frequency vibration. A conventional ultrasonic motor has a flat contact surface slider and a hundredth driving frequency; so, the tangential motion caused by the elasticity of the slider and stator with regard to the spherical slider of the SAW motor requires further investigation. In this paper, a dynamic simulation model for the SAW motor is proposed. From the simulation result, the mechanism of the SAW motor was clarified (i.e., levitation and contact conditions were repeated during the operation). The transient response of the motor speed was simulated. The relationships between frictional factor and time constant and vibration velocity of the stator and the slider speed were understood. The detailed research regarding the elastic deformation caused by preload would be helpful to construct an exact simulation model for the next work.

  18. Standing wave brass-PZT square tubular ultrasonic motor.

    Science.gov (United States)

    Park, Soonho; He, Siyuan

    2012-09-01

    This paper reports a standing wave brass-PZT tubular ultrasonic motor. The motor is composed of a brass square tube with two teeth on each tube end. Four PZT plates are attached to the outside walls of the brass tube. The motor requires only one driving signal to excite vibration in a single bending mode to generate reciprocating diagonal trajectories of teeth on the brass tube ends, which drive the motor to rotate. Bi-directional rotation is achieved by exciting different pairs of PZT plates to switch the bending vibration direction. Through using the brass-PZT tube structure, the motor can take high magnitude vibration to achieve a high output power in comparison to PZT tube based ultrasonic motors. Prototypes are fabricated and tested. The dimension of the brass-PZT tube is 3.975mm×3.975mm×16mm. Measured performance is a no-load speed of >1000RPM, a stall torque of 370μNm and a maximum output power of 16 mW when a sinusoidal driving voltage of 50V is applied. The working frequencies of the motor are 46,050Hz (clockwise) and 46,200Hz (counter-clockwise).

  19. The Effects of Piezoelectricity on the Interaction of Waves in Fluid-Loaded Poroelastic Half-Space

    Directory of Open Access Journals (Sweden)

    Vishakha Gupta

    2014-01-01

    Full Text Available The effects of piezoelectricity on the interaction of waves at fluid-poroelastic interface are studied. The constitutive equations and governing equations are formulated and their solution is obtained. The boundary conditions are described at fluid-solid interface. The effects of various parameters on the angle of refraction, amplitude ratios, displacements, electric potentials, and vertical component of slowness are studied numerically for a particular model. The results obtained are in agreement with the general laws of physics.

  20. Deep drilling and sampling via the wireline auto-gopher driven by piezoelectric percussive actuator and EM rotary motor

    Science.gov (United States)

    Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart; Zacny, Kris; Paulsen, Gale L.; Beegle, Luther; Bao, Xiaoqi

    2012-04-01

    The ability to penetrate subsurfaces and perform sample acquisition at depths of meters is critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars, Europa, and Enceladus. A corer/sampler was developed with the goal of acquiring pristine samples by reaching depths on Mars beyond the oxidized and sterilized zone. The developed rotary-hammering coring drill, called Auto-Gopher, employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor rotates the bit to remove the powdered cuttings. This sampler is a wireline drill that is incorporated with an inchworm mechanism allowing thru cyclic coring and core removal to reach great depths. The penetration rate is optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism, which is driven by a piezoelectric stack, demonstrated to require low axial preload. The Auto-Gopher has been produced taking into account the lessons learned from the development of the Ultrasonic/Sonic Gopher that was designed as a percussive ice drill and was demonstrated in Antarctica in 2005 to reach about 2 meters deep. A field demonstration of the Auto-Gopher is currently being planned with the objective of reaching as deep as 3 to 5 meters in tufa formation.

  1. Analysis and experimental verification of electroacoustic wave energy harvesting in a coupled piezoelectric plate-harvester system

    Science.gov (United States)

    Darabi, Amir; Leamy, Michael J.

    2017-03-01

    This paper introduces an analytical framework for predicting wave energy harvested by a circular piezoelectric disk attached to a thin plate. An harmonic point source excitation generates waves that are then incident on a piezoelectric disk—summing responses due to all such excitation enables general forcing profiles to be considered. The analysis approach decomposes the coupled system into two subdomains, one being the piezoelectric disk, and the other an infinite plate for which a Green's function is readily available. Interaction forces between the two subdomains couple the problems and lead to a closed-form solution for the propagation, transmission, and reflection of waves over the entire domain. In addition, the voltage generated by the harvester is calculated using coupled electromechanical equations. The analysis approach is first validated by comparing predicted response quantities to those computed using numerical simulations, documenting good agreement. The system is then studied in the frequency domain and the optimum harvester resistance is found for generating the most electrical power. Representative experiments are carried out to demonstrate the validity of the analytical approach and verify the harvested power versus resistance trend.

  2. Study on precision piezoelectric rotary step motors with inner anchor/loosen and outer drive

    Institute of Scientific and Technical Information of China (English)

    Jianfang LIU; Zhigang YANG; Ping ZENG; Zunqiang FAN

    2008-01-01

    A new precision rotary piezoelectric(PZT)actuator is proposed to improve its drive performance.Based on piezoelectric technology,the actuator adopts the principle of bionics,with a new method of stator inner anchor/loosen/rotor outer drive and a distortion structure of a thin shelf flexible hinge.This structure improves the stability of the anchor/loosen and step rotary.Its characteristics are evaluated by finite element analysis.The experiment shows that the new rotary PZT actuator works with higher frequency(40 Hz),higher speed (325 μrad/s),wider movement(360°),high resolution (1 μrad/step)and high torque(30 N·cm).The novel actuator can be applied in wide movement and high resolution driving devices such as those for optics engineering,precision positioning and some other micro-manipulation fields.

  3. Chaotic operation and chaos control of travelling wave ultrasonic motor.

    Science.gov (United States)

    Shi, Jingzhuo; Zhao, Fujie; Shen, Xiaoxi; Wang, Xiaojie

    2013-08-01

    The travelling wave ultrasonic motor, which is a nonlinear dynamic system, has complex chaotic phenomenon with some certain choices of system parameters and external inputs, and its chaotic characteristics have not been studied until now. In this paper, the preliminary study of the chaos phenomenon in ultrasonic motor driving system has been done. The experiment of speed closed-loop control is designed to obtain several groups of time sampling data sequence of the amplitude of driving voltage, and phase-space reconstruction is used to analyze the chaos characteristics of these time sequences. The largest Lyapunov index is calculated and the result is positive, which shows that the travelling wave ultrasonic motor has chaotic characteristics in a certain working condition Then, the nonlinear characteristics of travelling wave ultrasonic motor are analyzed which includes Lyapunov exponent map, the bifurcation diagram and the locus of voltage relative to speed based on the nonlinear chaos model of a travelling wave ultrasonic motor. After that, two kinds of adaptive delay feedback controllers are designed in this paper to control and suppress chaos in USM speed control system. Simulation results show that the method can control unstable periodic orbits, suppress chaos in USM control system. Proportion-delayed feedback controller was designed following and arithmetic of fuzzy logic was used to adaptively adjust the delay time online. Simulation results show that this method could fast and effectively change the chaos movement into periodic or fixed-point movement and make the system enter into stable state from chaos state. Finally the chaos behavior was controlled.

  4. A cylindrical standing wave ultrasonic motor using bending vibration transducer.

    Science.gov (United States)

    Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

    2011-07-01

    A cylindrical standing wave ultrasonic motor using bending vibration transducer was proposed in this paper. The proposed stator contains a cylinder and a bending vibration transducer. The two combining sites between the cylinder and the transducer locate at the adjacent wave loops of bending vibration of the transducer and have a distance that equal to the half wave length of bending standing wave excited in the cylinder. Thus, the bending mode of the cylinder can be excited by the bending vibration of the transducer. Two circular cone type rotors are pressed in contact to the end rims of the teeth, and the preload between the rotors and stator is accomplished by a spring and nut system. The working principle of the proposed motor was analyzed. The motion trajectories of teeth were deduced. The stator was designed and analyzed with FEM. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 165rpm and maximum torque of 0.45Nm at an exciting voltage of 200V(rms).

  5. The anisotropy of the basic characteristics of Lamb waves in a (001)-Bi12SiO20 piezoelectric crystal

    Science.gov (United States)

    Anisimkin, V. I.

    2016-03-01

    The orientation dependences of the phase velocity, the effective electromechanical coupling coefficient, and the angle between the wave normal and the energy flux vector are numerically calculated for zeroand first-order Lamb waves propagating in the (001) basal plane of a Bi12SiO20 cubic piezoelectric crystal. It is shown that the anisotropies of these modes are different and depend on the plate thickness h and the wavelength λ. For h/λ 1, it approximately coincides with the SAW anisotropy for all the characteristics.

  6. Contact analysis and mathematical modeling of traveling wave ultrasonic motors.

    Science.gov (United States)

    Zhu, Meiling

    2004-06-01

    An analysis of the contact layer and a mathematical modeling of traveling wave ultrasonic motors (TWUM) are presented for the guidance of the design of contact layer and the analyses of the influence of the compressive force and contact layer on motor performance. The proposed model starts from a model previously studied but differs from that model in that it adds the analysis of the contact layer and derives the steady-state solutions of the nonlinear equations in the frequency domain, rather than in the time domain, for the analyses of vibrational responses of the stator and operational characteristics of the motor. The maximum permissible compressive force of the motor, the influences of the contact layer material, the thickness of the contact layer, and the compressive force on motor performance have been discussed. The results show that by using the model, one can understand the influence of the compressive force and contact layer material on motor performance, guide the choice of proper contact layer material, and calculate the maximum permissible compressive force and starting voltage.

  7. Structural Health Monitoring System Using Piezoelectric Networks with Tuned Lamb Waves

    Directory of Open Access Journals (Sweden)

    Bruno Rocha

    2010-01-01

    Full Text Available The paper presents a structural health monitoring system based on propagation of tuned Lamb waves and their interference with discontinuities. The dispersion curves are studied to determine the appropriate type and dimension of transducers and to select the optimum scanning frequencies and relevant propagation modes. A piezoelectric sensor network was implemented in an aluminum plate in order to generate and to sense the wave propagation and associated reflections. The algorithm developed for damage detection relies on the comparison of undamaged and damaged responses of the structure. Combinations of filters and statistical methods were applied to detect differences in the sensor signals acquired for the two different states (damaged and undamaged, corresponding to damage reflections. In order to eliminate the false positives due to noise, a probability analysis is performed to obtain the final damage position. The software designed for the current application allows the automatic calculation of dispersion curves, it executes the scans, performs data processing, executes the detection algorithm and presents the probable damages and their positions in a graphical form. Experiments were performed with the introduction of cumulative damages in the plate such as surface and through-the-thickness holes and cuts, ranging from 7 mm to 1 mm in diameter. Additionally, a stringer was attached to the plate by a single rivet line to simulate an aircraft skin structure. Cuts originating from rivet holes and connecting adjacent rivets, as well as loosened rivets were detected by the system. The introduction of the stringer resulted in a loss of precision in the determination of the radial position of the damages near it. Also, the network revealed significant difficulties in the detection of damages beyond the stringer.

  8. Dispersion relations of elastic waves in one-dimensional piezoelectric/piezomagnetic phononic crystal with functionally graded interlayers.

    Science.gov (United States)

    Guo, Xiao; Wei, Peijun; Lan, Man; Li, Li

    2016-08-01

    The effects of functionally graded interlayers on dispersion relations of elastic waves in a one-dimensional piezoelectric/piezomagnetic phononic crystal are studied in this paper. First, the state transfer equation of the functionally graded interlayer is derived from the motion equation by the reduction of order (from second order to first order). The transfer matrix of the functionally graded interlayer is obtained by solving the state transfer equation with the spatial-varying coefficient. Based on the transfer matrixes of the piezoelectric slab, the piezomagnetic slab and the functionally graded interlayers, the total transfer matrix of a single cell is obtained. Further, the Bloch theorem is used to obtain the resultant dispersion equations of in-plane and anti-plane Bloch waves. The dispersion equations are solved numerically and the numerical results are shown graphically. Five kinds of profiles of functionally graded interlayers between a piezoelectric slab and a piezomagnetic slab are considered. It is shown that the functionally graded interlayers have evident influences on the dispersion curves and the band gaps.

  9. A standing wave-type noncontact linear ultrasonic motor.

    Science.gov (United States)

    Hu, J; Li, G; Chan, H L; Choy, C L

    2001-05-01

    In this study, a novel standing wave-type noncontact linear ultrasonic motor is proposed and analyzed. This linear ultrasonic motor uses a properly controlled ultrasonic standing wave to levitate and drive a slider. A prototype of the motor was constructed by using a wedge-shaped aluminum stator, which was placed horizontally and driven by a multilayer PZT vibrator. The levitation and motion of the slider were observed. Assuming that the driving force was generated by the turbulent acoustic streaming in the boundary air layer next to the bottom surface of the slider, a theoretical model was developed. The calculated characteristics of this motor were found to agree quite well with the experimental results. Based on the experimental and theoretical results, guidelines for increasing the displacement and speed of the slider were obtained. It was found that increasing the stator vibration displacement, or decreasing the gradient of the stator vibration velocity and the weight per unit area of the slider, led to an increase of the slider displacement. It was also found that increasing the amplitude and gradient of the stator vibration velocity, or decreasing the weight per unit area of the slider and the driving frequency, gave rise to an increase of the slider speed. There exists an optimum roughness of the bottom surface of the slider at which the slider speed has a maximum.

  10. Propagation of SH waves in a piezoelectric/piezomagnetic plate: Effects of interfacial imperfection couplings and the related physical mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Hong-Xing [Beijing Advanced Innovation Center for Imaging Technology, Capital Normal University, Beijing 100048 (China); Li, Yong-Dong, E-mail: LYDbeijing@163.com [Beijing Advanced Innovation Center for Imaging Technology, Capital Normal University, Beijing 100048 (China); Department of Mechanical Engineering, Academy of Armored Force Engineering, Beijing 100072 (China); Xiong, Tao [Department of Mechanical Engineering, Academy of Armored Force Engineering, Beijing 100072 (China); Guan, Yong [Beijing Advanced Innovation Center for Imaging Technology, Capital Normal University, Beijing 100048 (China)

    2016-09-07

    The problem of dispersive SH wave in a piezoelectric/piezomagnetic plate that contains an imperfect interface is considered in the present work. An imperfection coupling model is adopted to describe the magnetic, electric and mechanical imperfections on the interface. A transcendental dispersion equation is derived and numerically solved to get the phase velocity. The validity of the numerical procedure is verified in a degenerated case. The effects of the coupled interfacial imperfections on the dispersion behavior of SH waves are discussed in detail and the related underlying physical mechanisms are explained. - Highlights: • SH-wave is investigated in a multiferroic plate with coupled interfacial imperfections. • SH-wave is affected by both interfacial imperfections and their inter-couplings. • Physical mechanisms of the effects are explained via energy transformations.

  11. Lamb-Wave Embedded NDE with Piezoelectric Wafer Active Sensors for Structural Health Monitoring of Thin-Wall Structures

    Science.gov (United States)

    Giurgiutiu, Victor

    2004-02-01

    Piezoelectric wafer active sensors (PWAS) are inexpensive, non-intrusive, unobtrusive devices that can be surface-mounted on existing structures or inserted between the layers of new composite structures. The PWAS can be used in both active and passive modes. PWAS generate and detect Lamb waves and enable the development of embedded NDE concepts. This paper will present two embedded NDE concepts based on the PWAS technology and Lamb waves approach. The first concept utilizes traveling Lamb waves and could be described as embedded ultrasonics. It is shown that embedded PWAS are able to reproduce most of the conventional ultrasonic techniques, such as pitch-catch, pulse-echo, and phased array. Several experiments using Lamb waves traveling in thin-wall structures are presented.

  12. Plate-like structure health monitoring based on ultrasonic guided wave technology by using bonded piezoelectric ceramic wafers

    Science.gov (United States)

    Liu, Zenghua; Zhao, Jichen; He, Cunfu; Wu, Bin

    2008-11-01

    Piezoelectric ceramic wafers are applied for the excitation and detection of ultrasonic guided waves to determine the health state of plate-like structures. Two PZT wafers, whose diameter is 11mm and thickness is 0.4mm respectively, are bonded permanently on the surface of a 1mm thick aluminum plate. One of these wafers is actuated by sinusoidal tone burst at various frequencies ranging from 100kHz to 500kHz, the other one is used as a receiver for acquiring ultrasonic guided wave signals. According to the amplitudes and shapes of these received signals, guided wave modes and their proper frequency range by using these wafers are determined. For the improvement of the signal-to-noise ratio, the Daubechies wavelet of order 40 is used for signal denoising as the mother wavelet. Furthermore, the detection of an artificial cylindrical through-hole defect is achieved by using S0 at 300kHz. Experimental results show that it is feasible and effective to detect defects in plate-like structures based on ultrasonic guided wave technology by using bonded piezoelectric ceramic wafers.

  13. Three-port impedance model of a piezoelectric bar element: Application to generation and damping of extensional waves

    Science.gov (United States)

    Jansson, A.; Lundberg, B.

    2008-09-01

    A straight bar element containing piezoelectric members is viewed as a linear system with one electrical and two mechanical ports where it can interact with external electrical and mechanical devices through voltage, current, forces and velocities. A generalized force vector, with one voltage and two forces as elements, is expressed as the product of an impedance matrix and a generalized velocity vector, with one current and two velocities, as elements. Due to symmetry and reciprocity, this matrix is defined by four of its nine elements. Two applications are considered for a piezoelectric bar element (PBE) that constitutes a part of a long elastic or viscoelastic bar, viz. generation and damping of extensional waves in the bar. In the first, the PBE is driven by a given input voltage or by the output voltage from a linear power amplifier. In the second, the PBE supplies an output voltage to an external load. In numerical simulations carried out for a specific laminated PBE, an elastic bar, a serial RL load and a bell-shaped incident wave, the highest fraction of wave energy dissipated was 8.1%. This is much less than the 50% achievable for a harmonic wave under condition of electrical impedance matching.

  14. Multi-resonant piezoelectric shunting induced by digital controllers for subwavelength elastic wave attenuation in smart metamaterial

    Science.gov (United States)

    Wang, Gang; Cheng, Jianqing; Chen, Jingwei; He, Yunze

    2017-02-01

    Instead of analog electronic circuits and components, digital controllers that are capable of active multi-resonant piezoelectric shunting are applied to elastic metamaterials integrated with piezoelectric patches. Thanks to recently introduced digital control techniques, shunting strategies are possible now with transfer functions that can hardly be realized with analog circuits. As an example, the ‘pole-zero’ method is developed to design single- or multi-resonant bandgaps by adjusting poles and zeros in the transfer function of piezoelectric shunting directly. Large simultaneous attenuations in up to three frequency bands at deep subwavelength scale (with normalized frequency as low as 0.077) are achieved. The underlying physical mechanism is attributable to the negative group velocity of the flexural wave within bandgaps. As digital controllers can be readily adapted via wireless broadcasting, the bandgaps can be tuned easily unlike the electric components in analog shunting circuits, which must be tuned one by one manually. The theoretical results are verified experimentally with the measured vibration transmission properties, where large insulations of up to 20 dB in low-frequency ranges are observed.

  15. 一种双足驱动压电直线电机%A Double-Foot Driving Linear Piezoelectric Motor

    Institute of Scientific and Technical Information of China (English)

    李海林; 王寅; 黄卫清; 梁宇

    2014-01-01

    In order to develop high precision ,large travel ,heavy thrust linear piezoelectric motor ,a marching type linear piezoelectric motor was proposed based on the piezoelectric stack .The operating principles of the motor were presented ,the structure of the motor was designed ,a prototype was made and the experimental study was proceeded .The experimental results show that within a certain range of frequency the amplitude of the motor’s stator driving foot is linear to the driving voltage ,and the maximum amplitude is as 2.9μm .The maximum non-load velocity of the motor is as 796μm/s ,the maximum thrust force of the motor is as 4.8 N .The expected design objectives are obtained success-f ully .%为研制高精度、大行程、大推力的压电直线电机,设计了一种基于叠层压电陶瓷的步进式压电直线电机。分析了电机的工作原理,对电机的结构进行了设计,制作了原理样机,并进行了实验研究。实验表明,在一定频率范围内,定子驱动足振幅与电压成线性关系,且最大振幅可达2.9μm,电机最大无负载速度为796μm/s ,最大输出推力为4.8 N ,达到了预期的目的。

  16. Elastic friction drive of surface acoustic wave motor.

    Science.gov (United States)

    Kurosawa, Minoru Kuribayashi; Itoh, Hidenori; Asai, Katsuhiko

    2003-06-01

    Importance of elastic deformation control to obtain large output force with a surface acoustic wave (SAW) motor is discussed in this paper. By adding pre-load to slider, stator and slider surfaces are deformed in a few tens nanometer. Appropriate deformation in normal direction against normal vibration displacement amplitude of SAW existed. By moderate deformation, the output force of the SAW motor was enlarged up to about 10 N and no-load speed was 0.7 m/s. To produce this performance, the transducer weight and slider size were only 4.2 g and 4 x 4 mm(2).By traveling wave propagation, surface particles of the SAW device move in elliptical motion. Due to the amplitude of the elliptical motion is 10 or 20 nm order, the contact condition of the slider is very critical. To control the contact condition, namely, the elastic deformation of the slider and stator surface in nanometer order, a lot of projections were fabricated on the slider surface. The projection diameter was 20 micro m. In static condition, the elastic deformation and stress were evaluated with the FEM analysis. From this calculation and the simulation result, it is consider that the wave crest is distorted, hence the elasticity has influence on the friction drive condition. Elastic deformation of the stator surface beneath the projection from the initial position were evaluated. In 4 x 4 mm(2) square area, the sliders had from 1089 to 23,409 projections. Depression was independent to the contact pressure. However, the output force depended on the depression although the projection density were different. From the view point of the output power of the motor, the proper depression was independent to the projection density. Around 25 nm depression, the output force and output power were maximized. This depression value was almost same as the vibration displacement amplitude of the stator transducer.

  17. New Heuristics for Interfacing Human Motor System using Brain Waves

    Directory of Open Access Journals (Sweden)

    Mohammed El-Dosuky

    2012-09-01

    Full Text Available There are many new forms of interfacing human users to machines. We persevere here electric-mechanical form of interaction between human and machine. The emergence of brain-computer interface allows mind-to-movement systems. The story of the Pied Piper inspired us to devise some new heuristics for interfacing human motor system using brain waves, by combining head helmet and LumbarMotionMonitor. For the simulation we use java GridGain. Brain responses of classified subjects during training indicates that Probe can be the best stimulus to rely on in distinguishing between knowledgeable and not knowledgeable

  18. Adaptive Lagrange finite element methods for high precision vibrations and piezoelectric acoustic wave compu- tations in SMT structures and plates with nano interfaces

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper discusses the validity of (adaptive) Lagrange generalized plain finite element method(FEM) and plate element method for accurate analysis of acoustic waves in multi-layered piezoelectric structures with tiny interfaces between metal electrodes and surface mounted piezoelectric substrates. We have come to conclusion that the quantitative relationships between the acoustic and electric fields in a piezoelectric structure can be accurately determined through the proposed finite element methods. The higher-order Lagrange FEM proposed for dynamic piezoelectric computation is proved to be very accurate (prescribed relative error 0.02%-0.04%) and a great improvement in convergence accuracy over the higher order Mindlin plate element method for piezoelectric structural analysis due to the assumptions and corrections in the plate theories. The converged Lagrange finite element methods are compared with the plate element methods and the computed results are in good agreement with available exact and experimental data. The adaptive Lagrange finite element methods and a new FEA computer program developed for macro- and micro-scale analyses are reviewed, and recently extended with great potential to high-precision nano-scale analysis in this paper and the similarities between piezoelectric and seismic wave propagations in layered structures and plates are stressed.

  19. Adaptive Lagrange finite element methods for high precision vibrations and piezoelectric acoustic wave computations in SMT structures and plates with nano interfaces

    Institute of Scientific and Technical Information of China (English)

    张武; 洪涛

    2002-01-01

    This paper discusses the validity of (adaptive) Lagrange generalized plain finite element method (FEM) and plate element method for accurate analysis of acoustic waves in multi-layered piezoelectric structures with tiny interfaces between metal electrodes and surface mounted piezoelectric substrates. We have come to conclusion that the quantitative relationships between the acoustic and electric fields in a piezoelectric structure can be accurately determined through the proposed finite element methods. The higher-order Lagrange FEM proposed for dynamic piezoelectric computation is proved to be very accurate (prescribed relative error 0.02% - 0.04% ) and a great improvement in convergence accuracy over the higher order Mindlin plate element method for piezoelectric structural analysis due to the assumptions and corrections in the plate theories.The converged lagrange finite element methods are compared with the plate element methods and the computedresults are in good agreement with available exact and experimental data. The adaptive Lagrange finite elementmethods and a new FEA computer program developed for macro- and micro-scale analyses are reviewed, and recently extended with great potential to high-precision nano-scale analysis in this paper and the similarities between piezoelectric and seismic wave propagations in layered structures and plates are stressed.

  20. Measurement of absolute displacement-amplitude of ultrasonic wave using piezo-electric detection method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong Hyun; Kim, Jong Beom; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of)

    2017-02-15

    A nonlinear ultrasonic parameter is defined by the ratio of displacement amplitude of the fundamental frequency component to that of the second-order harmonic frequency component. In this study, the ultrasonic displacement amplitude of an SUS316 specimen was measured via a piezo-electric-based method to identify the validity of piezo-electric detection method. For comparison, the ultrasonic displacement was also determined via a laser-based Fabry-Pérot interferometer. The experimental results for both measurements were in good agreement. Additionally, the stability of the repeated test results from the piezo-electric method exceeded that of the laser-interferometric method. This result indicated that the piezo-electric detection method can be utilized to measure a nonlinear ultrasonic parameter due to its excellent stability although it involves a complicated process.

  1. Effects of adhesive thickness on the Lamb wave pitch-catch signal using bonded piezoelectric wafer transducers

    Science.gov (United States)

    Islam, M. M.; Huang, H.

    2016-08-01

    This paper investigates the effects of adhesive layer on Lamb wave ultrasound pitch-catch signals that are excited and sensed by piezoelectric wafer transducers bonded on a slender structure. Analytical models were established to simulate the longitudinal and flexural vibrations of the structures separately and parametric studies of the bonding layer properties, i.e. the shear transfer parameter, adhesive thickness, and shear modulus, were performed. The parametric studies indicate that there exists an optimal adhesive layer thickness that generates maximum ultrasound pitch-catch signal for both wave modes. This prediction was subsequently validated by measurements. In addition, an improved match between the measured and simulated pitch-catch signals was achieved by adjusting the adhesive layer parameters.

  2. Repeater F-waves are signs of motor unit pathology in polio survivors.

    Science.gov (United States)

    Hachisuka, Akiko; Komori, Tetsuo; Abe, Tatsuya; Hachisuka, Kenji

    2015-05-01

    The purpose of this study was to determine whether F-waves reveal electrophysiological features of anterior horn cells in polio survivors. Forty-three polio survivors and 20 healthy controls underwent motor nerve conduction studies of the median and tibial nerves bilaterally, including sampling of F-waves elicited by 100 stimuli and the determination of motor unit number estimation (MUNE). A significant increase in abnormally stereotyped ("repeater") F-waves and a reduction of F-wave persistence were observed in both nerves in the polio group as compared with the control group. Repeater F-waves had a negative correlation with MUNE. These trends in F-wave persistence and repeater F-waves after motor unit loss are characteristic findings in polio survivors. Repeater F-waves are a sign of motor unit pathology. © 2014 The Authors. Muscle & Nerve Published by Wiley Periodicals, Inc.

  3. Acoustic-wave detection via a piezoelectric field-effect transducer.

    Science.gov (United States)

    Greeneich, E. W.; Miller, R. S.

    1972-01-01

    An oriented piezoelectric film has been incorporated in the insulator region of a silicon insulated-gate field-effect transistor to provide a sensitive high-frequency strain transducer. With this device, strains as low as 10 to the -8th power have been detected, and gauge factors of roughly 7000 have been attained for applied ac strains at 5.6 MHz.

  4. A three-layer structure model for the effect of a soft middle layer on Love waves propagating in layered piezoelectric systems

    Institute of Scientific and Technical Information of China (English)

    Peng Li; Feng Jin; Tian-Jian Lu

    2012-01-01

    A three-layer structure model is proposed for investigating the effect of a soft elastic middle layer on the propagation behavior of Love waves in piezoelectric layered systems,with "soft" implying that the bulk-shear-wave velocity of the middle layer is smaller than that of the upper sensitive layer.Dispersion equations are obtained for unelectroded and traction-free upper surfaces which,in the limit,can be reduced to those for classical Love waves.Systematic parametric studies are subsequently carried out to quantify the effects of the soft middle layer upon Love wave propagation,including its thickness,mass density,dielectric constant and elastic coefficient.It is demonstrated that whilst the thickness and elastic coefficient of the middle layer affect significantly Love wave propagation,its mass density and dielectric constant have negligible influence.On condition that both the thickness and elastic coefficient of the middle layer are vanishingly small so that it degenerates into an imperfectly bonded interface,the three-layer model is also employed to investigate the influence of imperfect interfaces on Love waves propagating in piezoelectric layer/elastic substrate systems.Upon comparing with the predictions obtained by employing the traditional shear-lag model,the present three-layer structure model is found to be more accurate as it avoids the unrealistic displacement discontinuity across imperfectly bonded interfaces assumed by the shearlag model,especially for long waves when the piezoelectric layer is relatively thin.

  5. Load monitoring and compensation strategies for guided-waves based structural health monitoring using piezoelectric transducers

    Science.gov (United States)

    Roy, Surajit; Ladpli, Purim; Chang, Fu-Kuo

    2015-09-01

    Accurate interpretation of in-situ piezoelectric sensor signals is a challenging task. This paper presents the development of a numerical compensation model based on physical insight to address the influence of structural loads on piezo-sensor signals. The model requires knowledge of in-situ strain and temperature distribution in a structure while acquiring piezoelectric sensor signals. The parameters of the numerical model are obtained using experiments on flat aluminum plate under uniaxial tensile loading. It is shown that the model parameters obtained experimentally can be used for different structures, and sensor layout. Furthermore, the combined effects of load and temperature on the piezo-sensor response are also investigated and it is observed that both of these factors have a coupled effect on the sensor signals. It is proposed to obtain compensation model parameters under a range of operating temperatures to address this coupling effect. An important outcome of this study is a new load monitoring concept using in-situ piezoelectric sensor signals to track changes in the load paths in a structure.

  6. Dynamics of three unidirectionally coupled autonomous Duffing oscillators and application to inchworm piezoelectric motors: Effects of the coupling coefficient and delay

    Science.gov (United States)

    Tchakui, Murielle Vanessa; Woafo, Paul

    2016-11-01

    This work deals with the dynamics of three unidirectionally coupled Duffing oscillators and that of three coupled piezoelectric actuators, considering the special case of inchworm motors. Two configurations of the network are studied: ring configuration and chain configuration. The effects of the coupling coefficient and the time delay are analyzed through different bifurcation diagrams and phase difference variation. It is shown that varying the coupling coefficient and the time delay leads to the appearance of different dynamical behaviors: steady states, periodic and quasiperiodic oscillations, chaos, and phase synchronization.

  7. SCATTERING OF HARMONIC ANTI-PLANE SHEAR STRESS WAVES BY A CRACK IN FUNCTIONALLY GRADED PIEZOELECTRIC/PIEZOMAGNETIC MATERIALS

    Institute of Scientific and Technical Information of China (English)

    Liang Jun

    2007-01-01

    In this paper, the dynamic behavior of a permeable crack in functionally graded piezoelectric/piezomagnetic materials is investigated. To make the analysis tractable, it is assumed that the material properties vary exponentially with the coordinate parallel to the crack. By using the Fourier transform, the problem can be solved with the help of a pair of dual integral equations in which the unknown is the jump of displacements across the crack surfaces. These equations are solved to obtain the relations between the electric filed, the magnetic flux field and the dynamic stress field near the crack tips using the Schmidt method. Numerical examples are provided to show the effect pf the functionally graded parameter and the circular frequency of the incident waves upon the stress, the electric displacement and the magnetic flux intensity factors of the crack.

  8. Transverse acoustic waves in piezoelectric ZnO/MgO and GaN/AlN Fibonacci-periodic superlattices

    Science.gov (United States)

    Martínez-Gutiérrez, D.; Velasco, V. R.

    2014-06-01

    This work studies the transverse acoustic waves, including the piezoelectric coupling, in Fibonacci superlattices formed by wurtzite ZnO/MgO and GaN/AlN, respectively. We examine also other superlattice structures formed by combining different kinds of Fibonacci sequences and finite periodic systems. The possibility to use different Fibonacci sequences including layers with double length of one of the constituent materials produces important modifications in the dispersion curves. The effect is more important in the lower frequency range and affects the gaps appearing in this frequency range. It is also possible to find narrow and flat bands cutting the original gaps and producing narrower ones. There are modes at different frequency ranges having spatial confinement in one of the constituent parts of the superlattice period.

  9. Enhancing the sensitivity of three-axis detectable surface acoustic wave gyroscope by using a floating thin piezoelectric membrane

    Science.gov (United States)

    Lee, Munhwan; Lee, Keekeun

    2017-06-01

    A new type of surface acoustic wave (SAW) gyroscope was developed on a floating thin piezoelectric membrane to enhance sensitivity and reliability by removing a bulk noise effect and by importing a higher amplitude of SAW. The developed device constitutes a two-port SAW resonator with a metallic dot array between two interdigital transducers (IDTs), and a one-port SAW delay line. The bulk silicon was completely etched away, leaving only a thin piezoelectric membrane with a thickness of one wavelength. A voltage controlled oscillator (VCO) was connected to a SAW resonator to activate the SAW resonator, while the SAW delay line was connected to the oscilloscope to monitor any variations caused by the Coriolis force. When the device was rotated, a secondary wave was generated, changing the amplitude of the SAW delay line. The highest sensitivity was observed in a device with a full acoustic wavelength thickness of the membrane because most of the acoustic field is confined within an acoustic wavelength thickness from the top surface; moreover, the thin-membrane-based gyroscope eliminates the bulk noise effect flowing along the bulk substrate. The obtained sensitivity and linearity of the SAW gyroscope were ˜27.5 µV deg-1 s-1 and ˜4.3%, respectively. Superior directivity was observed. The device surface was vacuum-sealed using poly(dimethylsiloxane) (PDMS) bonding to eliminate environmental interference. A three-axis detectable gyroscope was also implemented by placing three gyrosensors with the same configuration at right angles to each other on a printed circuit board.

