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1
Tamburrano, Paolo, Andrew R. Plummer, Pietro De Palma, Elia Distaso, and Riccardo Amirante. "A Novel Servovalve Pilot Stage Actuated by a Piezo-electric Ring Bender: A Numerical and Experimental Analysis." Energies 13, no. 3 (February 4, 2020): 671. http://dx.doi.org/10.3390/en13030671.
Повний текст джерелаАнотація:
Electrohydraulic servovalves are widely used for precise motion control in aerospace and other industries due to their high accuracy and speed of response. However, commercial two-stage servovalves have several undesirable characteristics, such as the power consumption caused by the quiescent flow (internal leakage) in the pilot stage, and the complexity and high number of parts of the torque motor assembly, which affect the cost and the speed of manufacture. The solution to these problems can help to reduce costs, weight and power consumption, and enhance the reliability and reproducibility as well as the performance of these valves. For these reasons, this paper proposes a novel configuration for the pilot stage: it is composed of two normally closed two-way two-position (2/2) valves actuated by two piezo-electric ring benders; the opening and closing of the two piezo-valves can generate a differential pressure to be used to control the displacement of the main spool. In this way, there is negligible quiescent flow when the main stage is at rest; in addition, the torque motor and all its components are removed. To assess the performance of this novel pilot stage concept, a prototype of the piezo-valve has been constructed and tested. The experimental results indicate that the response speed of the new piezo-valve is very high. Furthermore, a numerical model is employed to show that, by adjusting specific parameters, the performance of the piezo-valve can be further improved, so that the valve can be fully opened or closed in less than 5 ms.
2
Ozaki, Takashi, and Norikazu Ohta. "Power-Efficient Driver Circuit for Piezo Electric Actuator with Passive Charge Recovery." Energies 13, no. 11 (June 4, 2020): 2866. http://dx.doi.org/10.3390/en13112866.
Повний текст джерелаАнотація:
Piezoelectric actuation is a promising principle for insect-scaled robots. A major concern while utilizing a piezoelectric actuator is energy loss due to its parasitic capacitance. In this paper, we propose a new concept to recover the charge stored in the parasitic capacitance; it requires only three additional lightweight passive components: two diodes and a resistor. The advantages of our concept are its small additional mass and simple operating procedure compared with existing charge recovery circuits. We provided a guideline for selecting a resistor using a simplified theoretical model and found that half of the charge can be recovered by employing a resistor that has a resistance sufficiently larger than the forward resistance of the additional diode. In addition, we experimentally demonstrated the concept. With a capacitive load (as a replacement for the piezoelectric actuator), it was successfully observed that the proposed concept decreased the power consumption to 58% of that in a circuit without charge recovery. Considering micro aerial vehicle (MAV) applications, we measured the lift-to-power efficiency of a flapping wing piezoelectric actuator by applying the proposed concept. The lift force was not affected by charge recovery; however, the power consumption was reduced. As a result, the efficiency was improved to 30.0%. We expect that the proposed circuit will contribute to the advancement of energy-saving microrobotics.
3
Poongkothai, Jeyaraman, Samydurai Mahesh, and Rajendran Selvamani. "Modeling and Assessment of Rotation and Gravity in a Piezoelectric Viscothermoelastic Multilayered Composite LEMV / CFRP Cylinder." Mathematical Modelling of Engineering Problems 8, no. 4 (August 31, 2021): 611–16. http://dx.doi.org/10.18280/mmep.080414.
Повний текст джерелаАнотація:
A mathematical model is developed to analysis the effects of gravitational force and rotation in a composite multilayered hollow cylinder which contain inner and outer piezo-thermoelasticity layers bonded by Linear Elastic Material with Voids (LEMV) is performed within the frame of dual-phase-lag model. The equation of displacement components, temperature, and electric are obtained using linear theory of elasticity. The dispersion equations are derived based on traction free boundary conditions and are numerically examined for CdSe material. The enumerated frequency, thermal and electrical nature against wave number is presented graphically. Adhesive layer LEMV is compared with Carbon Fiber Reinforced Polymer (CFRP) in the presence of gravity and rotation.
4
Lee, Min-Ku, Seung-Ho Han, Kyu-Hyun Park, Jin-Ju Park, Whung-Whoe Kim, Won-Ju Hwang, and Gyoung-Ja Lee. "Design Optimization of Bulk Piezoelectric Acceleration Sensor for Enhanced Performance." Sensors 19, no. 15 (July 31, 2019): 3360. http://dx.doi.org/10.3390/s19153360.
Повний текст джерелаАнотація:
While seeking to achieve high performances of a bulk piezoelectric acceleration sensor, we investigated the behavior of the design variables of the sensor components and optimized the sensor design using a numerical simulation based on piezoelectric analysis and metamodeling. The optimized results demonstrated that there was an exponential dependency in the trade-off relation between two performance indicators, the electric voltage and the resonant frequency, as induced by the design characteristics of the sensor. Among the design variables, a decrease in the base height and epoxy thickness and an increase in the piezo element’s inner diameter had a positive effect on two performances, while the head dimensions (diameter and height) exhibited the opposite effect on them. The optimal sensor designs are proposed within the valid range of resonant frequency (25–47.5 kHz). Our redesign of a commercial reference sensor improved the resonant frequency by 13.2% and the electric voltage by 46.1%.
5
Brenneis, Matthias, and Peter Groche. "Integration of Piezoceramic Tube under Prestress into a Load Carrying Structure." Advanced Materials Research 966-967 (June 2014): 651–58. http://dx.doi.org/10.4028/www.scientific.net/amr.966-967.651.
Повний текст джерелаАнотація:
Smart structures consisting of a load carrying structure and smart materials with actuatory and sensory capabilities feature high potential in numerous applications. However, to master the assembly conditions of smart structures, there is a need to integrate additional design parameters such as prestress of the smart material, critical loads and electric contacting as well as insulation into the process development. This paper focusses on the design of an incremental bulk forming process to integrate piezoceramic components into an aluminum tube simultaneously to the manufacturing process. Axial forces imposed on the piezoceramic are investigated numerically and experimentally to verify the design of critical components and the process control. Within this investigation, in situ measurement of the direct piezoelectric effect provides a method to validate the numerical design with regard to failure of the piezo tube and the functional properties of the overall structure.
