scholarly journals Energy Harvester Based on the Synchronization Phenomenon of a Circular Cylinder

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Junlei Wang ◽  
Jingyu Ran ◽  
Zhien Zhang
Keyword(s):  
Circular Cylinder ◽  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Lead Zirconate ◽  
Open Circuit ◽  
Fluid Field ◽  
Voltage Output ◽  
Lift And Drag ◽  
Lift And Drag Coefficient ◽  
High Level

A concept of generating power from a circular cylinder undergoing vortex-induced vibration (VIV) was investigated. Two lead zirconate titanate (PZT) beams which had high power density were installed on the cylinder. A theoretical model has been presented to describe the electromechanical coupling of the open-circuit voltage output and the vibration amplitudes based on a second-order nonlinear Van der pol equation and Gauss law. A numerical computation was applied to measure the capacity of the power generating system. The lift and drag coefficient and the vortex shedding frequency were obtained to verify how the nondimensional parameter reduced velocityUraffects the fluid field. Meanwhile, a single-degree of freedom system has been added to describe the VIV, presynchronization, and synchronization together with postsynchronization regimes of oscillating frequencies. And the amplitudes of the vibration have been obtained. Finally, the vibrational amplitudes and the voltage output could go up to a high level in the synchronization region. The maximum value of the voltage output and the corresponding reduced velocityUrwere 8.42 V and 5.6, respectively.

scholarly journals Electrothermal Phenomena in Ferroelectrics

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 93
Author(s):  
Kenji Uchino
Keyword(s):  
Thermal Diffusivity ◽  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Short Circuit ◽  
Electromechanical Coupling Factor ◽  
Lead Zirconate ◽  
Coupling Factor ◽  
Open Circuit ◽  
Comprehensive Knowledge ◽  
Poling Direction

Physical properties of lead-zirconate-titanate (PZT) ceramics change according to the initial electric poling process and electrical boundary conditions. This paper reports the electrothermal, piezothermal, and piezoelectric coupling phenomena in ferroelectrics from thermodynamics viewpoints, in particular, thermal property differences between unpoled and poled PZT’s in the poling direction for open circuit and short circuit conditions. We propose a new terminology, “secondary electrothermal” coupling factor kλ, which is analogous to the electromechanical coupling factor k, relating the elastic compliances under short- and open-circuit conditions, in order to explain the fact that the short-circuit condition exhibited the larger thermal diffusivity than the open-circuit condition. On the other hand, the unpoled specimen exhibits the lowest thermal diffusivity. This tutorial paper was authored for providing comprehensive knowledge on equilibrium and time-dependent thermodynamics in ferroelectrics.

Sol-Gel Derived PZT Thick Films with Nano-Sized Microstructure

2002 ◽  
Vol 748 ◽  
Author(s):  
C. L. Zhao ◽  
Z. H. Wang ◽  
W. Zhu ◽  
O. K. Tan ◽  
H. H. Hng
Keyword(s):  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Thick Films ◽  
Sol Gel ◽  
Essential Element ◽  
Processing Parameters ◽  
Lead Zirconate ◽  
Piezoelectric Response ◽  
Coupling Coefficients ◽  
Pzt Films

ABSTRACTLead zirconate titanate (PZT) films are promising for acoustic micro-devices applications because of their extremely high electromechanical coupling coefficients and excellent piezoelectric response. Thicker PZT films are crucial for these acoustic applications. A hybrid sol-gel technology has been developed as a new approach to realize simple and cost-effective fabrication of high quality PZT thick films. In this paper, PZT53/47 thick films with a thickness of 5–50 μm are successfully deposited on Pt-coated silicon wafer by using the hybrid sol-gel technology. The obtained PZT thick films are dense, crack-free, and have a nano-sized microstructure. The processing parameters of this technology have been evaluated. The microstructure of the film has been observed using field-emission scanning electron microscopy and the crystallization process has been monitored by the X-ray diffraction. The thick films thus made are good candidates for fabrication of piezoelectric diaphragm which will be an essential element of microspeaker and microphone arrays.