  10. An omnidirectional shear horizontal wave transducer based on ring array of face-shear (d24) piezoelectric ceramics

    CERN Document Server

    Miao, Hongchen; Wang, Qiangzhong; Li, Faxin

    2016-01-01

    The non-dispersive fundamental shear horizontal (SH0) wave in plate-like structures is of practical importance in non-destructive testing (NDT) and structural health monitoring (SHM). Theoretically, an omnidirectional SH0 transducer phased array system can be used to inspect defects in a large plate in the similar manner to the phased array transducers used in medical B-scan ultrasonics. However, very few omnidirectional SH transducers have been proposed so far. In this work, an omnidirectional SH wave piezoelectric transducer (OSH-PT) was proposed which consists of a ring array of twelve face-shear (d24) trapezoidal PZT elements. Each PZT element can produce face-shear deformation under applied voltage, resulting in circumferential shear deformation in the OSH-PT and omnidirectional SH waves in the hosting plate. Both finite element simulations and experiments were conducted to examine the performance of the proposed OSH-PT. Experimental testing shows that the OSH-PT exhibits good omnidirectional properties,...

  11. Scattering of shear waves by a two-phase multiferroic sensor embedded in a piezoelectric/piezomagnetic medium

    Science.gov (United States)

    Hashemi, Roohollah

    2017-03-01

    In this paper, a robust methodology with several desirable features is developed for the determination of the magneto-electro-elastic fields of a shear (SH) wave scattered by a two-phase multiferroic fiber embedded in an infinite transversely isotropic piezoelectric or piezomagnetic medium. While the traditional wave-function expansion approach commonly used in the literature ceases to hold when the geometry of the obstacle is not symmetric, the present theory is capable of treating eccentric coating-fiber ensemble. To put its wide range of applicability in perspective, my analytical methodology is applied to several descriptive examples with various degrees of complexity. The calculated results reveals the profound influence of material properties of constituent phases, the thickness and eccentricity of coating layer, as well as the frequency of propagating SH-wave on the pertinent scattered fields induced by the multiferroic fiber. It is expected that the formulation and numerical results of this paper serve as a useful reference for the design and manufacture of multiferroic materials with a durable and yet reliable performance under dynamics loadings.

  12. Surface effect on Bleustein-Gulyaev wave in a piezoelectric half-space

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Surface effect,which is attributed to the different environment surrounding the surface or near-surface atoms from that embracing the bulk atoms,may become significant when the surface-to-volume ratio of a body is large.This paper considers the effect of a plane boundary of a piezoelectric body modeled as a thin layer with specified material properties,for which a transfer relation between the state vectors at the top and bottom surfaces is derived based on the state-space formulations.The equations of surf...

  13. A uniform-sensitivity omnidirectional shear-horizontal (SH) wave transducer based on a thickness poled, thickness-shear (d15) piezoelectric ring

    Science.gov (United States)

    Huan, Qiang; Miao, Hongchen; Li, Faxin

    2017-08-01

    The fundamental shear horizontal (SH0) wave in plates is of great importance in the field of nondestructive testing (NDT) and structural health monitoring (SHM) since it is the unique non-dispersive guided wave mode. For practical applications, a phased array system based on omnidirectional SH0 wave transducers is most useful as it can cover a wide range of a plate. However, so far very few omnidirectional SH wave transducers have been developed. In this work, we proposed an omnidirectional SH wave piezoelectric transducer (OSH-PT) based on a thickness poled piezoelectric ring. The ring is equally divided into twelve sectors and the electric field is circumferentially applied, resulting in a new thickness-shear (d15) mode. Finite element analysis shows that the proposed OSH-PT can excite single-mode SH0 wave and receive the SH0 wave only. Experiments were then conducted to examine the performance of the proposed OSH-PT. Results indicated that it can generate and receive single-mode SH0 wave in a wide frequency range with nearly uniform sensitivities along all directions. Considering its quite simple configuration, compact size and low cost, the proposed OSH-PT is expected to greatly promote the applications of SH waves in the field of NDT and SHM.

  14. Load monitoring and compensation strategies for guided-waves based structural health monitoring using piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Surajit; Ladpli, Purim; Chang, Fu-Kuo

    2015-09-01

    Accurate interpretation of in-situ piezoelectric sensor signals is a challenging task. This article presents the development of a numerical compensation model based on physical insight to address the influence of structural loads on piezo-sensor signals. The model requires knowledge of in-situ strain and temperature distribution in a structure while acquiring sensor signals. The parameters of the numerical model are obtained using experiments on flat aluminum plate under uniaxial tensile loading. It is shown that the model parameters obtained experimentally can be used for different structures, and sensor layout. Furthermore, the combined effects of load and temperature on the piezo-sensor response are also investigated and it is observed that both of these factors have a coupled effect on the sensor signals. It is proposed to obtain compensation model parameters under a range of operating temperatures to address this coupling effect. An important outcome of this study is a new load monitoring concept using in-situ piezoelectric sensor signals to track changes in the load paths in a structure.

  15. Effect of gradient dielectric coefficient in a functionally graded material (FGM) substrate on the propagation behavior of love waves in an FGM-piezoelectric layered structure.

    Science.gov (United States)

    Cao, Xiaoshan; Shi, Junping; Jin, Feng

    2012-06-01

    The propagation behavior of Love waves in a layered structure that includes a functionally graded material (FGM) substrate carrying a piezoelectric thin film is investigated. Analytical solutions are obtained for both constant and gradient dielectric coefficients in the FGM substrate. Numerical results show that the gradient dielectric coefficient decreases phase velocity in any mode, and the electromechanical coupling factor significantly increases in the first- and secondorder modes. In some modes, the difference in Love waves' phase velocity between these two types of structure might be more than 1%, resulting in significant differences in frequency of the surface acoustic wave devices.

  16. A dendritic mechanism for decoding traveling waves: principles and applications to motor cortex.

    Directory of Open Access Journals (Sweden)

    Stewart Heitmann

    2013-10-01

    Full Text Available Traveling waves of neuronal oscillations have been observed in many cortical regions, including the motor and sensory cortex. Such waves are often modulated in a task-dependent fashion although their precise functional role remains a matter of debate. Here we conjecture that the cortex can utilize the direction and wavelength of traveling waves to encode information. We present a novel neural mechanism by which such information may be decoded by the spatial arrangement of receptors within the dendritic receptor field. In particular, we show how the density distributions of excitatory and inhibitory receptors can combine to act as a spatial filter of wave patterns. The proposed dendritic mechanism ensures that the neuron selectively responds to specific wave patterns, thus constituting a neural basis of pattern decoding. We validate this proposal in the descending motor system, where we model the large receptor fields of the pyramidal tract neurons - the principle outputs of the motor cortex - decoding motor commands encoded in the direction of traveling wave patterns in motor cortex. We use an existing model of field oscillations in motor cortex to investigate how the topology of the pyramidal cell receptor field acts to tune the cells responses to specific oscillatory wave patterns, even when those patterns are highly degraded. The model replicates key findings of the descending motor system during simple motor tasks, including variable interspike intervals and weak corticospinal coherence. By additionally showing how the nature of the wave patterns can be controlled by modulating the topology of local intra-cortical connections, we hence propose a novel integrated neuronal model of encoding and decoding motor commands.

  17. Structural Diagnostics of CFRP Composite Aircraft Components by Ultrasonic Guided Waves and Built-In Piezoelectric Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Matt, Howard M. [Univ. of California, San Diego, CA (United States)

    2006-01-01

    To monitor in-flight damage and reduce life-cycle costs associated with CFRP composite aircraft, an autonomous built-in structural health monitoring (SHM) system is preferred over conventional maintenance routines and schedules. This thesis investigates the use of ultrasonic guided waves and piezoelectric transducers for the identification and localization of damage/defects occurring within critical components of CFRP composite aircraft wings, mainly the wing skin-to-spar joints. The guided wave approach for structural diagnostics was demonstrated by the dual application of active and passive monitoring techniques. For active interrogation, the guided wave propagation problem was initially studied numerically by a semi-analytical finite element method, which accounts for viscoelastic damping, in order to identify ideal mode-frequency combinations sensitive to damage occurring within CFRP bonded joints. Active guided wave tests across three representative wing skin-to-spar joints at ambient temperature were then conducted using attached Macro Fiber Composite (MFC) transducers. Results from these experiments demonstrate the importance of intelligent feature extraction for improving the sensitivity to damage. To address the widely neglected effects of temperature on guided wave base damage identification, analytical and experimental analyses were performed to characterize the influence of temperature on guided wave signal features. In addition, statistically-robust detection of simulated damage in a CFRP bonded joint was successfully achieved under changing temperature conditions through a dimensionally-low, multivariate statistical outlier analysis. The response of piezoceramic patches and MFC transducers to ultrasonic Rayleigh and Lamb wave fields was analytically derived and experimentally validated. This theory is useful for designing sensors which possess optimal sensitivity toward a given mode-frequency combination or for predicting the frequency dependent

  18. Numerical comparison of patch and sandwich piezoelectric transducers for transmitting ultrasonic waves

    CSIR Research Space (South Africa)

    Loveday, PW

    2006-03-01

    Full Text Available and this principle has been used to excite waves in a rail. This paper compares the two transduction approaches, for launching bending waves in rectangular waveguides, with numerical modeling. The numerical modeling combined a waveguide finite element model...

  19. Acoustoelectric effects in reflection of leaky-wave-radiated bulk acoustic waves from piezoelectric crystal-conductive liquid interface.

    Science.gov (United States)

    Rimeika, Romualdas; Čiplys, Daumantas; Jonkus, Vytautas; Shur, Michael

    2016-01-01

    The leaky surface acoustic wave (SAW) propagating along X-axis of Y-cut lithium tantalate crystal strongly radiates energy in the form of an obliquely propagating narrow bulk acoustic wave (BAW) beam. The reflection of this beam from the crystal-liquid interface has been investigated. The test liquids were solutions of potassium nitrate in distilled water and of lithium chloride in isopropyl alcohol with the conductivity varied by changing the solution concentration. The strong dependences of the reflected wave amplitude and phase on the liquid conductivity were observed and explained by the acoustoelectric interaction in the wave reflection region. The novel configuration of an acoustic sensor for liquid media featuring important advantages of separate measuring and sensing surfaces and rigid structure has been proposed. The application of leaky-SAW radiated bulk waves for identification of different brands of mineral water has been demonstrated.

  20. Sleep spindle and slow wave frequency reflect motor skill performance in primary school-age children

    NARCIS (Netherlands)

    Astill, Rebecca G; Piantoni, Giovanni; Raymann, Roy J E M; Vis, Jose C; Coppens, Joris E; Walker, Matthew P; Stickgold, Robert; Van Der Werf, Ysbrand D; Van Someren, Eus J W

    2014-01-01

    Background and Aim: The role of sleep in the enhancement of motor skills has been studied extensively in adults. We aimed to determine involvement of sleep and characteristics of spindles and slow waves in a motor skill in children. Hypothesis: We hypothesized sleep-dependence of skill enhancement a

  1. A New Scheme for Experimental-Based Modeling of a Traveling Wave Ultrasonic Motor

    DEFF Research Database (Denmark)

    Mojallali, Hamed; Amini, R.; Izadi-Zamanabadi, Roozbeh

    2005-01-01

    In this paper, a new method for equivalent circuit modeling of a traveling wave ultrasonic motor is presented. The free stator of the motor is modeled by an equivalent circuit containing complex circuit elements. A systematic approach for identifying the elements of the equivalent circuit...

  2. A rod type linear ultrasonic motor utilizing longitudinal traveling waves: proof of concept

    Science.gov (United States)

    Wang, Liang; Wielert, Tim; Twiefel, Jens; Jin, Jiamei; Wallaschek, Jörg

    2017-08-01

    This paper proposes a non-resonant linear ultrasonic motor utilizing longitudinal traveling waves. The longitudinal traveling waves in the rod type stator are generated by inducing longitudinal vibrations at one end of the waveguide and eliminating reflections at the opposite end by a passive damper. Considering the Poisson’s effect, the stator surface points move on elliptic trajectories and the slider is driven forward by friction. In contrast to many other flexural traveling wave linear ultrasonic motors, the driving direction of the proposed motor is identical to the wave propagation direction. The feasibility of the motor concept is demonstrated theoretically and experimentally. First, the design and operation principle of the motor are presented in detail. Then, the stator is modeled utilizing the transfer matrix method and verified by experimental studies. In addition, experimental parameter studies are carried out to identify the motor characteristics. Finally, the performance of the proposed motor is investigated. Overall, the results indicate very dynamic drive characteristics. The motor prototype achieves a maximum mean velocity of 115 mm s-1 and a maximum load of 0.25 N. Thereby, the start-up and shutdown times from the maximum speed are lower than 5 ms.

  3. Band structure calculation of SH waves in nanoscale multilayered piezoelectric phononic crystals using radial basis function method with consideration of nonlocal interface effects.

    Science.gov (United States)

    Yan, Zhizhong; Wei, Chunqiu; Zhang, Chuanzeng

    2017-01-01

    In this paper, the radial basis function (RBF) collocation method based on the nonlocal Eringen piezoelectricity theory is developed to compute the band structures of nanoscale multilayered piezoelectric phononic crystals taking account of nonlocal interface effects. Detailed calculations are performed for anti-plane transverse waves propagating obliquely or vertically in the system. The correctness of the present method is verified by comparing the numerical results with those obtained by applying the transfer matrix method in the case of nonlocal perfect interfaces. The effects of nonlocal interface imperfections are considered by comparing with the nonlocal perfect interfaces. In addition, the influences of the piezoelectric constant, the nanoscale size, the impedance ratio and the incidence angle on the cut-off frequency and band structures are investigated and discussed in detail. Numerical results show that the nonlocal interface discontinuity has more obvious effect on the low-frequency band structures at the microscopic scale than at the macroscopic scale. Furthermore, at the macroscopic scale, the nonlocal interface imperfection has an obvious effect on the high frequency waves, but the effect on the low frequency waves is not obvious, and the nonlocal interface imperfection has no effect on the cut-off frequency at the microscopic scale. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Growth and characterization of piezoelectric AlN thin films for diamond-based surface acoustic wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Benetti, M. [C.N.R. Istituto di Acustica ' O. M. Corbino' , Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Cannata, D. [C.N.R. Istituto di Acustica ' O. M. Corbino' , Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Di Pietrantonio, F. [C.N.R. Istituto di Acustica ' O. M. Corbino' , Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Verona, E. [C.N.R. Istituto di Acustica ' O. M. Corbino' , Via del Fosso del Cavaliere 100, 00133 Rome (Italy)]. E-mail: enrico.verona@idac.rm.cnr.it; Generosi, A. [C.N.R. Istituto di Struttura della Materia, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Paci, B. [C.N.R. Istituto di Struttura della Materia, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Rossi Albertini, V. [C.N.R. Istituto di Struttura della Materia, Via del Fosso del Cavaliere 100, 00133 Rome (Italy)

    2006-02-21

    We report on the preparation and structural characterization of piezoelectric films of aluminium nitride onto diamond substrates. The samples were fabricated by sequential radio frequency reactive diode sputtering processes, carried out at various temperatures, in a head vacuum system starting from stechiometric targets. The structural characterization of the films was performed by energy dispersive X-ray diffraction analysis. The deposition temperature was found to play a relevant role to obtain highly textured films with the c-axis perpendicular to the substrate surface, as required by surface-acoustic-wave applications. In particular, a minimum substrate temperature of 300 deg. C was needed in order to obtain any internal order along the c-axis while, increasing the temperature, the AlN <002> orientation becomes preferential. The rocking curve analysis revealed a good crystalline quality of the AlN films whose degree of epitaxy can be well described by a linearly increasing function of the temperature at which the films are grown.

  5. Signal Analysis and Waveform Reconstruction of Shock Waves Generated by Underwater Electrical Wire Explosions with Piezoelectric Pressure Probes.

    Science.gov (United States)

    Zhou, Haibin; Zhang, Yongmin; Han, Ruoyu; Jing, Yan; Wu, Jiawei; Liu, Qiaojue; Ding, Weidong; Qiu, Aici

    2016-04-22

    Underwater shock waves (SWs) generated by underwater electrical wire explosions (UEWEs) have been widely studied and applied. Precise measurement of this kind of SWs is important, but very difficult to accomplish due to their high peak pressure, steep rising edge and very short pulse width (on the order of tens of μs). This paper aims to analyze the signals obtained by two kinds of commercial piezoelectric pressure probes, and reconstruct the correct pressure waveform from the distorted one measured by the pressure probes. It is found that both PCB138 and Müller-plate probes can be used to measure the relative SW pressure value because of their good uniformities and linearities, but none of them can obtain precise SW waveforms. In order to approach to the real SW signal better, we propose a new multi-exponential pressure waveform model, which has considered the faster pressure decay at the early stage and the slower pressure decay in longer times. Based on this model and the energy conservation law, the pressure waveform obtained by the PCB138 probe has been reconstructed, and the reconstruction accuracy has been verified by the signals obtained by the Müller-plate probe. Reconstruction results show that the measured SW peak pressures are smaller than the real signal. The waveform reconstruction method is both reasonable and reliable.

  6. Initial Rotor Position Estimation of Half-Wave Rectified Brushless Synchronous Motor

    Science.gov (United States)

    Abe, Takashi; Oyama, Jun; Higuchi, Tsuyoshi

    This paper presents an initial rotor position estimation of Half-Wave Rectified Brushless Synchronous Motor. In the previous paper, we proposed this motor as AC servo motor, which is based on the half-wave rectified brushless excitation principle. The basic principle of this estimation technique utilizes the dependence of inductance on the rotor position. The bias frequency component of half-Wave rectified brushless excitation is used to estimate the rotor position error. The magnetic pole is discriminated by the switching condition of the diode inserted into the rotor field winding. This estimation technique is confirmed by simulation include inverter circuit, control program and motor model. Finally, the effectiveness of the proposed estimation technique has been verified by experiments.

  7. Analyses of the temperature field of traveling-wave rotary ultrasonic motors.

    Science.gov (United States)

    Lu, Xiaolong; Hu, Junhui; Zhao, Chunsheng

    2011-12-01

    In this paper, the transient and steady-state temperature field of a traveling-wave rotary ultrasonic motor is analyzed by the finite element method, based on a theoretical model of power loss of this motor in rated operation. Using this model, the temperature field of this motor is calculated and the effects of the heat conductivity of friction material, motor size, ambient temperature, and pressure on the temperature field are estimated. The calculated temperature distribution and transient temperature change agree with the experimental results. The variation of heat conductivity of the friction material has little effect on the minimum temperature in the motor but this variation seriously affects the maximum temperature in the motor when the heat conductivity of the friction material is lower than 0.5 W/(m°C). Two indices are defined to express the non-uniformity of temperature field and how quickly the temperature field reaches its steady state for traveling-wave ultrasonic motors of different sizes. It is found that traveling-wave ultrasonic motors with different sizes have different nonuniformity of temperature field and take different amounts of time to reach thermal steady state. The maximum temperature rise is lower when the ambient temperature is higher; the maximum temperature increases as the vacuum degree increases and it is not affected by the vacuum degree when the vacuum degree is too high (<10(-3) Pa).

  8. A new visco-elastic contact model of traveling wave ultrasonic motor with stator frictional layer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new contact model of traveling wave ultrasonic motor (TWUSM) with a visco-elastic stator frictional layer was presented. In this model, the initial boundaries were revised, and the rotor revolution speed could be calculated iteratively. This model was compared with compliant slider and rigid stator model. The results of motor characteristics simulations showed that the motors based on this model would gain bigger stall torque. Then the friction and wear characteristics of two models were analyzed. The motors based on this model had lower coefficient of friction and better wear resistance.

  9. Study on Directivity of Rectangular Piezoelectric Sensors Sensing Lamb Waves%矩形压电片对Lamb波传感的方向性研究

    Institute of Scientific and Technical Information of China (English)

    陈西府; 刘建; 周海; 葛友华

    2012-01-01

    矩形压电片被广泛用作超声Lamb波的传感器与驱动器.理论推导了矩形压电片对Lamb波(A0模式)的传感灵敏度系数的函数表达式,同时对推导结果进行了实验验证.研究结果表明矩形压电片对Lamb波的传感具有很强的方向性.当Lamb波传播方向沿着矩形压电片长度方向时,矩形压电片传感响应电压最大.随着Lamb波入射角度的增大,响应电压幅值越来越小,当入射方向与矩形压电片长度方向垂直时,响应幅值达到最小.%Rectangular piezoelectric sensors are widely used as Lamb waves sensors and actuators. The function of sensitivity of rectangular piezoelectric sensors sensing Lamb waves (A0 mode) is deduced, and the results are testified by experiments. Results show that rectangular piezoelectric sensors have high directivity to sense Lamb waves. The amplitude of response gets its maximum when Lamb waves are in line with sensor lengthwise direction, the amplitude will turn smaller as the propagating angle increasing and the amplitude of response gets its minimum when Lamb waves are perpendicular to sensor lengthwise direction.

  10. Apparatus for measurement of acoustic wave propagation under uniaxial loading with application to measurement of third-order elastic constants of piezoelectric single crystals.

    Science.gov (United States)

    Zhang, Haifeng; Kosinski, J A; Karim, Md Afzalul

    2013-05-01

    We describe an apparatus for the measurement of acoustic wave propagation under uniaxial loading featuring a special mechanism designed to assure a uniform mechanical load on a cube-shaped sample of piezoelectric material. We demonstrate the utility of the apparatus by determining the effects of stresses on acoustic wave speed, which forms a foundation for the final determination of the third-order elastic constants of langasite and langatate single crystals. The transit time method is used to determine changes in acoustic wave velocity as the loading is varied. In order to minimize error and improve the accuracy of the wave speed measurements, the cross correlation method is used to determine the small changes in the time of flight. Typical experimental results are presented and discussed.

  11. The Simulation on Excitation Efficiency and Liquid Sensing of Love Wave with Double Piezoelectric Structure%双压电结构乐甫波激发效率和液体传感的仿真

    Institute of Scientific and Technical Information of China (English)

    韩超; 陈智军; 徐海林; 陈涛; 付俊

    2016-01-01

    乐甫波器件适于液体检测,但在工程上经常因为激发效率较低而影响应用。与“压电基底-非压电薄膜”的单压电结构乐甫波器件相比,双压电结构的特点是薄膜也选用压电材料,以期增大器件整体的压电效应。在建立理论模型的基础上,通过空气中和液体检测时双压电结构乐甫波与声表面波、单压电结构乐甫波的机电耦合系数仿真并对比,表明对于某些压电基底和薄膜,双压电结构具有更高的乐甫波激发效率。并且,以液体介电常数检测为例,仿真结果还表明了双压电结构乐甫波比单压电结构具有更高的灵敏度。%Love wave device is suitable for liquid measurement,but its low excitation efficiency in the liquid envi⁃ronment hinders its engineering applications. Compared with the“piezoelectric substrate-non-piezoelectric film”Love wave device with single piezoelectric structure,the peculiarity of the Love wave device with double piezoelec⁃tric structure is to use the piezoelectric film besides the piezoelectric substrate,which might enhance the piezoelec⁃tric effect of the device. Based on the establishment of the Love wave theoretical model in the air and with liquid loading,we compare the electromechanical coupling coefficient of the Love wave in the double piezoelectric struc⁃ture with that in the single piezoelectric structure and the corresponding surface acoustic wave,which shows that the device with double piezoelectric structure utilizing some certain piezoelectric substrate and film has higher excita⁃tion efficiency. Moreover,the simulation results also show that the Love wave device with double piezoelectric struc⁃ture has higher sensitivity in the case of liquid dielectric constant measurement.

  12. Desing And Implementation Of A Digitally Controlled Compact Speed Driver For Travelling Wave Ultrasonic Motor

    OpenAIRE

    Altan Gencer

    2013-01-01

    In this paper, a compact size digitally controlled speed driver for travelling wave ultrasonic motor was designed and implemented. Although the driver system is light in weight, simple, small in size, it is possible to enter speed and direction digitally as well as tracking the real motor speed, voltage and current on an LCD. The implemented system was tested in a laboratory for different speed and load cases and obtained results are presented.

  13. Desing And Implementation Of A Digitally Controlled Compact Speed Driver For Travelling Wave Ultrasonic Motor

    Directory of Open Access Journals (Sweden)

    Altan Gencer

    2013-05-01

    Full Text Available In this paper, a compact size digitally controlled speed driver for travelling wave ultrasonic motor was designed and implemented. Although the driver system is light in weight, simple, small in size, it is possible to enter speed and direction digitally as well as tracking the real motor speed, voltage and current on an LCD. The implemented system was tested in a laboratory for different speed and load cases and obtained results are presented.

  14. Piezoelectric allostery of protein

    Science.gov (United States)

    Ohnuki, Jun; Sato, Takato; Takano, Mitsunori

    2016-07-01

    Allostery is indispensable for a protein to work, where a locally applied stimulus is transmitted to a distant part of the molecule. While the allostery due to chemical stimuli such as ligand binding has long been studied, the growing interest in mechanobiology prompts the study of the mechanically stimulated allostery, the physical mechanism of which has not been established. By molecular dynamics simulation of a motor protein myosin, we found that a locally applied mechanical stimulus induces electrostatic potential change at distant regions, just like the piezoelectricity. This novel allosteric mechanism, "piezoelectric allostery", should be of particularly high value for mechanosensor/transducer proteins.

  15. Influence of timing variability between motor unit potentials on M-wave characteristics.

    Science.gov (United States)

    Rodriguez-Falces, Javier; Malanda, Armando; Latasa, Iban; Lavilla-Oiz, Ana; Navallas, Javier

    2016-10-01

    The transient enlargement of the compound muscle action potential (M wave) after a conditioning contraction is referred to as potentiation. It has been recently shown that the potentiation of the first and second phases of a monopolar M wave differed drastically; namely, the first phase remained largely unchanged, whereas the second phase underwent a marked enlargement and shortening. This dissimilar potentiation of the first and second phases has been suggested to be attributed to a transient increase in conduction velocity after the contraction. Here, we present a series of simulations to test if changes in the timing variability between motor unit potentials (MUPs) can be responsible for the unequal potentiation (and shortening) of the first and the second M-wave phases. We found that an increase in the mean motor unit conduction velocity resulted in a marked enlargement and narrowing of both the first and second M-wave phases. The enlargement of the first phase caused by a global increase in motor unit conduction velocities was apparent even for the electrode located over the innervation zone and became more pronounced with increasing distance to the innervation zone, whereas the potentiation of the second phase was largely independent of electrode position. Our simulations indicate that it is unlikely that an increase in motor unit conduction velocities (accompanied or not by changes in their distribution) could account for the experimental observation that only the second phase of a monopolar M wave, but not the first, is enlarged after a brief contraction. However, the combination of an increase in the motor unit conduction velocities and a spreading of the motor unit activation times could potentially explain the asymmetric potentiation of the M-wave phases.

  16. Excitation and reception of single torsional wave T(0,1) mode in pipes using face-shear d24 piezoelectric ring array

    Science.gov (United States)

    Miao, Hongchen; Huan, Qiang; Wang, Qiangzhong; Li, Faxin

    2017-02-01

    Excitation of single fundamental torsional wave T(0, 1) mode is of practical importance in inspecting or monitoring the structural integrity of pipelines, as T(0, 1) wave is the only non-dispersive mode in pipe-like structures. This work presents a piezoelectric ring array to excite and receive single T(0, 1) mode which is made up of a series of equally-spaced face-shear d24 PZT elements around the pipe. Firstly, we proposed that single T(0, 1) mode can be excited by the piezoelectric ring, when the number of d24 PZT elements is slightly greater than n, where F(n, 2) is the highest circumferential order flexural torsional mode within the frequency bandwidth of the drive signal. Then this proposed principle was confirmed by finite element simulations. Later, experimental testing was conducted on a 100 mm outer diameter, 3 mm thick aluminum pipe. Results show that the ring of 24 face-shear d24 PZT elements can suppress all the non-axisymmetric flexural modes at the excitation frequency of 150 kHz so that single T(0, 1) mode is generated. Moreover, such a piezoelectric ring transducer can also filter flexural modes and receive the T(0, 1) mode only at 150 kHz. Note that here the highest circumferential order flexural torsional mode within the frequency bandwidth is F(20, 2), so the experimental results are in good agreement with the proposed principle. The presented ring of face-shear d24 PZT elements is very suitable for severing as the T(0, 1) wave transducer in structural health monitoring system, as it is cost-effective and no external load is required for operation.

  17. Effect of motor imagery and voluntary muscle contraction on the F wave.

    Science.gov (United States)

    Hara, Motohiko; Kimura, Jun; Walker, D David; Taniguchi, Shinichirou; Ichikawa, Hiroo; Fujisawa, Reiko; Shimizu, Hiroshi; Abe, Tatsuya; Yamada, Thoru; Kayamori, Ryoji; Mizutani, Tomohiko

    2010-08-01

    We tested the validity of instructing patients to minimally contract the muscle to facilitate F-wave recording in clinical practice. In 12 healthy subjects, F waves were recorded from the first dorsal interosseous muscle at rest, during motor imagery, and at up to 30% of the maximal voluntary contraction (MVC). F-wave persistence increased significantly from 32.5 +/- 11.9% (mean +/- SD) at rest to 58.3 +/- 15.2% during motor imagery and 90.0 +/- 8.7% during 3% MVC. It then remained the same during stepwise changes to and from 30% MVC before decreasing significantly from 80.8 +/- 18.5% during 3% MVC to 48.7 +/- 23.8% during motor imagery and 27.0 +/- 16.0% at rest. The trial average of F-wave amplitude showed a similar pattern of facilitation. Motor imagery enhances F-wave persistence and amplitude, which further increase with a slight muscle contraction and show no additional change with a stronger effort.

  18. Propagation of Love waves with surface effects in an electrically-shorted piezoelectric nanofilm on a half-space elastic substrate.

    Science.gov (United States)

    Zhang, Sijia; Gu, Bin; Zhang, Hongbin; Feng, Xi-Qiao; Pan, Rongying; Alamusi; Hu, Ning

    2016-03-01

    The propagation of Love waves in the structure consisting of a nanosized piezoelectric film and a semi-infinite elastic substrate is investigated in the present paper with the consideration of surface effects. In our analysis, surface effects are taken into account in terms of the surface elasticity theory and the electrically-shorted conditions are adopted on the free surface of the piezoelectric film and the interface between the film and the substrate. This work focuses on the new features in the dispersion relations of different modes due to surface effects. It is found that with the existence of surface effects, the frequency dispersion of Love waves shows the distinct dependence on the thickness and the surface constants when the film thickness reduces to nanometers. In general, phase velocities of all dispersion modes increase with the decrease of the film thickness and the increase of the surface constants. However, surface effects play different functions in the frequency dispersions of different modes, especially for the first mode dispersion. Moreover, different forms of Love waves are observed in the first mode dispersion, depending on the presence of the surface effects on the surface and the interface.

  19. Giant repeater F-wave in patients with anterior horn cell disorders. Role of motor unit size.

    Science.gov (United States)

    Ibrahim, I K; el-Abd, M A

    1997-01-01

    Conventional F-wave responses as well as single motor unit F-wave responses together with the volitionally recruited motor unit action potentials (MUAP) were studied in hand and feet muscles of 10 healthy subjects and 32 patients with anterior horn cell disorders. The amplitude of the largest F-wave (Fl) was significantly greater in the affected patients compared with healthy subjects. Giant repeater F-wave responses "up to 4 mV" were recorded in muscles having volitionally recruited giant MUAPs. Although, the group mean percentage of motor unit F-wave responses per stimulation in all tested orthodromic MUAPs was significantly decreased in amyotrophic lateral sclerosis patients, the group mean percentage of motor unit F-wave responses per stimulation in all tested orthodromic MUAPs that gave motor unit F-wave response was significantly increased compared with healthy subjects. The responding orthodromic MUAP gave identical motor unit F-wave response, even for complex polyphasic units. Enhanced monosynaptic (H-) reflex, proximal axon reflex (A-wave), and repetitive muscle response as possible explanations for the giant F-wave responses could be discounted. The electrophysiologic behavior of the giant late responses described here fits well with the criteria of F-waves modulated by newly formed distal (and or proximal) axonal branching.

  20. A cylindrical traveling wave ultrasonic motor using a circumferential composite transducer.

    Science.gov (United States)

    Liu, Yingxiang; Liu, Junkao; Chen, Weishan

    2011-11-01

    This paper intends to present and verify a new idea for constructing traveling wave ultrasonic motors that may effectively avoid the drawbacks of conventional traveling wave motors using bonded PZT plates as the exciting elements. In the configuration of the motor's stator, a composite sandwich type transducer is used to excite a traveling wave in a cylinder with two cantilevers as the coupling bridges between the transducer and the cylinder. The design process of the stator is described using the FEM modal analysis method, and the establishment of traveling wave on the cylindrical stator was simulated by FEM transient analysis. To verify the theoretical analysis results, a laser Doppler scanner was employed to test the mode shapes of a prototype stator excited by the longitudinal and bending vibrations respectively. Finally, to validate the design idea, a prototype motor was fabricated and tested; the typical output features are no-load speed of 156 rpm and maximum torque of 0.75 N·m under exciting voltages of 70 V(rms) applied to excite the longitudinal vibration of the transducer and 200 V(rms) applied to excite the bending vibration.

  1. Improved linear ultrasonic motor performance with square-wave based driving-tip trajectory

    Science.gov (United States)

    Le, Adam Y.; Mills, James K.; Benhabib, Beno

    2015-03-01

    This paper proposes the application of a non-sinusoidal periodic excitation voltage to induce a near-square-wave driving tip trajectory in linear ultrasonic motors (LUSMs). A square-wave-based trajectory can deliver superior frictional force to the moving stage in the forward stroke of the driving tip motion and reduced frictional force during the return stroke. This would reduce lost power in the periodic driving tip motion, thereby, increasing the output force and power of the LUSM. An implementation procedure is suggested to achieve the near-square-wave driving tip trajectory. The proposed approach is illustrated through realistic finite-element-based simulations using a bimodal LUSM configuration.

