scholarly journals Dispersion of Switching Processes in Ferroelectric Ceramics

2017 ◽  
Vol 2017 ◽  
pp. 1-5
Author(s):  
O. V. Malyshkina ◽  
Anton Yurievich Eliseev ◽  
R. M. Grechishkin
Keyword(s):  
Electric Fields ◽  
Heating Temperature ◽  
Low Frequency ◽  
High Amplitude ◽  
Wide Frequency Range ◽  
The Self ◽  
Ferroelectric Ceramics ◽  
Field Frequency ◽  
Self Heating ◽  
Electric Field Frequency

The influence of the switching processes on self-heating of ferroelectric PZT ceramics samples was studied in high-amplitude sine and meander electric fields in a wide frequency range of 50 to 1500 Hz. It is shown that the linear dependence of the self-heating temperature on the electric field frequency is observed only in low-frequency region. It was found that there exists a maximum on the frequency dependence of the self-heating temperature. The critical frequency fcr corresponding to this maximum depends on both the properties of the material and geometry of the sample.

scholarly journals Stationary Self-Heating of the Circular and Annular Composite Plates Hinged on the Boundary under Axisymmetric Cyclic Loading

2011 ◽  
Vol 20 (5) ◽  
pp. 096369351102000 ◽  
Author(s):  
Andrzej Katunin
Keyword(s):  
Heat Transfer ◽  
Cyclic Loading ◽  
Transfer Equation ◽  
Heating Temperature ◽  
Composite Plates ◽  
The Self ◽  
Heat Transfer Equation ◽  
Dissipation Energy ◽  
Self Heating ◽  
Parametric Analyses

The present study is focused on the analytical modelling of the stationary self-heating caused by the hysteretic behaviour of the polymeric laminated circular and annular plates hinged on the boundary under axisymmetric transverse cyclic loading. The investigation was based on the complex parameters concept. The coupled thermoviscoelasticity problem was solved by substitution of the dissipation energy function to the heat transfer equation as a source function. The self-heating temperature distributions formulas were obtained by solving the heat transfer equation with appropriate thermal boundary conditions using trigonometric Fourier series. Numerous parametric analyses were presented. It was shown, that omitting the influence of the self-heating effect may results in the incorrect description of the behaviour of polymeric composites under cyclic loading.

scholarly journals Fatigue and Thermal Failure of Polymeric Composites Subjected to Cyclic Loading

2012 ◽  
Vol 21 (3) ◽  
pp. 096369351202100 ◽  
Author(s):  
Andrzej Katunin ◽  
Marek Fidali
Keyword(s):  
Cyclic Loading ◽  
Heating Temperature ◽  
Qualitative Evaluation ◽  
Polymeric Composites ◽  
The Self ◽  
Heating Effect ◽  
Thermal Failure ◽  
Self Heating ◽  
Measurement Results ◽  
Parametric Dependencies

In the presented study the experimental results for the investigation of fatigue of polymeric composites subjected to intensive cyclic loading with presence of the self-heating effect were presented. Experiments were carried out on laboratory stand, which provides the synchronous measurement of loading force, displacements and temperature. It was observed, that the fatigue process during occurrence of the self-heating effect consists of three phases, which were analyzed and described. The characteristic self-heating temperature distributions and their evolution during the whole loading history were analyzed. The parametric analysis of influence of loading conditions on the self-heating temperature evolution and fatigue of polymeric composites was presented. Basing upon the measurement results the authors proposed empirical models, which give a qualitative evaluation of parametric dependencies.

Stroboscopic X-Ray Diffraction Measurements of sub-ns Domain Dynamics in Ferroelectric Films

2004 ◽  
Vol 833 ◽  
Author(s):  
E. Zolotoyabko ◽  
J. P. Quintana ◽  
D. J. Towner ◽  
B. W. Wessels
Keyword(s):  
Electric Fields ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Electrical Circuit ◽  
X Ray Diffraction ◽  
Field Frequency ◽  
Time Resolved ◽  
Electric Field Frequency ◽  
Domain Motions ◽  
Domain Dynamics

ABSTRACTWe used the Advanced Photon Source (APS) at Argonne National Laboratory to perform fast (ps range) time-resolved diffraction measurements of the dynamic characteristics in BaTiO3 films subjected to strong high-frequency electric fields. The time-dependent lattice response measured at frequencies between 6.5 MHz and 1.3 GHz revealed damped domain movements with attenuation time rapidly increasing with electric field frequency, v. We found that at frequencies higher than ν ∼ 600 MHz the domain motions in BaTiO3 films become heavily damped, information that may be important to future device operation. A minimum attenuation time, τ ∼ 330 ps, measured at ν = 1.3 GHz was limited by the time constant of the electrical circuit.

scholarly journals Variable Surface Temperature Distribution as a Criticality Indicator of the Self-Heating Effect in Composites

2018 ◽  
Vol 18 (1) ◽  
pp. 5-12 ◽  
Author(s):  
A. Katunin
Keyword(s):  
Temperature Distribution ◽  
Surface Temperature ◽  
Heating Temperature ◽  
Measurement Techniques ◽  
Critical Value ◽  
The Self ◽  
Heating Effect ◽  
Self Heating ◽  
Surface Temperature Distribution ◽  
Variable Surface

AbstractSince self-heating effect may significantly intensify structural degradation, it is essential to investigate its criticality, i.e. the temperature value at which fatigue fracture is initiated. In this paper, a new and sensitive criticality indicator based on evaluation of evolution of surface temperature distribution was proposed and experimentally validated. It was shown that comparing to other measurement techniques the presented approach allows for precise evaluation of the critical value of the self-heating temperature. The properly determined critical value may be helpful both during design and operation of elements made of polymers and polymeric composite.