Piezoelectric nanoindentation

2006 ◽  
Vol 21 (3) ◽  
pp. 552-556 ◽  
Author(s):  
Andrei Rar ◽  
G.M. Pharr ◽  
W.C. Oliver ◽  
E. Karapetian ◽  
Sergei V. Kalinin
Keyword(s):  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Surface Displacement ◽  
Lead Zirconate ◽  
Ferroelectric Materials ◽  
Back Side ◽  
Structure Property ◽  
Load Dependence ◽  
Continuous Stiffness Measurement

Piezoelectric nanoindentation (PNI) has been developed to quantitatively address electromechanical coupling and pressure-induced dynamic phenomena in ferroelectric materials on the nanoscale. In PNI, an oscillating voltage is applied between the back side of the sample and the indenter tip, and the first harmonic of bias-induced surface displacement at the area of indenter contact is detected. PNI is implemented using a standard nanoindentation system equipped with a continuous stiffness measurement system. The piezoresponse of polycrystalline lead zirconate titanate (PZT) and BaTiO3 piezoceramics was studied during a standard nanoindentation experiment. For PZT, the response was found to be load independent, in agreement with theoretical predictions. In polycrystalline barium titanate, a load dependence of the piezoresponse was observed. The potential of piezoelectric nanoindentation for studies of phase transitions and local structure-property relations in piezoelectric materials is discussed.

Model Test Study on Vortex-Induced Motions of a Floating Cylinder

2009 ◽  
Author(s):  
Ying Wang ◽  
Jianmin Yang ◽  
Tao Peng ◽  
Xin Li
Keyword(s):  
Circular Cylinder ◽  
Scale Model ◽  
Visualization System ◽  
Forced Motion ◽  
Drag Forces ◽  
Fluid Field ◽  
Helical Strakes ◽  
Induced Motion ◽  
Motion Characteristics ◽  
Lift And Drag

Vortex-Induced Motions (VIM) under current flow is an important issue for surface piercing cylinders, such as Spar platforms and floating buoys, since it affects the motion performance of these structures greatly. In recent years this phenomenon attracts much attention and many researchers have been making efforts to deal with this problem. VIM is such a complicated phenomenon that more fundamental studies are needed to understand the essence behind VIM. This paper mainly concentrates on a circular cylinder, aiming to eliminate outside influences and reveal the inherent characteristic of vortex-induced motion mechanism. A circular cylinder with an aspect ratio of 1:2.4, which could be considered as a scale model for the hard tank of a typical Truss Spar, is studied by experimental method to investigate the surrounding fluid field, the excitation forces and Vortex-Induced Motion characteristics under various governing parameters, such as the current velocity and direction, the mooring stiffness and distribution, the use and efficiency of helical strakes, and so on. By using a simple flow visualization system, the unsteady flow passing the circular cylinder and the vortices in the wake are captured and recorded. The cylinder is tested respectively under fixed, forced-motion and elastically moored conditions. The fluid field, the vortex structures, and the lift and drag forces under fixed and forced-motion conditions are measured, the VIM performance of the cylinder with two different mooring distributions are studied, and strake efficiency is studied considering current directionality and strake height influence.

Influence of aspect ratio on effective electromechanical coupling of nanocomposites with lead zirconate titanate nanowire inclusion

2011 ◽  
Vol 22 (16) ◽  
pp. 1879-1886 ◽  
Author(s):  
Clark Andrews ◽  
Yirong Lin ◽  
Haixiong Tang ◽  
Henry A. Sodano
Keyword(s):  
Aspect Ratio ◽  
Mechanical Loading ◽  
Polymer Matrix ◽  
Lead Zirconate Titanate ◽  
Coupling Coefficient ◽  
High Aspect Ratio ◽  
Electromechanical Coupling ◽  
Lead Zirconate ◽  
Electromechanical Coupling Coefficient ◽  
Curved Surfaces

Piezoelectric ceramics offer exceptional sensing and actuation properties, however, they are prone to breakage and are difficult to apply to curved surfaces in their monolithic form. One method to alleviate these issues is through the use of 0–3 active composites, which are formed by embedding piezoelectric particles into a polymer matrix that protects the ceramic from breaking under mechanical loading. This class of material offers certain advantages over monolithic materials; however, they have seen little use due to the low electromechanical coupling offered by these materials. Here, we demonstrate that by controlling the aspect ratio of the filler, the electromechanical coupling coefficient can be significantly improved. For all volume fractions tested, nanocomposites with high aspect ratio lead nanowires filler had higher coupling with increases as large as 2.3 times. Furthermore, the nanocomposite’s coupling was more than 50% of the piezoceramic fillers’ when nanowires were used.