  2. Properties of Miniature Cantilever-Type Ultrasonic Motor Using Lead-Free Array-Type Multilayer Piezoelectric Ceramics of (Sr,Ca)2NaNb5O15 under High Input Power

    Science.gov (United States)

    Doshida, Yutaka; Shimizu, Hiroyuki; Mizuno, Youich; Tamura, Hideki

    2012-07-01

    The properties of miniature cantilever-type ultrasonic motors using lead-free array-type multilayer piezoelectric ceramics of (Sr,Ca)2NaNb5O15 (SCNN) developed using the design rule were investigated under high input power by comparison with the high-power properties of SCNN ceramics. The frequency dependence of the revolution speed reflected the nonlinear behavior of SCNN ceramics with the hard-spring effect and showed a mirror-reversed image relative to that of the motor of Pb(Zr,Ti)O3 (PZT) ceramics. The output power increased linearly with increasing input power up to 110 mW without heat generation, and the driving properties were almost the same as the expectations under low input power. The output power density characteristics of the motors were high in comparison with those of the commercialized motors of PZT ceramics. It appeared that the motors have a high potential as an environmental friendly piezoelectric device with excellent properties, reflecting the high-power properties of SCNN ceramics.

  3. Self-organization of waves and pulse trains by molecular motors in cellular protrusions.

    Science.gov (United States)

    Yochelis, A; Ebrahim, S; Millis, B; Cui, R; Kachar, B; Naoz, M; Gov, N S

    2015-09-03

    Actin-based cellular protrusions are an ubiquitous feature of cells, performing a variety of critical functions ranging from cell-cell communication to cell motility. The formation and maintenance of these protrusions relies on the transport of proteins via myosin motors, to the protrusion tip. While tip-directed motion leads to accumulation of motors (and their molecular cargo) at the protrusion tip, it is observed that motors also form rearward moving, periodic and isolated aggregates. The origins and mechanisms of these aggregates, and whether they are important for the recycling of motors, remain open puzzles. Motivated by novel myosin-XV experiments, a mass conserving reaction-diffusion-advection model is proposed. The model incorporates a non-linear cooperative interaction between motors, which converts them between an active and an inactive state. Specifically, the type of aggregate formed (traveling waves or pulse-trains) is linked to the kinetics of motors at the protrusion tip which is introduced by a boundary condition. These pattern selection mechanisms are found not only to qualitatively agree with empirical observations but open new vistas to the transport phenomena by molecular motors in general.

  4. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  5. Effect of Yb Addition on the Sintering Behavior and High Power Piezoelectric Properties of Pb(Zr,Ti)O3-Pb(Mn,Nb)O3

    Science.gov (United States)

    2007-11-02

    ultrasonic motors and piezoelectric transformers, as materials which can convert electrical energy to mechanical energy or vice versa at the...such as piezo-transformers and piezoelectric ultrasonic motors . The Curie temperature is one of important properties for high power piezoelectric...devices such as piezoelectric transformers and ultrasonic motors . IV. Conclusion electric characteristics were investigated for the 0.9Pb

  6. Conditioning effect of transcranial magnetic stimulation evoking motor-evoked potential on V-wave response.

    Science.gov (United States)

    Grosprêtre, Sidney; Martin, Alain

    2014-12-01

    The aim of this study was to examine the collision responsible for the volitional V-wave evoked by supramaximal electrical stimulation of the motor nerve during voluntary contraction. V-wave was conditioned by transcranial magnetic stimulation (TMS) over the motor cortex at several inter-stimuli intervals (ISI) during weak voluntary plantar flexions (n = 10) and at rest for flexor carpi radialis muscle (FCR; n = 6). Conditioning stimulations were induced by TMS with intensity eliciting maximal motor-evoked potential (MEPmax). ISIs used were ranging from -20 to +20 msec depending on muscles tested. The results showed that, for triceps surae muscles, conditioning TMS increased the V-wave amplitude (~ +250%) and the associated mechanical response (~ +30%) during weak voluntary plantar flexion (10% of the maximal voluntary contraction -MVC) for ISIs ranging from +6 to +18 msec. Similar effect was observed at rest for the FCR with ISI ranging from +6 to +12 msec. When the level of force was increased from 10 to 50% MVC or the conditioning TMS intensity was reduced to elicit responses of 50% of MEPmax, a significant decrease in the conditioned V-wave amplitude was observed for the triceps surae muscles, linearly correlated to the changes in MEP amplitude. The slope of this correlation, as well as the electro-mechanical efficiency, was closed to the identity line, indicating that V-wave impact at muscle level seems to be similar to the impact of cortical stimulation. All these results suggest that change in V-wave amplitude is a great index to reflect changes in cortical neural drive addressed to spinal motoneurons.

  7. A review on energy harvesting approaches for renewable energies from ambient vibrations and acoustic waves using piezoelectricity

    Science.gov (United States)

    Ahmed, Riaz; Mir, Fariha; Banerjee, Sourav

    2017-08-01

    The principal objective of this article is to categorically review and compare the state of the art vibration based energy harvesting approaches. To evaluate the contemporary methodologies with respect to their physics, average power output and operational frequencies, systematically divided and easy readable tables are presented followed by the description of the energy harvesting methods. Energy harvesting is the process of obtaining electrical energy from the surrounding vibratory mechanical systems through an energy conversion method using smart structures, like, piezoelectric, electrostatic materials. Recent advancements in low power electronic gadgets, micro electro mechanical systems, and wireless sensors have significantly increased local power demand. In order to circumvent the energy demand; to allow limitless power supply, and to avoid chemical waste from conventional batteries, low power local energy harvesters are proposed for harvesting energy from different ambient energy sources. Piezoelectric materials have received tremendous interest in energy harvesting technology due to its unique ability to capitalize the ambient vibrations to generate electric potential. Their crystalline configuration allows the material to convert mechanical strain energy into electrical potential, and vice versa. This article discusses the various approaches in vibration based energy scavenging where piezoelectric materials are employed as the energy conversion medium.

  8. Research on resonance and antiresonance states of free stator of traveling wave ultrasonic motors

    Institute of Scientific and Technical Information of China (English)

    ZU Jiakui; ZHAO Chunsheng

    2004-01-01

    Under the condition of high-power drive, the experimental phenomena of free stator of traveling wave ultrasonic motor takes on strong nonlinear effects. Firstly, its corresponding theories are established to analyze and compare the stator's performances at the resonance and antiresonance states. At the same time, some important parameters, such as resonance/antiresonance frequency, mechanical quality, electro-mechanic coupling, and the relative vibration effect, are selected elaborately to evaluate the vibrational performances of free stator. Then, some experimental schemes based on the laser vibration measurement are designed respectively. Under the different drives conditions, the experimental characterizations of free stator at the resonance and antiresonance states are analyzed systematically. Finally, The investigative results show that the performance at the antiresonance state is much better than that at the resonance state. Some conclusions of this paper can provide novel idea and guidance for the choosing of the operating states and driving modes of traveling wave ultrasonic motor.

  9. A new traveling wave ultrasonic motor using thick ring stator with nested PZT excitation.

    Science.gov (United States)

    Chen, Weishan; Shi, Shengjun; Liu, Yingxiang; Li, Pei

    2010-05-01

    To avoid the disadvantages of conventional traveling wave ultrasonic motors--lower efficiency PZT working mode of d(31), fragility of the PZT element under strong excitation, fatigue of the adhesive layer under harsh environmental conditions, and low volume of the PZT material in the stator--a new type of traveling wave ultrasonic motor is presented in this paper. Here we implement the stator by nesting 64 PZT stacks in 64 slots specifically cut in a thick metal ring and 64 block springs nested within another 64 slots to produce preloading on the PZT stacks. In this new design, the d33 mode of the PZT is used to excite the flexural vibrations of the stator, and fragility of the PZT ceramics and fatigue of the adhesive layer are no longer an issue. The working principle, FEM simulation, fabrication, and performance measurements of a prototype motor were demonstrated to validate the proposed ideas. Typical output of the prototype motor is no-load speed of 15 rpm and maximum torque of 7.96 N x m. Further improvement will potentially enhance its features by increasing the accuracy in fabrication and adopting appropriate frictional material into the interface between the stator and the rotor.

  10. An Integrated Laser-Induced Piezoelectric/Differential Confocal Surface Acoustic Wave System for Measurement of Thin Film Young’s Modulus

    Directory of Open Access Journals (Sweden)

    Xiaotang Hu

    2012-09-01

    Full Text Available The present paper presents the design and development results of a system setup for measuring Young’s modulus of thin films by laser-induced surface acoustic waves based on the integration of two detection methods, namely, piezoelectric transducer detection and differential confocal detection, which may be used for conducting consecutive or simultaneous measurements. After demonstrating the capabilities of each detection approach, it is shown how, depending on a wider range of applications, sample materials and measurement environments, the developed integrated system inherits and harnesses the main characteristics of its detection channels, resulting in an more practical and flexible equipment for determining Young’s modulus than traditional nanoindentation equipment, and also suitable for cross-validation purposes.

  11. Non-local dynamic solution of two parallel cracks in a functionally graded piezoelectric material under harmonic anti-plane shear wave

    Science.gov (United States)

    Liu, Hai-Tao; Sang, Jian-Bing; Zhou, Zhen-Gong

    2016-10-01

    This paper investigates a functionally graded piezoelectric material (FGPM) containing two parallel cracks under harmonic anti-plane shear stress wave based on the non-local theory. The electric permeable boundary condition is considered. To overcome the mathematical difficulty, a one-dimensional non-local kernel is used instead of a two-dimensional one for the dynamic fracture problem to obtain the stress and the electric displacement fields near the crack tips. The problem is formulated through Fourier transform into two pairs of dual-integral equations, in which the unknown variables are jumps of displacements across the crack surfaces. Different from the classical solutions, that the present solution exhibits no stress and electric displacement singularities at the crack tips.

  12. Piezoelectric Film.

    Science.gov (United States)

    Garrison, Steve

    1992-01-01

    Presents activities that utilize piezoelectric film to familiarize students with fundamental principles of electricity. Describes classroom projects involving chemical sensors, microbalances, microphones, switches, infrared sensors, and power generation. (MDH)

  13. A model of TMS-induced I-waves in motor cortex.

    Science.gov (United States)

    Rusu, Cătălin V; Murakami, Max; Ziemann, Ulf; Triesch, Jochen

    2014-01-01

    Transcranial magnetic stimulation (TMS) allows to manipulate neural activity non-invasively, and much research is trying to exploit this ability in clinical and basic research settings. In a standard TMS paradigm, single-pulse stimulation over motor cortex produces repetitive responses in descending motor pathways called I-waves. However, the details of how TMS induces neural activity patterns in cortical circuits to produce these responses remain poorly understood. According to a traditional view, I-waves are due to repetitive synaptic inputs to pyramidal neurons in layer 5 (L5) of motor cortex, but the potential origin of such repetitive inputs is unclear. Here we aim to test the plausibility of an alternative mechanism behind D- and I-wave generation through computational modeling. This mechanism relies on the broad distribution of conduction delays of synaptic inputs arriving at different parts of L5 cells' dendritic trees and their spike generation mechanism. Our model consists of a detailed L5 pyramidal cell and a population of layer 2 and 3 (L2/3) neurons projecting onto it with synapses exhibiting short-term depression. I-waves are simulated as superpositions of spike trains from a large population of L5 cells. Our model successfully reproduces all basic characteristics of I-waves observed in epidural responses during in vivo recordings of conscious humans. In addition, it shows how the complex morphology of L5 neurons might play an important role in the generation of I-waves. In the model, later I-waves are formed due to inputs to distal synapses, while earlier ones are driven by synapses closer to the soma. Finally, the model offers an explanation for the inhibition and facilitation effects in paired-pulse stimulation protocols. In contrast to previous models, which required either neural oscillators or chains of inhibitory interneurons acting upon L5 cells, our model is fully feed-forward without lateral connections or loops. It parsimoniously explains

  14. 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...

  15. Modeling stick-slip-separation dynamics in a bimodal standing wave ultrasonic motor

    Science.gov (United States)

    Li, Xiang; Yao, Zhiyuan; Lv, Qibao; Liu, Zhen

    2016-11-01

    Ultrasonic motor (USM) is an electromechanical coupling system with ultrasonic vibration, which is driven by the frictional contact force between the stator (vibrating body) and the rotor/slider (driven body). Stick-slip motion can occur at the contact interface when USM is operating, which may affect the performance of the motor. This paper develops a physically-based model to investigate the complex stick-slip-separation dynamics in a bimodal standing wave ultrasonic motor. The model includes both friction nonlinearity and intermittent separation nonlinearity of the system. Utilizing Hamilton's principle and assumed mode method, the dynamic equations of the stator are deduced. Based on the dynamics of the stator and the slider, sticking force during the stick phase is derived, which is used to examine the stick-to-slip transition. Furthermore, the stick-slip-separation kinematics is analyzed by establishing analytical criteria that predict the transition between stick, slip and separation of the interface. Stick-slip-separation motion is observed in the resulting model, and numerical simulations are performed to study the influence of parameters on the range of possible motions. Results show that stick-slip motion can occur with greater preload and smaller voltage amplitude. Furthermore, a dimensionless parameter is proposed to predict the occurrence of stick-slip versus slip-separation motions, and its role in designing ultrasonic motors is discussed. It is shown that slip-separation motion is favorable for the slider velocity.

  16. Impedance control in a wave-based teleoperator for rehabilitation motor therapies assisted by robots.

    Science.gov (United States)

    Mendoza, Marco; Bonilla, Isela; González-Galván, Emilio; Reyes, Fernando

    2016-01-01

    This paper presents an improved wave-based bilateral teleoperation scheme for rehabilitation therapies assisted by robot manipulators. The main feature of this bilateral teleoperator is that both robot manipulators, master and slave, are controlled by impedance. Thus, a pair of motion-based adaptive impedance controllers are integrated into a wave-based configuration, in order to guarantee a stable human-robot interaction and to compensate the position drift, characteristic of the available schemes of bilateral teleoperation. Moreover, the teleoperator stability, in the presence of time delays in the communication channel, is guaranteed because the wave-variable approach is included to encode the force and velocity signals. It should be noted that the proposed structure enables the implementation of several teleoperator schemes, from passive therapies, without the intervention of a human operator on the master side, to fully active therapies where both manipulators interact with humans in a stable manner. The suitable performance of the proposed teleoperator is verified through some results obtained from the simulation of the passive and active-constrained modes, by considering typical tasks in motor-therapy rehabilitation, where an improved behavior is observed when compared to implementations of the classical wave-based approach.

  17. 基于含金属芯压电纤维与Lamb波的一维结构损伤定位研究%Damage Localization Based On metal-core piezoelectric ceramic fiber and Lamb wave

    Institute of Scientific and Technical Information of China (English)

    刘建; 裘进浩; 常伟杰; 季宏丽; 朱孔军

    2011-01-01

    含金属芯压电纤维(Metal-core Piezoelectric Ceramic Fiber,MPF)是一种新型压电功能器件.介绍了MPF的结构及其对圆形压电片激励Lamb波的传感响应模型.利用Gabor小波变换计算损伤反射信号到达时间延迟的原理,把MPF传感单一模式Lamb波在一维结构中进行了损伤定位研究.研究结果表明:MPF可以进行Lamb波的单一模式传感,采用Gabor小波变换计算损伤反射信号到达时间延迟效果较好,损伤定位精度较高.%Metal-core piezoelectric ceramic fiber (MPF) is a new type piezoelectric ceramic device. Its configuration and response to Lamb wave fields excited by a circular crested actuator were presented here. According to calculating time delays of damage signals with Gabor wavelet transformation, MPF sensing single-mode Lamb waves to be used in one-dimensional structural damage localization was investigated. Results showed that MPF can be used as a sensor for single mode Lamb wave; its performance of calculating time delays of damage signals with Gabor wavelet transformation is good; the damage localization accuracy is also high.

  18. Ciliae-based actuator with piezoelectric excitation

    Science.gov (United States)

    Pott, Peter P.; Carrasco, Alvaro; Schlaak, Helmut F.

    2012-06-01

    Small actuators based on the inverse piezoelectric effect are successfully deployed in commercial applications. Usually, ultrasonic motors are used. Based on resonance effects these motors provide a pronounced nonlinearity at low speeds and thus put high demands on the control algorithm. In contrast, piezoelectric stepping motors are mechanically complex and provide only low speeds. The contribution at hand describes a proposed design for a new piezoelectric motor based on cilia friction that can be manufactured at low costs. The cilia are made from uniaxial carbon-fibre reinforced plastics. The derived CFRP-brushes are pressed perpendicularly to the rotor surface to produce force or torque. First experiments prove the feasibility of the concept. A net pushing force of 500 mN is achieved.

  19. Elastic contact conditions to optimize friction drive of surface acoustic wave motor.

    Science.gov (United States)

    Kuribayashi Kurosawa, M; Takahashi, M; Higuchi, T

    1998-01-01

    The optimum pressing force, namely the preload, for a slider to obtain superior operation conditions in a surface acoustic wave motor have been examined. We used steel balls as sliders. The preload was controlled using a permanent magnet. The steel balls were 0.5, 1, and 2 mm diameter, with the differences in diameter making it possible to change contact conditions, such as the contact pressure, contact area, and deformation of the stator and the slider. The stator transducer was lithium niobate, 128 degrees rotated, y-cut x-propagation substrate. The driving frequency of the Rayleigh wave was about 10 MHz. Hence, the particle vibration amplitude at the surface is as small as 10 nm. For superior friction drive conditions, a high contact pressure was required. For example, in the case of the 1 mm diameter steel ball at the sinusoidal driving voltage of 180 V(peak), the slider speed was 43 cm/sec, the thrust output force was 1 mN, and the acceleration was 23 times as large as the gravitational acceleration at a contact pressure of 390 MPa. From the Hertz theory of contact stress, the contact area radius was only 3 microm. The estimation of the friction drive performance was carried out from the transient traveling distance of the slider in a 3 msec burst drive. As a result, the deformation of the stator and the slider by the preload should be half of the vibration amplitude. This condition was independent of the ball diameter and the vibration amplitude. The output thrust per square millimeter was 50 N, and the maximum speed was 0.7 m/sec. From these results, we conclude that it is possible for the surface acoustic wave motor to have a large output force, high speed, quick response, long traveling distance, and a thin micro linear actuator.

  20. The analysis of the effect of homogeneous mechanical stress on the acoustic wave propagation in the "La3Ga5SiO14/fused silica" piezoelectric layered structure.

    Science.gov (United States)

    Burkov, S I; Zolotova, O P; Sorokin, B P; Turchin, P P

    2015-01-01

    The results of computer simulation taking into account the linear and nonlinear material constants have been presented. Study of the influence of external uniaxial mechanical stress on the dispersive characteristics of elastic waves in piezoelectric structures as "La3Ga5SiO14/fused silica" has been executed. The comparison of elastic wave velocity changes under the influence of an uniaxial stress while a full set of nonlinear material constants of crystalline layer+geometric nonlinearity, or only geometric nonlinearity of the layer induced by the static deformation of a substrate, has been fulfilled.

  1. 界面缺陷对压电薄层复合结构中Love波的影响%Effect of interfacial defect on Love waves in composite structures with piezoelectric thin film

    Institute of Scientific and Technical Information of China (English)

    王惠明; 赵志城

    2012-01-01

    基于剪切弹簧模型,建立考虑界面缺陷情形的弹性基底上覆盖压电薄层的复合结构中Love波的频散方程,并研究界面缺陷对Love波传播特性的影响,给出铝基底上覆盖PZT4压电薄层复合结构中Love波的频散曲线.数值结果表明:(1)对于长波情形,不同缺陷程度复合结构的Love波一阶模态的相速度均趋于弹性基底层的剪切波波速,而对于短波情形,则趋于压电薄层的Bleustein-Gulyaev(B-G)波波速;(2)界面缺陷的存在总是降低该复合结构内Love波的相速度,在一些特殊频率范围,Love波的相速度对界面缺陷非常敏感;(3)界面缺陷对压电层内的机械位移模态和电势模态有显著影响,且影响最大区域出现在界面附近.%Based on the shear spring model, the dispersion equation was established for Love waves propagating in a composite structure with interfacial defect. The composite structure consists of an elastic substrate covered by a piezoelectric thin film. The effect of the interfacial defect on the propagation properties of Love waves was investigated. The dispersion curves were presented for Love waves propagating in an aluminum substrate covered by a PZT4 piezoelectric thin film. Numerical results show that; (1) For different interfacial defects, the phase velocities of Love waves of the first mode at long wavelength region approach to the velocities of shear waves in elastic substrate, while those at short wavelength region approach to the velocities of Bleustein-Gulyaev (B-G) waves in piezoelectric thin film; (2) The existence of the interfacial defect always decreases the phase velocities of Love waves. At some special frequency ranges, the phase velocities of Love waves are more sensitive to the interfacial defect; (3) The interfacial defect has significant effect on the mode shapes of the mechanical displacement and the electric potential in the piezoelectric thin film, and the most susceptive region appears near

  2. Perfectly matched layer stability in 3-D finite-difference time-domain simulation of electroacoustic wave propagation in piezoelectric crystals with different symmetry class.

    Science.gov (United States)

    Nova, Omar; Peña, Néstor; Ney, Michel

    2015-03-01

    Perfectly matched layer stability in 3-D finite-difference time-domain simulations is demonstrated for two piezoelectric crystals: barium sodium niobate and bismuth germanate. Stability is achieved by adapting the discretization grid to meet a central-difference scheme. Stability is demonstrated by showing that the total energy of the piezoelectric system remains constant in the steady state.

  3. F-wave of single firing motor units: correct or misleading criterion of motoneuron excitability in humans?

    Science.gov (United States)

    Kudina, Lydia P; Andreeva, Regina E

    2017-03-01

    Motoneuron excitability is a critical property for information processing during motor control. F-wave (a motoneuronal recurrent discharge evoked by a motor antidromic volley) is often used as a criterion of motoneuron pool excitability in normal and neuromuscular diseases. However, such using of F-wave calls in question. The present study was designed to explore excitability of single low-threshold motoneurons during their natural firing in healthy humans and to ascertain whether F-wave is a correct measure of motoneuronal excitability. Single motor units (MUs) were activated by gentle voluntary muscle contractions. MU peri-stimulus time histograms and motoneuron excitability changes within a target interspike interval were analysed during testing by motor antidromic and Ia-afferent volleys. It was found that F-waves could be occasionally recorded in some low-threshold MUs. However, during evoking F-wave, in contrast with the H-reflex, peri-stimulus time histograms revealed no statistically significant increase in MU discharge probability. Moreover, surprisingly, motoneurons appeared commonly incapable to fire a recurrent discharge within the most excitable part of a target interval. Thus, the F-wave, unlike the H-reflex, is the incorrect criterion of motoneuron excitability resulting in misleading conclusions. However, it does not exclude the validity of the F-wave as a clinical tool for other aims. It was concluded that the F-wave was first explored in low-threshold MUs during their natural firing. The findings may be useful at interpretations of changes in the motoneuron pool excitability in neuromuscular diseases.

  4. Research on a Linear Piezoelectric Motor Working in Low Frequency with Unlimit Travel Range%一种低频大行程直线型压电电机的研究

    Institute of Scientific and Technical Information of China (English)

    李艳林; 黄卫清

    2009-01-01

    基于叠层式压电陶瓷在低频带范围内的变形幅值大,与驱动电压线性度好且基本不随驱动频率变化的特点,提出并研制了一种低频大行程直线型压电电机.与共振式压电电机相比,该电机在低频范围内输出速度与驱动频率的线性度好,可控性较好.对电机的工作机理进行了分析,同时利用有限元软件对电机的结构进行设计,并试制了原理样机.实验结果表明,电机可在100 Hz~2 kHz的频带工作,其速度在100 Hz~1 kHz的频带内基本和频率成正比,最大空载速度为60 mm/min.%Based on characteristic of piezoelectric stack, such as the amplitude of displacement was big, linear to the driving voltage and almost the same at low frequency, a linear motor based on non-resonant vibration of piezoelectric ceramics stack was investigated. In contrast to the ultrasonic motor with resonant vibration, the speed of this motor was linear to the driving frequency and the control performance was more acceptable at low frequency. The working principle of the motor was presented. The structure was designed by finite element software. The motor could work in the frequency between 100 Hz and 2 kHz with virtually unlimited travel rang. And the highest no-load speed was 60 mm/min. In the frequency between the 100 Hz and 1 kHz, the speed of stator was linear to the driving frequency.

  5. Doping effects of CuO additives on the properties of low-temperature-sintered PMnN-PZT-based piezoelectric ceramics and their applications on surface acoustic wave devices.

    Science.gov (United States)

    Tsai, Cheng-Che; Chu, Sheng-Yuan; Lu, Chun-Hsien

    2009-03-01

    To develop the anisotropic ceramic substrate with low sintering temperature for surface acoustic wave (SAW) applications, the low cost and feasible material with moderate piezoelectric properties, good dielectric properties, and higher Curie temperature were explored. The piezoelectric ceramics with compositions of Pb[(Mn(1/3)Nb(2/3))(0.06-) (Zr(0.52)Ti(0.48))0.94] O(3) (PMnN-PZT) + 0.5 wt.% PbO + x wt.% CuO (0.05 = x = 0.3) had been prepared by the conventional mixed-oxides method. CuO dopants were used as the sintering aid to improve the bulk density under low sintering temperature (i.e., 980-1040 degrees C). The phase structures, microstructures, frequency behavior of dielectric properties (up to 50 MHz), piezoelectric properties, ferroelectric properties, and temperature stability with the amount of CuO additive were systematically investigated. Experimental results showed that the sintering temperature could be lowered down to 1020 degrees C and still keep reasonably good piezoelectric activity (i.e., high electromechanical coupling factor (k(p)), (k(t)) and dielectric and ferroelectric properties. The preferable composition, obtained at x = 0.1, presented the values of the electromechanical coupling factor (k(p)) (k(t)), mechanical quality factor (Q(m)), piezoelectric charge constant (d(33)), dielectric constant, dielectric loss, temperature coefficient of resonant frequency (TCF(B)), and Curie point (T(c)) of 0.54, 0.48, 850, 238 pc/N, 1450, 0.0023, 1.1 kV/mm, 26 coul/cm(2), -150 ppm/ degrees C, and 348 degrees C. Using this developed low-temperature-sintered material to make the piezoelectric substrate, the SAW filter was fabricated and its properties were measured. Results showed that this device possessed very high value of k(2)(7.13%) with a good TCF (-40.15 ppm/ degrees C), and a surface wave velocity (V(P)) of 2196 m/s.

  6. Characteristics Analysis of Square Wave BLDC Motor Considering Magnetization Distribution of Permanent Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Byung Il; Park, Seung Chan [Hanyang University (Korea, Republic of); Im, Tae Bin [Korea Electronics Technology Institute (Korea, Republic of); Kang, Young Gyu [Samsung Electro-Mechanics R and D Center (Korea, Republic of)

    1998-04-01

    This paper deals with the characteristics analysis of a permanent magnet brushless DC(BLDC) motor. The analysis method is to utilize the time-stepped finite element method considering the square wave voltage of MOS FET inverter. The system matrix that unknown parameters are magnetic vector potentials at nodes and phases currents is constructed through the finite element formulation and circuit equations, and then solved by bi-conjugate gradient(BCG) method. The analyzed model has a inner rotor which is consisted of a permanent magnet of ring shape and a laminated steel core. The current carrying free-wheeling diode of inverter is neglected because of low value of the winding inductance of motor. The magnetization distribution in the permanent magnet i determined by solving inverse problem that the calculated flux densities values on the surface of the permanent magnet are led to the same values that measured by gauss meter. And then, torque and phase currents, which are calculated by finite element analysis are compared with experimental values. (author). 12 refs., 17 figs., 2 tabs.

  7. 含金属芯压电纤维传感Lamb波方向性研究%Study of directivity of metal-core piezoelectric fiber sensing Lamb waves*

    Institute of Scientific and Technical Information of China (English)

    刘建; 裘进浩; 常伟杰; 季宏丽; 朱孔军

    2011-01-01

    Metal-core piezoelectric ceramic fiber (MPF) is a new type of piezoelectric ceramic device. The calculating principle of Lamb wave energy factor based on wavelet transform is introduced. MPF is used as sensor of Lamb wave. The directivity of MPF sensing Lamb wave is researched using amplitude and wavelet transform energy factor method respectively. Results show that MPF has high directivity to sense Lamb wave, the directivity characterized by wavelet transformation energy factor shows more clear in comparison with amplitude.%含金属芯压电纤维(MPF)是一种新型压电功能器件.阐述了基于小波变换的Lamb波能量因子计算原理,把MPF作为Lamb波传感器,分别采用幅值和小波变换能量因子的方法对MPF传感Lamb波的方向性进行了研究.研究结果表明:MPF对Lamb波的传感表现出很强的方向性.相比采用幅值表征的结果,采用能量因子进行传感方向性表征更能体现出MPF对Lamb波的方向性传感特性.

  8. Advances in Piezoelectric Systems: An Application-Based Approach

    DEFF Research Database (Denmark)

    Zsurzsan, Tiberiu-Gabriel

    . First, the capacitive behavior is studied, with the Piezoelectric Actuator Drive motor as a direct application. At low frequencies, piezoelectric devices are ideal as micro-and nanoscale positioning actuators but they are plagued by high levels of hysteretic nonlinearities. A model is developed...

  9. Piezoelectric particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Mark A.; Jongewaard, Erik N.; Haase, Andrew A.; Franzi, Matthew

    2017-08-29

    A particle accelerator is provided that includes a piezoelectric accelerator element, where the piezoelectric accelerator element includes a hollow cylindrical shape, and an input transducer, where the input transducer is disposed to provide an input signal to the piezoelectric accelerator element, where the input signal induces a mechanical excitation of the piezoelectric accelerator element, where the mechanical excitation is capable of generating a piezoelectric electric field proximal to an axis of the cylindrical shape, where the piezoelectric accelerator is configured to accelerate a charged particle longitudinally along the axis of the cylindrical shape according to the piezoelectric electric field.

  10. High-amplitude THz and GHz strain waves, generated by ultrafast screening of piezoelectric fields in InGaN/GaN multiple quantum wells

    DEFF Research Database (Denmark)

    Porte, Henrik; van Capel, P.J.S.; Turchinovich, Dmitry

    2010-01-01

    Screening of large built-in piezoelectric fields in InGaN/GaN quantum wells leads to high-amplitude acoustic emission. We will compare acoustic emission by quantum wells with different thicknesses with photoluminescence; indicating screening.......Screening of large built-in piezoelectric fields in InGaN/GaN quantum wells leads to high-amplitude acoustic emission. We will compare acoustic emission by quantum wells with different thicknesses with photoluminescence; indicating screening....

  11. Analysis of piezoelectric structures and devices

    CERN Document Server

    Chen, Weiqiu; Wang, Ji

    2013-01-01

    This edited work covers piezoelectric materials in the form of beams, plates, shells, and other structural components in modern devices and structures. Applications are frequency control and detection functions in resonators, sensors, actuators, oscillations, and other smart and intelligent structures. The contributions cover novel methods for the analysis of piezoelectric structures including wave propagation, high frequency vibration, material characterization, and optimization of structures. Understanding of these methods is increasingly important in the design and modelling of next generat

  12. Derivation of Piezoelectric Losses from Admittance Spectra

    Science.gov (United States)

    Zhuang, Yuan; Ural, Seyit O.; Rajapurkar, Aditya; Tuncdemir, Safakcan; Amin, Ahmed; Uchino, Kenji

    2009-04-01

    High power density piezoelectrics are required to miniaturize devices such as ultrasonic motors, transformers, and sound projectors. The power density is limited by the heat generation in piezoelectrics, therefore, clarification of the loss mechanisms is necessary. This paper provides a methodology to determine the electromechanical losses, i.e., dielectric, elastic and piezoelectric loss factors in piezoelectrics by means of a detailed analysis of the admittance/impedance spectra. This method was applied to determine the piezoelectric losses for lead zirconate titanate ceramics and lead magnesium niobate-lead titanate single crystals. The analytical solution provides a new method for obtaining the piezoelectric loss factor, which is usually neglected in practice by transducer designers. Finite element simulation demonstrated the importance of piezoelectric losses to yield a more accurate fitting to the experimental data. A phenomenological model based on two phase-shifts and the Devonshire theory of a polarizable-deformable insulator is developed to interpret the experimentally observed magnitudes of the mechanical quality factor at resonance and anti-resonance.

  13. The effects of the use of piezoelectric motors in a 1.5-Tesla high-field magnetic resonance imaging system (MRI).

    Science.gov (United States)

    Wendt, O; Oellinger, J; Lüth, T C; Felix, R; Boenick, U

    2000-01-01

    This paper presents the results of an experimental investigation with two different rotatory piezomotors in a closed 1.5 Tesla high-field MRI. The focus of the investigation was on testing the functionality of these motors within the MRI and to determining the image interference they caused. To obtain a differentiated estimate of the interference the motors were tested in both the passive (turned off, i.e. without current flow) and active (turned on, i.e. with current flow) state during MRI scanning. Three different types of sequences were used for the test: Spin-Echo (SE), Gradient-Echo (GE) and Echo-Planar Imaging (EPI). A plastic container filled with a gadolinium-manganese solution was used for representation of the artefacts. The motors investigated were placed parallel to the container at predetermined distances during the experiment. The results show that the motors investigated suffered no functional limitations in the magnetic field of the MRI but, depending on the type of motor, the measurement distance and the state of the motor, the motors had different effects on the sequence images. A motor in the off-state placed immediately next to the object to be measured mainly causes artefacts because of its material properties. If, on the other hand, the piezomotor is in the on-state images with strong noise result when the motor is immediately next to the object being measured. The images regain their normal quality when the motor is approximately at a distance of 1 m from the object being investigated. Driving the motor inside the MRI, therefore, is only to be recommended during the pauses in scanning: this delivers artefact-free images if minimal, motor-specific distances are kept to. With regard to the three different types of sequences it was determined that the SE sequence was the least sensitive and the EPI sequence the most sensitive to disturbance. The GE sequence showed only minimal differences to the SE sequence with regard to signal-to-noise ratios

  14. A novel two-degree-of-freedom spherical ultrasonic motor using three travelling-wave type annular stators

    Institute of Scientific and Technical Information of China (English)

    王剑; 胡锡幸; 王班; 郭吉丰

    2015-01-01

    In order to promote the tolerance and controllability of the multi-degree-of-freedom (M-DOF) ultrasonic motor, a novel two-degree-of-freedom (2-DOF) spherical ultrasonic motor using three traveling-wave type annular stators was put forward. Firstly, the structure and working principle of this motor were introduced, especially a spiral spring as the preload applied component was designed for adaptive adjustment. Then, the friction drive model of 2-DOF spherical motor was built up from spatial geometric relation between three annular stators and the spherical rotor which was used to analyze the mechanical characteristics of the motor. The optimal control strategy for minimum norm solution of three stators’ angular velocity was proposed, using Moore-Penrose generalized inverse matrix. Finally, a 2-DOF prototype was fabricated and tested, which ran stably and controllably. The maximum no-load velocity and stall torque are 92 r/min and 90 mN·m, respectively. The 2-DOF spherical ultrasonic motor has compact structure, easy assembly, good performance and stable operation.