6
Zhang, Bin, Benjamin Ducharne, Bhaawan Gupta, Gael Sebald, Daniel Guyomar, and Jun Gao. "Experimental sea wave energy extractor based on piezoelectric Ericsson cycles." Journal of Intelligent Material Systems and Structures 29, no. 6 (September 26, 2017): 1102–12. http://dx.doi.org/10.1177/1045389x17730917.
Повний текст джерелаАнотація:
Recycling ambient energies with electric generators instead of employing batteries with limited lifespans has motivated a large scientist community over two decades. Sea waves exhibit a large energy density. The amount of energy that could be extracted from the sea waves is very high. This work describes a technique of sea wave energy extraction based on a piezoelectric conversion and an analogy with thermodynamic Ericsson loops. By synchronizing external electric field to the maximum and the minimum of the sea wave mechanical stress excitations, the piezoelectric material dielectric hysteresis loop area is increased corresponding to the maximum of the energy available. In this article, technical solutions are proposed for the in site deployment of the proposed technique (maximum and minimum detection, external electric field source synchronization). Experimental measuring benches have been developed to monitor the sea wave mechanical excitation and to determine precisely the energy-harvesting potential. Adequate dielectric hysteresis model is proposed to numerically determine the best configuration (frequency, amplitude) of electric field to impose. Even if the Ericsson technique requires external electronic devices, the weak consumption of such components allows a large enhancement of the amount of energy extracted compared to a basic piezo element conversion.
7
Riches, S. T., I. White, G. Rickard, and G. Chadwick. "Implementation of Silicon-on-Insulator (SOI) Control Electronics to Accelerometers for High Temperature Applications." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2011, HITEN (January 1, 2011): 000233–37. http://dx.doi.org/10.4071/hiten-paper5-sriches.
Повний текст джерелаАнотація:
The requirement to install control systems integrated with sensors in high temperature environments has posed a challenge to the traditional limit of 125°C for conventional electronics. There is a need to operate at temperatures of 200°C and above in restricted space for example in down-well, aero-engine or geothermal applications in combination with high pressures, vibrations and potentially corrosive environments. Piezo-electric accelerometers based on ferro-electric ceramics have been used in a wide range of applications for measuring vibrations, fluid flow and turbulence and are capable of operating as a transducer alone at temperatures up to 250°C, which has made them attractive in sensing applications for down-well drilling and aero-engine health and usage monitoring. However, the electronics traditionally used to carry out the signal conditioning and processing (e.g. charge to voltage conversion, filtering) has been limited to a qualification limit of 125°C, which results in a reduced sensitivity of the transducer output as the signal conditioning and processing cannot be performed close to the sensor. With the development of Silicon-On-Insulator (SOI) semiconductor technology, which can operate at temperatures of up to 250°C, many of the signal conditioning and processing operations can be carried out in-situ with the accelerometers to create a new generation of high temperature products. In addition, the integration of many of the functions that used to require discrete components into one SOI based device has led to further miniaturisation opportunities and a protection against obsolescence of specialist analogue devices. This paper will describe the migration of the traditional low temperature electronics to a high temperature SOI based ASIC device and the implementation of high temperature electronics packaging technology to instrumentation for piezo-electric accelerometers, leading to products that are suitable for high temperature monitoring in restricted spaces in down-well drilling and aero-engine applications.
8
Li, R., and G. A. Kardomateas. "The Mode III Interface Crack in Piezo-Electro-Magneto-Elastic Dissimilar Bimaterials." Journal of Applied Mechanics 73, no. 2 (June 1, 2005): 220–27. http://dx.doi.org/10.1115/1.2073328.
Повний текст джерелаАнотація:
The mode III interface crack problem is investigated for dissimilar piezo-electro-magneto-elastic bimaterial media, taking the electro-magnetic field inside the crack into account. Closed form solutions are derived for impermeable and permeable cracks. The conventional singularity of r−1∕2 is found for the fields at the distance r ahead of the interface crack tip. Expressions for extended crack tip stress fields and crack opening displacements (ECODs) are derived explicitly, and so are some fracture parameters, such as extended stress intensity factors (ESIFs) and energy release rate (G) for dissimilar bimaterials. An approach called the “energy method,” finding the stationary point of the saddle surface of energy release rate with respect to the electro-magnetic field inside the crack, is proposed. By this method, the components of the induced electro-magnetic field inside the crack are determined, and the results are in exact agreement with those in the literature if the two constituents of the bimaterial media are identical. The effects from mechanical and electro-magnetic property mismatches, such as differences in the stiffness, electric permittivity and magnetic permeability, between the two constituents of the bimedia on the mode III interface crack propagation are illustrated by numerical simulations. The results show that the applied electric and magnetic loading usually retard the growth of the interface crack and the directions of the combined mechanical, electric, and magnetic loading have a significant influence on the mode III interface crack propagation.
9
WANG, YANZHONG, and BIN WEI. "MIXED-MODAL DISK GAS SQUEEZE FILM THEORETICAL AND EXPERIMENTAL ANALYSIS." International Journal of Modern Physics B 27, no. 25 (September 12, 2013): 1350168. http://dx.doi.org/10.1142/s0217979213501683.
Повний текст джерелаАнотація:
In order to investigate the gas squeeze film characteristics with mixed-modal disk excitation, an actuator with piezo-electric components is designed. Experiments show that different modal shapes of the disk are excited along with the changes of the actuator excitation frequency. The amplitude of the modal shape can reach the same order of magnitude as the squeeze film thickness, so the modal effects on the squeeze film characteristics cannot be ignored. In this paper, the simulating and fitting of the exciting disk modal shapes were finished by ANSYS and MATLAB. The actual film thickness equation was amended by the modal shape fitting curve. The gas film characteristic can be obtained by solving the Reynolds equation which is coupled with film thickness and motion equation. In this study, finite element simulation and differential numerical calculation results provided a good guidance to the piezoelectric actuator design.