Electrical Tomography Sensing and Dielectrophoresis in Microchannel for 3D Particle Mixing

2011 ◽  
Author(s):  
Nur Tantiyani Ali Othman ◽  
Je-Eun Choi ◽  
Masahiro Takei
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Electric Fields ◽  
Cross Sections ◽  
Electrical Tomography ◽  
Field Frequency ◽  
Particle Mixing ◽  
Measurement Plane ◽  
Electric Field Frequency ◽  
The Relationship

The present study describes the electrical tomography sensing and dielectrophoresis (DEP) force for visualize the 3D particle mixing in the microchannel system. In the presence of non-uniform electric fields generated by point microelectrodes, the dynamic distribution behaviors of a polystyrene particle and deionized water had been investigated in this system. Microchannel was fabricated with five cross sections where 12 electrodes were installed for each measurement plane. In this experiment, the relationship between electric field frequency and DEP force of particles are calculated at different electric frequencies and diameter of particles. The applied electric field intensities are E = ±1 V/mm, ±3 V/mm and ±5 V/mm while the electric field frequencies are f = 1 kHz, 10 kHz, 100 kHz and 1 MHz and the diameter of particles are 1.3μm, 1.5μm and 2.0μm are investigated in this experiment. Simultaneously, imaged by manipulating tomography sensing at cross section A, C and D and the coupled DEP forces at cross section B and D, the particles flowing had been visualized and concentrate uniformly at near the outlets. The electrical capacitances and DEP forces between the electrode pairs of the microchannel were measured and the ECT tomograms representing the particle distribution were constructed from the measured capacitance data for each cross section in microchannel.

SMA (NiTi): The Coupling between Time, Temperature and Cycling Frequency

2012 ◽  
Vol 730-732 ◽  
pp. 853-858
Author(s):  
Vicenç Torra ◽  
Carlota Auguet ◽  
Antonio Isalgue ◽  
Guillem Carreras ◽  
Francisco C. Lovey
Keyword(s):  
Temperature Effects ◽  
Heating Temperature ◽  
The Self ◽  
Dissipated Energy ◽  
Hysteresis Cycle ◽  
Hysteresis Width ◽  
Self Heating ◽  
Heating Effects ◽  
Cycle Shape ◽  
Cycling Frequency

The main interest focuses in the necessary tools for accurate simulation of the damper behavior in their application. It’s essential a well determined knowledge of the dissipated energy and of the hysteresis cycle shape for a correct simulation. The self-heating effects and the coupling between hysteresis and the relevant temperature effects associated to continuous cycling were studied. In particular, the experimental analysis concentrates in the action of cycling frequency on the hysteresis width and on the dissipated energy. The external and the self-heating temperature effects were studied. In particular, the convective actions of cooling in the conditioned air were visualized. The study of self-heating actions at extremely slow cycles, built by strain steps, shows minor latent heat dissipations in the entire sample. For trained samples, the temperature measurements establish that the transformation is “distributed” not “localized” in the complete sample.

scholarly journals Buoyancy-Free Janus Microcylinders as Mobile Microelectrode Arrays for Continuous Microfluidic Biomolecule Collection within a Wide Frequency Range: A Numerical Simulation Study

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 289 ◽  
Author(s):  
Weiyu Liu ◽  
Yukun Ren ◽  
Ye Tao ◽  
Hui Yan ◽  
Congda Xiao ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Particle Surface ◽  
Low Frequency ◽  
Wide Frequency Range ◽  
Main Body ◽  
Wide Field ◽  
Frequency Range ◽  
Field Frequency ◽  
Ac Electrokinetics ◽  
Induced Charge

We numerically study herein the AC electrokinetic motion of Janus mobile microelectrode (ME) arrays in electrolyte solution in a wide field frequency, which holds great potential for biomedical applications. A fully coupled physical model, which incorporates the fluid-structure interaction under the synergy of induced-charge electroosmotic (ICEO) slipping and interfacial Maxwell stress, is developed for this purpose. A freely suspended Janus cylinder free from buoyancy, whose main body is made of polystyrene, while half of the particle surface is coated with a thin conducting film of negligible thickness, will react actively on application of an AC signal. In the low-frequency limit, induced-charge electrophoretic (ICEP) translation occurs due to symmetric breaking in ICEO slipping, which renders the insulating end to move ahead. At higher field frequencies, a brand-new electrokinetic transport phenomenon called “ego-dielectrophoresis (e-DEP)” arises due to the action of the localized uneven field on the inhomogeneous particle dipole moment. In stark contrast with the low-frequency ICEP translation, the high-frequency e-DEP force tends to drive the asymmetric dipole moment to move in the direction of the conducting end. The bidirectional transport feature of Janus microspheres in a wide AC frequency range can be vividly interpreted as an array of ME for continuous loading of secondary bioparticles from the surrounding liquid medium along its direction-controllable path by long-range electroconvection. These results pave the way for achieving flexible and high-throughput on-chip extraction of nanoscale biological contents for subsequent on-site bioassay based upon AC electrokinetics of Janus ME arrays.

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