  15. 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...... exhibited by piezoelectric ceramics causes losses. Therefore, this paper presents a straightforward method to measure piezoelectric stack actuator equiv- alent parameters that includes nonlinearities. By folding the nonlinearities into a newly-defined cou- pling coefficient, the inherent hysteretic behavior...... of piezoelectric stack actuators can be greatly reduced through precompensation. Experimental results show a fitting accuracy of 98.8 % between the model and measurements and a peak absolute error reduction by a factor of 10 compared to the manufacturer- provided parameter. This method improves both the static...

  16. 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

  17. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Delvendahl, Igor; Pechmann, Astrid;

    2012-01-01

    Transcranial magnetic stimulation (TMS) commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor...... hand area (M1-HAND), if the induced tissue current has a posterior-to-anterior (PA) or anterior-to-posterior (AP) direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration....

  18. Conceptual design and application studies of piezoelectric crystal motors under ultra-high vacuum conditions; Konzepterstellung und Verwendungsmoeglichkeiten eines Piezokristallmotors im Ultrahochvakuum

    Energy Technology Data Exchange (ETDEWEB)

    Nagler, Jens

    2009-08-15

    For the operation of accelerators it is important that motions in the vacuum occur. The here produced diploma thesis deals with the possibility to perform thes motions with piezocrystal motors in order to abandon wear-susceptible membrane bellows. For this studies have been performed, which should show for which it is useful to apply a piezocrystal motor. Limits are shown, advances and disadvantages are weighted in the thesis. Construction with with subsequent test of a tandem facility and an outlook on possible future concepts form the main content. [German] Fuer den Betrieb von Beschleunigern ist es wichtig, dass Bewegungen im Vakuum stattfinden. Die hier angefertigte Diplomarbeit befasst sich mit der Moeglichkeit, diese Bewegungen mit Piezokristallmotoren durchzufuehren, um auf verschleissanfaellige Membranbaelge zu verzichten. Hierfuer sind Studien durchgefuehrt worden, die zeigen sollen, wofuer es ratsam ist, einen Piezokristallmotor zu verwenden. Grenzen werden aufgezeigt, Vor- und Nachteile werden in der Arbeit abgewogen. Konstruktion mit anschliessenden Tests eines Tandemaufbaus und ein Ausblick auf moegliche zukuenftige Konzepte bilden den Kerninhalt. (orig.)

  19. Explosive Line Wave Generators

    Science.gov (United States)

    2013-12-01

    curvature produced by each line wave generator. Piezoelectric pins were used for an additional assessment of the explosive lens design...to a visual assessment of the wave curvature from the high speed camera images, the explosive lens design was also evaluated using piezoelectric pins...High Explosive Firing Complex (HEFC). The various explosive line wave generators were taped vertically on a supporting board and the detonation wave

  20. Performance improvement of rectangular-plate linear ultrasonic motors using dual-frequency drive.

    Science.gov (United States)

    Ming, Yang; Richardson, Robert C; Levesley, Martin C; Walker, Peter G; Watterson, Kevin

    2004-12-01

    To improve the performances of a rectangular-plate linear ultrasonic motor for specific applications, a dual-frequency drive has been proposed and investigated. Through careful design of the rectangular piezoelectric ceramic plate, its first longitudinal resonant frequency coincides with its second lateral bending resonant frequency and is one-third of its higher lateral bending resonant frequency. When a square-wave voltage is used to drive the motor, its first longitudinal and second bending and the higher bending vibration modes are excited. Experimental results show that the maximum thrust force and maximum velocity of the motor are over 170% of those obtained from the single-frequency sine-wave drive when the voltage performance of the motor becomes saturated.

  1. Gross motor control

    Science.gov (United States)

    Gross motor control is the ability to make large, general movements (such as waving an arm or lifting a leg). ... Gross motor control is a milestone in the development of an infant. Infants develop gross motor control before they develop ...

  2. A piezoelectric transformer

    Science.gov (United States)

    Won, C. C.

    1993-01-01

    This work describes a modeling and design method whereby a piezoelectric system is formulated by two sets of second-order equations, one for the mechanical system, and the other for the electrical system, coupled through the piezoelectric effect. The solution to this electromechanical coupled system gives a physical interpretation of the piezoelectric effect as a piezoelectric transformer that is a part of the piezoelectric system, which transfers the applied mechanical force into a force-controlled current source, and short circuit mechanical compliance into capacitance. It also transfers the voltage source into a voltage-controlled relative velocity input, and free motional capacitance into mechanical compliance. The formulation and interpretation simplify the modeling of smart structures and lead to physical insight that aids the designer. Due to its physical realization, the smart structural system can be unconditional stable and effectively control responses. This new concept has been demonstrated in three numerical examples for a simple piezoelectric system.

  3. Piezoelectric Wheel System

    Science.gov (United States)

    Juang, Puu-An

    2007-10-01

    A piezoelectric wheel system is proposed for used as a microstepping displacement device including a carrier and two displacement members, which are separately pivoted on the carrier. Each displacement member includes two wheels, and which can not rotate. In addition, each wheel includes a wheel sheet and a piezoelectric element embedded on its surface. When the piezoelectricity element generates and transmits power to the wheel sheet, the wheel induces vibration and deformation. Therefore, owing to the wheel sheets and the touched ground involving their relative motion, the displacement device can be moved or can be oriented its motion direction. The wheel system involves direct movement, and has no rotor requirement. In this research, a three-dimensional (3D) mechanical element with an extra electrical degree of freedom is employed to simulate the dynamic vibration modes of the linear piezoelectric, mechanical, and piezoelectric-mechanical behaviours of the piezoelectric wheel.

  4. Growth of piezoelectric crystals by Czochralski method

    OpenAIRE

    Cochet-Muchy, D.

    1994-01-01

    The Czochralski method is one of the most widely used industrial technique to grow single-crystals, since it applies to a very large range of compounds, such as semiconductors, oxides, fluorides, etc... Many exhibit piezoelectric properties and some of them find applications in Surface-Acoustic-Waves or Bulk-Acoustic-Waves devices. That explains the large amount of work made on the development of the corresponding growth processes and the high levels of production achieved in the world today....

  5. Piezoelectric energy harvesting

    CERN Document Server

    Erturk, Alper

    2011-01-01

    The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-

  6. Advanced Mechanics of Piezoelectricity

    CERN Document Server

    Qin, Qing-Hua

    2013-01-01

    "Advanced Mechanics of Piezoelectricity" presents a comprehensive treatment of piezoelectric materials using linear electroelastic theory, symplectic models, and Hamiltonian systems. It summarizes the current state of practice and presents the most recent research findings in piezoelectricity. It is intended for researchers and graduate students in the fields of applied mechanics, material science and engineering, computational engineering, and aerospace engineering. Dr. Qinghua Qin is a professor at the School of Engineering, Australian National University, Australia.

  7. Extracorporeal piezoelectric lithotripsy for retained bile duct stones.

    Science.gov (United States)

    Weber, J; Adamek, H E; Riemann, J F

    1992-05-01

    Extracorporeal piezoelectric shock wave lithotripsy (EPL) was performed in 35 patients with endoscopically non-extractable stones. With this lithotripter, stones are visualized by ultrasound and shock waves are produced by a piezoelectric acoustic generator. The stones could be localized in 32 out of 35 patients. Fragmentation was achieved in 91.4% and complete stone removal in 77.1%. These results show that piezoelectric lithotripsy is also a useful method for the treatment of complicated bile duct stones, as already demonstrated for the electrohydraulically and electromagnetically generated shock waves systems. The piezoelectric system is especially useful in elderly and frail patients because no general anesthesia is needed and only 14% of cases require analgesia or sedation.

  8. Hybrid thermoelectric piezoelectric generator

    Science.gov (United States)

    Montgomery, D. S.; Hewitt, C. A.; Carroll, D. L.

    2016-06-01

    This work presents an integration of flexible thermoelectric and piezoelectric materials into a single device structure. This device architecture overcomes several prohibitive issues facing the combination of traditional thermoelectric and piezoelectric generators, while optimizing performance of the combined power output. The structure design uses a carbon nanotube/polymer thin film as a flexible thermoelectric generator that doubles as an electrode on a piezoelectric generator made of poly(vinylidene fluoride). An example 2 × 2 array of devices is shown to generate 89% of the maximum thermoelectric power, and provide 5.3 times more piezoelectric voltage when compared with a traditional device.

  9. Analytical modeling and experimental validation of a V-shape piezoelectric ultrasonic transducer

    Science.gov (United States)

    Li, Xiaoniu; Yao, Zhiyuan

    2016-07-01

    In this paper, an analytical model of a V-shape piezoelectric ultrasonic transducer is presented. The V-shape piezoelectric ultrasonic transducer has been widely applied to the piezoelectric actuator (ultrasonic motor), ultrasonic aided fabrication, sensor, and energy harvesting device. The V-shape piezoelectric ultrasonic transducer consists of two Langevin-type transducers connected together through a coupling point with a certain coupling angle. Considering the longitudinal and lateral movements of a single beam, the symmetrical and asymmetrical modals of the V-shape piezoelectric ultrasonic transducer are calculated. By using Hamilton-Lagrange equations, the electromechanical coupling model of the V-shape piezoelectric ultrasonic transducer is proposed. The influence of the coupling angle and cross-section on modal characteristics and electromechanical coupling coefficient are analyzed by the analytical model. A prototype of the V-shape piezoelectric ultrasonic transducer is fabricated, and the results of the experiments are in good agreement with the analytical model.

  10. 微型化矩形振子近似行波型直线超声波电动机%Quasi-Traveling Wave Ultrasonic Linear Motor Using a Miniature Rectangular Vibrator

    Institute of Scientific and Technical Information of China (English)

    张顺鑫; 李朝东

    2012-01-01

    With the aim of realizing quasi-traveling wave drive in ultrasonic linear micromotor, a novel quasi-traveling wave ultrasonic linear motor using a ring type rectangular vibrator with the size of 39 mmx6 mmxl2. 7 mm was proposed. Combined with the finite element modal analysis, the motor operating principle was described, that the traveling wave was excited and propagated along the ring type rectangular vibrator depending on the superposition of two orthogonal flexural-vi-bration modes with a spatial phase shift of 90 degrees. 7 piezoelectric ceramic elements were used to excite two working modes of the vibrator. In order to amplify the amplitude, the comb-tooth structure was designed in the bottom of the vibrator. The vibrator structure was designed and eigenfrequency degeneration was realized by Finite Element Analysis ( FEA) method. The modal test showed that the design scheme was tenable. The excitation and propagation of quasi-traveling wave was proved by tip rotation direction test. The trial motor gave a maximum driving velocity of 162. 5 mm/s and a maximum load of 8. 5 N,while the excitation frequency was 66 kHz and voltage peak-peak was 160 V. The motor can satisfy the preliminary design objective.%探索了在微型直线超声波电动机中实现近似行波驱动的途径,研制了一种外形尺寸为39 mm×6 mm×12.7 mm的环状矩形振子近似行波型直线超声波电动机.结合电机振子的有限元模态分析,阐述了依靠激发空间相位差为90°的两个正交弯曲振动模态,实现行波在环状矩形振子上被激发和传播的电机运动原理.使用7块压电陶瓷片来分别激发振子的两个工作模态.在振子底部设计了梳齿状结构,以放大振幅.利用有限元法进行结构设计,使两个工作模态的频率简并.通过激光测振,证实了电机振子设计方案的有效性.通过对实际样机的驱动齿旋向测试,初步证实近似行波的形成及传播的存在.初步的样机特

  11. Introduction to ultrasonic motors

    Energy Technology Data Exchange (ETDEWEB)

    Sashida, Toshiiku; Kenjo, Takashi.

    1993-01-01

    The ultrasonic motor, invented in 1980, utilizes the piezoelectric effect in the ultrasonic frequency range to provide the motive force. (In conventional electric motors the motive force is electromagnetic.) The result is a motor with unusually good low-speed high-torque and power-to-weight characteristics. It has already found applications in camera autofocus mechanisms, medical equipment subject to high magnetic fields, and motorized car accessories. Its applications will increase as designers become more familiar with its unique characteristics. This book is the result of a collaboration between the inventor and an expert in conventional electric motors: the result is an introduction to the general theory presented in a way that links it to conventional motor theory. It will be invaluable both to motor designers and to those who design with and use electric motors as an introduction to this important new invention.

  12. Piezoelectric cantilever sensors

    Science.gov (United States)

    Shih, Wan Y. (Inventor); Shih, Wei-Heng (Inventor); Shen, Zuyan (Inventor)

    2008-01-01

    A piezoelectric cantilever with a non-piezoelectric, or piezoelectric tip useful as mass and viscosity sensors. The change in the cantilever mass can be accurately quantified by monitoring a resonance frequency shift of the cantilever. For bio-detection, antibodies or other specific receptors of target antigens may be immobilized on the cantilever surface, preferably on the non-piezoelectric tip. For chemical detection, high surface-area selective absorbent materials are coated on the cantilever tip. Binding of the target antigens or analytes to the cantilever surface increases the cantilever mass. Detection of target antigens or analytes is achieved by monitoring the cantilever's resonance frequency and determining the resonance frequency shift that is due to the mass of the adsorbed target antigens on the cantilever surface. The use of a piezoelectric unimorph cantilever allows both electrical actuation and electrical sensing. Incorporating a non-piezoelectric tip (14) enhances the sensitivity of the sensor. In addition, the piezoelectric cantilever can withstand damping in highly viscous liquids and can be used as a viscosity sensor in wide viscosity range.

  13. Droplets Fusion in a Microchannel on a Piezoelectric Substrate

    OpenAIRE

    Fu Xiang-ting; Zha Yan; Zhang An-liang

    2013-01-01

    Fusion droplets is a key operation in a microfluidic device for microfluidic analysis. A new fusion method for droplets was presented. An interditigal transducer and a reflector were fabricated on 1280-yx LiNbO3 piezoelectric substrate using microelectric technology. A poly-dimethyl silicone micro-channel was made by soft lithography technology and mounted on the piezoelectric substrate. Droplets in the microchannel were actuated by surface acoustic wave and fussed each other. Coloured dye so...

  14. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    Directory of Open Access Journals (Sweden)

    Jung Nikolai H

    2012-11-01

    Full Text Available Abstract Background Transcranial magnetic stimulation (TMS commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor hand area (M1-HAND, if the induced tissue current has a posterior-to-anterior (PA or anterior-to-posterior (AP direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration. Results In 10 young participants, we applied half-sine pulses to the right M1-HAND which elicited PA or AP currents with respect to the orientation of the central sulcus. Measurements of the motor evoked potential (MEP revealed that PA half-sine stimulation resulted in lower resting motor threshold (RMT than AP stimulation. When stimulus intensity (SI was gradually increased as percentage of maximal stimulator output, the stimulus–response curve (SRC of MEP amplitude showed a leftward shift for PA as opposed to AP half-sine stimulation. Further, MEP latencies were approximately 1 ms shorter for PA relative to AP half-sine stimulation across the entire SI range tested. When adjusting SI to the respective RMT of PA and AP stimulation, the direction-specific differences in MEP latencies persisted, while the gain function of MEP amplitudes was comparable for PA and AP stimulation. Conclusions Using half-sine pulse configuration, single-pulse TMS elicits consistent direction-specific effects in M1-HAND that are similar to TMS with monophasic pulses. The longer MEP latency for AP half-sine stimulation suggests that PA and AP half-sine stimulation preferentially activates different sets of cortical neurons that are involved in the generation of different corticospinal descending volleys.

  15. Notes on Piezoelectricity

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-03

    These notes provide a pedagogical discussion of the physics of piezoelectricity. The exposition starts with a brief analysis of the classical (continuum) theory of piezoelectric phenomena in solids. The main subject of the notes is, however, a quantum mechanical analysis. We first derive the Frohlich Hamiltonian as part of the description of the electron-phonon interaction. The results of this analysis are then employed to derive the equations of piezoelectricity. A couple of examples with the zinc blende and and wurtzite structures are presented at the end

  16. 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

  17. Interfacial effects in electromagnetic coupling within piezoelectric phononic crystals

    Institute of Scientific and Technical Information of China (English)

    F. J. Sabina; A. B. Movchan

    2009-01-01

    In this paper, we discuss waves in piezoelectric periodic composite, with the emphasis on the connection between the electromechanical coupling and the effects of dispersion of Bloch-Floquet waves. A particular attention is given to structures containing interfaces between dissimi-lar media and localization of the electrical fields near such interfaces.

  18. 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.

  19. 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...

  20. Energy collection via Piezoelectricity

    Science.gov (United States)

    Naveen Kumar, Ch

    2015-12-01

    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.

  1. Design considerations for piezoelectric polymer ultrasound transducers.

    Science.gov (United States)

    Brown, L F

    2000-01-01

    Much work has been published on the design of ultrasound transducers using piezoelectric ceramics, but a great deal of this work does not apply when using the piezoelectric polymers because of their unique electrical and mechanical properties. The purpose of this paper is to review and present new insight into seven important considerations for the design of active piezoelectric polymer ultrasound transducers: piezoelectric polymer materials selection, transducer construction and packaging requirements, materials characterization and modeling, film thickness and active area design, electroding selection, backing material design, and front protection/matching layer design. Besides reviewing these design considerations, this paper also presents new insight into the design of active piezoelectric polymer ultrasonic transducers. The design and fabrication of an immersible ultrasonic transducer, which has no adhesive layer between the active element and backing layer, is included. The transducer features direct deposition of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer onto an insulated aluminum backing substrate. Pulse-echo tests indicated a minimum insertion loss of 37 dB and -6 dB bandwidth of 9.8 to 22 MHz (71%). The use of polymer wear-protection/quarter-wave matching layers is also discussed. Test results on a P(VDF-TrFE) transducer showed that a Mylar/sup TM/ front layer provided a slight increase in pulse-echo amplitude of 15% (or 1.2 dB) and an increase in -6 dB pulse-echo fractional bandwidth from 86 to 95%. Theoretical derivations are reported for optimizing the active area of the piezoelectric polymer element for maximum power transfer at resonance. These derivations are extended to the special case for a low profile (i.e., thin) shielded transducer. A method for modeling the non-linear loading effects of a commercial pulser-receiver is also included.

  2. A study of analysis of the brain wave with respected to action observation and motor imagery: a pilot randomized controlled trial.

    Science.gov (United States)

    Kim, Jung-Hee; Chung, Eun-Jung; Lee, Byoung-Hee

    2013-07-01

    [Purpose] The purpose of this study was to compare the effects of action observation training and motor imagery training on recovery from chronic stroke. [Subjects] Thirty patients (who were over six months post stroke) participated in this study and were randomly allocated to three groups. [Methods] The action observation training group practiced additional action observation training for five 30-minute sessions over a four-week period. The motor imagery training group practiced additional motor imagery training for five 30-minute sessions over a four-week period. Electroencephalogram were used to compare brain waves between the three groups. [Results] The action observation group showed significant changes in relative alpha power in Fp1 and Fp2 and relative beta power in Fp2 and C3. [Conclusion] Action observation induces higher levels of cognitive activities than motor imagery and physical training. Action observation is expected to be more effective for stroke patients.

  3. Piezoelectric Energy Harvesting Solutions

    Directory of Open Access Journals (Sweden)

    Renato Caliò

    2014-03-01

    Full Text Available 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.

  4. Piezoelectrically Enhanced Photocathodes

    Science.gov (United States)

    Beach, Robert A.; Nikzad, Shouleh; Bell, Lloyd Douglas; Strittmatter, Robert

    2011-01-01

    Doping of photocathodes with materials that have large piezoelectric coefficients has been proposed as an alternative means of increasing the desired photoemission of electrons. Treating cathode materials to increase emission of electrons is called "activation" in the art. It has been common practice to activate photocathodes by depositing thin layers of suitable metals (usually, cesium). Because cesium is unstable in air, fabrication of cesiated photocathodes and devices that contain them must be performed in sealed tubes under vacuum. It is difficult and costly to perform fabrication processes in enclosed, evacuated spaces. The proposed piezoelectrically enhanced photocathodes would have electron-emission properties similar to those of cesiated photocathodes but would be stable in air, and therefore could be fabricated more easily and at lower cost. Candidate photocathodes include nitrides of elements in column III of the periodic table . especially compounds of the general formula Al(x)Ga(1.x)N (where 0< or = x < or =.1). These compounds have high piezoelectric coefficients and are suitable for obtaining response to ultraviolet light. Fabrication of a photocathode according to the proposal would include inducement of strain in cathode layers during growth of the layers on a substrate. The strain would be induced by exploiting structural mismatches among the various constituent materials of the cathode. Because of the piezoelectric effect in this material, the strain would give rise to strong electric fields that, in turn, would give rise to a high concentration of charge near the surface. Examples of devices in which piezoelectrically enhanced photocathodes could be used include microchannel plates, electron- bombarded charge-coupled devices, image tubes, and night-vision goggles. Piezoelectrically enhanced photocathode materials could also be used in making highly efficient monolithic photodetectors. Highly efficient and stable piezoelectrically enhanced

  5. Rapid Determination of Bacteria Counts in Rice Noodles using Piezoelectric Bulk Acoustic Wave Biosensors%压电体声波传感器快速检测米粉中菌落总数

    Institute of Scientific and Technical Information of China (English)

    任佳丽; 马丽娜; 周超; 陈若钰; 李忠海; 林亲录

    2012-01-01

    A piezoelectric bulk acoustic wave biosensor was developed for determination of bacteria counts in rice noodles in real time. The system consists of piezoelectric quartz crystal, detection cell, oscillator, frequency counter and monitor. The determination was based on the sensitive response of the piezoelectric bulk acoustic wave biosensor to the change of culture media during bacteria growth. The frequency shift versus time response curves were recorded by self-developed software. Microbiology detection time(MDT) corresponding to the significant change of frequency shift value was used as a parameter to quantitatively determine bacteria. The calibration curve of detection time against the logarithm of bacteria initial concentration showed a linear correlation coefficient (r =0.985) over the range of 103~108 cfu/mL. The biosensor could acquire sufficient data rapidly (within 7.8 h) and enabled real-time monitoring of bacteria growth. Comparing tests were also carried out using pour plate counts. The results showed that the biosensor has potential application in the detection of bacteria concentration in food at management of quality sampling.%采用压电体声波传感器实时快速检测米粉中的菌落总数.该传感器包括压电石英晶体、检测池、振荡器、频率计和显示器,其检测原理是基于压电体声波传感器对微生物存在的培养体系的电参数变化有灵敏的频移响应,而自制软件能以频移-时间的形式将此变化过程实时记录下来.本研究中将频移显著变化的点所对应的时间定义为微生物检出时间(MDT),将基于MDT检出微生物的方法称为频移检测法.将不同污染程度的米粉样品用频移检测法获得的MDT与平板计数法获得的初始菌落数建立标定方程.当微生物初始菌落数在103~108 cfu/g之间时获得标定方程logC=7.7923-0.0071MDT(r=0.985).通过标定方程得到的不合格样品(参照国家和地方标准)的测定时间仅需7

  6. Stretchable piezoelectric nanocomposite generator

    Science.gov (United States)

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-06-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  7. Energy Harvesting via Piezoelectricity

    Directory of Open Access Journals (Sweden)

    Tanvi Dikshit

    2010-01-01

    Full Text Available In the present era, 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. For example, in the applications such as villages, border areas, forests, hilly areas, where generally remote controlled devices are used, continuous charging of the microcells is not possible by conventional charging methods .So, some alternative methods needs 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.. To resolve such problems, Energy harvesting technique is proposed as the best alternative. There exists variety of energy harvesting techniques but mechanical energy harvesting happens to be the most prominent. This technique utilizes piezoelectric components where deformations produced by different means are directly converted to electrical charge via piezoelectric effect. Subsequently the electrical energy can be regulated or stored for further use. 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. In this paper two important techniques are stressed upon to harness the energy viz Piezoelectric Windmill and Increased Bandwidth Piezoelectric Crystal. Current work also illustrates the working principle of piezoelectric crystal and various sources of vibration for the crystal.

  8. Simple electronics for inertial and Pan-type piezoelectric positioners used in scanning probe microscopes.

    Science.gov (United States)

    Chen, LeuJen; Kim, Seong Heon; Lee, Alfred K H; de Lozanne, Alex

    2012-01-01

    We describe a new type of circuit designed for driving piezoelectric positioners that rely on the stick-slip phenomenon. The circuit can be used for inertial positioners that have only one piezoelectric element (or multiple elements that are moved simultaneously) or for designs using a sequential movement of independent piezoelectric elements. A relay switches the piezoelectric elements between a high voltage source and ground, thus creating a fast voltage step followed by a slow ramp produced by the exponential discharging of the piezoelectric elements through a series resistor. A timing cascade is generated by having each relay power the next relay in the sequence. This design is simple and inexpensive. While it was developed for scanning probe microscopes, it may be useful for any piezoelectric motor based on a fast jump followed by a slow relaxation.

  9. In-plane shear piezoelectric wafer active sensor phased arrays for structural health monitoring

    Science.gov (United States)

    Wang, Wentao; Zhou, Wensong; Wang, Peng; Wang, Chonghe; Li, Hui

    2016-04-01

    This paper proposes a new way for guided wave structural health monitoring using in-plane shear (d36 type) piezoelectric wafer active sensors phased arrays. Conventional piezoelectric wafer active sensors phased arrays based on inducing into specific Lamb wave modes (d31 type) has already widely used for health monitoring of the thin-wall structures. Rather than Lamb wave modes, the in-plane shear piezoelectric wafer active sensors phased arrays induces in-plane shear horizontal (SH) guided waves. The SH guided waves are distinct with the Lamb waves with simple waveform and less additional converted wave modes and the zero symmetric mode (SH0) is non-dispersive. In this paper, the advantage of the shear horizontal wave and the in-plane shear piezoelectric wafers capability to generate SH waves is first reviewed. Then finite element analysis of a 4-in-plane shear wafer active sensors phased array embedded on a rectangular aluminium plate is performed. In addition, numerical simulations with respect to creaks with different sizes as well as locations are implemented by the in-plane shear wafer active sensors phased array. For comparison purposes, the same numerical simulations using the conventional piezoelectric wafer active sensors phased arrays are also employed at the same time. Results indicate that the in-plane shear (d36 type) piezoelectric wafer active sensors phased arrays has the potential to identify damage location and assess damage severity in structural health monitoring.

  10. Progress in the analysis of non-axisymmetric wave propagation in a homogeneous solid circular cylinder of a piezoelectric transversely isotropic material

    CSIR Research Space (South Africa)

    Every, AG

    2010-01-01

    Full Text Available at www.sciencedirect.com Physics Procedia 00 (2009) 000?000 www.elsevier.com/locate/procedia International Congress on Ultrasonics, Universidad de Santiago de Chile, January 2009 Progress in the analysis of non-axisymmetric wave propagation in a...

  11. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  12. Stability analysis of piezoelectric beams

    NARCIS (Netherlands)

    Voß, T.; Scherpen, J.M.A.

    2011-01-01

    Piezoelectric materials are used in many engineering application. When modeling piezoelectric materials the standard assumption is that the electromagnetic field which is used to actuate the piezoelectric material is quasi static. In this paper we show that although the assumption of a quasi static

  13. Developmental trajectories of EEG sleep slow wave activity as a marker for motor skill development during adolescence: a pilot study.

    Science.gov (United States)

    Lustenberger, Caroline; Mouthon, Anne-Laure; Tesler, Noemi; Kurth, Salome; Ringli, Maya; Buchmann, Andreas; Jenni, Oskar G; Huber, Reto

    2017-01-01

    Reliable markers for brain maturation are important to identify neural deviations that eventually predict the development of mental illnesses. Recent studies have proposed topographical EEG-derived slow wave activity (SWA) during NREM sleep as a mirror of cortical development. However, studies about the longitudinal stability as well as the relationship with behavioral skills are needed before SWA topography may be considered such a reliable marker. We examined six subjects longitudinally (over 5.1 years) using high-density EEG and a visuomotor learning task. All subjects showed a steady increase of SWA at a frontal electrode and a decrease in central electrodes. Despite these large changes in EEG power, SWA topography was relatively stable within each subject during development indicating individual trait-like characteristics. Moreover, the SWA changes in the central cluster were related to the development of specific visuomotor skills. Taken together with the previous work in this domain, our results suggest that EEG sleep SWA represents a marker for motor skill development and further supports the idea that SWA mirrors cortical development during childhood and adolescence. © 2016 Wiley Periodicals, Inc.

  14. Frequency spectra of laminated piezoelectric cylinders

    Science.gov (United States)

    Siao, J. C.-T.; Dong, S. B.; Song, J.

    1994-07-01

    A finite-element method is presented for determining the vibrational characteristics of a circular cylinder composed of bonded piezoelectric layers. Finite-element modeling occurs in the radial direction only using quadratic polynomials and the variationally derived partial differential equations are functions of the hoop and axial coordinates (theta, z) and time t. Using solution form Q exp (i(xi(z) + n(theta) + (omega)t)), with Q as the nodal amplitudes, leads to an algebraic eigensystem where any one of the three parameters (n, xi, omega), the circumferential or axial wave number or natural frequency, can act as the eigenvalue. Integer values always are assigned to n, leaving two possible eigenvalue problems. With omega as the eigenvalue and real values assigned to xi, the solutions represent propagating waves or harmonic standing vibrations in an infinite cylinder. When xi is the eigenvalue and real values assigned to omega, this eigensystem admits both real and complex eigendata. Real xi's represent propagating waves or harmonic standing vibrations as noted before. Complex conjugate pairs of xi 's describe end vibrations, which arise when an incident wave impinges upon a free end of a cylindrical bar. They are standing waves whose amplitudes decay sinusoidally or exponentially from the free end into the interior. Two examples are given to illustrate the method of analysis, viz., a solid piezoelectric cylinder of PZT-4 ceramic material and a two-layer cylinder of PZT-4 covering an isotropic material.

  15. 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.

  16. Design of motion adjusting system for space camera based on ultrasonic motor

    Science.gov (United States)

    Xu, Kai; Jin, Guang; Gu, Song; Yan, Yong; Sun, Zhiyuan

    2011-08-01

    Drift angle is a transverse intersection angle of vector of image motion of the space camera. Adjusting the angle could reduce the influence on image quality. Ultrasonic motor (USM) is a new type of actuator using ultrasonic wave stimulated by piezoelectric ceramics. They have many advantages in comparison with conventional electromagnetic motors. In this paper, some improvement was designed for control system of drift adjusting mechanism. Based on ultrasonic motor T-60 was designed the drift adjusting system, which is composed of the drift adjusting mechanical frame, the ultrasonic motor, the driver of Ultrasonic Motor, the photoelectric encoder and the drift adjusting controller. The TMS320F28335 DSP was adopted as the calculation and control processor, photoelectric encoder was used as sensor of position closed loop system and the voltage driving circuit designed as generator of ultrasonic wave. It was built the mathematic model of drive circuit of the ultrasonic motor T-60 using matlab modules. In order to verify the validity of the drift adjusting system, was introduced the source of the disturbance, and made simulation analysis. It designed the control systems of motor drive for drift adjusting system with the improved PID control. The drift angle adjusting system has such advantages as the small space, simple configuration, high position control precision, fine repeatability, self locking property and low powers. It showed that the system could accomplish the mission of drift angle adjusting excellent.

  17. Modeling of functionally graded piezoelectric ultrasonic transducers.

    Science.gov (United States)

    Rubio, Wilfredo Montealegre; Buiochi, Flávio; Adamowski, Julio Cezar; Silva, Emílio Carlos Nelli

    2009-05-01

    The application of functionally graded material (FGM) concept to piezoelectric transducers allows the design of composite transducers without interfaces, due to the continuous change of property values. Thus, large improvements can be achieved, as reduction of stress concentration, increasing of bonding strength, and bandwidth. This work proposes to design and to model FGM piezoelectric transducers and to compare their performance with non-FGM ones. Analytical and finite element (FE) modeling of FGM piezoelectric transducers radiating a plane pressure wave in fluid medium are developed and their results are compared. The ANSYS software is used for the FE modeling. The analytical model is based on FGM-equivalent acoustic transmission-line model, which is implemented using MATLAB software. Two cases are considered: (i) the transducer emits a pressure wave in water and it is composed of a graded piezoceramic disk, and backing and matching layers made of homogeneous materials; (ii) the transducer has no backing and matching layer; in this case, no external load is simulated. Time and frequency pressure responses are obtained through a transient analysis. The material properties are graded along thickness direction. Linear and exponential gradation functions are implemented to illustrate the influence of gradation on the transducer pressure response, electrical impedance, and resonance frequencies.

  18. 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...

  19. 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....

  20. 行波超声波电动机混沌建模与分析%Chaos Modeling and Analysis of Traveling Wave Ultrasonic Motor

    Institute of Scientific and Technical Information of China (English)

    李文娟; 史敬灼

    2012-01-01

    作为一个复杂的非线性动力学系统,在一定的参数范围和外部输入条件下,行波超声波电动机系统存在复杂的混沌运动,但至今未见相关研究.在建立行波超声波电动机非线性混沌分析模型基础上,分析行波超声波电动机转速控制系统的Lyapunov指数谱、分岔图及电压相对于转速的轨迹图等非线性运行特性,为超声波电动机的混沌控制及反控制研究奠定了基础.%The traveling wave ultrasonic motor, which is a nonlinear dynamic system, can exhibit a variety of chaotic phenomenon under some choices of system parameters and external inputs, and its chaotic characteristics have not been studied until now. Based on the non-linear chaos model of a traveling wave ultrasonic motor, its nonlinear characteristics were analyzed with respect to the bifurcation diagram, Lyapunov exponent map and the locus of voltage relative to speed. The results show that the traveling wave ultrasonic motor has chaos characteristic under certain working condition. The theoretic foundation was established for the control and anti-control of chaos in traveling wave ultrasonic motor.