10
Andreaus, U., F. Dell’Isola, and M. Porfiri. "Piezoelectric Passive Distributed Controllers for Beam Flexural Vibrations." Journal of Vibration and Control 10, no. 5 (May 2004): 625–59. http://dx.doi.org/10.1177/1077546304038224.
Повний текст джерелаАнотація:
Recent technological developments have made available efficient bender transducers based on the piezoelectric effect. In this paper an electrical circuit analog to the Timoshenko beam is synthesized using a Lagrangian method and by paralleling capacitive flux linkages to rotation and transverse displacement. A Piezo-ElectroMechanical (PEM) beam is conceived by uniformly distributing piezoelectric transducers on a beam and interconnecting their electric terminals via the found analog circuit, completed with suitable resistors. The high performance features of the synthesized novel circuit include the following. (i) The circuit topology is extremely reduced, the used components are all but one two-terminal elements, and the only two-port network needed is an ideal transformer. (ii) One and the same dissipative circuit ensures a multiresonance coupling with the vibrating beam and the optimal electrical dissipation of mechanical vibrations energy. (iii) For a prototype of a PEM beam, the design of the analog circuit is possible and the obtained nominal values of the circuital elements ensure that can be technically realized without any external feeding. The insertion of resistors in the analog circuit is determined according to two optimality criteria (namely minimization of strain energy time envelope and maximization of vibration time rate decay), based on specific engineering needs. The former seems to be suitable for applications in fatigue phenomena and the latter when the amplitude of vibrations must be rapidly decreased, independently of the initial conditions.
11
Opalka, Susanne M., Louis G. Hector, Steven R. Schmid, Ronald A. Reich, and June M. Epp. "Boundary Additive Effect on Abrasive Wear During Single Asperity Plowing of a 3004 Aluminum Alloy." Journal of Tribology 121, no. 2 (April 1, 1999): 384–93. http://dx.doi.org/10.1115/1.2833951.
Повний текст джерелаАнотація:
Aluminum forming processes such as rolling, extrusion, and ironing involve the transfer of large loads through a tooling/workpiece interface to plastically deform the workpiece to a desired shape. Sharp tool surface asperities can plow the workpiece and lead to elevated friction and temperatures in the interface with a subsequent increase in abrasive wear debris which in turn degrades the surface aesthetics of the final product. To minimize associated friction and wear levels in aluminum forming processes, a base oil with one or more boundary additives is used as a lubricant. At the present time, however, little is known about the mechanisms by which a given additive influences abrasive wear in an aluminum metal forming interface. In the present work, a series of single asperity plowing experiments on a 3004-O aluminum alloy with selected lubricant components was conducted. Three additives were separately investigated, viz., stearic acid, butyl stearate, and lauryl alcohol. The plowing motion of a pyramidal diamond indentor with a cutting edge oriented in the plowing direction (i.e., a sharp indentor) was controlled with the piezo-electric transducers of an atomic force microscope. The experiments help to provide insight about the interplay between additive reaction with the surface and plowing mechanics. Further insight into this interplay and abrasive wear debris generation was sought, albeit qualitatively, through additional experiments involving a diamond indentor for which no one cutting edge was oriented in the plowing direction (i.e., a blunt indentor). The tests allowed evaluation of the boundary lubricant mechanism and propensity for generating wear debris.
12
Celmer, Mateusz, and Krzysztof J. Opieliński. "Research and Modeling of Mechanical Crosstalk in Linear Arrays of Ultrasonic Transducers." Archives of Acoustics 41, no. 3 (September 1, 2016): 599–612. http://dx.doi.org/10.1515/aoa-2016-0058.
Повний текст джерелаАнотація:
Abstract Linear arrays of ultrasonic transducers are commonly used as ultrasonic probes in medical diagnostics for imaging the interior of a human body in vivo. The crosstalk phenomenon occurs during the operation of transducers in which electrical voltages and mechanical vibrations are transmitted to adjacent components. As a result of such additional excitation of the transducers in the array, the directivity characteristics of the aperture used changes, and consequently there is interference with properoperation of a given array and the emergence of distortions in the obtained ultra sound image that reduce its quality. This paper studies the manner of propagation of mechanical crosstalk in the designed model of a linear array of ultrasonic transducers on the basis of unwanted signals, which appeared on elementary piezo-electric transducers when power is supplied to the selected transducer in the array. The universal model of linear array of ultrasonic transducers, which has been developed, allowed the simulation of mechanical crosstalk, taking in to account the cross-coupling phenomenon in all of its structure with the use of finite elements method (FEM) implemented in COMSOL Multiphysics software. The analysis of crosstalk signals showed that they consist of aggregated pulses propagating with different speeds and frequencies. This signifies the formation of different vibration modes transmitted simultaneously via different paths. The paper is an original approach which enables to identify different vibration modes and estimate their participation in the crosstalk signal and their ways of propagation. Conclusions from the research allow predicting specific design changes which are significant due to the minimization of mechanical crosstalk in linear arrays of ultrasonic transducers.
13
Pearson, J. T., M. Tsudzuki, Y. Nakane, R. Akiyama, and H. Tazawa. "Development of heart rate in the precocial king quail Coturnix chinensis." Journal of Experimental Biology 201, no. 7 (April 1, 1998): 931–41. http://dx.doi.org/10.1242/jeb.201.7.931.
