• Title/Summary/Keyword: Electromechanical strain

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Performance evaluation of differently structured RCE-DR GdBCO coated conductor tapes under uniaxial tension at 77 K

  • Diaz, Mark Angelo E.;Shin, Hyung-Seop;Jung, Ho-Sang;Lee, Jaehun
    • Progress in Superconductivity and Cryogenics
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    • v.24 no.1
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    • pp.13-17
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    • 2022
  • The mechanical properties of REBCO coated conductor (CC) tapes under uniaxial tension are mainly determined by the thick layer Components like the substrate and the stabilizer. Depending on the applications of the CC tapes, it is also needed to externally reinforce thin metallic foils to one side or both sides of the CC tapes. This study investigated the effect of additional stabilizer layers or lamination on the electrical resistivity and electromechanical properties in RCE-DR processed GdBCO CC tapes with different structures. The strain/stress tolerance of Ic in differently processed 12 mm-wide REBCO CC tapes under uniaxial tension at 77 K and self-field could be determined by the loading-unloading scheme. As a result, Sn-Cu stabilized CC tape showed a significant decrease in mechanical properties due to its soft but thick stabilizing layer. However, similar electromechanical properties have been observed on both Sn-Cu and Sn-stabilized CC tapes, the Ic degradation behavior was independent of whether the CC tape has an external reinforcement or different stabilizing layers.

Characteristics of PBZT Ceramics for Electrostrictive Actuator according to $WO_3$ (전외 액츄에이터용 PBZT 세라믹스의 $WO_3$ 첨가에 따른 특성)

  • 김규수;윤광희;윤현상;박창엽;홍재일;류주현
    • Electrical & Electronic Materials
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    • v.10 no.9
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    • pp.909-915
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    • 1997
  • To improve the electro-induced strain and to decease the hysteresis of that W $O_3$dopant of which amount is 0~0.8wt% was added to (P $b_{0.73}$/B $a_{0.27}$)(Z $r_{0.75}$/ $Ti_{0.25}$) $O_3$+0.1wt% $Y_{2}$/ $O_3$ceramics. At the specimen with 0.4 wt% W $O_3$the electromechanical coupling coefficient( $K_{31}$ ) showed the maximum value of 23.6% at D.C 10 kV/cm electric field. At the same W $O_3$addition amount the piezoelectric constant( $d_{31}$ ) and the electro-induced strain($\Delta$$\ell$/$\ell$)showed the highest values of 182$\times$10$^{-12}$ [C/N] 210$\times$10$^{-6}$ $\Delta$$\ell$/$\ell$at D.C. 10 kV/cm electric field. respectively0 kV/cm electric field. respectivelyvely.

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Effects of High-Energy Ball Milling and Sintering Time on the Electric-Field-Induced Strain Properties of Lead-Free BNT-Based Ceramic Composites

  • Nga-Linh Vu;Nga-Linh Vu;Dae-Jun Heo;Thi Hinh Dinh;Chang Won Ahn;Chang Won Ahn;Hyoung-Su Han;Jae-Shin Lee
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.5
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    • pp.505-512
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    • 2023
  • This study investigated crystal structures, microstructures, and electric-field-induced strain (EFIS) properties of Bi-based lead-free ferroelectric/relaxor composites. Bi1/2Na0.82K0.18)1/2TiO3 (BNKT) as a ferroelectric material and 0.78Bi1/2(Na0.78K0.22)1/2TiO3-0.02LaFeO3 (BNKT2LF) as a relaxor material were synthesized using a conventional solid-state reaction method, and the resulting BNKT2LF powders were subjected to high-energy ball milling (HEBM) after calcination. As a result, HEBM proved a larger average grain size of sintered samples compared to conventional ball milling (CBM). In addition, the increased sintering time led to grain growth. Furthermore, HEBM treatment and sintering time demonstrated a significant effect on EFIS of BNKT/BNKT2LF composites. At 6 kV/mm, 0.35% of the maximum strain (Smax) was observed in the HEBM sample sintered for 12 h. The unipolar strain curves of CBM samples were almost linear, indicating almost no phase transitions, while HEBM samples displayed phase transitions at 5~6 kV/mm for all sintering time levels, showing the highest Smax/Emax value of 700 pm/V. These results indicated that HEBM treatment with a long sintering time might significantly enhance the electromechanical strain properties of BNT-based ceramics.