  1. Potential of M-Wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation for Motor Rehabilitation

    Directory of Open Access Journals (Sweden)

    Naoto Miura

    2016-01-01

    Full Text Available Clinical studies on application of functional electrical stimulation (FES to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between electrical stimulations help recovery of muscle activation level. In this paper, M-waves elicited by double pulses were examined in muscle fatigue evaluation during repetitive movements considering rehabilitation training with surface electrical stimulation. M-waves were measured under the two conditions of repetitive stimulation: knee extension force production under the isometric condition and the dynamic movement condition by knee joint angle control. Amplitude of M-wave elicited by the 2nd pulse of a double pulse decreased during muscle fatigue in both measurement conditions, while the change in M-waves elicited by single pulses in a stimulation burst was not relevant to muscle fatigue in repeated activation with stimulation interval of 1 s. Fatigue index obtained from M-waves elicited by 2nd pulses was suggested to provide good estimation of muscle fatigue during repetitive movements with FES.

  2. High Performance Piezoelectric Actuated Gimbal (HIERAX)

    Energy Technology Data Exchange (ETDEWEB)

    Charles Tschaggeny; Warren Jones; Eberhard Bamberg

    2007-04-01

    This paper presents a 3-axis gimbal whose three rotational axes are actuated by a novel drive system: linear piezoelectric motors whose linear output is converted to rotation by using drive disks. Advantages of this technology are: fast response, high accelerations, dither-free actuation and backlash-free positioning. The gimbal was developed to house a laser range finder for the purpose of tracking and guiding unmanned aerial vehicles during landing maneuvers. The tilt axis was built and the test results indicate excellent performance that meets design specifications.

  3. Dynamic anti-plane characteristic on an infinite piezoelectric medium with a movable rigid cylindrical inclusion

    Institute of Scientific and Technical Information of China (English)

    SONG Tian-shu; SUN Li-li; YU Zhen-dong

    2005-01-01

    Scattering and dynamic stress concentrations of time harmonic SH-wave in an infinite elastic piezoelectric medium with a movable rigid cylindrical inclusion are studied in this paper with the help of complex variable and wave function expansion method. The relations that a movable rigid cylindrical inclusion depends on intensity of incident wave and electric field are revealed. The expressions of dynamic stress at the edge of the inclusion are obtained. Numerical calculations are made with different wave numbers and different piezoelectric characteristic parameters. The calculating results show that dynamic stress concentrations at the edge of the inclusion have linear dependence on the incident electric field. And dynamic analyses are very important for an infinite piezoelectric medium with a movable rigid cylindrical inclusion at larger piezoelectric characteristic parameters.

  4. 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...... 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...... 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...

  5. 一种新型高功率密度的正弦波永磁电机%A Novel Sinusoidal-Wave Permanent Magnetic Motor with High Power Density

    Institute of Scientific and Technical Information of China (English)

    崔巍; 江建中; 汪信尧

    2004-01-01

    A novel high power-density PMSM (permanent magnetic synchronous motor) with independent magnetic flux path for each phase is proposed in the paper. The complex mathematic model of PMSM is simplified by decoupling of magnetic flux paths between motor phases. In addition, harmonic components are lowered through optimum design of EMF (electric motive force) wave. Thus the ripple torque caused by EMF wave distortion is suppressed.

  6. Two Mode Resonator and Contact Model for Standing Wave Piezomotor

    DEFF Research Database (Denmark)

    Andersen, B.; Blanke, Mogens; Helbo, J.

    2001-01-01

    The paper presents a model for a standing wave piezoelectric motor with a two bending mode resonator. The resonator is modelled using Hamilton's principle and the Rayleigh-Ritz method. The contact is modelled using the Lagrange Multiplier method under the assumption of slip and it is showed how...... to solve the set of differential-algebraic equations. Detailled simulations show resonance frequencies as function of the piezoelement's position, tip trajectories and contact forces. The paper demonstrates that contact stiffness and stick should be included in such model to obtain physically realistic...

  7. Piezoelectric Ceramics Characterization

    Science.gov (United States)

    2001-09-01

    alloys, electrostrictive materials, magnetostrictive materials, electrorheological fluids are some examples of currently available smart materials...piezoelectric coefficients but also increase the dielectric constant and loss. They are utilized as actuators in vibration and noise control, benders, optical...or strain and electric field (equations (2) and (3)). High d-coefficients are desirable in materials utilized as actuators , such as in motional and

  8. Piezoelectric actuator renaissance

    Science.gov (United States)

    Uchino, Kenji

    2015-03-01

    This paper resumes the content of the invited talk of the author, read at the occasion of the International Workshop on Relaxor Ferroelectrics, IWRF 14, held on October 12-16, 2014 in Stirin, Czech Republic. It reviews the recent advances in materials, designing concepts, and new applications of piezoelectric actuators, as well as the future perspectives of this area.

  9. Fpga-based control of piezoelectric actuators

    Directory of Open Access Journals (Sweden)

    Juhász László

    2011-01-01

    Full Text Available In many industrial applications like semiconductor production and optical inspection systems, the availability of positioning systems capable to follow trajectory paths in the range of several centimetres, featuring at the same time a nanometre-range precision, is demanding. Pure piezoelectric stages and standard positioning systems with motor and spindle are not able to meet such requirements, because of the small operation range and inadequacies like backlash and friction. One concept for overcoming these problems consists of a hybrid positioning system built through the integration of a DC-drive in series with a piezoelectric actuator. The wide range of potential applications enables a considerable market potential for such an actuator, but due to the high variety of possible positioned objects and dynamic requirements, the required control complexity may be significant. In this paper, a real-time capable state-space control concept for the piezoelectric actuators, embedded in such a hybrid micropositioning system, is presented. The implementation of the controller together with a real-time capable hysteresis compensation measure is performed using a low-budget FPGA-board, whereas the superimposed integrated controller is realized with a dSPACE RCP-system. The advantages of the designed control over a traditional proportional-integral control structure are proven through experimental results using a commercially available hybrid micropositioning system. Positioning results by different dynamic requirements featuring positioning velocities from 1 μm/s up to 5 cm/s are given.

  10. Electron-phonon metamaterial featuring nonlinear tri-interleaved piezoelectric topologies and its application in low-frequency vibration control

    Science.gov (United States)

    Bao, Bin; Guyomar, Daniel; Lallart, Mickaël

    2016-09-01

    This article proposes a nonlinear tri-interleaved piezoelectric topology based on the synchronized switch damping on inductor (SSDI) technique, which can be applied to phononic metamaterials for elastic wave control and effective low-frequency vibration reduction. A comparison of the attenuation performance is made between piezoelectric phononic metamaterial with distributed SSDI topology (each SSDI shunt being independently connected to a single piezoelectric element) and piezoelectric phononic metamaterial with the proposed electronic topology. Theoretical results show excellent band gap hybridization (near-coupling between Bragg scattering mechanism and wideband resonance mechanism induced by synchronized switch damping networks in piezoelectric phononic metamaterials) with the proposed electronic topology over the investigated frequency domain. Furthermore, piezoelectric phononic metamaterials with proposed electronic topology generated a better low-frequency broadband gap, which is experimentally validated by measuring the harmonic response of a piezoelectric phononic metamaterial beam under clamped-clamped boundary conditions.

  11. Tunable Broadband Acoustic Gain in Piezoelectric Semiconductors at ε-Near-Zero Response

    DEFF Research Database (Denmark)

    Christensen, Johan; Willatzen, Morten

    2015-01-01

    Piezoelectric semiconductors have emerged as materials capable to amplify sound waves when electrons are set to drift at supersonic speeds. Several experiments have demonstrated this behaviour at moderate amplification levels for some intrinsic semiconductors and carrier concentrations. On a theo......Piezoelectric semiconductors have emerged as materials capable to amplify sound waves when electrons are set to drift at supersonic speeds. Several experiments have demonstrated this behaviour at moderate amplification levels for some intrinsic semiconductors and carrier concentrations...

  12. Model of a Piezoelectric Transducer

    Science.gov (United States)

    Goodenow, Debra

    2004-01-01

    It's difficult to control liquid and gas in propellant tanks in zero gravity. A possible a design would utilize acoustic liquid manipulation (ALM) technology which uses ultrasonic beams conducted through a liquid and solid media, to push gas bubbles in the liquid to desirable locations. We can propel and control the bubble with acoustic radiation pressure by aiming the acoustic waves on the bubble s surface. This allows us to design a so called smart tank in which the ALM devices transfer the gas to the outer wall of the tank and isolating the liquid in the center. Because the heat transfer rate of a gas is lower of that of the liquid it would substantially decrease boil off and provide of for a longer storage life. The ALM beam is composed of little wavelets which are individual waves that constructively interfere with each other to produce a single, combined acoustic wave front. This is accomplished by using a set of synchronized ultrasound transducers arranged in an array. A slight phase offset of these elements allows us to focus and steer the beam. The device that we are using to produce the acoustic beam is called the piezoelectric transducer. This device converts electrical energy to mechanical energy, which appears in the form of acoustic energy. Therefore the behavior of the device is dependent on both the mechanical characteristics, such as its density, cross-sectional area, and its electrical characteristics, such as, electric flux permittivity and coupling factor. These devices can also be set up in a number of modes which are determined by the way the piezoelectric device is arranged, and the shape of the transducer. For this application we are using the longitudinal or thickness mode for our operation. The transducer also vibrates in the lateral mode, and one of the goals of my project is to decrease the amount of energy lost to the lateral mode. To model the behavior of the transducers I will be using Pspice, electric circuit modeling tool, to

  13. Piezoelectric and Semiconducting Ribbon for Flexible Energy Harvesting

    Science.gov (United States)

    2012-06-08

    360k total) • Lockheed Martin, “Investigation of Wireless Energy Harvesting,” $50k total • Essig- Enright and Insley Blair Pyne Funds, “Studying... ROBERT F. SERVICE www .. sciencem ag~ or g SOE C.E VOL 328 1 6 APR~ L 201 0 Power surfing on waves Wavy strips of piezoelectric materials on

  14. 非理想界面正交各向异性层/压电半空间结构中Love波传播特性%Propagation behavior of love waves in an orthotropic layer/piezoelectric half-space with an imperfect interface

    Institute of Scientific and Technical Information of China (English)

    王艳红; 兰姣霞; 刘金喜

    2012-01-01

    The propagation behavior of love waves was investigated in a layered half-space structure with an imperfect interface. The structure consisted of an orthotropic elastic layer and a piezoelectric half-space. The imperfect level of the interface was described with a shear-lag model. The surface of the orthotropic layer was assumed to be mechanically free. The wave equations of the piezoelectric material and the orthotropic material were solved firstly, and then, the dispersion equation was derived in an explicit function form with boundary conditions and interface conditions. The numerical examples were provided to show the combined effects of imperfect interface, orthotropic level and material properties of piezoelectric layer on the dispersion characteristics. The results showed that the velocity of love waves decreases with wakening of interface constraint intensity; the orthotropic level and the piezoelectric constants have little effect on the velocity of love waves when the interface is highly imperfect.%研究了正交各向异性层与压电半空间非理想连接时Love波的传播特性.其中,界面条件由剪切滞后模型表征,正交各向异性层表面机械自由.首先,对压电材料和正交各向异性材料的波动方程进行求解,然后利用界面条件和边界条件推导显函形式的频散方程,最后进行数值计算,分析界面性态、压电材料性能和正交各向异性程度对频散特性的影响.分析结果表明:Love波的传播速度随着界面约束强度的降低而减小;当不理想程度较高时,正交各向异性程度和压电材料性能对Love波的传播速度影响不大.

  15. Piezoelectric Resonator with Two Layers

    Science.gov (United States)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  16. Piezoelectric step-motion actuator

    Science.gov (United States)

    Mentesana; Charles P.

    2006-10-10

    A step-motion actuator using piezoelectric material to launch a flight mass which, in turn, actuates a drive pawl to progressively engage and drive a toothed wheel or rod to accomplish stepped motion. Thus, the piezoelectric material converts electrical energy into kinetic energy of the mass, and the drive pawl and toothed wheel or rod convert the kinetic energy of the mass into the desired rotary or linear stepped motion. A compression frame may be secured about the piezoelectric element and adapted to pre-compress the piezoelectric material so as to reduce tensile loads thereon. A return spring may be used to return the mass to its resting position against the compression frame or piezoelectric material following launch. Alternative embodiment are possible, including an alternative first embodiment wherein two masses are launched in substantially different directions, and an alternative second embodiment wherein the mass is eliminated in favor of the piezoelectric material launching itself.

  17. Piezoelectric Analysis of Saw Sensor Using Finite Element Method

    OpenAIRE

    Vladimír KUTIŠ; Gabriel GÁLIK; Ivan RÝGER; Murín, Justín; Juraj HRABOVSKÝ; Juraj PAULECH; Tibor LALINSKÝ

    2013-01-01

    In this contribution modeling and simulation of surface acoustic waves (SAW) sensor using finite element method will be presented. SAW sensor is made from piezoelectric GaN layer and SiC substrate. Two different analysis types are investigated - modal and transient. Both analyses are only 2D. The goal of modal analysis, is to determine the eigenfrequency of SAW, which is used in following transient analysis. In transient analysis, wave propagation in SAW sensor is investigated. Both analyses ...

  18. High-fidelity piezoelectric loudspeaker

    OpenAIRE

    Fernández Martínez, Javier

    2014-01-01

    This project reports on a literature review about piezoelectric loudspeakers and on an experimental research about how to improve some features of a particular horned piezoelectric tweeter. The work involves an investigation of the performance and principle of operation of piezoelectric loudspeakers to understand how the sound is generated and what its main parameters are. Also, previous research papers about how to improve this type of speakers are reported. The knowledge gained was us...

  19. 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

  20. ANALYSIS OF BEAMS WITH PIEZOELECTRIC ACTUATORS

    Institute of Scientific and Technical Information of China (English)

    林启荣; 刘正兴; 王宗利

    2001-01-01

    Based on the two-dimensional constitutive relationships of the piezoelectric material, an analytical solution for an intelligent beam excited by a pair of piezoelectric actuators is derived. With the solution the force and moment generated by two piezoelectric actuators and a pair of piezoelectric actuator/sensor are obtained. Examples of a cantilever piezoelectric laminated beam or a simply supported piezoelectric laminated beam, applied with voltages, are given.

  1. Control and sensor techniques for PAD servo motor drive

    DEFF Research Database (Denmark)

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

    2015-01-01

    The Piezoelectric Actuator Drive (PAD) is a new type of electrical motor that employs piezoelectric multilayer actuators coupled with a form-fitted micro-mechanical gearing to generate rotary motion. The PAD is precise, having a positioning error of less than 2 arc-seconds. Its typical output tor...

  2. Control and sensor techniques for PAD servo motor drive

    DEFF Research Database (Denmark)

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

    2015-01-01

    The Piezoelectric Actuator Drive (PAD) is a new type of electrical motor that employs piezoelectric multilayer actuators coupled with a form-fitted micro-mechanical gearing to generate rotary motion. The PAD is precise, having a positioning error of less than 2 arc-seconds. Its typical output...

  3. Black Branes as Piezoelectrics

    CERN Document Server

    Armas, Jay; Obers, Niels A

    2012-01-01

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  4. Black branes as piezoelectrics.

    Science.gov (United States)

    Armas, Jay; Gath, Jakob; Obers, Niels A

    2012-12-14

    We find a realization of linear electroelasticity theory in gravitational physics by uncovering a new response coefficient of charged black branes, exhibiting their piezoelectric behavior. Taking charged dilatonic black strings as an example and using the blackfold approach we measure their elastic and piezolectric moduli. We also use our results to draw predictions about the equilibrium condition of charged dilatonic black rings in dimensions higher than six.

  5. Piezoelectric wind turbine

    Science.gov (United States)

    Kishore, Ravi Anant; Priya, Shashank

    2013-03-01

    In past few years, there has been significant focus towards developing small scale renewable energy based power sources for powering wireless sensor nodes in remote locations such as highways and bridges to conduct continuous health monitoring. These prior efforts have led to the development of micro-scale solar modules, hydrogen fuel cells and various vibration based energy harvesters. However, the cost effectiveness, reliability, and practicality of these solutions remain a concern. Harvesting the wind energy using micro-to-small scale wind turbines can be an excellent solution in variety of outdoor scenarios provided they can operate at few miles per hour of wind speed. The conventional electromagnetic generator used in the wind mills always has some cogging torque which restricts their operation above certain cut-in wind speed. This study aims to develop a novel piezoelectric wind turbine that utilizes bimorph actuators for electro-mechanical energy conversion. This device utilizes a Savonius rotor that is connected to a disk having magnets at the periphery. The piezoelectric actuators arranged circumferentially around the disk also have magnets at the tip which interacts with the magnetic field of the rotating disk and produces cyclical deflection. The wind tunnel experiments were conducted between 2-12 mph of wind speeds to characterize and optimize the power output of the wind turbine. Further, testing was conducted in the open environment to quantify the response to random wind gusts. An attempt was made towards integration of the piezoelectric wind turbine with the wireless sensor node.

  6. Piezoelectric pressure transducer technique for oxidizing atmospheres

    Science.gov (United States)

    Roberts, Ted A.; Burton, Rodney L.

    1992-07-01

    The diaphragm sensing tip of a high-speed piezoelectric pressure transducer can be destroyed when measuring transient impulse pressures in hot oxidizing atmospheres, e.g., oxygen at 3000 K and 34 atm for times of tens of milliseconds. A technique is presented to preserve the transducer under these conditions, which uses a protective layer of 0.025-0.050-mm-thick brass foil, held in place with double-sided tape. The integrity of the transducer is preserved, and the response time to a shock wave is increased from 1 to 2-6/microsec using the technique.

  7. Hybrid piezoelectric energy harvesting transducer system

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  8. An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting

    Science.gov (United States)

    Lu, Shaohua; Boussaid, Farid

    2015-01-01

    This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD) capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier. PMID:26610492

  9. An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Shaohua Lu

    2015-11-01

    Full Text Available This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier.

  10. 正交各向异性弹性层/功能梯度压电半空间结构中Love波的传播%Propagation of Love Waves in the Orthotropic Layer/Functionally Graded Piezoelectric Half-Space

    Institute of Scientific and Technical Information of China (English)

    孔艳平; 陈长虹; 刘金喜

    2013-01-01

    This paper investigated Love waves propagating in the layered half-space structure consisting of an orthotropic layer and a functionally graded piezoelectric half-space. The interface conditions of the layered half-space structure are perfect and imperfect. The material properties of the piezoelectric half-spaces vary exponentially in the direction perpendicular to the interfaces. Based on the dispersion equations, the numerical examples were presented to show the effects of variations of material properties, the cut angle of the orthotropic material and combined effects of the imperfect interface on the phase velocity. The obtained results are useful for the application of functionally graded piezoelectric materials to acoustic wave devices such as plate resonators, filters and sensors.%研究了功能梯度压电半空间上覆盖一层正交各向异性弹性层结构中Love波的传播特性.覆盖层与基底的界面连接方式分别考虑了理想接触和非理想接触2种模式,功能梯度压电半空间的材料性能沿垂直于界面方向以指数函数形式变化.基于推导的频散方程,结合数值算例分析了材料性能梯度变化、正交各向异性材料的切割角度和非理想界面的连接程度对相速度的影响,其结果对功能梯度压电材料的覆层结构在声波器件中的应用具有重要的参考价值.

  11. Performance and Applications of L1B2 Ultrasonic Motors

    Directory of Open Access Journals (Sweden)

    Gal Peled

    2016-06-01

    Full Text Available Piezoelectric ultrasonic motors offer important advantages for motion applications where high speed is coupled with high precision. The advances made in the recent decades in the field of ultrasonic motor based motion solutions allow the construction of complete motion platforms in the fields of semiconductors, aerospace and electro-optics. Among the various motor designs, the L1B2 motor type has been successful in industrial applications, offering high precision, effective control and operational robustness. This paper reviews the design of high precision motion solutions based on L1B2 ultrasonic motors—from the basic motor structure to the complete motion solution architecture, including motor drive and control, material considerations and performance envelope. The performance is demonstrated, via constructed motion stages, to exhibit fast move and settle, a repeatability window of tens of nanometers, lifetime into the tens of millions of operational cycles, and compatibility with clean room and aerospace environments. Example stages and modules for semiconductor, aerospace, electro-optical and biomedical applications are presented. The described semiconductor and aerospace solutions are powered by Nanomotion HR type motors, driven by a sine wave up to 80 V/mm rms, having a driving frequency of 39.6 kHz, providing a maximum force up to 4 N per driving element (at 5 W power consumption per element and a maximum linear velocity above 300 mm/s. The described electro-optical modules are powered by small Nanomotion Edge motors driven by voltages up to 11 V AC, providing stall forces up to 0.35 N (power consumption up to 0.75 W and maximum linear velocity above 200 mm/s.

  12. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function [Retraction

    Directory of Open Access Journals (Sweden)

    Wang L

    2016-10-01

    Full Text Available Wang L, Jiang Y, Jiang Z, Han L. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function. Neuropsychiatr Dis Treat. 2016 Aug 31;12:2189–2198. doi: 10.2147/NDT.S82864.This article was found to have plagiarized the content of:Low-energy extracorporeal shock wave therapy promotes vascular endothelial growth factor expression and improves locomotor recovery after spinal injury published in the Journal of Neurosurgery in 2014 (J Neurosurg. 121: 1514–1525, 2014.Accordingly, Dr Pinder, Editor-in-Chief of Neuropsychiatric Disease and Treatment has decided to issue a Retraction notice and advise the academic supervisors of Dr Wang et al of this matter. This Retraction relates to

  13. Repeater F waves: a comparison of sensitivity with sensory antidromic wrist-to-palm latency and distal motor latency in the diagnosis of carpal tunnel syndrome.

    Science.gov (United States)

    Macleod, W N

    1987-05-01

    Thirty-five thousand six hundred supramaximal shocks were applied to 209 healthy and 147 entrapped median nerves (carpal tunnel syndrome--CTS) to characterize the backfiring behavior of the alpha motor neuron pool of abductor pollicis brevis in health and the modifying effect of a compressive neuropathy. A contraction of the normal subpopulation of active F-wave generators was found in CTS, while active neurons backfired at higher than normal frequencies (p less than 0.001). These modifications in spinal behavior are reflected in the % Repeater F-wave value, whose sensitivity in the detection of CTS approaches that of sensory wrist-to-palm latency estimation. This technique offers an alternative to latency measurement in the diagnosis of CTS. An economical strategy for the electrodiagnosis of CTS is proposed.

  14. Fatigue crack monitoring with coupled piezoelectric film acoustic emission sensors

    Science.gov (United States)

    Zhou, Changjiang

    Fatigue-induced cracking is a commonly seen problem in civil infrastructures reaching their original design life. A number of high-profile accidents have been reported in the past that involved fatigue damage in structures. Such incidences often happen without prior warnings due to lack of proper crack monitoring technique. In order to detect and monitor the fatigue crack, acoustic emission (AE) technique, has been receiving growing interests recently. AE can provide continuous and real-time monitoring data on damage progression in structures. Piezoelectric film AE sensor measures stress-wave induced strain in ultrasonic frequency range and its feasibility for AE signal monitoring has been demonstrated recently. However, extensive work in AE monitoring system development based on piezoelectric film AE sensor and sensor characterization on full-scale structures with fatigue cracks, have not been done. A lack of theoretical formulations for understanding the AE signals also hinders the use of piezoelectric film AE sensors. Additionally, crack detection and source localization with AE signals is a very important area yet to be explored for this new type of AE sensor. This dissertation presents the results of both analytical and experimental study on the signal characteristics of surface stress-wave induced AE strain signals measured by piezoelectric film AE sensors in near-field and an AE source localization method based on sensor couple theory. Based on moment tensor theory, generalized expression for AE strain signal is formulated. A special case involving the response of piezoelectric film AE sensor to surface load is also studied, which could potentially be used for sensor calibration of this type of sensor. A new concept of sensor couple theory based AE source localization technique is proposed and validated with both simulated and experimental data from fatigue test and field monitoring. Two series of fatigue tests were conducted to perform fatigue crack

  15. Piezoelectric Inertia Motors—A Critical Review of History, Concepts, Design, Applications, and Perspectives

    Directory of Open Access Journals (Sweden)

    Matthias Hunstig

    2017-02-01

    Full Text Available Piezoelectric inertia motors—also known as stick-slip motors or (smooth impact drives—use the inertia of a body to drive it in small steps by means of an uninterrupted friction contact. In addition to the typical advantages of piezoelectric motors, they are especially suited for miniaturisation due to their simple structure and inherent fine-positioning capability. Originally developed for positioning in microscopy in the 1980s, they have nowadays also found application in mass-produced consumer goods. Recent research results are likely to enable more applications of piezoelectric inertia motors in the future. This contribution gives a critical overview of their historical development, functional principles, and related terminology. The most relevant aspects regarding their design—i.e., friction contact, solid state actuator, and electrical excitation—are discussed, including aspects of control and simulation. The article closes with an outlook on possible future developments and research perspectives.

  16. Multilayer Piezoelectric Stack Actuator Characterization

    Science.gov (United States)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  17. Power enhancement of piezoelectric transformers for power supplies

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Steenstrup, Anders Resen; Zhang, Zhe

    2016-01-01

    This paper studies power enhancement of piezoelectric transformers to be used in inductorless, half-bridge, piezoelecteric-based switch mode power supplies for driving a piezo actuator motor system in a high strength magnetic environment for magnetic resonance imaging and computed tomography...... applications. A new multi element-piezo transformer solution is proposed along with a dual mode piezo transformer, providing power scaling and potentially improving the internal heat-up of a high power piezo transformer system....

  18. Acoustic Prism for Continuous Beam Steering Based on Piezoelectric Metamaterial

    CERN Document Server

    Xu, Jiawen

    2016-01-01

    This paper investigates an acoustic prism for continuous acoustic beam steering by a simple frequency sweep. This idea takes advantages of acoustic wave velocity shifting in metamaterials in the vicinity of local resonance. We apply this concept into the piezoelectric metamaterial consisting of host medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are carried out. It is shown that the phase velocity of acoustic wave changes dramatically in the vicinity of local resonance. The directions of acoustic wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of the excitation frequency. Such an electro-mechanical coupling system has a feature of adjusting local resonance without altering the mechanical part of the system.

  19. On acoustic band gaps in homogenized piezoelectric phononic materials

    Directory of Open Access Journals (Sweden)

    Rohan E.

    2010-07-01

    Full Text Available We consider a composite medium made of weakly piezoelectric inclusions periodically distributed in the matrix which ismade of a different piezoelectricmaterial. Themediumis subject to a periodic excitation with an incidence wave frequency independent of scale ε of the microscopic heterogeneities. Two-scale method of homogenization is applied to obtain the limit homogenized model which describes acoustic wave propagation in the piezoelectric medium when ε → 0. In analogy with the purely elastic composite, the resulting model allows existence of the acoustic band gaps. These are identified for certain frequency ranges whenever the so-called homogenized mass becomes negative. The homogenized model can be used for band gap prediction and for dispersion analysis for low wave numbers. Modeling such composite materials seems to be perspective in the context of Smart Materials design.

  20. Extracorporeal piezoelectric lithotripsy for complicated bile duct stones.

    Science.gov (United States)

    Weber, J; Adamek, H E; Riemann, J F

    1991-02-01

    Today, common bile duct stones are extracted endoscopically. After endoscopic sphincterotomy, nearly 90% of all stones can be removed with a Dormia basket or a mechanical lithotripter. Problems are encountered if there are larger stones or a duct stenosis. New conservative therapies do serve as an alternative to surgical intervention for those few patients in whom endoscopic measures have failed. Stone fragmentation can be achieved by extracorporeal shock wave lithotripsy, and remaining fragments can be removed endoscopically. So far, authors of most reports on the successful disintegration of common bile duct stones used the Dornier lithotripter. Stone localization is thus achieved with x-rays, and the shock waves are generated by an underwater spark discharge. We report on our experiences and results with extracorporeal piezoelectric shock wave lithotripsy (EPL) in 19 patients with complicated bile duct stones. With this lithotripter, stones are visualized by ultrasound, and shock waves are produced by a piezoelectric acoustic generator. Fragmentation was achieved in 84.2%, and complete stone removal in 78.9%. These results show that piezoelectric lithotripsy is also a useful method for the treatment of complicated bile duct stones, as has already been proved for the electrohydraulic- and electromagnetic-generated shock waves systems. However, the renunciation of general anesthesia and the need for analgesia or sedation in only 25% of the treatments render this lithotripter system attractive, especially for elderly and frail patients.

  1. 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

  2. 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.

  3. Piezoelectric extraction of ECG signal

    Science.gov (United States)

    Ahmad, Mahmoud Al

    2016-11-01

    The monitoring and early detection of abnormalities or variations in the cardiac cycle functionality are very critical practices and have significant impact on the prevention of heart diseases and their associated complications. Currently, in the field of biomedical engineering, there is a growing need for devices capable of measuring and monitoring a wide range of cardiac cycle parameters continuously, effectively and on a real-time basis using easily accessible and reusable probes. In this paper, the revolutionary generation and extraction of the corresponding ECG signal using a piezoelectric transducer as alternative for the ECG will be discussed. The piezoelectric transducer pick up the vibrations from the heart beats and convert them into electrical output signals. To this end, piezoelectric and signal processing techniques were employed to extract the ECG corresponding signal from the piezoelectric output voltage signal. The measured electrode based and the extracted piezoelectric based ECG traces are well corroborated. Their peaks amplitudes and locations are well aligned with each other.

  4. New Swallowing Evaluation Using Piezoelectricity in Normal Individuals.

    Science.gov (United States)

    Sogawa, Yuichiro; Kimura, Shinji; Harigai, Toru; Sakurai, Naoki; Toyosato, Akira; Nishikawa, Taro; Inoue, Makoto; Murasawa, Akira; Endo, Naoto

    2015-12-01

    This study aimed to elucidate the relationship between the piezoelectric waveform latency, hyoid bone movement, surface electromyogram (sEMG), and the pharyngeal transit time (PTT) during swallowing. Forty-one healthy subjects were divided into three age groups: younger (20-39 years, n = 8), middle-aged (40-59 years, n = 9), and older (60-79 years, n = 24). Motion analysis of the hyoid bone using videofluorography (VF), waveform analysis of the front neck using piezoelectric films, and sEMG of the suprahyoid muscle group were performed simultaneously. Latencies of the three movement phases were defined as upward (VFS1), forward (VFS2), and returning to starting position (VFS3). The three phases of the piezoelectric waveform-from wave initiation of the negative wave to the start of the second deep negative wave; from the start of the second deep negative wave to the start of the last positive wave (SLPW); and from the SLPW to the end of the last positive wave-were defined as PS1, PS2, and PS3, respectively. VFS1-3 and PS1-3 were significantly correlated. VFS1 and PS1 latencies were significantly longer with thick liquid than with thin liquid. VFS2, PS1, and PS2 latencies were longer in the older group than in the other two groups. The start of PS1 was nearly equal to those of sEMG and VFS1. Bolus arrival time in the valleculae was statistically equal to the end of the PS1 with both thin and thick liquids. To establish the swallowing screening using Piezoelectric film, further investigation is necessary in the dysphagia patients.

  5. All-Optical Micro Motors Based on Moving Gratings in Photosensitive Media

    Science.gov (United States)

    Curley, M.; Sarkisov, S. S.; Fields, A.; Smith, C.; Kukhtarev, N.; Kulishov, M. B.; Adamovsky, Grigory

    2001-01-01

    An all-optical micromotor with a rotor driven by a traveling wave of surface deformation of a stator being in contact with the rotor is being studied. Instead of an ultrasonic wave produced by an electrically driven piezoelectric actuator as in ultrasonic motors, the wave is a result of a photo-induced surface deformation of a photosensitive material produced by an incident radiation. A thin piezoelectric polymer will deform more easily LiNbO3 or metal when irradiated with light. The type of photosensitive material studied are piezoelectric polymers with and without coatings for connecting electrodes. In order to be considered as a possible candidate for micromotors, the material should exhibit surface deformation produced by a laser beam of the order of 10 microns. This is compared to the deformations produced by static holographic gratings studied in photorefractive crystals of LiNbO3 using high vertical resolution surface profilometer Dektak 3 and surface interferometer WYKO. An experimental setup showing the oscillations has been developed. The setup uses a chopped beam from an Argon ion laser to produce the deformation while a probe beam is reflected by the thin film into a fiber which is then detected on an oscilloscope. A ramp voltage signal generator will drive the piezoelectric film in another experiment to determine the resonance of the film. A current is generated when light is incident upon the film and this current can be measured. The reverse process has already been demonstrated in other piezoelectric actuators. Changing voltage, polarity, and frequency of the signal can easily generate vibrations similar to those when light is incident on the film. This can be compared to the effects of laser interaction with light absorbing fluids such as solutions of 2,9,16,23-Tetrakis(phenylthio)-29H, 31 H-phthalocyanine in chlorobenzene in capillary tubes, The possibility of using a liquid with the piezoelectric film would be a novel idea for a micromotor since

  6. Simple piezoelectric translation device

    Science.gov (United States)

    Niedermann, Ph.; Emch, R.; Descouts, P.

    1988-02-01

    We describe a piezoelectric device which allows continuous movement and high-resolution micropositioning, without distance limitation. Both mechanical construction and the electronics for the device are very simple. The movement is obtained via a stick-slip mechanism, and steps as small as 10 nm are obtained. A displacement speed of 0.4 mm/s has been attained, and the device was capable of carrying several times its own weight, exerting a horizontal force, or climbing a plane inclined by 7°. Due to its compact construction, the device shows prospects for miniaturization.

  7. Enhanced Piezoelectric Shunt Design

    Directory of Open Access Journals (Sweden)

    Chul H. Park

    2003-01-01

    Full Text Available Piezoceramic material connected to an electronic shunt branch circuit has formed a successful vibration reduction device. One drawback of the conventional electronic shunt circuit is the large inductance required when suppressing low frequency vibration modes. Also, the large internal resistance associated with this large inductance exceeds the optimal design resistance needed for low frequency vibration suppression. To solve this problem, a modified and enhanced piezoelectric shunt circuit is designed and analyzed by using mechanical-electrical analogies to present the physical interpretation. The enhanced shunt circuit developed in this paper is proved to significantly reduce the targeted vibration mode of a cantilever beam, theoretically and experimentally.

