Design, fabrication, and properties of 2-2 connectivity cement/polymer based piezoelectric composites with varied piezoelectric phase distribution

AbstractThe force-electric coupling relationship of the mechanical and electrical properties of piezoelectric composites has been the main factor in the research and development of piezoelectric composites in practical application. A novel orthotropic piezoelectric composite material (OPCM) element is studied in this paper. The properties of the piezoelectric phase and the polymer phase and the influence of the geometrical dimensions of the OPCM on the longitudinal wave drive element are analyzed from the perspective of mechanics and electric power, respectively, and the structural design is optimized. This provides a theoretical basis for the development of OPCM and of new longitudinal ultrasonic phased array actuators.

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Study on Novel Relaxor Ferroelectric Single Crystal PMNT/Epoxy Composite

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.475-476.1257 ◽

2013 ◽

Vol 475-476 ◽

pp. 1257-1261

Author(s):

Guang Li ◽

Gui Dong Luan ◽

Hao Qu

Keyword(s):

Epoxy Composite ◽

Theoretical Calculations ◽

Structural Characteristics ◽

Structural Parameters ◽

Relaxor Ferroelectric ◽

Piezoelectric Composite ◽

Mechanical And Thermal Properties ◽

Piezoelectric Crystal ◽

Piezoelectric Composites ◽

Piezoelectric Phase

Use relaxor ferroelectric single crystals PMNT as piezoelectric phase, epoxy resin as a non-piezoelectric phase material, take the cutting - filling method fabricated piezoelectric composite. Its structure character is achieved 1-3 type piezoelectric composites and piezoelectric crystal substrate composite again inseries by the integration, the composite horizontal and vertical bracket to be supported by piezoelectric crystal frame, it has a good impact resistance and affected by changes in ambient temperature characteristics. This composite material both has the advantages of 1-3 type composites, and has stable mechanical and thermal properties. Based on R.E.Newnhams series-parallel theory, combined with the structural characteristics of this composite, given the formula of piezoelectric composites density, piezoelectric constant, and dielectric constant. Fabricated the PMNT / epoxy composites and piezoelectric PZT / epoxy piezoelectric composite materials samples, which have the same scale, the same structural parameters. The experimental results show that, the piezoelectric composite test parameter values match theoretical calculations. The PMNT/epoxy composite has batter function than PZT/epoxy composite.

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Prototype Design of Cement/Emulsified Asphalt Based Piezoelectric Composites and its Potential Application in Vehicle Speed Sensing

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211004580 ◽

2021 ◽

pp. 036119812110045

Author(s):

Xingyi Zhu ◽

Xudong Zhou ◽

Fangyong Ye ◽

Zhao Du

Keyword(s):

Performance Optimization ◽

Volume Fraction ◽

Moving Load ◽

Matrix Phase ◽

Traffic Information ◽

Piezoelectric Composites ◽

Voltage Output ◽

Piezoelectric Phase ◽

The Matrix ◽

Emulsified Asphalt

Piezoelectric composites (PC) embedded in pavement have shown great potential in traffic information sensing. As the main form of transportation, the road is the source of much traffic information including vehicle load information. The research into PC can supplement the collection of traffic information used in the development of intelligent technologies and provide effective solutions to problems existing in the process of information gathering. In this study, a 2-2 cement/emulsified asphalt-based PC was prepared with the cutting-filling method. To optimize the PC preparation, the effects of the volume fraction of the piezoelectric phase and the matrix phase composition on the piezoelectric properties of the PC were investigated by employing the finite element method. The results indicated that the smaller the volume fraction of the piezoelectric phase, the higher the voltage output of the PC, and the higher the sensitivity to external load, but the greater the stress concentration at the interface between the piezoelectric phase and the matrix phase. In addition, the greater the amount of emulsified asphalt in the matrix phase, the higher the voltage output of the PC. However, a higher content of emulsified asphalt will undermine the fluidity of the matrix phase. Based on the simulation analysis, performance optimization of the cement/emulsified asphalt PC was achieved. According to the voltage output characteristic of PC under a moving load, a placement scheme of PCs in the asphalt pavement was also proposed, which enables vehicle speeds to be be sensed with high precision.