Повний текст джерелаАнотація:
Our aim was to examine changes in heart rate (fh) during the embryonic and posthatching periods of the smallest precocial avian species, Coturnix chinensis. In experiment I, repeated measurements of mean fh were made for individual quail by ballistocardiogram (BCG) during incubation, and by both piezo-electric film and electrocardiogram (ECG) during the posthatching period (resting and thermoneutral conditions). Mean fh of all embryos increased during the second half of incubation and the first week posthatching, but a few embryos experienced a very brief period of decreased fh prior to internal pipping. After the first week, fh of posthatching quail was maintained at high levels (550-650 beats min-1), then decreased with age and increase in body mass. The maximal fh of quail chicks represents a greater posthatching increase in fh than is found in larger precocial chickens, this difference being attributable to the higher demands of thermoregulation at small body masses in the quail. In experiment II, the mean fh of quail embryos (day 2-16) was recorded by ECG, and embryonic stage, yolk-free embryo mass (wet and dry) and water content were measured. Mean fh was linearly related to embryo mass throughout incubation, except on the day prior to internal pipping, when the fh of a few embryos declined below this linear relationship. Measurements of instantaneous fh of late incubation embryos, young and adult quail all showed spontaneous fluctuations in fh. Two main frequency components of fh fluctuations were identified for the first time in an avian species. Low-frequency (mean 0.09 Hz, 12.6 s) and high-frequency (1.4 Hz, 0.9 s) oscillations in both young chicks and adult quail were detected and are considered to reflect baroreflex mediation of fh and respiratory sinus arrhythmia, respectively.
14
Devidas, G. B., Sunar Abdul Khader, Asiya Parveez, Nityananda Das, and T. Sankarappa. "Dielectric Studies of Ferrimagnetic-Piezoelectric Composites." Materials Science Forum 1019 (January 2021): 129–34. http://dx.doi.org/10.4028/www.scientific.net/msf.1019.129.
Повний текст джерелаАнотація:
Magneto-electric composites of two distinct phases, ferrimagnetic-piezoelectric system with general compositional formula (x) ferromagnetic + (1-x) piezoelectric were synthesized using a hybrid technique, mechano-chemical method by sintering the mixtures of piezo-electric BaTiO3 (BTO) and ferri-magnetic Mg0.2Cu0.5Zn0.3Fe2O4 (MCZF). Here, ferri-magnetic phase component MCZF (Mg0.2Cu0.5Zn0.3Fe2O4) was prepared using auto-combustion method, whereas piezo-electric BTO was procured commercially from Sigma-Aldrich. Here, the general composition of composites is given by (x) Mg0.2Cu0.5Zn0.3Fe2O4+(1-x) BaTiO3(x=15%, 30% and 45%). Presences of two phases in these magneto-electric composites were probed using X-ray diffraction (XRD) studies. Peaks observed in the XRD spectrum indicated spinel cubic structure for MCZF ferrite and tetragonal perovskite structure for BTO and, both spinel and pervoskite structures for synthesized composites. Micro-structure of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM). Frequency dependent dielectric properties of synthesized composites were measured from 100 Hz to 1 MHz at room temperature using a precision HIOKI make LCR HI-TESTER. Dielectric dispersion was observed at lower frequencies for the synthesized composites.
15
Fuentes, L., and O. Raymond. "Texture, Piezoelectricity and Ferroelectricity." Textures and Microstructures 23, no. 4 (January 1, 1995): 221–36. http://dx.doi.org/10.1155/tsm.23.221.
Повний текст джерелаАнотація:
A Quantitative Texture Analysis approach to polycrystal piezoelectric and ferroelectric phenomena is given. Monocrystal longitudinal piezoelectric moduli are expanded in Bunge's symmetry- adapted functional bases. Suitable expansion coefficients are given. Orientation Distribution Function based algorithms for polycrystal piezo-moduli prediction are presented. Significant odd-order expansion terms are calculated and their relation to ghost phenomena is commented. Polycrystal ferroelectricity is characterized. Quantitative describers associated to crystallographic and electric orientation distributions are presented and related. Their evolution during heat and poling processes is discussed. Two computer-simulated examples are analyzed: (a) Texture-modulated longitudinal piezo-modulus is calculated for an ideal quartz single-component texture. (b) Barium titanate fibre texture transformation during a hypothetical technological process is investigated.
16
Lal, Achchhe, and Niranjan L. Shegokar. "Thermoelectrically induced nonlinear free vibration analysis of piezo laminated composite conical shell panel with random fiber orientation." Curved and Layered Structures 4, no. 1 (September 26, 2017): 237–54. http://dx.doi.org/10.1515/cls-2017-0016.
Повний текст джерелаАнотація:
Abstract This paper presents the free vibration response of piezo laminated composite geometrically nonlinear conical shell panel subjected to a thermo-electrical loading. The temperature field is assumed to be a uniform distribution over the shell surface and through the shell thickness and the electric field is assumed to be the transverse component E2 only. The material properties are assumed to be independent of the temperature and the electric field. The basic formulation is based on higher order shear deformation plate theory (HSDT) with von-Karman nonlinearity. A C0 nonlinear finite element method based on direct iterative approach is outlined and applied to solve nonlinear generalized eigenvalue problem. Parametric studies are carried out to examine the effect of amplitude ratios, stacking sequences, cone angles, piezoelectric layers, applied voltages, circumferential length to thickness ratios, change in temperatures and support boundary conditions on the nonlinear natural frequency of laminated conical shell panels. The present outlined approach has been validated with those available results in the literature.
17
Tommasino, Domenico, Federico Moro, Bruno Bernay, Thibault De Lumley Woodyear, Enrique de Pablo Corona, and Alberto Doria. "Vibration Energy Harvesting by Means of Piezoelectric Patches: Application to Aircrafts." Sensors 22, no. 1 (January 4, 2022): 363. http://dx.doi.org/10.3390/s22010363.
Повний текст джерелаАнотація:
Vibration energy harvesters in industrial applications usually take the form of cantilever oscillators covered by a layer of piezoelectric material and exploit the resonance phenomenon to improve the generated power. In many aeronautical applications, the installation of cantilever harvesters is not possible owing to the lack of room and/or safety and durability requirements. In these cases, strain piezoelectric harvesters can be adopted, which directly exploit the strain of a vibrating aeronautic component. In this research, a mathematical model of a vibrating slat is developed with the modal superposition approach and is coupled with the model of a piezo-electric patch directly bonded to the slat. The coupled model makes it possible to calculate the power generated by the strain harvester in the presence of the broad-band excitation typical of the aeronautic environment. The optimal position of the piezoelectric patch along the slat length is discussed in relation with the modes of vibration of the slat. Finally, the performance of the strain piezoelectric harvester is compared with the one of a cantilever harvester tuned to the frequency of the most excited slat mode.