  8. Nanostructured piezoelectric energy harvesters

    CERN Document Server

    Briscoe, Joe

    2014-01-01

    This book covers a range of devices that use piezoelectricity to convert mechanical deformation into electrical energy and relates their output capabilities to a range of potential applications. Starting with a description of the fundamental principles and properties of piezo- and ferroelectric materials, where applications of bulk materials are well established, the book shows how nanostructures of these materials are being developed for energy harvesting applications. The authors show how a nanostructured device can be produced, and put in context some of the approaches that are being invest

  9. High Temperature, High Power Piezoelectric Composite Transducers

    OpenAIRE

    Hyeong Jae Lee; Shujun Zhang; Yoseph Bar-Cohen; Stewart Sherrit

    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 le...

  10. Overview of static current for sine wave permanent magnet synchronous motor%正弦波永磁同步电机静态电流概述

    Institute of Scientific and Technical Information of China (English)

    黄明

    2013-01-01

    In the numerical control machine, the enabled sine wave permanent magnet synchronous motor has been in zero velocity state. The stator winding has continuous static current to complete locking servo motor rotor. For its current detection and combining the maintenance experience and motion control system theory, A kind of theoretical calculation method of AC permanent magnet synchronous motor static current is proposed.%  数控机床中,已经使能的正弦波交流永磁同步电机零速状态下,其定子绕组存在持续静态电流,完成对伺服电机转子的锁定。针对正弦波永磁同步电机静态电流检测问题,结合运动控制系统理论和维修经验,提出一种交流永磁同步电机静态电流理论计算方法。

  11. Tuning of band gaps for a two-dimensional piezoelectric phononic crystal with a rectangular lattice

    Institute of Scientific and Technical Information of China (English)

    Yize Wang; Fengming Li; Yuesheng Wang; Kikuo Kishimoto; Wenhu Huang

    2009-01-01

    In this paper, the elastic wave propagation in a two-dimensional piezoelectric phononic crystal is studied by considering the mechanic-electric coupling. The gener-alized eigenvalue equation is obtained by the relation of the mechanic and electric fields as well as the Bloch-Floquet the-orem. The band structures of both the in-plane and anti-plane modes are calculated for a rectangular lattice by the plane-wave expansion method. The effects of the lattice constant ratio and the piezoelectricity with different filling fractions are analyzed. The results show that the largest gap width is not always obtained for a square lattice. In some situations, a rectangular lattice may generate larger gaps. The band gap characteristics are influenced obviously by the piezoelectric-ity with the larger lattice constant ratios and the filling frac-tions.

  12. A nut-type ultrasonic motor and its application in the focus system

    Institute of Scientific and Technical Information of China (English)

    ZHOU TieYing; ZHANG Yun; CHEN Yu; LU CunYue; FU DeYong; LI Yi; HU XiaoPing

    2009-01-01

    This article reports a screw-driven polyhedron linear ultrasonic motor (USM) of nut-type. It is comprised of a stator, which is a threaded metal nut bonded with piezoelectric plates on its external surface, and a rotor with external threads, which engage with the internal threads of the stator. A traveling wave in the plane is stimulated on the stator when harmonic electric signals are applied to the piezoelectric plates. The traveling wave drives the rotor to rotate, and the threads transform the rotation into a linear motion. The lens can be fixed in the rotor and realize the integrated design of the auto focus system. This structure can omit retarder and directly drive to obtain a high accuracy of positioning, and it is shock-proof. A mini AF cellular phone module (8.5 mm×8.5 mm×5.9 mm) driven by this motor was made and an image resolution of 3 5 MP was obtained in the module prototypes of the cellular phone.

  13. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many t...

  14. Piezoelectric properties of Sr3Ga2Ge4O14 single crystals

    Indian Academy of Sciences (India)

    Anhua Wu; Jiayue Xu; Juan Zhou; Hui Shen

    2007-04-01

    A new piezoelectric single crystal, Sr3Ga2Ge4O14 (SGG), has been grown successfully by the vertical Bridgman method with crucible-sealing technique. SGG crystal up to 2″ in diameter has been obtained. The relative dielectric constants, the piezoelectric strain constants, elastic compliance constants and electromechanical coupling factors have been determined with resonance and anti-resonance frequencies method by using the impedance analyzer (Agilent 4294A). The results show that the piezoelectric strain constants and electromechanical coupling factors of SGG single crystal are higher than those of LGS single crystals making it a potential substrate material for surface-acoustic wave applications.

  15. Relaxor-PT Single Crystal Piezoelectric Sensors

    OpenAIRE

    Xiaoning Jiang; Jinwook Kim; Kyugrim Kim

    2014-01-01

    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 futu...

  16. Miniaturization of planar horn motors

    Science.gov (United States)

    Sherrit, Stewart; Ostlund, Patrick N.; Chang, Zensheu; Bao, Xiaoqi; Bar-Cohen, Yoseph; Widholm, Scott E.; Badescu, Mircea

    2012-04-01

    There is a great need for compact, efficient motors for driving various mechanisms including robots or mobility platforms. A study is currently underway to develop a new type of piezoelectric actuators with significantly more strength, low mass, small footprint, and efficiency. The actuators/motors utilize piezoelectric actuated horns which have a very high power density and high electromechanical conversion efficiency. The horns are fabricated using our recently developed novel pre-stress flexures that make them thermally stable and increases their coupling efficiency. The monolithic design and integrated flexures that pre-stresses the piezoelectric stack eliminates the use of a stress bolt. This design allows embedding solid-state motors and actuators in any structure so that the only macroscopically moving parts are the rotor or the linear translator. The developed actuator uses a stack/horn actuation and has a Barth motor configuration, which potentially generates very large torque and speeds that do not require gearing. Finite element modeling and design tools were investigated to determine the requirements and operation parameters and the results were used to design and fabricate a motor. This new design offers a highly promising actuation mechanism that can potentially be miniaturized and integrated into systems and structures. It can be configured in many shapes to operate as multi-degrees of freedom and multi-dimensional motors/actuators including unidirectional, bidirectional, 2D and 3D. In this manuscript, we are reporting the experimental measurements from a bench top design and the results from the efforts to miniaturize the design using 2×2×2 mm piezoelectric stacks integrated into thin plates that are of the order of 3 × 3 × 0.2 cm.

  17. 无刷直流电动机的正弦波电流驱动方法%Sine-wave Current Drive Method for Brushless DC Motors

    Institute of Scientific and Technical Information of China (English)

    朱信舜; 林明耀; 刘文勇

    2011-01-01

    分析了无刷直流电动机方波驱动方式和传统正弦波驱动方式的优缺点,利用三相Hall信号,得到正弦波电流的周期和幅值,通过软件算法生成六路SVPWM信号来驱动无刷直流电动机.采用数字信号控制器(DSC)dsPIC30F4011作为主控芯片,设计了无刷直流电动机的控制系统,详细分析了SVPWM波的生成方法,并给出了软件流程.实验结果验证了提出方法的正确性和可行性.%The performances of square-wave drive and sine-wave drive of brushless DC motor( BLDCM) were analyzed in this paper, a method to drive the BLDCM which makes use of three-phase Hall position signals to get the cycle and magnitude of the sine-wave and a proper software program to generate six-way SVPWM waves was presented. Adopting the DSC dsPIC30F4011, the control system of BLDCM was designed. The method to get SVPWM wave was analyzed in detail in the paper, and the software flow chart was also given. Experimental results verified the validity and feasibility of the proposed method.

  18. Longitudinal-bending mode micromotor using multilayer piezoelectric actuator.

    Science.gov (United States)

    Yao, K; Koc, B; Uchino, K

    2001-07-01

    Longitudinal-bending mode ultrasonic motors with a diameter of 3 mm were fabricated using stacked multilayer piezoelectric actuators, which were self-developed from hard lead zirconate titanate (PZT) ceramic. A bending vibration was converted from a longitudinal vibration with a longitudinal-bending coupler. The motors could be bidirectionally operated by changing driving frequency. Their starting and braking torque were analyzed based on the transient velocity response. With a load of moment of inertia 2.5 x 10(-7) kgm2, the motor showed a maximum starting torque of 127.5 microNm. The braking torque proved to be a constant independent on the motor's driving conditions and was roughly equivalent to the maximum starting torque achievable with our micromotors.

  19. Ultrasonic Linear Motor with Anisotropic Composite

    Institute of Scientific and Technical Information of China (English)

    曾周末; 王新辉; 赵伯雷

    2004-01-01

    An idea to make up the vibrating body of ultrasonic motor with anisotropic composite is proposed and a linear piezoelectric motor is developed in this paper. Relative problems such as actuating mechanism, resonant frequency are discussed theoretically. According to the feature that impulse exists between the elastic body of composite ultrasonic linear motor and the base, an impulse analysis is presented to calculate the motor′s friction driving force and frictional conversion efficiency. The impulse analysis essentially explains the reason why the ultrasonic motor has great driving force, and can be applied to analyze the non-linear ultrasonic motor.

  20. 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...... 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 displacememnt and electric potential is given. The influence of a fluid half-space is also...

  1. Two-Mode Resonator and Contact Model for Standing Wave Piezomotor

    DEFF Research Database (Denmark)

    Andersen, B.; Blanke, Mogens; Helbo, J.

    2001-01-01

    The paper presents a model for a standing wave piezoelectric motor with a two bending mode resonator. The resonator is modelled using Hamilton's principle and the Rayleigh-Ritz method. The contact is modelled using the Lagrange Multiplier method under the assumption of slip and it is showed how...... to solve the set of differential-algebraic equations. Detailed simulations show resonance frequencies as function of the piezoelement's position, tip trajectories and contact forces. The paper demonstrates that contact stiffness and stick should be included in such model to obtain physically realistic...

  2. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function

    Directory of Open Access Journals (Sweden)

    Wang L

    2016-08-01

    Full Text Available Lei Wang, Yuquan Jiang, Zheng Jiang, Lizhang Han Department of Neurosurgery, Qilu Hospital of Shandong University, Jinan, People’s Republic of China Background: Latest studies show that low-energy extracorporeal shock wave therapy (ESWT can upregulate levels of vascular endothelial growth factor (VEGF. VEGF can ease nervous tissue harm after spinal cord injury (SCI. This study aims to explore whether low-energy ESWT can promote expression of VEGF, protect nervous tissue after SCI, and improve motor function.Methods: Ninety adult female rats were divided into the following groups: Group A (simple laminectomy, Group B (laminectomy and low-energy ESWT, Group C (spinal cord injury, and Group D (spinal cord injury and low-energy ESWT. Impinger was used to cause thoracic spinal cord injury. Low-energy ESWT was applied as treatment after injury three times a week, for 3 weeks. After SCI, the Basso, Beattie, and Bresnahan (BBB scale was used to evaluate motor function over a period of 42 days at different time points. Hematoxylin and eosin (HE staining was used to evaluate nerve tissue injury. Neuronal nuclear antigen (NeuN staining was also used to evaluate loss of neurons. Polymerase chain reaction was used to detect messenger RNA (mRNA expression of VEGF and its receptor fms-like tyrosine kinase 1 (Flt-1. Immunostaining was used to evaluate VEGF protein expression level in myeloid tissue.Results: BBB scores of Groups A and B showed no significant result related to dyskinesia. HE and NeuN staining indicated that only using low-energy ESWT could not cause damage of nervous tissue in Group B. Recovery of motor function at 7, 35, and 42 days after SCI in Group D was better than that in Group C (P<0.05. Compared with Group C, number of NeuN-positive cells at 42 days after SCI increased significantly (P<0.05. The mRNA levels of VEGF and Flt-1 and VEGF expression at 7 days after SCI in Group D were significantly higher than those in Group C (P<0

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

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh

    , this brings an open area for conducting further research which has been subject of this project. The research on this type of power converters are progressive but still very new in the technology to become a successful commercial product. The unique characteristics of piezoelectric transformers i.e. low...... 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...... lamps, backlight for LCD displays in notebook computers. Piezoelectric ceramic devices vibrate at their mechanical resonance. The operating principle of the piezoelectric transformers is based on electromechanical energy conversion. There is electromechanical coupling between the primary...

  4. NEW PRECISION PIEZOELECTRIC STEP ACTUATOR

    Institute of Scientific and Technical Information of China (English)

    LIU Jianfang; YANG Zhigang; FAN Zunqiang; CHENG Guangming

    2006-01-01

    A new precision piezoelectric actuator is proposed to improve its drive capabilities. The actuator is based on the piezoelectric technology. It adopts the principle of bionics and works with a new method of stator initiative anchoring/loosen and a distortion structure of double-side thin flexible hinge. It solves the problem of anchoring/loosen, frequency, journey, resolution and velocity. The experiment shows that the new linear piezoelectric actuator works with high frequency (100 Hz), high speed (502 μm/s), large travel (>10 mm), high resolution (0.05 μm) and high load (100 N). This kind of new piezoelectric actuator will be applied for large travel and high resolution driving device, optics engineering, precision positioning and some micromanipulation field.

  5. Piezoelectric enhancement under negative pressure

    Science.gov (United States)

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-07-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  6. A piezoelectrically actuated ball valve

    Science.gov (United States)

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.

    1972-01-01

    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  7. Piezoelectric materials involved in road traffic applications test system; Banco de ensayos para materiales piezoelectricos en aplicaciones viales

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

    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.

  8. 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

  9. Droplets Fusion in a Microchannel on a Piezoelectric Substrate

    Directory of Open Access Journals (Sweden)

    Fu Xiang-ting

    2013-07-01

    Full Text Available Fusion droplets is a key operation in a microfluidic device for microfluidic analysis. A new fusion method for droplets was presented. An interditigal transducer and a reflector were fabricated on 1280-yx LiNbO3 piezoelectric substrate using microelectric technology. A poly-dimethyl silicone micro-channel was made by soft lithography technology and mounted on the piezoelectric substrate. Droplets in the microchannel were actuated by surface acoustic wave and fussed each other. Coloured dye solution droplets were used to fusion experiments. Results show that the two droplets in the microchannel can be fused by help of surface acoustic wave, and size of droplets, distance of droplets and RF signal power can affect successful fusion of the droplets. The fusion method is valuable for microlfuidic biological and chemical analysis in a microfluidic device.

  10. Three-dimensional modeling of piezoelectric materials.

    Science.gov (United States)

    Brissaud, Michel

    2010-09-01

    This paper deals with 3-D modeling of piezoelectric materials. The model is based on an exact description of the potential and electric field inside a material. Moreover, coherent piezoelectric equations are used. Modeling has been applied to rectangular and cylindrical elements. In each case, the exact equations of the displacements along the three coordinate axes and the corresponding electric impedance are calculated. The general resonance conditions are stated for these two geometries. It is shown that, contrary to the 1-D models, a unique equation describes lateral and thickness vibrations, or radial and thickness vibrations. These properties enable us to analytically calculate the frequency spectrum of rectangular elements, thick disks, or cylinders and also thick rings or hollow cylinders versus the width to thickness ratio. It is then very easy to determine the corresponding dispersion diagram related to each geometry sample. These resonance conditions are similar to those deduced from the 1-D model described in the IEEE standard but are more general and necessitate no cancelling out assumptions. In addition, contrary to 1-D models, the wave velocities and the permittivity are independent of the element geometry (parallelepiped or cylindrical). The wave velocities are equal to those stated for the wave propagation in infinite medium and measured with pulse-echo techniques. It is the coupling inside the material which modifies the resonance conditions and not the geometrical dimensions of the vibrating element. 3-D modeling and 1-D radial mode of the admittance of a thick disk are calculated and compared with experimental measurements. Theoretical and measured admittances are compared and discussed.

  11. Performance and Applications of L1B2 Ultrasonic Motors

    OpenAIRE

    Gal Peled; Roman Yasinov; Nir Karasikov

    2016-01-01

    Piezoelectric ultrasonic motors offer important advantages for motion applications where high speed is coupled with high precision. The advances made in the recent decades in the field of ultrasonic motor based motion solutions allow the construction of complete motion platforms in the fields of semiconductors, aerospace and electro-optics. Among the various motor designs, the L1B2 motor type has been successful in industrial applications, offering high precision, effective control and operat...

  12. DYNAMIC BEHAVIOR OF TWO UNEQUAL PARALLEL PERMEABLE INTERFACE CRACKS IN A PIEZOELECTRIC LAYER BONDED TO TWO HALF PIEZOELECTRIC MATERIALS PLANES

    Institute of Scientific and Technical Information of China (English)

    SUN Jian-liang; ZHOU Zhen-gong; WANG Biao

    2005-01-01

    The dynamic behavior of two unequal parallel permeable interface cracks in a piezoelectric layer bonded to two half-piezoelectric material planes subjected to harmonic anti-plane shear waves is investigated. By using the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations in which the unknown variables were the jumps of the displacements across the crack surfaces. Numerical results are presented graphically to show the effects of the geometric parameters, the frequency of the incident wave on the dynamic stress intensity factors and the electric displacement intensity factors. Especially, the present problem can be returned to static problem of two parallel permeable interface cracks. Compared with the solutions of impermeable crack surface condition, it is found that the electric displacement intensity factors for the permeable crack surface conditions are much smaller.

  13. Piezoelectric Nanowires in Energy Harvesting Applications

    Directory of Open Access Journals (Sweden)

    Zhao Wang

    2015-01-01

    Full Text Available Recently, the nanogenerators which can convert the mechanical energy into electricity by using piezoelectric one-dimensional nanomaterials have exhibited great potential in microscale power supply and sensor systems. In this paper, we provided a comprehensive review of the research progress in the last eight years concerning the piezoelectric nanogenerators with different structures. The fundamental piezoelectric theory and typical piezoelectric materials are firstly reviewed. After that, the working mechanism, modeling, and structure design of piezoelectric nanogenerators were discussed. Then the recent progress of nanogenerators was reviewed in the structure point of views. Finally, we also discussed the potential application and future development of the piezoelectric nanogenerators.

  14. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function

    Science.gov (United States)

    Wang, Lei; Jiang, Yuquan; Jiang, Zheng; Han, Lizhang

    2016-01-01

    Background Latest studies show that low-energy extracorporeal shock wave therapy (ESWT) can upregulate levels of vascular endothelial growth factor (VEGF). VEGF can ease nervous tissue harm after spinal cord injury (SCI). This study aims to explore whether low-energy ESWT can promote expression of VEGF, protect nervous tissue after SCI, and improve motor function. Methods Ninety adult female rats were divided into the following groups: Group A (simple laminectomy), Group B (laminectomy and low-energy ESWT), Group C (spinal cord injury), and Group D (spinal cord injury and low-energy ESWT). Impinger was used to cause thoracic spinal cord injury. Low-energy ESWT was applied as treatment after injury three times a week, for 3 weeks. After SCI, the Basso, Beattie, and Bresnahan (BBB) scale was used to evaluate motor function over a period of 42 days at different time points. Hematoxylin and eosin (HE) staining was used to evaluate nerve tissue injury. Neuronal nuclear antigen (NeuN) staining was also used to evaluate loss of neurons. Polymerase chain reaction was used to detect messenger RNA (mRNA) expression of VEGF and its receptor fms-like tyrosine kinase 1 (Flt-1). Immunostaining was used to evaluate VEGF protein expression level in myeloid tissue. Results BBB scores of Groups A and B showed no significant result related to dyskinesia. HE and NeuN staining indicated that only using low-energy ESWT could not cause damage of nervous tissue in Group B. Recovery of motor function at 7, 35, and 42 days after SCI in Group D was better than that in Group C (Ptherapy for spinal injury. PMID:27621630

  15. High precise control method for a new type of piezoelectric electro-hydraulic servo valve

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new type of piezoelectric electro-hydraulic servo valve system was proposed. And then multilayer piezoelectric actuator based on new piezoelectric ceramic material was used as the electricity-machine converter of the proposed piezoelectric electro-hydraulic servo valve. The proposed piezoelectric electro-hydraulic servo valve has ascendant performance compared with conventional ones. But the system is of high nonlinearity and uncertainty, it cannot achieve favorable control performance by conventional control method. To develop an efficient way to control piezoelectric electro-hydraulic servo valve system, a high-precise fuzzy control method with hysteresis nonlinear model in feedforward loop was proposed. The control method is separated into two parts: a feedforward loop with Preisach hysteresis nonlinear model and a feedback loop with high-precise fuzzy control. Experimental results show that the hysteresis loop and the maximum output hysteresis by the PID control method are 4.22%and 2.11 μm, respectively; the hysteresis loop and the maximum output hysteresis by the proposed control method respectively are 0.74% and 0.37 μm, respectively; the maximum tracking error by the PID control method for sine wave reference signal is about 5.02%, the maximum tracking error by the proposed control method for sine wave reference signal is about 0.85%.

  16. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Li Lin; Deng Pengcheng; Fan Yu

    2015-01-01

    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 har-monic 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.

  18. Bar piezoelectric ceramic transformers.

    Science.gov (United States)

    Erhart, Jiří; Pulpan, Půlpán; Rusin, Luboš

    2013-07-01

    Bar-shaped piezoelectric ceramic transformers (PTs) working in the longitudinal vibration mode (k31 mode) were studied. Two types of the transformer were designed--one with the electrode divided into two segments of different length, and one with the electrodes divided into three symmetrical segments. Parameters of studied transformers such as efficiency, transformation ratio, and input and output impedances were measured. An analytical model was developed for PT parameter calculation for both two- and three-segment PTs. Neither type of bar PT exhibited very high efficiency (maximum 72% for three-segment PT design) at a relatively high transformation ratio (it is 4 for two-segment PT and 2 for three-segment PT at the fundamental resonance mode). The optimum resistive loads were 20 and 10 kΩ for two- and three-segment PT designs for the fundamental resonance, respectively, and about one order of magnitude smaller for the higher overtone (i.e., 2 kΩ and 500 Ω, respectively). The no-load transformation ratio was less than 27 (maximum for two-segment electrode PT design). The optimum input electrode aspect ratios (0.48 for three-segment PT and 0.63 for two-segment PT) were calculated numerically under no-load conditions.

  19. Disc piezoelectric ceramic transformers.

    Science.gov (United States)

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

  20. Cryogenic Piezoelectric Actuator

    Science.gov (United States)

    Jiang, Xiaoning; Cook, William B.; Hackenberger, Wesley S.

    2009-01-01

    In this paper, PMN-PT single crystal piezoelectric stack actuators and flextensional actuators were designed, prototyped and characterized for space optics applications. Single crystal stack actuators with footprint of 10 mm x10 mm and the height of 50 mm were assembled using 10 mm x10mm x0.15mm PMN-PT plates. These actuators showed stroke > 65 - 85 microns at 150 V at room temperature, and > 30 microns stroke at 77 K. Flextensional actuators with dimension of 10mm x 5 mm x 7.6 mm showed stroke of >50 microns at room temperature at driving voltage of 150 V. A flextensional stack actuator with dimension of 10 mm x 5 mm x 47 mm showed stroke of approx. 285 microns at 150 V at room temperature and > 100 microns at 77K under driving of 150 V should be expected. The large cryogenic stroke and high precision of these actuators are promising for cryogenic optics applications.

  1. Effective piezoelectric response of substrate-integrated ZnO nanowire array devices on galvanized steel.

    Science.gov (United States)

    Velazquez, By Jesus M; Baskaran, Sivapalan; Gaikwad, Anil V; Ngo-Duc, Tam-Triet; He, Xiangtong; Oye, Michael M; Meyyappan, M; Rout, Tapan K; Fu, John Y; Banerjee, Sarbajit

    2013-11-13

    Harvesting waste energy through electromechanical coupling in practical devices requires combining device design with the development of synthetic strategies for large-area controlled fabrication of active piezoelectric materials. Here, we show a facile route to the large-area fabrication of ZnO nanostructured arrays using commodity galvanized steel as the Zn precursor as well as the substrate. The ZnO nanowires are further integrated within a device construct and the effective piezoelectric response is deduced based on a novel experimental approach involving induction of stress in the nanowires through pressure wave propagation along with phase-selective lock-in detection of the induced current. The robust methodology for measurement of the effective piezoelectric coefficient developed here allows for interrogation of piezoelectric functionality for the entire substrate under bending-type deformation of the ZnO nanowires.

  2. Solution of two-dimensional scattering problem in piezoelectric/piezomagnetic media using a polarization method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using a polarization method, the scattering problem for a two-dimensional inclusion embedded in infinite piezoelectric/piezomagnetic matrices is investigated. To achieve the purpose, the polarization method for a two-dimensional piezoelectric/piezo-magnetic "comparison body" is formulated. For simple harmonic motion, kernel of the polarization method reduces to a 2-D time-harmonic Green's function, which is ob-tained using the Radon transform. The expression is further simplified under condi-tions of low frequency of the incident wave and small diameter of the inclusion. Some analytical expressions are obtained. The analytical solutions for generalized piezoelec-tric/piezomagnetic anisotropic composites are given followed by simplified results for piezoelectric composites. Based on the latter results, two numerical results are provided for an elliptical cylindrical inclusion in a PZT-5H-matrix, showing the effect of different factors including size, shape, material properties, and piezoelectricity on the scattering cross-section.

  3. Piezoelectric Analysis of Saw Sensor Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Vladimír KUTIŠ

    2013-06-01

    Full Text Available In this contribution modeling and simulation of surface acoustic waves (SAW sensor using finite element method will be presented. SAW sensor is made from piezoelectric GaN layer and SiC substrate. Two different analysis types are investigated - modal and transient. Both analyses are only 2D. The goal of modal analysis, is to determine the eigenfrequency of SAW, which is used in following transient analysis. In transient analysis, wave propagation in SAW sensor is investigated. Both analyses were performed using FEM code ANSYS.

  4. Linear ultrasonic motor using quadrate plate transducer

    Institute of Scientific and Technical Information of China (English)

    Jiamei JIN; Chunsheng ZHAO

    2009-01-01

    A linear ultrasonic motor using a quadrate plate transducer was developed for precision positioning. This motor consists of two pairs of Pb(Zr, Ti)O3 piezo-electric ceramic elements, which are piezoelectrically excited into the second-bending mode of the motor stator's neutral surface in two orthogonal directions, on which the tops of four projections move along an elliptical trajectory, which in turn drives a contacted slider into linear motion via frictional forces. The coincident frequency of the stator is easily obtained for its coincident characteristic dimen-sion in two orthogonal directions. The performance characteristics achieved by the motor are: 1) a maximum linear speed of more than 60 mm/s; 2) a stroke of more than 150 mm; 3) a driving force of more than 5.0 N; and 4) a response time of about 2 ms.

  5. Analytical and numerical modeling of resonant piezoelectric devices in China-A review

    Institute of Scientific and Technical Information of China (English)

    YANG JiaShi; YANG ZengTao

    2008-01-01

    The results on theoretical and numerical modeling of resonant piezoelectric devices in China are reviewed.Solutions to dynamic problems of the propagation of bulk acoustic waves (BAW),surface acoustic waves (SAW),vibrations of finite bodies,and analyses of specific devices are discussed.Results from both the ultrasonics community and mechanics researchers are included.It is hoped that the paper will be useful for the understanding,communication and collaboration between Chinese and foreign scholars.The paper may also be helpful for bridging the gap between ultrasonics and mechanics researchers on piezoelectricity re-search.The paper contains 316 references.

  6. Giant piezoelectric response in piezoelectric/dielectric superlattices due to flexoelectric effect

    Science.gov (United States)

    Liu, Chang; Wu, Huaping; Wang, Jie

    2016-11-01

    Flexoelectricity describes the linear response of electrical polarization to a strain gradient, which can be used to enhance the piezoelectric effect of piezoelectric material or realize the piezoelectric effect in nonpiezoelectric materials. Here, we demonstrate from thermodynamics theory that a giant piezoelectric effect exists in piezoelectric/dielectric superlattices due to flexoelectric effect. The apparent piezoelectric coefficient is calculated from the closed-form of analytical expression of the polarization distribution in the piezoelectric/dielectric superlattice subjected to a normal stress, in which the flexoelectric effect is included. It is found that there exists a strong nonlinear coupling between the flexoelectric and piezoelectric effects, which significantly enhances the apparent piezoelectric coefficient in the piezoelectric/dielectric superlattice. For a specific thickness ratio of the piezoelectric and dielectric layers, the enhanced apparent piezoelectric coefficient in the superlattice is ten times larger than that of its pure piezoelectric counterpart. The present work suggests an effective way to obtain giant apparent piezoelectric effect in piezoelectric/dielectric superlattices through flexoelectric effect.

  7. Closed-form solution for free vibration of piezoelectric coupled annular plates using Levinson plate theory

    Science.gov (United States)

    Hosseini Hashemi, Sh.; Es'haghi, M.; Karimi, M.

    2010-04-01

    Free vibration analysis of annular moderately thick plates integrated with piezoelectric layers is investigated in this study for different combinations of soft simply supported, hard simply supported and clamped boundary conditions at the inner and outer edges of the annular plate on the basis of the Levinson plate theory (LPT). The distribution of electric potential along the thickness direction in the piezoelectric layer is assumed as a sinusoidal function so that the Maxwell static electricity equation is approximately satisfied. The differential equations of motion are solved analytically for various boundary conditions of the plate. In this study the closed-form solution for characteristic equations, displacement components of the plate and electric potential are derived for the first time in the literature. To demonstrate the accuracy of the present solution, comparison studies is first carried out with the available data in the literature and then natural frequencies of the piezoelectric coupled annular plate are presented for different thickness-radius ratios, inner-outer radius ratios, thickness of piezoelectric, material of piezoelectric and boundary conditions. Present analytical model provides design reference for piezoelectric material application, such as sensors, actuators and ultrasonic motors.

  8. 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.

  9. Note: Direct piezoelectric effect microscopy.

    Science.gov (United States)

    Mori, T J A; Stamenov, P; Dorneles, L S

    2015-07-01

    An alternative method for investigating piezoelectric surfaces is suggested, exploiting the direct piezoeffect. The technique relies on acoustic (ultrasonic) excitation of the imaged surface and mapping of the resulting oscillatory electric potential. The main advantages arise from the spatial resolution of the conductive scanning probe microscopy in combination with the relatively large magnitude of the forward piezo signal Upf, which can be of the order of tens of mV even for non-ferroelectric piezoelectric materials. The potency of this experimental strategy is illustrated with measurements on well-crystallized quartz surfaces, where Upf ∼ 50 mV, for a piezoelectric coefficient of d33 = - 2.27  ×  10(-12) m/V, and applied stress of about T3 ∼ 5.7 kPa.

  10. [Effect of Acupuncture plus Different Frequency Shock-wave Interventions on Pain Reactions and Motor Function in Knee Osteoarthritis Patients].

    Science.gov (United States)

    Li, Jian-wei; Zheng, Shi-jiang; Zhang, Jing-chun; Huang, Jian-jun; Liu, Xiao-gang

    2015-08-01

    To observe the clinical effect of acupuncture plus shock-wave (SW) intervention for osteoarthritis (WA), so as to explore its practicability in clinical practice. A total of 120 cases of knee OA patients were randomly divided into 4 groups, namely acupuncture (acupunct) + LFSW, acupunct + MFSW, acupunct + HFSW and routine acupunct groups, with 30 cases in each group. Xuehai (SP 10) , Liangqiu (ST 34), Yanglingquan (GB 34), Xiyan (ST 35) and Ashi-point were punctured with filiform needles which were manipulated with uniform reinforcing-reducing techniques for 15-20 min, once every other day for 7 times. In addition, these acupoints were also respectively stimulated with shock waves(10 Hz, 14 Hz and 18 Hz, pressure: 1-4 bar) delivered from a DolorClastEMS therapeutic apparatus for 600 times in 3 acupunct+ SW groups. The patients' pain response changes of the knee-joint were assessed by using visual analog scale (VAS) and the motility was evaluated by using a 0-3 grade scale. RESULTS After 7 times of treatment, the patients' VAS scores and motility scores were significantly decreased in the acupunct+ LFSW, acupunct+ MFSW, acupunct+ HFSW and routine acupunct groups compared with their own basic values before treatment (P Deqi sensation score of the acupunct+ MFSW group was markedly higher than those of the other 3 groups (P Deqi-sensation.

  11. Research on the Effects of Pulse Waves Through a Long Cable on Motor Terminal Overvoltage%长电缆传输脉冲波对电机端过电压影响的研究

    Institute of Scientific and Technical Information of China (English)

    张椿; 戴鹏; 宗伟林; 潘庆山

    2013-01-01

    基于传输线理论分析了脉冲波在电缆中的反射过程及电机端过电压的产生机理,通过Matlab仿真软件对脉冲波反射过程进行了分析.根据反射原理,对电机端各反射波分量和入射波分量进行叠加,得到电机端电压.通过PSpice仿真软件建立了单个脉冲-无损电缆-电机仿真模型,并对电机端产生过电压临界脉冲传输的时间做了仿真研究;在此基础上建立了PWM脉冲-无损电缆-电机仿真模型,仿真结果验证了PWM脉冲占空比最大时电机端电压达到最大值.%The reflection of pulse waves through a long cable and the mechanism of motor terminal overvoltage using transmission line theory was analyzed.The pulse wave reflection prosses was simulated with Matlab software. According to the reflection principle,motor terminal over-voltage is the piling up of the incident and reflected wave components.Pusle-lossless cable-motor model was set up in PSpice software, while the critical state and the most likely moment occurring motor terminal overvoltage was studied with the model.And then PWM pulse-lossless cable-motor model was set up to verify that motor terminal voltage reached its maximum as PWM pulse duty cycle is the largest.

  12. 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.

  13. The effect of friction reduction in presence of ultrasonic vibrations and its relevance to travelling wave ultrasonic motors.

    Science.gov (United States)

    Storck, H; Littmann, W; Wallaschek, J; Mracek, M

    2002-05-01

    In many ultrasonic applications frictional effects play an important role (e.g. ultrasonic machining, ultrasonic motors). For optimising the applications in terms of quality, efficiency and lifetime it is important to understand the frictional coupling of the vibrating and the non-vibrating part. This contribution is devoted to give an explanation for the reduction of friction forces which is often observed when ultrasonic vibrations are superimposed to macroscopic motions. Usually adopted coefficients of friction are used for modelling such conditions suggesting special frictional mechanisms for high frequency oscillations, whereas the present paper shows that Coulomb's friction law provides a very good description of the observed phenomena if the kinematics of the system is taken into account. Two systems are investigated. In the first system the ultrasonic and macroscopic movements are parallel and in the second they are perpendicular to each other but also within the plane of contact. Both systems were investigated analytically and experimentally using a specially designed test rig. The measurements confirmed the analytically derived equations and therefore the validity of Coulomb's friction law even for ultrasonic conditions.