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Digital phase analysis in interference electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106272 ◽

1988 ◽

Vol 46 ◽

pp. 842-843

Author(s):

S. Hasegawa ◽

T. Kawasaki ◽

J. Endo ◽

M. Futamoto ◽

A. Tonomura

Keyword(s):

Magnetic Field ◽

Electron Microscopy ◽

Phase Distribution ◽

Magnetic Recording Media ◽

Electron Wave ◽

Vector Potentials ◽

Weak Magnetic Fields ◽

Leakage Magnetic Field ◽

Optical Reconstruction ◽

Processing Techniques

Interference electron microscopy enables us to record the phase distribution of an electron wave on a hologram. The distribution is visualized as a fringe pattern in a micrograph by optical reconstruction. The phase is affected by electromagnetic potentials; scalar and vector potentials. Therefore, the electric and magnetic field can be reduced from the recorded phase. This study analyzes a leakage magnetic field from CoCr perpendicular magnetic recording media. Since one contour fringe interval corresponds to a magnetic flux of Φo(=h/e=4x10-15Wb), we can quantitatively measure the field by counting the number of finges. Moreover, by using phase-difference amplification techniques, the sensitivity for magnetic field detection can be improved by a factor of 30, which allows the drawing of a Φo/30 fringe. This sensitivity, however, is insufficient for quantitative analysis of very weak magnetic fields such as high-density magnetic recordings. For this reason we have adopted “fringe scanning interferometry” using digital image processing techniques at the optical reconstruction stage. This method enables us to obtain subfringe information recorded in the interference pattern.

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Application of electron holography to material science studies on magnetic domain states of small particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100150976 ◽

1993 ◽

Vol 51 ◽

pp. 1028-1029

Author(s):

T. Hirayama ◽

Q. Ru ◽

T. Tanji ◽

A. Tonomura

Keyword(s):

Magnetic Field ◽

Material Science ◽

Science Studies ◽

Phase Distribution ◽

Carbon Film ◽

Objective Lens ◽

Electron Holography ◽

Transform Method ◽

Transmission Electron ◽

Thin Carbon

The observation of small magnetic materials is one of the most important applications of electron holography to material science, because interferometry by means of electron holography can directly visualize magnetic flux lines in a very small area. To observe magnetic structures by transmission electron microscopy it is important to control the magnetic field applied to the specimen in order to prevent it from changing its magnetic state. The easiest method is tuming off the objective lens current and focusing with the first intermediate lens. The other method is using a low magnetic-field lens, where the specimen is set above the lens gap.Figure 1 shows an interference micrograph of an isolated particle of barium ferrite on a thin carbon film observed from approximately [111]. A hologram of this particle was recorded by the transmission electron microscope, Hitachi HF-2000, equipped with an electron biprism. The phase distribution of the object electron wave was reconstructed digitally by the Fourier transform method and converted to the interference micrograph Fig 1.

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Microstructure and microanalysis of sintered Fe-Nd-B permanent magnets

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178082 ◽

1990 ◽

Vol 48 (4) ◽

pp. 990-991

Author(s):

Mahesh Chandramouli

Keyword(s):

Electron Microscope ◽

Liquid Phase ◽

Permanent Magnets ◽

Phase Distribution ◽

Energy Dispersive Spectrometer ◽

Nucleation And Growth ◽

Liquid Phase Sintering ◽

Domain Wall Energy ◽

Oxide Phases ◽

Scanning Electron

Magnetization reversal in sintered Fe-Nd-B, a complex, multiphase material, occurs by nucleation and growth of reverse domains making the isolation of the ferromagnetic Fe14Nd2B grains by other nonmagnetic phases crucial. The magnets used in this study were slightly rich in Nd (in comparison to Fe14Nd2B) to promote the formation of Nd-oxides at multigrain junctions and incorporated Dy80Al20 as a liquid phase sintering addition. Dy has been shown to increase the domain wall energy thus making nucleation more difficult while Al is thought to improve the wettability of the Nd-oxide phases.Bulk polished samples were examined in a JEOL 35CF scanning electron microscope (SEM) operated at 30keV equipped with a Be window energy dispersive spectrometer (EDS) detector in order to determine the phase distribution.

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