18
Tamburrano, Paolo, Andrew R. Plummer, Pietro De Palma, Elia Distaso, and Riccardo Amirante. "A Novel Servovalve Pilot Stage Actuated by a Piezo-Electric Ring Bender (Part II): Design Model and Full Simulation." Energies 13, no. 9 (May 4, 2020): 2267. http://dx.doi.org/10.3390/en13092267.
Повний текст джерелаАнотація:
In part I of this study, we experimentally and numerically investigated the pilot stage of a novel two-stage servovalve architecture. The novelty of the proposed configuration is the torque motor being removed and replaced with two small two-way two-position (2/2) valves actuated by piezoelectric ring benders, which can effectively control the opening degree of a main spool valve. With this novel architecture, the typical drawbacks of two-stage servovalves can be overcome, such as the high complexity of the torque motor and the high internal leakage in the pilot stage when the main valve is at rest in the neutral position (null). The low complexity and the negligible internal leakage of the piezo-valves are accompanied by the high response speed typical of piezoelectric actuators. The valve assessment is completed in the present study, since the entire valve architecture (main stage + pilot stage) is investigated. In particular, a simplified numerical model is developed to provide a design tool that allows, for a given main stage spool, the values of the geometrical parameters of the pilot stage to be chosen along with the characteristics of the ring bender. This design procedure is applied to a 7 mm diameter main spool; afterward, a detailed numerical model of the entire valve, solved by SimScape Fluids software, is employed to demonstrate that the response of the main stage valve is very rapid while ensuring negligible internal leakage through the piezo-valves when the main stage is closed (resulting in lower power consumption). For this reason, the proposed valve can be regarded as a “clean” component for energy conversion, having lower energy consumption than commercially available servovalves.
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Banerjee, D. P. K., B. G. Anandarao, J. N. Desai, S. K. Jain, and D. C. V. Mallik. "Evidence of Expansion in the Central Region of NGC 2346." Symposium - International Astronomical Union 131 (1989): 187. http://dx.doi.org/10.1017/s0074180900137957.
Повний текст джерелаАнотація:
We present observations of the bipolar planetary nebula NGC 2346 carried out with the 1-m telescope at the Vainu Bappu Observatory in Kavalur, India using (1) a high resolution piezo-electric scanned Fabry-Pérot Spectrometer (with a velocity resolution of 10 km s−1) for line studies in the 6000 A - 7000 A spectral range and (2) a pressure scanned Fabry-Pérot spectrometer (with a velocity-resolution of 5 km s−1) in the green region. The nebula was observed in the H I 6563 A and [N II] 6583 A emission lines using a 15″ aperture and in the [O III] 5007 A line using an 8″ aperture centered on the bright central spot. A number of scans in each of these lines were co-added to improve the signal-to-noise ratio. The [O III] profile shows a well defined split between the blue and the red component, typical of an expanding shell. The [N II] profile does not show a well resolved split, although a pronounced suggestion of a split was observed in all the scans. The Hα profile was broad and asymmetric. The composite [O III] and [N II] profiles were decomposed into two individual Gaussians for obtaining the expansion velocity.
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Kitahama, Yoshihiro, Hiroo Shizuka, Ritsu Kimura, Tomo Suzuki, Yukoh Ohara, Hideaki Miyake, and Katsuhiko Sakai. "Fluid Lubrication and Cooling Effects in Diamond Grinding of Human Iliac Bone." Medicina 57, no. 1 (January 14, 2021): 71. http://dx.doi.org/10.3390/medicina57010071.
Повний текст джерелаАнотація:
Background and Objectives: Although there have been research on bone cutting, there have been few research on bone grinding. This study reports the measurement results of the experimental system that simulated partial laminectomy in microscopic spine surgery. The purpose of this study was to examine the fluid lubrication and cooling in bone grinding, histological characteristics of workpieces, and differences in grinding between manual and milling machines. Materials and Methods: Thiel-fixed human iliac bones were used as workpieces. A neurosurgical microdrill was used as a drill system. The workpieces were fixed to a 4-component piezo-electric dynamometer and fixtures, which was used to measure the triaxial power during bone grinding. Grinding tasks were performed by manual activity and a small milling machine with or without water. Results: In bone grinding with 4-mm diameter diamond burs and water, reduction in the number of sudden increases in grinding resistance and cooling effect of over 100 °C were confirmed. Conclusion: Manual grinding may enable the control of the grinding speed and cutting depth while giving top priority to uniform torque on the work piece applied by tools. Observing the drill tip using a triaxial dynamometer in the quantification of surgery may provide useful data for the development of safety mechanisms to prevent a sudden deviation of the drill tip.
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Vu, Thanh Tung, Hong Hai Hoang, Toan Thang Vu, and Ngoc Tam Bui. "A Displacement Measuring Interferometer Based on a Frequency-Locked Laser Diode with High Modulation Frequency." Applied Sciences 10, no. 8 (April 13, 2020): 2693. http://dx.doi.org/10.3390/app10082693.