  14. Finite element analysis of piezoelectric underwater transducers for acoustic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hwan [Inha University, Incheon (Korea, Republic of); Kim, Heung Soo [Catholic University, Daegu (Korea, Republic of)

    2009-02-15

    This paper presents a simulation technique for analyzing acoustic characteristics of piezoelectric underwater transducers. A finite element method is adopted for modeling piezoelectric coupled problems including material damping and fluid-structure interaction problems by taking system matrices in complex form. For the finite element modeling of unbounded acoustic fluid, infinite wave envelope element (IWEE) is adopted to take into account the infinite domain. An in-house finite element program is developed and technical issues for implementing the program are explained. Using the simulation program, acoustic characteristics of tonpilz transducer are analyzed in terms of modal analysis, radiated pressure distribution, pressure spectrum, transmitting-voltage response and impedance analysis along with experimental comparison. The developed simulation technique can be used for designing ultrasonic transducers in the areas of nondestructive evaluation, underwater acoustics and bioengineering

  15. A planar nano-positioner driven by shear piezoelectric actuators

    Directory of Open Access Journals (Sweden)

    W. Dong

    2016-08-01

    Full Text Available A planar nano-positioner driven by the shear piezoelectric actuators is proposed in this paper based on inertial sliding theory. The performance of the nano-positioner actuated by different driving signals is analyzed and discussed, e.g. the resolution and the average velocity which depend on the frequency, the amplitude and the wave form of the driving curves. Based on the proposed design, a prototype system of the nano-positioner is developed by using a capacitive sensor as the measurement device. The experiment results show that the proposed nano-positioner is capable of outputting two-dimensional motions within an area of 10 mm × 10 mm at a maximum speed of 0.25 mm/s. The corresponding resolution can be as small as 21 nm. The methodology outlined in this paper can be employed and extended to shear piezoelectric actuators involved in high precision positioning systems.

  16. General solutions for special orthotropic piezoelectric media

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper presents the forms of the general solution for general anisotropic piezoelectric media starting from the basic equations of piezoelasticity by using the operator method introduced by Lur'e (1964), and gives the analytical form of the general solution for special orthotropic piezoelectric media. This paper uses the non-uniqueness of the general solution to obtain the generalized LHN solution and the generalized E-L solution for special orthotropic piezoelectric media. When the special orthotropic piezoelectric media degenerate to transversely piezoelectric media, the solution given by this paper degenerates to the solution for transversely isotropic piezoelectric media accordingly, so that this paper generalized the results in transversely isotropic piezoelectric media.

  17. Vibration Control of Manipulators with Flexible Nonprismatic Links Using Piezoelectric Actuators and Sensors

    Directory of Open Access Journals (Sweden)

    Valdecir Bottega

    2009-01-01

    robotic manipulator using simultaneously motor torques and piezoelectric actuators. The dynamic model of the flexible manipulator is obtained in a closed form through the Lagrange equations. The control uses the motor torques for the joints tracking control and also to reduce the low-frequency vibration induced in the manipulator links. The stability of this control is guaranteed by the Lyapunov stability theory. Piezoelectric actuators and sensors are added for controlling vibrations with frequencies beyond the reach of motor torque control. The naturals frequencies are calculated by the finite element method, and the approximated eigenfunctions are interpolated by polynomials. Three eigenfunctions are used for the dynamics of the arm, while only two are used for the control. Numerical experiments on Matlab/Simulink are used to verify the efficiency of the control model.

  18. 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.

  19. Vacuum mounting for piezoelectric transducers

    Science.gov (United States)

    Tiede, D. A.

    1977-01-01

    Special housing couples piezoelectric transducers to nonporous surfaces for ultrasonic or acoustic-emission testing. Device, while providing sound isolation on flat or nonflat surfaces, can be attached and detached quickly. Vacuum sealing mechanism eliminates need for permanent or semipermanent bonds, viscous coupling liquids, weights, magnets, tape, or springs ordinarily used.

  20. Experimental evaluation of a cruciform piezoelectric energy harvester

    Science.gov (United States)

    Tsuruta, Karina M.; Rade, Domingos A.; Finzi Neto, Roberto M.; Cavalini, Aldemir A.

    2016-10-01

    This paper describes the development and experimental evaluation of a particular type of piezoelectric energy harvester, composed of four aluminum cantilever blades to which piezoelectric patches are bonded, in such way that electric energy is generated when the blades undergo bending vibrations. Concentrated masses, whose values can be varied, are attached to the tips of the blades. Due to the geometric shape of the harvester, in which the four blades are oriented forming right angles, the harvester is named cruciform. As opposed to the large majority of previous works on the subject, in which harvesters are excited at their bases by prescribed acceleration, herein the harvester is connected to a vibrating structure excited by an imbalance force. Hence, the amount of harvested energy depends upon the dynamic interaction between the harvester and the host structure. Laboratory experiments were carried-out on a prototype connected to a tridimensional truss. The experimental setup includes a force generator consisting of an imbalanced disc driven by an electrical motor whose rotation is controlled electronically, a voltage rectifier circuit, and a battery charged with the harvested energy. After characterization of the dynamic behavior of the harvester and the host structure, both numerically and experimentally, the results of experiments are presented and discussed in terms of the voltage output of the piezoelectric transducers as function of the excitation frequency and the values of the tip masses. Also, the capacity of the harvester to charge a Lithium battery is evaluated.

  1. High Power Piezoelectric Characterization for Piezoelectric Transformer Development

    Science.gov (United States)

    Ural, Seyit O.

    The major goal was to develop characterization techniques to identify and define guidelines to manufacture high power density actuators. We particularly aim at improving the strengths of piezoelectric transformers, namely the high efficiency, ease of manufacturing, low electromagnetic noise, and high power to weight ratio resulting in an adaptor application by identifying material limitations, geometrical limitations and offer guidelines to counter drawbacks limiting the power density. There are 3 losses present in piezoelectrics. Namely dielectric, elastic and piezoelectric losses. These losses can be calculated using mechanical quality factors of the resonating piezoelectric actuator. But in order to calculate all three losses, the mechanical quality factor for resonance and anti resonance need to be measured. Although the mechanical quality factor for resonance is conventionally measured, measurements in antiresonance have been ignored. Since there was no unique measurement technique to address antiresonance and resonance Q in one single sweep, in this study constant vibration velocity method was developed. During the constant vibration velocity measurement, the input electrical energy is monitored and significant differences between resonance and antiresonance drives are observed. For the same output work (identical vibration velocity) significant differences in the losses were observed. Thermographic images have shown increasing temperature differences for resonance and antiresonance nodal point temperatures, with higher vibration velocities. The theoretical evaluation identified the difference observed in the mechanical quality factors at resonance and antiresonance to stem from the piezoelectric loss. In order to investigate losses in the absence of thermal effects a transient characterization technique was adopted. The burst technique, originally developed for characterization of the mechanical quality factor at resonance, has been modified with a switch

  2. Modified Continuum Mechanics Modeling on Size-Dependent Properties of Piezoelectric Nanomaterials: A Review

    Science.gov (United States)

    Yan, Zhi; Jiang, Liying

    2017-01-01

    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. PMID:28336861

  3. 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.

  4. Electromechanical and Photoluminescence Properties of Al-doped ZnO Nanorods Applied in Piezoelectric Nanogenerators

    Science.gov (United States)

    Chang, Wen-Yang; Fang, Te-Hua; Tsai, Ju-Hsuan

    2015-02-01

    A piezoelectric nanogenerator based on Al-doped ZnO (AZO) nanorods with a V-zigzag layer is investigated at a low temperature. The growth temperature, growth time, growth concentration, photoluminescence (PL) spectrum, and AZO epitaxial growth on the ITO glass substrate using aqueous solution are reported and the associated electromechanical and PL properties are discussed. In general, the properties of piezoelectric nanogenerators and their functionality at ultralow temperatures (near liquid helium temperature) are important for applications in extreme environments. A V-zigzag layer is used to enhance the bending and compression deformation of the piezoelectric nanogenerator. The electromechanical properties of AZO nanorods are tested using an ultrasonic wave generator. Results show that the percent transmittance decreases with increasing growth time and growth temperature. The intensities of the PL spectrum and the (002) peak orientation increases with increasing growth temperature. AZO at a low growth temperature of 90 C has good piezoelectric harvesting efficiency when the piezoelectric nanogenerator has a zigzag structure. The average current, voltage, and power density of the piezoelectric harvesting are 0.76 A, 1.35 mV, and 1.026 nW/mm, respectively. These results confirm the feasibility of growing AZO at low temperature. AZO nanorods have potential for energy harvester applications.

  5. Flexible piezoelectric thin-film energy harvesters and nanosensors for biomedical applications.

    Science.gov (United States)

    Hwang, Geon-Tae; Byun, Myunghwan; Jeong, Chang Kyu; Lee, Keon Jae

    2015-04-02

    The use of inorganic-based flexible piezoelectric thin films for biomedical applications has been actively reported due to their advantages of highly piezoelectric, pliable, slim, lightweight, and biocompatible properties. The piezoelectric thin films on plastic substrates can convert ambient mechanical energy into electric signals, even responding to tiny movements on corrugated surfaces of internal organs and nanoscale biomechanical vibrations caused by acoustic waves. These inherent properties of flexible piezoelectric thin films enable to develop not only self-powered energy harvesters for eliminating batteries of bio-implantable medical devices but also sensitive nanosensors for in vivo diagnosis/therapy systems. This paper provides recent progresses of flexible piezoelectric thin-film harvesters and nanosensors for use in biomedical fields. First, developments of flexible piezoelectric energy-harvesting devices by using high-quality perovskite thin film and innovative flexible fabrication processes are addressed. Second, their biomedical applications are investigated, including self-powered cardiac pacemaker, acoustic nanosensor for biomimetic artificial hair cells, in vivo energy harvester driven by organ movements, and mechanical sensor for detecting nanoscale cellular deflections. At the end, future perspective of a self-powered flexible biomedical system is also briefly discussed with relation to the latest advancements of flexible electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Electrical properties and sensing ability of novel piezoelectric ceramic fibers with Pt core

    Science.gov (United States)

    Du, Jianzhou; Qiu, Jinhao; Zhu, Kongjun; Ji, Hongli; Zhao, Huayun

    2012-04-01

    The traditional sintering method was used to sinter the pure and Fe2O3 doped 0.55Pb(Ni0.33Nb0.67)O3-0.45Pb(Zr0.3Ti0.7)O3 (abbreviate as PNN-PZT and PFNN-PZT, respectively) ceramics. The addition of Fe2O3 significantly improved the microstructure and electrical properties. Compared with pure PNN-PZT ceramics, higher dielectric and piezoelectric properties of d31~-390 pC/N, ɛ r ~6298 were obtained for the PFNN-PZT sample sintered at 1175°C for 2 h. Hence, the PFNN-PZT ceramics sample was selected to fabricate piezoelectric ceramic fibers with Pt core (PFC). Both the green fibers and bulk ceramics were sintered at 1150-1225°C for 2 h in a closed crucible, respectively. The effect of sintering temperature on the microstructure and electrical properties of the PFNN-PZT fibers was investigated. The optimal piezoelectric properties are obtained for the sample sintered at 1175°C for 2 h. The relative dielectric constant and piezoelectric constant show peak values of ɛ r~3683, d31~-197.4 pC/N, respectively. The PFC is a new type piezoelectric device, which can be used for sensors or actuators. The results of sensing experiment show that the piezoelectric ceramic fiber with Pt core has high sensitivity for the Lamb waves.

  7. New piezoelectric materials for SAW filters

    Science.gov (United States)

    Anghelescu, Adrian; Nedelcu, Monica

    2010-11-01

    Scientific research of surface acoustic wave (SAW) devices had an early start by the end of 1960s and led to the development of high frequency and small size piezo devices. A sustained effort was dedicated for these components to be transformed into many more interesting applications for telecom market. Recently the employment of new piezo materials and crystallographic orientations open new opportunities for SAW filters. New piezoelectric crystals of gallium orthophosphate (GaPO4) provide higher electromechanical coupling than quartz, while maintaining temperature compensated characteristics similar to quartz. Based on this material phase transition of 970°C, development of new piezo devices to operate at higher temperatures up to 800°C can be done. SAW velocities about 30% lower than ST-X quartz, favors smaller and more compact devices. Other advantages of GaPO4 are: stability with high resistance to stress induced twinning, 3~4 times higher electromechanical coupling than quartz and existence of SAW temperature compensated orientations. Another family of new materials of the trigonal 32 class has received much attention recently because of their temperature behavior similar to quartz and the promise of higher electromechanical coupling coefficients. It is the family of langasite (LGS, La3Ga5SiO14), langatate (LGT, La3Ga5.5Ta0.5O14) and langanite (La3Ga5.5Nb0.5O14). Langasite crystals, easier to obtain and with the value of electromechanical coupling coefficient intermediate between quartz and lithium tantalate (k2=0.32% for 0°, 140°, 22.5° orientation and k2=0.38% for 0°, 140°, 25° orientation), enable us to design SAW filters with a relative pass band of 0.3% to 0.85%. Other piezoelectric materials are reviewed for comparison.

  8. Virus-based piezoelectric energy generation.

    Science.gov (United States)

    Lee, Byung Yang; Zhang, Jinxing; Zueger, Chris; Chung, Woo-Jae; Yoo, So Young; Wang, Eddie; Meyer, Joel; Ramesh, Ramamoorthy; Lee, Seung-Wuk

    2012-05-13

    Piezoelectric materials can convert mechanical energy into electrical energy, and piezoelectric devices made of a variety of inorganic materials and organic polymers have been demonstrated. However, synthesizing such materials often requires toxic starting compounds, harsh conditions and/or complex procedures. Previously, it was shown that hierarchically organized natural materials such as bones, collagen fibrils and peptide nanotubes can display piezoelectric properties. Here, we demonstrate that the piezoelectric and liquid-crystalline properties of M13 bacteriophage (phage) can be used to generate electrical energy. Using piezoresponse force microscopy, we characterize the structure-dependent piezoelectric properties of the phage at the molecular level. We then show that self-assembled thin films of phage can exhibit piezoelectric strengths of up to 7.8 pm V(-1). We also demonstrate that it is possible to modulate the dipole strength of the phage, hence tuning the piezoelectric response, by genetically engineering the major coat proteins of the phage. Finally, we develop a phage-based piezoelectric generator that produces up to 6 nA of current and 400 mV of potential and use it to operate a liquid-crystal display. Because biotechnology techniques enable large-scale production of genetically modified phages, phage-based piezoelectric materials potentially offer a simple and environmentally friendly approach to piezoelectric energy generation.

  9. Virus-based piezoelectric energy generation

    Science.gov (United States)

    Lee, Byung Yang; Zhang, Jinxing; Zueger, Chris; Chung, Woo-Jae; Yoo, So Young; Wang, Eddie; Meyer, Joel; Ramesh, Ramamoorthy; Lee, Seung-Wuk

    2012-06-01

    Piezoelectric materials can convert mechanical energy into electrical energy, and piezoelectric devices made of a variety of inorganic materials and organic polymers have been demonstrated. However, synthesizing such materials often requires toxic starting compounds, harsh conditions and/or complex procedures. Previously, it was shown that hierarchically organized natural materials such as bones, collagen fibrils and peptide nanotubes can display piezoelectric properties. Here, we demonstrate that the piezoelectric and liquid-crystalline properties of M13 bacteriophage (phage) can be used to generate electrical energy. Using piezoresponse force microscopy, we characterize the structure-dependent piezoelectric properties of the phage at the molecular level. We then show that self-assembled thin films of phage can exhibit piezoelectric strengths of up to 7.8 pm V-1. We also demonstrate that it is possible to modulate the dipole strength of the phage, hence tuning the piezoelectric response, by genetically engineering the major coat proteins of the phage. Finally, we develop a phage-based piezoelectric generator that produces up to 6 nA of current and 400 mV of potential and use it to operate a liquid-crystal display. Because biotechnology techniques enable large-scale production of genetically modified phages, phage-based piezoelectric materials potentially offer a simple and environmentally friendly approach to piezoelectric energy generation.

  10. Piezoelectric impact force sensor array for tribological research on rigid disk storage media

    NARCIS (Netherlands)

    Burger, G.J.; Lammerink, T.S.J.; Fluitman, J.H.J.; Imai, S.; Tokuyama, M.; Hirose, S.

    1995-01-01

    This paper presents a method to measure impact forces on a surface by means of a piezoelectric thin film sensor array. The output signals of the sensor array provide information about the position, magnitude and wave form of the impact force. The sensor array may be used for tribological studies to

  11. Application of the dvldt Wave Filter to the Protection of Inductive Motors%dv/dr滤波器在感应电动机保护中的应用

    Institute of Scientific and Technical Information of China (English)

    朱乃将

    2012-01-01

    通过对全变频自动扶梯故障案例的分析,得出PWM逆变器在应用中产生的dv/dt及脉冲电压是损坏电动机绝缘的主要根源的结论。通过实验表明,dv/dt滤波器可降低峰值电压及dv/dt,从而对电动机的线圈起到保护作用,提高电动机的可靠性以及延长电动机的使用寿命。最后,强调dv/dt滤波器在全变频控制系统中对电动机保护的重要性与必要性。%According to the analysis of full variable frequency escalator's accident, this article draws a conclusion that dv/dt and impulse voltage which caused by application of PWM controller inverter is the main cause of damaging motor insulation. Experiments show that dv/dt wave filter reduces peak value voltage and dv/dt result in the protection of motor coil and promote the reliability and longevity of motor. We emphasize the dv/dt wave filter's importance and necessity of protecting motor in full variable frequency control system.

  12. Static and dynamic analysis of a four-tube piezoelectric actuator.

    Science.gov (United States)

    Ma, Yuting; Feng, Zhihua; Pan, Chengliang; Kong, Fanrang

    2009-06-01

    Piezoelectric tubes with film electrodes on their outer and inner surfaces can be used to compose multitube actuators. The actuator of four piezoelectric tubes can substitute the traditional single-tube actuator with quartered electrodes which has been widely used in scanning probe microscopy and piezoelectric motors. In this article, the static deflection, static bending moment, resonant frequency, and dynamic deflection of the four-tube actuator are all studied in detail. The comparison between this actuator and the traditional single-tube actuator is also done and the results show that the four-tube actuator has better performances under certain conditions. The experiment results of a prototype actuator testified the validation of the analysis.

  13. Coupled improvement between thermoelectric and piezoelectric materials

    Science.gov (United States)

    Montgomery, David; Hewitt, Corey; Dun, Chaochao; Carroll, David

    A novel coupling effect in a thermoelectric and piezoelectric meta-structure is discussed. Thermo-piezoelectric generators (TPEGs) exhibit a synergistic effect that amplifies output voltage, and has been observed to increase piezoelectric voltages over 500% of initial values a time dependent thermoelectric/pyroelectric effect. The resulting improvement in voltage has been observed in carbon nanotubes as well as inorganics such as two-dimensional Bismuth Selenide platelets and Telluride nanorods thin-film thermoelectrics. TPEGs are built by integrating insulating layers of polyvinylidene fluoride (PVDF) piezoelectric films between flexible thin film p-type and n-type thermoelectrics. The physical phenomena arising in the interaction between thermoelectric and piezoelectrics is discussed and a model is presented to quantify the expected coupling voltage as a function of stress, thermal gradient, and different thermoelectric materials. TPEG are ideal to capture waste heat and vibrational energy while creating larger voltages and minimizing space when compared with similar thermoelectric or piezoelectric generators.

  14. Piezoelectric Power Requirements for Active Vibration Control

    Science.gov (United States)

    Brennan, Matthew C.; McGowan, Anna-Maria Rivas

    1997-01-01

    This paper presents a method for predicting the power consumption of piezoelectric actuators utilized for active vibration control. Analytical developments and experimental tests show that the maximum power required to control a structure using surface-bonded piezoelectric actuators is independent of the dynamics between the piezoelectric actuator and the host structure. The results demonstrate that for a perfectly-controlled system, the power consumption is a function of the quantity and type of piezoelectric actuators and the voltage and frequency of the control law output signal. Furthermore, as control effectiveness decreases, the power consumption of the piezoelectric actuators decreases. In addition, experimental results revealed a non-linear behavior in the material properties of piezoelectric actuators. The material non- linearity displayed a significant increase in capacitance with an increase in excitation voltage. Tests show that if the non-linearity of the capacitance was accounted for, a conservative estimate of the power can easily be determined.

  15. Surface modification of piezoelectric aluminum nitride with functionalizable organosilane adlayers

    Science.gov (United States)

    Chan, Edmund; Jackson, Nathan; Mathewson, Alan; Galvin, Paul; Alamin Dow, Ali B.; Kherani, Nazir P.; Blaszykowski, Christophe; Thompson, Michael

    2013-10-01

    The world of biosensors is expanding at a rapid pace with an ever-increasing demand for more sensitive miniaturized devices. Acoustic wave biosensors are not spared from this trend. In this domain, the search for enhanced sensitivity is increasingly oriented toward the rational design of new piezoelectric materials with superior properties to substitute for prevalent quartz. With respect to surface chemistry, construction of the biorecognition element, more often than not, requires the use of bifunctional molecules that can spontaneously assemble on the substrate and form organic surfaces readily biofunctionalizable in a subsequent, ideally single step. In this context, we present herein the surface modification of aluminum nitride (AlN) with alkyltrichlorosilane cross-linking molecules bearing a functionalizable benzenethiosulfonate moiety. This latter feature is next demonstrated through the straightforward, preactivation-free immobilization of thiolated biotin probes. To date, AlN has only received little attention in the field of piezoelectric biosensors despite its many attractive properties and the perspective to operate devices at ultra-high frequencies (GHz) with unprecedented sensitivity. To our knowledge, this work describes one of the first examples of direct surface derivatization of AlN with bifunctional trichlorosilane molecules. It also constitutes a first step toward the development of electrodeless GHz piezoelectric biosensing platforms based on AlN and trichlorosilane surface chemistry.

  16. Introduction to Piezoelectric Actuators and Transducers

    Science.gov (United States)

    2007-11-02

    1 Introduction to Piezoelectric Actuators and Transducers Kenji Uchino, International Center for Actuators and Transducers, Penn State University...REPORT DATE 00 JUN 2003 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Introduction to Piezoelectric Actuators and Transducers...now used in various fields. The sound source is made from piezoelectric ceramics as well as magnetostrictive materials. Piezoceramics are generally

  17. Piezoelectric field in strained GaAs.

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Weng Wah; Wieczorek, Sebastian Maciej

    2005-11-01

    This report describes an investigation of the piezoelectric field in strained bulk GaAs. The bound charge distribution is calculated and suitable electrode configurations are proposed for (1) uniaxial and (2) biaxial strain. The screening of the piezoelectric field is studied for different impurity concentrations and sample lengths. Electric current due to the piezoelectric field is calculated for the cases of (1) fixed strain and (2) strain varying in time at a constant rate.

  18. Heartbeat detection system using piezoelectric transducer

    Science.gov (United States)

    Hamonangan, Yosua; Purnamaningsih, Wigajatri

    2017-02-01

    This paper presents a simple piezoelectric based heartbeat detection system. The signal produced by the piezoelectric will undergo signal conditioning and then converted into digital data by Arduino Nano. Using serial communication, the data will be sent to a computer for display and further analysis. The detection of heartbeat is carried out on three locations; wrist, chest, and diaphragm. From the measurement results, it is shown that the system work best when the piezoelectric is placed on wrist.

  19. Piezoelectric actuator for pulsating jets

    Science.gov (United States)

    Brissaud, Michel; Gonnard, Paul; Bera, Jean-Christophe; Sunyach, Michel

    2000-08-01

    Recent researches in aeronautics showed that fluidic actuator systems could offer possibilities for drag reduction and lift improvement. To this end many actuator types were designed. This paper deals with the design, fabrication and test of piezoelectric actuator in order to generate pulsated jets normal to a surface and control air flow separation. It is based on the flexural displacement of a rectangular metal plate clamped on one of its large edge. Piezoelectric patches cemented on the plate were used for driving into vibration the actuator. Experimental measurements show that pulsed flow velocities are adjustable from 1.5m/s to 35m/s through a 100x1mm2 slit andwithin a 100 to 400 Hz frequency range. Prototype provides the jet performances classically required for active control flow.

  20. 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.

  1. The dynamic modeling and design improvement of a piezoelectric exciter of a touch screen device for efficient tactile feedback

    Science.gov (United States)

    Park, Young-Min; Kim, Kwang-Joon

    2011-05-01

    Piezoelectric exciters have been receiving greater attention recently as a vibration source for tactile feedback in devices with touch screens, such as a mobile phones, in place of DC motors due to lower energy consumption and smaller volume. Their insufficient excitation level, however, still remains a problem. In this paper, dynamic modeling and design improvement of a piezoelectric exciter are presented. The excitation performance is defined as the acceleration response at the center of a touch screen per electric power and to be maximized around 250 Hz where the index finger is most sensitive. The piezoelectric exciter consists of a z-shaped metal beam, a piezoelectric layer on the long horizontal segment and an adhesive layer between the short horizontal segment and the touch screen. Assuming that the piezoelectric exciter is attached onto a rigid ground due to its low mechanical impedance compared with that of the touch screen, the piezoelectric exciter is dynamically modeled by applying Hamilton's principle, where the adhesive layer is treated as a distributed stiffness. The touch screen is modeled approximately as a simply supported beam such that it may have the same fundamental natural frequency and bending stiffness as the screen based on measurements. The performance improvement is focused on the change of five geometric parameters of the piezoelectric exciter: length of the long horizontal segment, thickness of the piezoelectric layer, thickness of the elastic metal layer, width of the beams and tip mass. The procedure to improve the performance of the piezoelectric exciter via dynamic modeling is presented together with experimental results on a prototype. Effectiveness of the design modification and limitations in practice are further discussed as well.

  2. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  3. Piezoelectric Energy Harvesting for Roadways

    OpenAIRE

    Xiong, Haocheng

    2015-01-01

    Energy harvesting technologies have drawn much attention as an alternative power source of roadway accessories in different scales. Piezoelectric energy harvesting consisting of PZT piezoceramic disks sealed in a protective package is developed in this work to harness the deformation energy of pavement induced by traveling vehicles and generate electrical energy. Six energy harvesters are fabricated and installed at the weigh station on I-81 at Troutville, VA to perform on-site evaluation. T...

  4. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  5. FLUTTER SUPPRESSION USING DISTRIBUTED PIEZOELECTRIC ACTUATORS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Flutter suppression using distributed piezoelectric actuators has been analyzed and tested. In constructing the finite element equation, effects of piezoelectric matrices are investigated. LQG method is used in designing the control law. In reducing the order of the control law, both balance realization and LK methods are used. For the rational approximation of the unsteady aerodynamic forces LS method is improved. In determining the piezoelectric constants d31 a new dynamic response method is developed. Laser vibrameter is used to pick up the model response and in ground resonance test the model is excited by piezoelectric actuators. Reasonable agreement of the wind tunnel flutter suppression test with calculated results is obtained.

  6. Structural Damage Detection with Piezoelectric Wafer Active Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Giurgiutiu, Victor, E-mail: victorg@sc.edu [University of South Carolina, SC 29205 (United States)

    2011-07-19

    Piezoelectric wafer active sensors (PWAS) are lightweight and inexpensive enablers for a large class of damage detection and structural health monitoring (SHM) applications. This paper starts with a brief review of PWAS physical principles and basic modelling and continues by considering the various ways in which PWAS can be used for damage detection: (a) embedded guided-wave ultrasonics, i.e., pitch-catch, pulse-echo, phased arrays, thickness mode; (b) high-frequency modal sensing, i.e., the electro-mechanical (E/M) impedance method; (c) passive detection, i.e., acoustic emission and impact detection. An example of crack-like damage detection and localization with PWAS phased arrays on a small metallic plate is given. The modelling of PWAS detection of disbond damage in adhesive joints is achieved with the analytical transfer matrix method (TMM). The analytical methods offer the advantage of fast computation which enables parameter studies and carpet plots. A parametric study of the effect of crack size and PWAS location on disbond detection is presented. The power and energy transduction between PWAS and structure is studied analytically with a wave propagation method. Special attention is given to the mechatronics modeling of the complete transduction cycle from electrical excitation into ultrasonic acoustic waves by the piezoelectric effect, the transfer through the structure, and finally reverse piezoelectric transduction to generate the received electric signal. It is found that the combination of PWAS size and wave frequency/wavelength play an important role in identifying transduction maxima and minima that could be exploited to achieve an optimum power-efficient design. The multi-physics finite element method (MP-FEM), which permits fine discretization of damaged regions and complicated structural geometries, is used to study the generation of guided waves in a plate from an electrically excited transmitter PWAS and the capture of these waves as electric

  7. Structural Damage Detection with Piezoelectric Wafer Active Sensors

    Science.gov (United States)

    Giurgiutiu, Victor

    2011-07-01

    Piezoelectric wafer active sensors (PWAS) are lightweight and inexpensive enablers for a large class of damage detection and structural health monitoring (SHM) applications. This paper starts with a brief review of PWAS physical principles and basic modelling and continues by considering the various ways in which PWAS can be used for damage detection: (a) embedded guided-wave ultrasonics, i.e., pitch-catch, pulse-echo, phased arrays, thickness mode; (b) high-frequency modal sensing, i.e., the electro-mechanical (E/M) impedance method; (c) passive detection, i.e., acoustic emission and impact detection. An example of crack-like damage detection and localization with PWAS phased arrays on a small metallic plate is given. The modelling of PWAS detection of disbond damage in adhesive joints is achieved with the analytical transfer matrix method (TMM). The analytical methods offer the advantage of fast computation which enables parameter studies and carpet plots. A parametric study of the effect of crack size and PWAS location on disbond detection is presented. The power and energy transduction between PWAS and structure is studied analytically with a wave propagation method. Special attention is given to the mechatronics modeling of the complete transduction cycle from electrical excitation into ultrasonic acoustic waves by the piezoelectric effect, the transfer through the structure, and finally reverse piezoelectric transduction to generate the received electric signal. It is found that the combination of PWAS size and wave frequency/wavelength play an important role in identifying transduction maxima and minima that could be exploited to achieve an optimum power-efficient design. The multi-physics finite element method (MP-FEM), which permits fine discretization of damaged regions and complicated structural geometries, is used to study the generation of guided waves in a plate from an electrically excited transmitter PWAS and the capture of these waves as electric

  8. Fabrication of Piezoelectric Cellulose Paper and Audio Application

    Institute of Scientific and Technical Information of China (English)

    Jung-Hwan Kim; Sungryul Yun; Joo-Hyung Kim; Jaehwan Kim

    2009-01-01

    We report the fabrication process of piezoelectric cellulose paper and the enhancement method of its piezoelectric property.Stretching method with different wet-drawing ratios was introduced to increase the piezoelectric property of cellulose paper during regeneration process. It is observed that the Young's modulus and the piezoelectric charge constants are very dependent on the drawing ratio and the direction of nanofibrils of piezoelectric paper. Using the enhanced piezoelectric property, we prove that the flexible regenerated piezoelectric cellulose can be applied to the potential acoustic applications such as thin piezoelectric paper speaker.

  9. Optimization of the Excitation signal for a novel piezoelectric micro-jet

    Directory of Open Access Journals (Sweden)

    Li Kai

    2016-01-01

    Full Text Available Fourier series expansions of different excitation signals for a novel piezoelectric micro-jet is deducted in this paper. By comparison and analysis of the Fourier series expansions, we find that the motivational effect of square wave is preferable than the sine wave which is better than triangle wave. And by analysing the Fourier series expansion of trapezoidal wave, it indicates that the ratio of the waveform parameters to the period should be studied rather than the numerical value of the parameters for improving the injection performance. The numerical simulations and experiments are carried out, and the results are consistent with theoretical calculations.

  10. Piezoelectric, Mechanical and Acoustic Properties of KNaNbOF5 from First-Principles Calculations

    Directory of Open Access Journals (Sweden)

    Han Han

    2015-12-01

    Full Text Available Recently, a noncentrosymmetric crystal, KNaNbOF5, has attracted attention due to its potential to present piezoelectric properties. Although α- and β-KNaNbOF5 are similar in their stoichiometries, their structural frameworks, and their synthetic routes, the two phases exhibit very different properties. This paper presents, from first-principles calculations, comparative studies of the structural, electronic, piezoelectric, and elastic properties of the α and the β phase of the material. Based on the Christoffel equation, the slowness surface of the acoustic waves is obtained to describe its acoustic prosperities. These results may benefit further applications of KNaNbOF5.

  11. Investigation of bond quality effects on piezoelectric sensing of impact damage

    Science.gov (United States)

    Na, Jeong K.; Blackshire, James L.

    2007-04-01

    Elastic waves generated by foreign materials impacting surfaces of aerospace vehicle can be used to detect and quantify the severity of damage. Passive acoustical emission sensors, made of piezoelectric elements, are typically used as impact signal detection devices. In this study, we have concentrated on characterizing the bonding qualities of piezoelectric sensors in terms of various bonding materials and adhesion conditions such as bond strength, bond stiffness, partial bonding, and disbonding. The experiment has been performed with an automated impact testing setup under controlled bonding and disbonding conditions in an attempt to establish a standardized sensor bond quality inspection methodology.

  12. Note: A novel rotary actuator driven by only one piezoelectric actuator.

    Science.gov (United States)

    Huang, Hu; Fu, Lu; Zhao, Hongwei; Shi, Chengli; Ren, Luquan; Li, Jianping; Qu, Han

    2013-09-01

    This paper presents a novel piezo-driven rotary actuator based on the parasitic motion principle. Output performances of the rotary actuator were tested and discussed. Experiment results indicate that using only one piezoelectric actuator and simple sawtooth wave control, the rotary actuator reaches the rotation velocity of about 20,097 μrad/s when the driving voltage is 100 V and the driving frequency is 90 Hz. The actuator can rotate stably with the minimum resolution of 0.7 μrad. This paper verifies feasibility of the parasitic motion principle for applications of rotary actuators, providing new design ideas for precision piezoelectric rotary actuators.

  13. SAW filter manufacture and piezoelectric materials evaluation based on printed electronics technology

    Science.gov (United States)

    Liu, Xiao-chen; Li, Kun; Xuan, Xiu-wei; Cao, Yang; Teng, Jian-fu

    2014-09-01

    In this paper, the silver nanoparticle ink and ink-jet printing technology are used to manufacture the surface acoustic wave (SAW) filters. The characteristics of three common substrate piezoelectric materials of ST-quartz, Y36°-LiTaO3 and Y128°-LiNbO3 are evaluated. The experimental results show that Y128°-LiNbO3 matches the ink much better than others. The printed SAW filter with Y128°-LiNbO3 as piezoelectric substrate is realized, and its center frequency and bandwidth are 18.4 MHz and 500 kHz, respectively.