Wet-Etch Patterning of Lead Zirconate Titanate (PZT) Thick Films for Microelectromechanical Systems (MEMS) Applications

2000 ◽  
Vol 657 ◽  
Author(s):  
L.-P. Wang ◽  
R. Wolf ◽  
Q. Zhou ◽  
S. Trolier-McKinstry ◽  
R. J. Davis
Keyword(s):  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Microelectromechanical Systems ◽  
Sol Gel ◽  
Lead Zirconate ◽  
Metal Fluoride ◽  
Zirconate Titanate ◽  
Pzt Films ◽  
High Etch Rate ◽  
Wet Etch

ABSTRACTLead zirconate titanate (PZT) films are very attractive for microelectromechanical systems (MEMS) applications because of their high piezoelectric coefficients and good electromechanical coupling. In this work, wet-etch patterning of sol-gel PZT films for MEMS applications, typically with film thicknesses ranging from 2 to 10 microns, was studied. A two- step wet-etch process was developed. In the first step, 10:1 buffered HF is used to remove the majority of the film at room temperature. Then a solution of 2HCl:H2O at 45°C is used to remove metal-fluoride residues remaining from the first step. This enabled successful patterning of PZT films up to 8 microns thick. A high etch rate (0.13μm/min), high selectivity with respect to photoresist, and limited undercutting (2:1 lateral:thickness) were obtained. The processed PZT films have a relative permittivity of 1000, dielectric loss of 1.6%, remanent polarization (Pr) of 24μC/cm2, and coercive field (Ec) of 42.1kV/cm, all similar to those of unpatterned films of the same thickness.

Variation of Material Properties of Piezoelectric Ceramics due to Electric Loading Evaluated by Resonance Frequency

2007 ◽  
Vol 345-346 ◽  
pp. 1521-1524 ◽  
Author(s):  
Mamoru Mizuno ◽  
Nozomi Odagiri ◽  
Mitsuhiro Okayasu
Keyword(s):  
Electric Field ◽  
Resonance Frequency ◽  
Lead Zirconate Titanate ◽  
Material Properties ◽  
Electromechanical Coupling ◽  
Domain Switching ◽  
Piezoelectric Ceramics ◽  
Lead Zirconate ◽  
Electromechanical Coupling Coefficient ◽  
Resonance Frequencies

In the present paper, lead zirconate titanate (PZT) and lead titanate (PT) piezoelectric ceramics were subjected to both high electric field (which is higher than the coercive electric field) with low frequency and low electric field with high frequency (which is the resonance frequency). After applying certain electric field systematically, resonance and anti-resonance frequencies and an electrostatic capacity were measured by means of an impedance analyzer, and an electromechanical coupling coefficient, a dielectric constant, an elastic coefficient and a piezoelectric constant were evaluated from the frequencies and capacity measured. Then variation of the material properties in process of time was investigated experimentally, and the dependence of the variation of the properties due to mainly domain switching on conditions of applied electric field was elucidated.

scholarly journals Acoustic instrumentation of the new generation of MTR: effect of nuclear radiation on modified Bismuth Titanate piezoelectric elements

2020 ◽  
Vol 225 ◽  
pp. 04012
Author(s):  
JY. Ferrandis ◽  
O. Gatsa ◽  
P. Combette ◽  
D. Fourmentel ◽  
C. Destouches ◽  
...  
Keyword(s):  
Lead Zirconate Titanate ◽  
Electromechanical Coupling ◽  
Bismuth Titanate ◽  
Piezoelectric Materials ◽  
Lead Zirconate ◽  
Nuclear Radiation ◽  
Electromechanical Coupling Coefficient ◽  
Jozef Stefan Institute ◽  
Stefan Institute ◽  
New Generation

In this article we present a first part of the results obtained during an irradiation campaign conducted at the Jozef Stefan Institute to observe the behaviour of piezoelectric materials under gamma and neutron flux. Specific instrumentation has been developed and has enabled the monitoring throughout the irradiation of several materials such as lead zirconate titanate (PZT) or modified Bismuth Titanate (BiT) in either massive or thick film form. Various parameters such as resonance frequency, electromechanical coupling coefficient, electrical capacitance, dielectric losses were measured as a function of the flow and dose received. The results obtained confirm that the samples work up to doses of 10 18 n°/cm2 and that the behaviour of the samples varies according to their composition and form.

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