Повний текст джерелаАнотація:
Laser interferometers can achieve a nanometer-order uncertainty of measurements when their frequencies are locked to the reference frequencies of the atom or molecule transitions. There are three types of displacement-measuring interferometers: homodyne, heterodyne, and frequency modulation (FM) interferometers. Among these types of interferometer, the FM interferometer has many advantageous features. The interference signal is a series of time-dependent harmonics of modulation frequency, so the phase shift can be detected accurately using the synchronous detection method. Moreover, the FM interferometer is the most suitable for combination with a frequency-locked laser because both require frequency modulation. In previous research, low modulation frequencies at some tens of kHz have been used to lock the frequency of laser diodes (LDs). The low modulation frequency for the laser source means that the maximum measurement speed of the FM interferometers is limited. This paper proposes a novel contribution regarding the application of a high-frequency modulation for an LD to improve both the frequency stability of the laser source and the measurement speed of the FM interferometer. The frequency of the LD was locked to an I2 hyperfine component at 1 MHz modulation frequency. A high bandwidth lock-in amplifier was utilized to detect the saturated absorption signals of the I2 hyperfine structure and induce the signal to lock the frequency of the LD. The locked LD was then used for an FM displacement measuring interferometer. Moreover, a suitable modulation amplitude that affected the signal-to-noise ratio of both the I2 absorption signal and the harmonic intensity of the interference signal was determined. In order to verify the measurement resolution of the proposed interferometer, the displacement induced by a piezo electric actuator was concurrently measured by the interferometer and a capacitive sensor. The difference of the displacement results was less than 20 nm. To evaluate the measurement speed, the interferometer was used to measure the axial error of a high-speed spindle at 500 rpm. The main conclusion of this study is that a stable displacement interferometer with high accuracy and a high measurement speed can be achieved using an LD frequency locked to an I2 hyperfine transition at a high modulation frequency.
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Albrecht-Zagar, Philipp, and Rudolf Scheidl. "A Piezo-Electric Valve Actuator for Hydraulic Exoskeleton Drives." International Journal of Fluid Power, September 29, 2022. http://dx.doi.org/10.13052/ijfp1439-9776.23310.
Повний текст джерелаАнотація:
In many exoskeleton applications where heavy lifting is involved (e.g. in military or industrial applications) hydraulic actuators are used because of their high power density. For such applications it is necessary to develop compact and light hydraulic components so that the exoskeleton’s mass and size are low and, therefore, wearing comfort is high and power consumption is reduced to a minimum. Crucial components of hydraulic exoskeletons concerning this weight aspect are hydraulic valves and particularly their actuators, since conventional solenoids contribute the lion share of valve size and weight. As one option to solve this weight and size problem the application of smart materials such as piezo-ceramics to electrically actuate hydraulic valves are seen. The contribution at hand deals with the systematic design of a piezo-actuator which shall be used to switch a hydraulic valve. To overcome the problem of very low strain of the piezo a mechanism for amplification via a bistable buckling beam is analyzed analytically and numerically and an actuator prototype is designed and manufactured. This paper intends to carve out crucial challenges such as the requirements for snapping through of the buckling beam, the bearings of the beam and the integration of the piezo stack.
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Lee, Sung Q., Hye Jin Kim, Sang Kyun Lee, Jae Woo Lee, and Kang Ho Park. "PMN-PT Single Crystal Piezo-Electric Acoustic Sensor." MRS Proceedings 1034 (2007). http://dx.doi.org/10.1557/proc-1034-k03-46.
Повний текст джерелаАнотація:
AbstractThe MEMS (micro-electro-mechanical systems) microphone enables the manufacturing of small mechanical components on the surface of a silicon wafer. The MEMS microphones are less susceptible to vibration because of the smaller diaphragm mass and an excellent candidate for chip-scale packaging. In this paper, we present a piezoelectric MEMS microphone based on (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) single crystal diaphragm. The PMN-PT materials exhibit extremely high piezoelectric coefficients and other desirable properties for an acoustic sensor. The piezoelectric-based microphone can offer the ability to passively sense without the power requirements. In particular, this paper introduces the design of a PMN-PT single crystal diaphragm with interdigitated electrode. We were able to fabricate miniaturized PMN-PT single crystal diaphragms. The fabricated sensor exhibits the sensitivity of 1.5mV/Pa. This implies that the PMN-PT thin film microphone has a potential of excellent acoustic characteristics.
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Ganguly, Ronit, Soumya Bandyopadhyay, Kumaraswamy Miriyala, Vijayabhaskar Gunasekaran, Saswata Bhattacharya, Amit Acharyya, and Ranjith Ramadurai. "Tunable polarization components and electric field induced crystallization in polyvinylidenefluoride: A piezo polymer." POLYMER CRYSTALLIZATION 2, no. 1 (February 2019). http://dx.doi.org/10.1002/pcr2.10027.
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Al Ahmad, Mahmoud, Fabio Coccetti, and Robert Plana. "Piezoelectric Materials for Advanced Integrated RF Components." MRS Proceedings 1075 (2008). http://dx.doi.org/10.1557/proc-1075-j03-01.
Повний текст джерелаАнотація:
AbstractThis paper will first address the piezoelectric material characterization using a capacitance measurement technique. An original simple and efficient technique for the determination of the d33 piezoelectric coefficient of lead zirconate titanate thin films is described. Classical capacitor plate theory and piezoelectric material analysis are used to calculate the capacitance variation in lead zirconate titanate film, enabling piezo-electric coefficient to be determined. The technique outlined here avoids the use of mechanical/optical apparatus that may require heavy preparation of sample substrate geometry. Then, this work also treats design and fabrication issues associated with innovative tunable front-end components which combine two different ceramic technologies, namely multilayer ceramic circuit boards (low temperature cofired ceramics or LTCC) and piezoelectric actuator technology within a single device.
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"Contactless Excitation of Piezoelectric Device through Curvilinear shaped Electric Field Generator." International Journal of Engineering and Advanced Technology 9, no. 1 (October 30, 2019): 4165–68. http://dx.doi.org/10.35940/ijeat.a1413.109119.
Повний текст джерелаАнотація:
Contactless excitation of piezoelectric (PZT) component through focused E-field has been investigated in this work. In the intended technique, E-field is focused to ground electrode from a curvilinear-shaped potential electrode so that maximum E-field can penetrate sufficiently through PZT component which is positioned inbetween the electrodes. Simulation analysis shows that the contactless energization of PZT component is due to electric resonance as well as piezo-electric resonance. The maximum vibration occurs across the PZT components when the E-field generator operating frequency (f0 ) matches with the mechanical resonance frequency (fm). The max output power across the contactless energized PZT component mainly rely on operating frequency, resonance, position & resistive load. The output power achieved across the contactless excited PZT component by focused E-field generator is higher than the output power achieved across the contactless excited PZT component by capacitor like E- field generator. The max output power of 9.9mW is obtained across PZT component at 1295 kHz resonance frequency (fr ) and 19.5 kΩ optimum loads with an input of 50 V and 8 mm electrode separation. By enactment of this excitation methods provide free actuation of PZT component so as to overcome the difficulties associated with the confined motion for different applications.