  14. Forecast of Piezoelectric Properties of Crystalline Materials from First Principle Calculation

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Piezo crystals including quartz, quartz-like crystals, known and novel crystals of langasite-type structure were 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 principle calculation opens a door to the search and design of new piezoelectric material. Further application of first principle calculation to forecast the whole piezoelectric properties was also discussed.

  15. Piezoelectric resonance enhanced microwave and optoelectronic interactive devices

    Science.gov (United States)

    McIntosh, Robert

    Electro-optic (EO) devices that modulate optical signals by electric fields are an integrative part of the photonics industry and device optimization is an important area of research. As applications move to large bandwidth and higher frequency, low electro-optic effects and the requirement for large dimension become restrictive for microwave-optical devices. Both experimental and computational evaluations indicate that strain and polarization distribution have a significant impact on electromagnetic wave propagation resulting from a resonant structure; however, no systematic study or fundamental understandings are available. This dissertation research has been carried out to study and further develop the subject of piezoelectric resonance enhanced electro-acoustic-optic process, in order to improve the sensitivity and efficiency of electro-optic sensors and to explore novel applications. Many finite element models have been constructed for evaluating the mechanisms of the phenomena and the effectiveness of the device structure. The enhancement in transmission is found to be directly related to the strain-coupled local polarization. At piezoelectric resonance oscillating dipoles or local polarizations become periodic in the material and have the greatest impact on transmission. Results suggest that the induced charge distribution by a piezoelectric material at certain resonant frequencies is effective for aiding or impeding the transmission of a propagating wave. The behavior of both piezoelectric-defined (or intrinsic piezoelectric materials) and engineered periodic structures are reported. The piezoelectric response of the surface displacement of samples is investigated using an ultra-high frequency laser Doppler vibrometer. A two dimensional view of the surface is obtained and the surface displacement, velocity and acceleration are compared to the electro-optic response under the resonant condition. A study of the acousto-optic (AO) effect in a family of oxide

  16. Vibrations and waves

    CERN Document Server

    Kaliski, S

    2013-01-01

    This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth

  17. DYNAMIC BEHAVIOR OF TWO COLLINEAR PERMEABLE CRACKS IN A PIEZOELECTRIC LAYER BONDED TO TWO HALF SPACES

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The dynamic behavior of two collinear cracks in a piezoelectric layer bonded to two half spaces under harmonic anti-plane shear waves was investigated by means of Schmidt method. The cracks are vertically to the interfaces of the piezoelectric layer.The boundary conditions of the electrical field were assumed to be the permeable crack surface. By using the Fourier transform, the problem can be solved with the help of two pairs of triple integral equations. Numerical examples were presented to show the effect of the geometry of the interacting cracks, the piezoelectric constants of the materials and the frequency of the incident waves upon the stress intensity factors. The results show that the dynamic field will impede or enhance the propagation of the crack in a piezoelectric material at different stages of the frequency of the incident waves. It is found that the electric displacement intensity factors for the permeable crack surface conditions are much smaller than that for the impermeable crack surface conditions.

  18. Design, modeling and control of a novel multi functional translational-rotary micro ultrasonic motor

    Science.gov (United States)

    Tuncdemir, Safakcan

    The major goal of this thesis was to design and develop an actuator, which is capable of producing translational and rotary output motions in a compact structure with simple driving conditions, for the needs of small-scale actuators for micro robotic systems. Piezoelectric ultrasonic motors were selected as the target actuator schemes because of their unbeatable characteristics in the meso-scale range, which covers the structure sizes from hundred micrometers to ten millimeters and with operating ranges from few nanometers to centimeters. In order to meet the objectives and the design constraints, a number of key research tasks had to be undertaken. The design constraints and objectives were so stringent and entangled that none of the existing methods in literature could solve the research problems individually. Therefore, several unique methods were established to accomplish the research objectives. The methods produced novel solutions at every stage of design, development and modeling of the multi functional micro ultrasonic motor. Specifically, an ultrasonic motor utilizing slanted ceramics on a brass rod was designed. Because of the unique slanted ceramics design, longitudinal and torsional mode vibration modes could be obtained on the same structure. A ring shaped mobile element was loosely fitted on the metal rod stator. The mobile element moved in translational or rotational, depending on whether the vibration mode was longitudinal or torsional. A new ultrasonic motor drive method was required because none of the existing ultrasonic motor drive techniques were able to provide both output modes in a compact and cylindrical structure with the use of single drive source. By making use of rectangular wave drive signals, saw-tooth shaped displacement profile could be obtained at longitudinal and torsional resonance modes. Thus, inheriting the operating principle of smooth impact drive method, a new resonance type inertial drive was introduced. This new technique

  19. Surface acoustic wave propagation in graphene film

    Energy Technology Data Exchange (ETDEWEB)

    Roshchupkin, Dmitry, E-mail: rochtch@iptm.ru; Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Irzhak, Dmitry [Institute of Microelectronics Technology and High-Purity Materials Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Ortega, Luc [Laboratoire de Physique des Solides, Univ. Paris-Sud, CNRS, UMR 8502, 91405 Orsay Cedex (France); Zizak, Ivo; Erko, Alexei [Institute for Nanometre Optics and Technology, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein Strasse 15, 12489 Berlin (Germany); Tynyshtykbayev, Kurbangali; Insepov, Zinetula [Nazarbayev University Research and Innovation System, 53 Kabanbay Batyr St., Astana 010000 (Kazakhstan)

    2015-09-14

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  20. Surface acoustic wave propagation in graphene film

    Science.gov (United States)

    Roshchupkin, Dmitry; Ortega, Luc; Zizak, Ivo; Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Erko, Alexei; Tynyshtykbayev, Kurbangali; Irzhak, Dmitry; Insepov, Zinetula

    2015-09-01

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  1. Diffractometric measurement of the temperature dependence of piezoelectric tensor in GMO monocrystal

    Science.gov (United States)

    Breczko, Teodor; Lempaszek, Andrzej

    2007-04-01

    Functional materials, of which an example is ferroelectric, ferroelastic monocrystal of molybdate (III) gadolinium (VI), are often used in the micro-motor operators (micro-servo motors) working in changeable environment conditions. Most frequently this change refers to temperature. That is why the important practical problem is the precise measurement of the value of piezoelectric tensor elements in dependence on the temperature of a particular monocrystal. In the presented article for this kind of measurements, the use of X-ray diffractometer has been shown. The advantage of the method presented is that, apart from precise dependence measurement between the temperature of a monocrystal and the value of piezoelectric tensor elements, it enables synchronous measurement of the value of thermal expansion tensor elements for a monocrystal.

  2. The First-Principle Calculation of La-doping Effect on Piezoelectricity in Tetragonal KNN Crystal

    Science.gov (United States)

    Zhang, Qiaoli; Zhu, Jiliang; Yuan, Daqing; Zhu, Bo; Wang, Mingsong; Zhu, Xiaohong; Fan, Ping; Zuo, Yi; Zheng, Yongnan; Zhu, Shengyun

    2012-05-01

    The La-dopping effect on the piezoelectricity in the K0.5Na0.5NbO3 (KNN) crystal with a tetragonal phase is investigated for the first time using the first-principle calculation based on density functional theory. The full potentiallinearized augumented plane wave plus local orbitals (APW-LO) method and the supercell method are used in the calculation for the KNN crystal with and without the La doping. The results show that the piezoelectricity originates from the strong hybridization between the Nb atom and the O atom, and the substitution of the K or Na atom by the La impurity atom introduces the anisotropic relaxation and enhances the piezoelectricity at first and then restrains the hybridization of the Nb-O atoms when the La doping content further increases.

  3. The First-Principle Calculation of La-doping Effect on Piezoelectricity in Tetragonal KNN Crystal

    Institute of Scientific and Technical Information of China (English)

    张乔丽; 朱基亮; 袁大庆; 朱波; 王明松; 朱小红; 范平; 左翼; 郑永男; 朱升云

    2012-01-01

    The La-dopping effect on the piezoelectricity in the K0.5Na0.5NbO3 (KNN) crystal with a tetragonal phase is investigated for the first time using the first-principle calculation based on density functional theory. The full potentiallinearized augumented plane wave plus local orbitals (APW-LO) method and the supercell method are used in the calculation for the KNN crystal with and without the La doping. The results show that the piezoelectricity originates from the strong hybridization between the Nb atom and the O atom, and the substitution of the K or Na atom by the La impurity atom introduces the anisotropic relaxation and enhances the piezoelectricity at first and then restrains the hybridization of the Nb-O atoms when the La doping content further increases.

  4. Application of Energy Finite Element Method in Active Vibration Control of Piezoelectric Intelligent Beam

    Directory of Open Access Journals (Sweden)

    Jinhua Xie

    2012-01-01

    Full Text Available Based on the transmission and equilibrium relationship of vibration energy in beam-like structures, the Galerkin weighted residual method was applied to equation discretization. An equivalent transformation of feedback element was suggested to develop the Energy Finite Element model of a composite piezoelectric cantilever beam driven by harmonic excitation on lateral direction, with both systems with and without time delay being studied and the power input estimation of harmonic excitation was discussed for the resolution of Energy Finite Element function. Then the energy density solutions of the piezoelectric coupling beam through Energy Finite Element Method (EFEM and classical wave theory were compared to verify the EFEM model, which presented a good accordance. Further investigation was undertaken about the influence of control parameters including the feedback gain and arrangement of piezoelectric patches on characteristics of system energy density distribution.

  5. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

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

    2014-08-08

    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.

  6. 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…

  7. 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.)

  8. 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 prem

  9. 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.

  10. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

    Full Text Available 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.

  11. 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 t

  12. Design of a piezoelectric rotation actuator

    NARCIS (Netherlands)

    Holterman, J.; de Vries, Theodorus J.A.; Babakhani, B.; Brouwer, Dannis Michel

    2012-01-01

    In order to facilitate active damping within a linear motion system, a self-sensing piezoelectric rotation actuator has been designed. The rotation actuator consists of two piezoelectric stacks that function as linear actuators, embedded in a mechanical interface with several elastic elements, thus

  13. Evaluation on mass sensitivity of SAW sensors for different piezoelectric materials using finite-element analysis.

    Science.gov (United States)

    Abdollahi, Amir; Jiang, Zhongwei; Arabshahi, Sayyed Alireza

    2007-12-01

    The mass sensitivity of the piezoelectric surface acoustic wave (SAW) sensors is an important factor in the selection of the best gravimetric sensors for different applications. To determine this value without facing the practical problems and the long theoretical calculation time, we have shown that the mass sensitivity of SAW sensors can be calculated by a simple three-dimensional (3-D) finite-element analysis (FEA) using a commercial finite-element platform. The FEA data are used to calculate the wave propagation speed, surface particle displacements, and wave energy distribution on different cuts of various piezoelectric materials. The results are used to provide a simple method for evaluation of their mass sensitivities. Meanwhile, to calculate more accurate results from FEA data, surface and bulk wave reflection problems are considered in the analyses. In this research, different cuts of lithium niobate, quartz, lithium tantalate, and langasite piezoelectric materials are applied to investigate their acoustic wave properties. Our analyses results for these materials have a good agreement with other researchers' results. Also, the mass sensitivity value for the novel cut of langasite was calculated through these analyses. It was found that its mass sensitivity is higher than that of the conventional Rayleigh mode quartz sensor.

  14. 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.

  15. COMBINED DAMAGE FRACTURE CRITERIA FOR PIEZOELECTRIC CERAMICS

    Institute of Scientific and Technical Information of China (English)

    Yang Xinhua; Chen Chuanyao; Hu Yuantai; Wang Cheng

    2005-01-01

    Mechanical and electrical damages are introduced to study the fracture mechanics of piezoelectric ceramics in this paper. Two kinds of piezoelectric fracture criteria are established using the method of least squares combined with a damage analysis of the well-known piezoelectric fracture experiments of Park and Sun's. One is based on a linear combination of the mechanical and electrical damages and the other on their nonlinear combination. When the combined damage D is up to its critical value Dc, piezoelectric fracture occurs. It is found from the qualitative comparison of the numerical results with the experimental data that the nonlinearly combined damage fracture criterion can give a better prediction of piezoelectric fracture. And it is concluded from the nonlinearly combined damage fracture criterion that a negative electric field impedes fracture whereas the effect of a positive electric field on fracture depends on its magnitude.

  16. 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.

  17. Analytical Optimization of Piezoelectric Circular Diaphragm Generator

    Directory of Open Access Journals (Sweden)

    S. Mohammadi

    2013-01-01

    Full Text Available This paper presents an analytical study of the piezoelectric circular diaphragm microgenerator using strain energy method. Piezoelectrics are the intelligent materials that can be used as transducer to convert mechanical energy into electrical energy and vice versa. The aim of this paper is to optimize produced electrical energy from mechanical pressure. Therefore, the circular metal plate equipped with piezoelectric circular patch has been considered with simply and clamped supports. A comprehensive modeling, parametrical study and the effect of the boundary conditions on the performance of the microgenerator have been investigated. The system is under variable pressure from an oscillating pressure source. Results are presented for PZT and PMN-PT piezoelectric materials with steel and aluminum substrates. An optimal value for the radius and thickness of the piezoelectric layer with a special support condition has been obtained.

  18. 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.

  19. Polymeric Piezoelectric Transducers for Hydrophone Applications

    Directory of Open Access Journals (Sweden)

    D. K. Kharat

    2007-01-01

    Full Text Available Conventional ceramic piezoelectric materials have been used in hydrophones for sonarapplications since 1940's. In the last few years since the discovery of polymeric piezoelectrichydrophones, the technology has matured, applications have emerged in extraordinary number ofcases such as underwater navigation, biomedical applications, biomimetics, etc. Hydrophones areused underwater at high hydrostatic pressures. In the presence of hydrostatic pressures, theanisotropic piezoelectric response of ceramic materials is such that it has poor hydrophone performancecharacteristics whereas polymeric piezoelectric materials show enough hydrostatic piezoelectriccoefficients. Moreover, piezoelectric polymers have low acoustic impedance, which is only 2-6 timethat of water, whereas in piezoelectric ceramics, it is typically 11-time greater than that of water. Aclose impedance match permits efficient transduction of acoustic signals in water and tissues. Newlydeveloped hydrostatic-mode polyvinylidene flouride (PVDF hydrophones use a pressure-releasesystem to achieve improved sensitivity. Recently, voided PVDF materials have been used for makinghydrophones having higher sensitivity and figure of merit than unvoided PVDF materials.

  20. 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.

  1. Integrated Structural Health Assessment Using Piezoelectric Active Sensors

    Directory of Open Access Journals (Sweden)

    Jeannette R. Wait

    2005-01-01

    Full Text Available This paper illustrates an integrated approach for identifying structural damage. The method presented utilizes piezoelectric (PZT materials to actuate/sense the dynamic response of the structures. Two damage identification techniques are integrated in this study, including impedance methods and Lamb wave propagations. The impedance method monitors the variations in structural mechanical impedance, which is coupled with the electrical impedance of the PZT patch. In Lamb wave propagations, one PZT patch acting as an actuator launches an elastic wave through the structure, and responses are measured by an array of PZT sensors. The changes in both wave attenuation and reflection are used to detect and locate the damage. Both the Lamb wave and impedance methods operate in high frequency ranges at which there are measurable changes in structural responses even for incipient damage such as small cracks, debonding, or loose connections. The combination of the local impedance method with the wave propagation based approach allows a better characterization of the system’s structural integrity. The paper concludes with experimental results to demonstrate the feasibility of this integrated active sensing technology.

  2. Piezoelectric accelerometers with integral electronics

    CERN Document Server

    Levinzon, Felix

    2014-01-01

    This book provides an invaluable reference to Piezoelectric Accelerometers with Integral Electronics (IEPE). It describes the design and performance parameters of IEPE accelerometers and their key elements, PE transducers and FET-input amplifiers. Coverage includes recently designed, low-noise and high temperature IEPE accelerometers. Readers will benefit from the detailed noise analysis of the IEPE accelerometer, which enables estimation of its noise floor and noise limits. Other topics useful for designers of low-noise, high temperature silicon-based electronics include noise analysis of FET

  3. Behavior of piezoelectric wafer active sensor in various media

    Science.gov (United States)

    Kamas, Tuncay

    The dissertation addresses structural health monitoring (SHM) techniques using ultrasonic waves generated by piezoelectric wafer active sensors (PWAS) with an emphasis on the development of theoretical models of standing harmonic waves and guided waves. The focal objective of the research is to extend the theoretical study of electro-mechanical coupled PWAS as a resonator/transducer that interacts with standing and traveling waves in various media through electro-mechanical impedance spectroscopy (EMIS) method and guided wave propagation. The analytical models are developed and the coupled field finite element analysis (CF-FEA) models are simulated and verified with experiments. The dissertation is divided into two parts with respect to the developments in EMIS methods and GWP methods. In the first part, analytical and finite element models have been developed for the simulation of PWAS-EMIS in in-plane (longitudinal) and out-of-plane (thickness) mode. Temperature effects on free PWAS-EMIS are also discussed with respect to the in-plane mode. Piezoelectric material degradation on certain electrical and mechanical properties as the temperature increases is simulated by our analytical model for in-plane circular PWAS-EMIS that agrees well with the sets of experiments. Then the thickness mode PWAS-EMIS model was further developed for a PWAS resonator bonded on a plate-like structure. The latter analytical model was to determine the resonance frequencies for the normal mode expansion method through the global matrix method by considering PWAS-substrate and proof mass-PWAS-substrate models. The proof mass concept was adapted to shift the systems resonance frequencies in thickness mode. PWAS in contact with liquid medium on one of its surface has been analytically modeled and simulated the electro-mechanical response of PWAS with various liquids with different material properties such as the density and the viscosity. The second part discusses the guided wave propagation

  4. 基于UCC3895的行波型超声波电机驱动器设计%Design of traveling wave rotary ultrasonic motor driver based on UCC3895

    Institute of Scientific and Technical Information of China (English)

    宋人权; 王剑; 郭吉丰

    2012-01-01

    Previous ultrasonic motor driver based on non-intelligent chip is limited by its disadvantage of complex circuit and difficult phase-modulation. Aiming at this problem, the basic principle and characteristics of traveling wave type ultrasonic motor driver was introduced. According to the requirement of ultrasonic motor driven signal,a multi-function adjustable traveling wave type ultrasonic motor driver was designed based on BiCMOS advanced phase shift pulse width modulation(PWM) controller UCC3895. The relevant circuits and experiment waveforms were also provided. Experimental results verify the feasibility of design.%以往的基于非智能芯片的超声波电机驱动器往往存在电路复杂,调相困难等不足,因而限制了其使用范围.针对这一问题,首先简要介绍了行波型超声波电机驱动电路基本原理和性能要求;在比较以往驱动器优缺点的基础上提出了一种基于UUC3895的多功能可调节的行波型超声波电机驱动器,该驱动器基于BiCMOS相移谐振脉宽调制(PWM)控制原理,具有调频、调压和调相功能,并可扩展外部控制器;最后,给出了实验数据与波形图.实验结果验证了该设计的可行性.

  5. Development of Piezoelectric Zinc Oxide Nanoparticle-Poly(Vinylidene Fluoride) Nanocomposites for Sensing and Actuation

    Science.gov (United States)

    Dodds, John Steven

    Structural health monitoring (SHM) is vital for detecting the onset of damage and for preventing catastrophic failure of civil infrastructure systems. In particular, piezoelectric transducers have the ability to excite and actively interrogate structures (e.g., using surface waves) while measuring their response for damage detection. In fact, piezoelectric transducers such as lead zirconate titanate (PZT) and poly(vinylidene fluoride) (PVDF) have been used for various laboratory and field tests and have demonstrated significant advantages as compared to visual inspection and vibration-based methods, to name a few. However, PZTs are inherently brittle, and PVDF films do not possess high piezoelectricity, thereby limiting each of these devices to certain specific applications. Piezoelectric nanocomposites, which enjoy a combination of the best properties of these material types, are at the forefront of emerging SHM technologies. The objective of this study is to design, characterize, and validate piezoelectric nanocomposites consisting of zinc oxide (ZnO) nanoparticles assembled in a PVDF copolymer matrix for sensing and actuation. It will be shown that these films provide greater mechanical flexibility as compared to PZTs, yet possess enhanced piezoelectricity as compared to pristine PVDF copolymers. The results obtained from this research will be crucial for future SHM applications using these piezoelectric nanocomposites. This study began with spin coating dispersed ZnO-based solutions for piezoelectric nanocomposite fabrication. The concentration of ZnO nanoparticles was varied from 0 to 20 wt.% (in 5% increments) to determine their influence on bulk film piezoelectricity. Second, their electric polarization responses were obtained for quantifying thin film remnant polarization, which is directly correlated to piezoelectricity. Based on these results, the films were poled at 50 MV-m-1 to permanently align film electrical domains and to enhance bulk film

  6. 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

  7. Measurement of Micro Vibration of Car by Piezoelectric Ceramics

    Science.gov (United States)

    Kurihara, Yosuke; Masuyama, Kosuke; Nakamura, Testuo; Bamba, Takeshi; Watanabe, Kajiro

    Recently, there are various accidents and crimes related to the car. In some cases, the accidents and the crimes can be prevented if it is possible to detect a human who is in the car. For example, we can prevent a baby who is left in a car under the hot weather from dehydration or death occurred by heat inside disease. In another case, it is estimated that the United States currently has as many as 12 million illegal immigrants. In order to prevent further influx of illegal immigrants, the police are physically searching incoming vehicles at national boundaries aiming at finding those who are hiding inside. However, the physical inspections require much manpower cost and time. An inspection method to see inside the vehicles through X-ray images has also been used for this end. But the cost and the installation places are the problems of the large-scale X-ray system. Proposed in this paper is a piezoelectric ceramic system to handily measure the micro vibrations of motor vehicles. And applying the algorithm of Support Vector Machine (SVM), the existence of human body inside vehicles can be detected. The experiment was carried out using four types of vehicles: a mini car; an auto mobile; a van; and a truck weighing 1.5 tons. As the results, the correct determination ratio was 91.2% for the experiment with the piezoelectric ceramic under the front wheels and 97.0% under the rear wheels, when the vehicle used for the examination had also been used together with other three types of vehicles to obtain SVM training data. When the vehicle used for the examination had not been used together with the other three to obtain SVM training data, on the other hand, the correct determination ratio was 93.7% for the experiment with the piezoelectric ceramic under the front wheels and 95.7% under the rear wheels.

  8. Control and sensor techniques for PAD servo motor drive

    DEFF Research Database (Denmark)

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

    2015-01-01

    The Piezoelectric Actuator Drive (PAD) is a new type of electrical motor that employs piezoelectric multilayer actuators coupled with a form-fitted micro-mechanical gearing to generate rotary motion. The PAD is precise, having a positioning error of less than 2 arc-seconds. Its typical output...... torque is 4 Nm, without any additional gearing. The whole motor is fully non-magnetic, enabling its use in applications where magnetic neutrality is of importance. The main challenges of the PAD are the hysteretic behavior of the ceramic actuators used and their highly capacitive nature. After...... compensating for the hysteretic behavior, the current waveforms of the motor can be used to extract all necessary parameters for sensorless operation. Moreover, these signals provide a qualitative information about the precision in motor centering and show any mismatch between the actuators used....

  9. A novel in-plane mode rotary ultrasonic motor

    Directory of Open Access Journals (Sweden)

    Lu Xiaolong

    2014-04-01

    Full Text Available Ultrasonic motors have the merits of high ratio of torque to volume, high positioning precision, intrinsic holding torque, etc., compared to the conventional electromagnetic motors. There have been several potential applications for this type of motor in aerospace exploration, but bearings and bonding mechanism of the piezoelectric ring in the motors limit the performance of them in the space operation conditions. It is known that the Langevin type transducer has excellent energy efficiency and reliability. Hence using the Langevin type transducer in ultrasonic motors may improve the reliability of piezoelectric motors for space applications. In this study, a novel in-plane mode rotary ultrasonic motor is designed, fabricated, and characterized. The proposed motor operates in in-plane vibration mode which is excited by four Langevin-type bending vibrators separately placed around a ring-shaped stator. Two tapered rotors are assembled to the inner ring of the stator and clamped together by a screw nut. In order to make the motor more stable and convenient to fix, a thin cylindrical support is placed under the stator ring. Due to its no-bearing structure and Langevin transducer excitation, the prototype ultrasonic motor may operate well in aeronautic and astronautic environments.

  10. Modeling and optimization of ultrasonic linear motors

    OpenAIRE

    Fernandez Lopez, José; Perriard, Yves

    2007-01-01

    Ultrasonic motors have received much attention these last years, in particular with regard to their modeling and their design principle. Their operating principle is based on piezoelectric ceramics that convert electrical energy into mechanical energy in the form of vibrations of an elastic body whose surface points perform an elliptic motion with a frequency in the ultrasonic range (≥ 20 kHz). The moving part, which is pressed against the vibrating body by a prestressing force, can move than...

  11. Phase structure and electrical properties of PSN-PMN-PZ-PT quaternary piezoelectric ceramics near the morphotropic phase boundary

    Science.gov (United States)

    Chen, Haiyan; Fan, Chunhua

    2010-04-01

    0.06Pb(Sb 1/2Nb 1/2)O 3-0.06Pb(Mn 1/3Nb 2/3)O 3-0.88Pb(Zr xTi 1-x)O 3 (PSN-PMN-PZ-PT) quaternary piezoelectric ceramics with varying Zr/Ti ratios located near the morphotropic phase boundary (MPB) were prepared by powder solid-state reaction. The phase structure, dielectric and piezoelectric properties and temperature stability of the systems were investigated. In the present system the MPB, in which the tetragonal and rhombohedral phases coexist, is in a composition range of 0.49ultrasonic motors.

  12. Visualization technique for fatigue cracks at steel structures integrating a scanning laser source with piezoelectric sensors

    Science.gov (United States)

    Lee, Changgil; Kim, Ju-Won; Kim, Hyun Uk; Park, Seunghee

    2013-04-01

    In this research, a noncontact nondestructive testing (NDT) method is proposed to detect the fatigue crack and to identify the location of the damage. To achieve this goal, Lamb wave propagation of a plate-like structure is analyzed, which is induced by scanning laser source actuation system. A ND: YAG pulsed laser system is used to generate Lamb wave exerted at the multiple points of the plate and a piezoelectric sensor is installed to measure the structural responses. Multiple time signals measured by the piezoelectric sensor are aligned along the vertical and horizontal axes corresponding to laser impinging points so that 3 dimensional data can be constructed. Then, the 3 dimensional data is sliced along the time axis to visualize the wave propagation. The scattering of Lamb wave due to the damage can be described in the wave propagation image and hence the damage can be localized and quantified. Damage-sensitive features, which are reflected wave from the damage, are clearly extracted by wave-number filtering based on the 3 dimensional Fourier transform of the visualized data. Additional features are extracted by observing different scales of wavelet coefficients so that the time of flight (TOF) of Lamb wave modes can be clearly separated. Steel plates with fatigue cracks are investigated to verify the effectiveness and the robustness of the proposed NDT approach.

  13. Dynamic substructure model for multiple impact responses of micro/nano piezoelectric precision drive system

    Institute of Scientific and Technical Information of China (English)

    SHEN YuNian; YIN XiaoChun

    2009-01-01

    A dynamic substructure technique which considers the electromechanlcal coupling effect of the PZT and the inertial effect of flexible components is presented to study the multiple impact dynamic be-havior of micro/nano piezoelectric impact drive systems. It can investigate the step-like motion of ob-ject body and the multiple impacts behaviors reasonably by the comparison of the experimental data and the numerical solution of the spring-mass model. It is expected to have higher accuracy in the numerical simulations of the motion and the responses, especially to high frequency pulse voltage excitations. The present dynamic substructure technique has firstly studied reasonably the propaga-tions of piezoelectric-induced transient waves and impact-induced transient waves. It is helpful to the failure analysis and the design of piezoelectric stack and flexible components. The present dynamic substructure technique can be applied to the transient dynamics optimization design and the precision control of the micro/nano piezoelectric impact drive systems.

  14. Dynamic substructure model for multiple impact responses of micro/nano piezoelectric precision drive system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A dynamic substructure technique which considers the electromechanical coupling effect of the PZT and the inertial effect of flexible components is presented to study the multiple impact dynamic be- havior of micro/nano piezoelectric impact drive systems. It can investigate the step-like motion of ob- ject body and the multiple impacts behaviors reasonably by the comparison of the experimental data and the numerical solution of the spring-mass model. It is expected to have higher accuracy in the numerical simulations of the motion and the responses, especially to high frequency pulse voltage excitations. The present dynamic substructure technique has firstly studied reasonably the propaga- tions of piezoelectric-induced transient waves and impact-induced transient waves. It is helpful to the failure analysis and the design of piezoelectric stack and flexible components. The present dynamic substructure technique can be applied to the transient dynamics optimization design and the precision control of the micro/nano piezoelectric impact drive systems.

  15. Analysis of piezoelectric ultrasonic transducers attached to waveguides using waveguide finite elements.

    Science.gov (United States)

    Loveday, Philip W

    2007-10-01

    A finite-element modeling procedure for computing the frequency response of piezoelectric transducers attached to infinite constant cross-section waveguides, as encountered in guided wave ultrasonic inspection, is presented. Two-dimensional waveguide finite elements are used to model the waveguide. Conventional three-dimensional finite elements are used to model the piezoelectric transducer. The harmonic forced response of the waveguide is used to obtain a dynamic stiffness matrix (complex and frequency dependent), which represents the waveguide in the transducer model. The electrical and mechanical frequency response of the transducer, attached to the waveguide, can then be computed. The forces applied to the waveguide are calculated and are used to determine the amplitude of each mode excited in the waveguide. The method is highly efficient compared to time integration of a conventional finite-element model of a length of waveguide. In addition, the method provides information about each mode that is excited in the waveguide. The method is demonstrated by modeling a sandwich piezoelectric transducer exciting a waveguide of rectangular cross section, although it could be applied to more complex situations. It is expected that the modeling method will be useful during the optimization of piezoelectric transducers for exciting specific wave propagation modes in waveguides.

  16. Piezoelectric single crystals for ultrasonic transducers in biomedical applications

    OpenAIRE

    Zhou, Qifa; Lam, Kwok Ho; Zheng, Hairong; Qiu, Weibao; Shung, K. Kirk

    2014-01-01

    Piezoelectric single crystals, which have excellent piezoelectric properties, have extensively been employed for various sensors and actuators applications. In this paper, the state–of–art in piezoelectric single crystals for ultrasonic transducer applications is reviewed. Firstly, the basic principles and design considerations of piezoelectric ultrasonic transducers will be addressed. Then, the popular piezoelectric single crystals used for ultrasonic transducer applications, including LiNbO...

  17. Piezoelectric materials and devices applications in engineering and medical sciences

    CERN Document Server

    Vijaya, M S

    2012-01-01

    Piezoelectric Materials and Devices: Applications in Engineering and Medical Sciences provides a complete overview of piezoelectric materials, covering all aspects of the materials starting from fundamental concepts. The treatment includes physics of piezoelectric materials, their characteristics and applications. The author uses simple language to explain the theory of piezoelectricity and introduce readers to the properties and design of different types of piezoelectric materials, such as those used in engineering and medical device applications.This book: Introduces various types of dielect

  18. A continuum damage model for piezoelectric materials

    Institute of Scientific and Technical Information of China (English)

    Yiming Fu; Xianqiao Wang

    2008-01-01

    In this paper, a constitutive model is proposed for piezoelectric material solids containing distributed cracks.The model is formulated in a framework of continuum damage mechanics using second rank tensors as internal variables. The Helmhotlz free energy of piezoelectric mate-rials with damage is then expressed as a polynomial including the transformed strains, the electric field vector and the ten-sorial damage variables by using the integrity bases restricted by the initial orthotropic symmetry of the material. By using the Talreja's tensor valued internal state damage variables as well as the Helmhotlz free energy of the piezoelectric mate-rial, the constitutive relations of piezoelectric materials with damage are derived. The model is applied to a special case of piezoelectric plate with transverse matrix cracks. With theKirchhoff hypothesis of plate, the free vibration equationsof the piezoelectric rectangular plate considering damage isestablished. By using Galerkin method, the equations are sol-ved. Numerical results show the effect of the damage on the free vibration of the piezoelectric plate under the close-circuit condition, and the present results are compared with those of the three-dimensional theory.

  19. Piezoelectric paint sensor for ultrasonic NDE

    Science.gov (United States)

    Li, X.; Zhang, Y.

    2007-04-01

    This paper deals with a distributed acoustic emission sensing method, which is especially suitable for piezoelectric paint. Piezoelectric paint is a composite piezoelectric material that is comprised of tiny piezoelectric particles randomly dispersed within a polymer matrix phase. An overview of the distributed acoustic emission sensing method for defect monitoring is given in this paper. The use of piezoelectric materials for ultrasonic signal measurements is next discussed along with a series of ultrasonic tests performed to verify the ultrasonic sensing capability of piezoelectric paint. To examine the mechanism of the distributed acoustic emission sensing method for crack initiation detection, the results of a finite element simulation based study is presented in this paper. The finite element model used in the parametric study is calibrated with experimental data. The effect of sensor numbers included in the array has been studied using both simulation and experimental data. Based on the preliminary results of this study, piezoelectric paint sensor appears to hold a potential for use in on-line monitoring of cracks such as those caused by fatigue in metal structures although more work is still needed before successful practical application can be made.

  20. Quantitative Modeling of Coupled Piezo-Elastodynamic Behavior of Piezoelectric Actuators Bonded to an Elastic Medium for Structural Health Monitoring: A Review

    Directory of Open Access Journals (Sweden)

    Guoliang Huang

    2010-04-01

    Full Text Available Elastic waves, especially guided waves, generated by a piezoelectric actuator/sensor network, have shown great potential for on-line health monitoring of advanced aerospace, nuclear, and automotive structures in recent decades. Piezoelectric materials can function as both actuators and sensors in these applications due to wide bandwidth, quick response and low costs. One of the most fundamental issues surrounding the effective use of piezoelectric actuators is the quantitative evaluation of the resulting elastic wave propagation by considering the coupled piezo-elastodynamic behavior between the actuator and the host medium. Accurate characterization of the local interfacial stress distribution between the actuator and the host medium is the key issue for the problem. This paper presents a review of the development of analytical, numerical and hybrid approaches for modeling of the coupled piezo-elastodynamic behavior. The resulting elastic wave propagation for structural health monitoring is also summarized.