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Nouh, M., O. Aldraihem, and A. Baz. "Onset of Oscillations in Traveling Wave Thermo-Acoustic-Piezo-Electric Harvesters Using Circuit Analogy and SPICE Modeling." Journal of Dynamic Systems, Measurement, and Control 136, no. 6 (August 8, 2014). http://dx.doi.org/10.1115/1.4028050.
Повний текст джерелаАнотація:
Equations governing different physical fields such as mechanical, acoustical, and electrical are inherently similar. This enables mechanical, thermal, and acoustical networks to be fully described with analogous electric networks. For thermo-acoustic-piezo-electric (TAP) harvesters, such a modeling approach allows the whole system to be characterized in the electrical domain and facilitates the understanding of the underlying physics. In this paper, a traveling wave thermo-acoustic-piezoelectric (TWTAP) energy harvester is considered which converts thermal energy, such as solar or waste heat energy, directly into electrical energy without the need for any moving components. The input thermal energy generates a steep temperature gradient along a porous regenerator. At a critical threshold of the temperature gradient, self-sustained acoustic waves are developed inside an acoustic resonator. The associated pressure fluctuations impinge on a piezo-electric diaphragm, placed at the end of the resonator, to generate electricity. The acoustic pressure oscillations are amplified by a specially designed acoustic feedback loop that introduces appropriate phasing to make the pulsations take the form of traveling waves. The behavior of this TWTAP is modeled using electrical circuit analogy. The developed model combines the descriptions of the acoustic resonator, feedback loop, and the regenerator with the characteristics of the piezo-electric diaphragm. With the help of a simulation program with integrated circuit emphasis (SPICE) code, the developed electric circuit is used to analyze the system’s stability with regard to the input heat and hence predict the necessary temperature ratio required to establish the onset of self-sustained oscillations inside the harvester’s resonator. The predictions are compared with published results obtained using root locus and numerical methods and validated against experiments. This approach provides a very practical approach to the design of TAP energy harvesters both in the time and frequency domain. Such capabilities do not exist presently in the well-known design tool design environment for low-amplitude thermo-acoustic energy conversion (DeltaEC) developed at Los Almos National Laboratory which is limited to steady-state analysis. This is in contrast to the present approach which can be applicable to both steady as well as transient analysis.
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Burovikhin, Dmitrii, Ernst Dalhoff, Andreas Wagner, Fritz Schneider, and Michael Lauxmann. "Finite Element Model of a Piezo-Electric Actuator Coupled to the Middle Ear." Journal of Biomechanical Engineering, August 16, 2022. http://dx.doi.org/10.1115/1.4055237.
Повний текст джерелаАнотація:
Abstract The Hearing Contact Lens® (HCL) is a new type of hearing aid devices. One of its main components is a piezo-electric actuator. In order to evaluate and maximize the HCL's performance, a model of the HCL coupled to a middle-ear model was developed using finite element approach. The model was validated step by step starting with the HCL only. To validate the HCL model, vibrational measurements on the HCL were performed using a Laser-Doppler-Vibrometer (LDV). Then, a silicone cap was placed onto the HCL to provide an interface between the HCL and the tympanic membrane of the middle-ear model and additional LDV measurements on temporal bones were performed to validate the coupled model that was used to evaluate the equivalent sound pressure of the HCL. Moreover, a deeper insight was gained into the contact between the HCL and tympanic membrane and its effects on the HCL performance. The model can be used to investigate the sensitivity of geometrical and material parameters with respect to performance measures of the HCL and evaluate the feedback behavior.
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NAIDU, G. JITHENDRA, K. PRANAY KUMAR REDDY, and S. SIVA PRASAD. "PIEZO BASED ELECTRIC POWER GENERATION USING 3- DIMENSIONAL MECHANICAL VIBRATIONS PRODUCED IN VEHICLES." International Journal of Electronics and Electical Engineering, October 2013, 133–38. http://dx.doi.org/10.47893/ijeee.2013.1083.
Повний текст джерелаАнотація:
Due to advancement in the field of technology in recent years, wireless data transmission techniques are commonly used in electronic devices. For powering them we rely upon power supply through wires charging, else power may be supplied from batteries. But while travelling for longer distances continuously we may not be able to obtain power supply for these devices to operate or to recharge their batteries. So in order to operate them continuously we need a power source that provides continuous energy to operate these devices. The mechanical vibrations which are produced by the automobiles can be utilized as a source of energy for generating electrical energy that can be utilized by these electronic equipment to operate. These vibrations are produced by different vehicles around us which is going as a waste. This technique utilizes piezoelectric components where deformations produced by vibrations are directly converted to electrical charge via piezoelectric effect and principle of electromagnetic induction between coil and magnetic field which produces Electromotive force in the coil provided displacement to magnet by the vibrations. The piezoelectric materials and permanent magnets are used as energy conversion devices for converting mechanical vibrations to electrical energy. In this context, we introduced two methods and considered its output performance provided input vibrations, by using piezoelectric materials such as PZT for electro mechanical conversion using Mass-spring system as medium of conversion of force from vibrations applied on PZT materials and by using spring-magnet system where relative displacement of magnet with respect to coil, provided input vibrations generates Electromotive force in coil.
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Huang, Wenyu, Cangmin Wang, Yichao Liu, Shaoting Wang, Weifeng Ge, Huaili Qiu, Ting Zhang, Yuanjun Yang, Hui Zhang, and Chen Gao. "Strain-Mediated Magnetoelectric Control of Tunneling Magnetoresistance in Magnetic Tunneling Junction/Ferroelectric Hybrid Structures." Chinese Physics B, February 7, 2022. http://dx.doi.org/10.1088/1674-1056/ac523e.
Повний текст джерелаАнотація:
Abstract Because of the wide selectivity of ferromagnetic and ferroelectric (FE) components, electric-field (E-field) control of magnetism with via strain mediation can be easily realized through composite multiferroic heterostructures. Here, an MgO-based magnetic tunnel junction (MTJ) is chosen rationally as ferromagnetic constitution and a high-activity (001)-Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-0.3PT) single crystal is selected as FE component to create a multiferroic MTJ/FE hybrid structure. The shape of tunneling magnetoresistance (TMR) vs. in situ E-fields imprints the butterfly loop of piezo-strain of the FE without magnetic field biasing. The E-field-controlled change of the TMR ratio is up to -0.27% without magnetic-field bias. Moreover, when a typical magnetic field (~±10-Oe) is applied along the minor axis of the MTJ, the butterfly loop is changed significantly by E-fields relative to that without magnetic field biasing. This suggests that the E-field-controlled junction resistance is spin-dependent and correlated with magnetization switching in the free layer of the MTJ. In addition, based on such a multiferroic heterostructure, a strain-gauge factor up to approximately 40 is achieved, which decreases further with a sign change from positive to negative with increasing magnetic fields. This multiferroic hybrid structure is a promising avenue to control TMR through E-fields in low-power-consumption spintronic and straintronic devices at room temperature.
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Zhang, Yifeng, Frederic Cegla, and Joseph Corcoran. "Ultrasonic monitoring of pipe wall interior surface temperature." Structural Health Monitoring, September 22, 2020, 147592172095759. http://dx.doi.org/10.1177/1475921720957592.
Повний текст джерелаАнотація:
Accurate temperature measurement is a crucial aspect of structural health monitoring and prognosis. Conventional temperature measurement devices are either incapable of measuring subsurface temperatures in solids or need to be invasively installed. This study investigates the use of an ultrasonic technique for non-invasive measurement of subsurface temperatures in steel components; the temperature of a point on an inaccessible surface is inferred using a time-of-flight measurement from a transducer placed on an opposing accessible surface. Two different inversion approaches are presented, one named the assumed distribution method and the other named the inverse thermal modelling method. The robustness and accuracy of the two ultrasonic temperature inversion methods are quantitatively assessed via simulations and controlled experiments. It was found that both the assumed distribution and inverse thermal modelling methods demonstrate short thermal response times and are able to track the temperature evolution of inaccessible surfaces. A series of experimental studies show that in the presence of a 15°C difference between the accessible and inaccessible surfaces, the inaccessible surface temperature is typically measured to within better than 2°C with respect to a resistance temperature detector reference measurement. Additionally, the article compares the measurement performance achieved using a deployable electromagnetic acoustic transducer and a permanently installed piezo-electric PZT transducer. The time-of-flight measurements taken using the electromagnetic acoustic transducer system had higher random noise than the PZT system (standard deviations of 0.42 and 0.016 ns, respectively), subsequently leading to higher random noise in the temperature estimates.
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"CJ90-40. The structural optimization design of a three-component piezo-electric dynamometer." International Journal of Mechanical Sciences 32, no. 11 (January 1990): 962. http://dx.doi.org/10.1016/0020-7403(90)90075-t.
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Lotfy, Kh, E. S. Elidy, and Ramdan S. Tantawi. "Piezo-photo-thermoelasticity transport process for hyperbolic two-temperature theory of semiconductor material." International Journal of Modern Physics C, March 12, 2021, 2150088. http://dx.doi.org/10.1142/s0129183121500881.
Повний текст джерелаАнотація:
A general solution for propagating waves in a generalized piezo-photo-thermoelastic medium for the one-dimensional (1D) problem under the hyperbolic two-temperature theory is investigated. The governing equations of the elastic waves, carrier density (plasma wave), quasi-static electric field, heat conduction equation, hyperbolic two temperature coefficient and constitutive relationships for the peizo-thermoelastic medium are obtained using Laplace transformation method in 1D. On the interface adjacent to the vacuum, mechanical stress loads, thermal and plasma boundary conditions are applied to obtain the main basic physical quantities in the Laplace domain. The inversion of Laplace transform by a numerical method is applied to obtain the complete solutions in the Laplace time domain for the main physical fields in this phenomenon. The effects on the force stress, displacement component, temperature distribution and carrier density of the thermoelastic, thermoelectric and hyperbolic two-temperature parameters by the applied force were graphically discussed.
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Zribi, Jihene, Debora Pierucci, Federico Bisti, Biyuan Zheng, Jose Avila, Lama Khalil, Cyrine Ernandes, et al. "Unidirectional Rashba spin splitting in single layer WS2(1-x)Se2x alloy." Nanotechnology, November 8, 2022. http://dx.doi.org/10.1088/1361-6528/aca0f6.
Повний текст джерелаАнотація:
Abstract Atomically thin two-dimensional (2D) layered semiconductors such as transition metal dichalcogenides (TMDs) have attracted considerable attention due to their tunable band gap, intriguing spin-valley physics, piezoelectric effects and potential device applications. Here we study the electronic properties of a single layer WS1.4Se0.6 alloys. The electronic structure of this alloy, explored using angle resolved photoemission spectroscopy, shows a clear valence band structure anisotropy characterized by two paraboloids shifted in one direction of the k-space by a constant in-plane vector. This band splitting is a signature of a unidirectional Rashba spin splitting with a related giant Rashba parameter of 2.8± 0.7 eV Å. The combination of angle resolved photoemission spectroscopy with piezo force microscopy highlights the link between this giant unidirectional Rashba spin splitting and an in-plane polarization present in the alloy. These peculiar anisotropic properties of the WS1.4Se0.6 alloy can be related to local atomic orders induced during the growth process due the different size and electronegativity between S and Se atoms. This distorted crystal structure combined to the observed macroscopic tensile strain, as evidenced by photoluminescence, displays electric dipoles with a strong in-plane component, as shown by piezoelectric microscopy. The interplay between semiconducting properties, in-plane spontaneous polarization and giant out-of-plane Rashba spin-splitting in this two-dimensional material has potential for a wide range of applications in next-generation electronics, piezotronics and spintronics devices.