First-Principles Investigation on the Electromechanical Properties of Monolayer 1H Pb-Dichalcogenides

  • Nguyen Hoang Linh;Nguyen Minh Son;Tran The Quang;Nguyen Van Hoi;Vuong Thanh;Do Van Truong
    • Korean Journal of Materials Research
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    • v.33 no.5
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    • pp.189-194
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    • 2023
  • This study uses first-principles calculations to investigate the mechanical properties and effect of strain on the electronic properties of the 2D material 1H-PbX2 (X: S, Se). Firstly, the stability of the 1H Pb-dichalcogenide structures was evaluated using Born's criteria. The obtained results show that the 1H-PbS2 material possesses the greatest ideal strength of 3.48 N/m, with 3.68 N/m for 1H-PbSe2 in biaxial strain. In addition, 1H-PbS2 and 1H-PbSe2 are direct semiconductors at equilibrium with band gaps of 2.30 eV and 1.90 eV, respectively. The band gap was investigated and remained almost unchanged under the strain εxx but altered significantly at strains εyy and εbia. At the fracture strain in the biaxial direction (19 %), the band gap of 1H-PbS2 decreases about 60 %, and that of 1H-PbSe2 decreases about 50 %. 1H-PbS2 and 1H-PbSe2 can convert from direct to indirect semiconductor under the strain εyy. Our findings reveal that the two structures have significant potential for application in nanoelectronic devices.

Fabrication of Multilayer Ceramic Actuator using Tape Casting Method (Tape casting 법을 이용한 적층형 세라믹 액츄에이터의 제작)

  • Ha, Mun-Su;Lee, Dong-Man;Jeong, Soon-Jong;Kim, In-Sung;Min, Bok-Ki;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.556-560
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    • 2002
  • The rheological characteristics of PNN-PZT ceramics with high electromechanical coupling factor and electricstrictive constant was investigated. Green sheets of piezoelectric PNN-PZT ceramics were made by tape-casting method with controlling the mixing ratio of a dispersant, an organic binder, and a plasticizer. When the dispersant content was 1 wt.%, the slurry showed the best rheological characteristics for tape casting. The amounts of the plasticizer and the binder was simultaneously varied in the ranges of 1.5~18 and 3~9 wt.%, respectively. When both the plasticizer and binder of 6 wt.% mixed in the solution, respectiveley, the highest green density of the sheet was obtained without macrodefects. Multilyered structures of PNN-PZT/Ag-Pd were successfully fabricated using the optimized tape casting condition. The polarization behavior of these actuators seemed to similar to typical electricstrictive polarization behavior. The multilayer ceramic actuator is about $0.6{\times}10^{-3}$ of strain.

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Structural, Dielectric and Field-Induced Strain Properties of La-Modified Bi1/2Na1/2TiO3-BaTiO3-SrZrO3 Ceramics

  • Hussain, Ali;Maqbool, Adnan;Malik, Rizwan Ahmed;Zaman, Arif;Lee, Jae Hong;Song, Tae Kwon;Lee, Jae Hyun;Kim, Won Jeong;Kim, Myong Ho
    • Korean Journal of Materials Research
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    • v.25 no.10
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    • pp.566-570
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    • 2015
  • $Bi_{0.5}Na_{0.5}TiO_3$ (BNT) based ceramics are considered potential lead-free alternatives for $Pb(Zr,Ti)O_3$(PZT) based ceramics in various applications such as sensors, actuators and transducers. However, BNT-based ceramics have lower electromechanical performance as compared with PZT based ceramics. Therefore, in this work, lead-free bulk $0.99[(Bi_{0.5}Na_{0.5})_{0.935}Ba_{0.065}]_{(1-x)}La_xTiO_3-0.01SrZO_3$ (BNBTLax-SZ, with x = 0, 0.01, 0.02) ceramics were synthesized by a conventional solid state reaction The crystal structure, dielectric response, degree of diffuseness and electric-field-induced strain properties were investigated as a function of different La concentrations. All samples were crystallized into a single phase perovskite structure. The temperature dependent dielectric response of La-modified BNBT-SZ ceramics showed lower dielectric response and improved field-induced strain response. The field induced strain increased from 0.17%_for pure BNBT-SZ to 0.38 % for 1 mol.% La-modified BNBT-SZ ceramics at an applied electric field of 6 kV/mm. These results show that La-modified BNBT-SZ ceramic system is expected to be a new candidate material for lead-free electronic devices.

Fabrication and Straining Model of a CNT/EAP Composite Film (카본나노튜브/도전성폴리머(CNT/EAP) 복합재 필름의 제조 및 특성분석)

  • Zhang, Shuai;Kim, Cheol
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.117-120
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    • 2005
  • The relationship between strain and applied potential was derived for composite actuators consisting single-wall carbon nanotubes (SWNTs) and conductive polymers (CPs). During deriving the relationship, an electrochemical ionic approach is utilized to formulate the electromechanical actuation of the composite film actuator. The results show that the well-aligned SWNTs composite actuator can give good actuation responses and high actuating forces available. The actuation is found to be affected by both SWNTs and CPs components and the actuation of SWNTs component has two kinds of influences on that of the CPs component: reinforcement at the positive voltage and abatement at the negative voltage. CNT/EAP was fabricated successfully using the chemical polymerization method.

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Degradation of 0.2PMN-0.8PZT Multilayer Ceramic Actuators

  • Song, Jae-Sung;Koh, Jung-Hyuk;Jeong, Soon-Jong;Wee, Sang-Bong
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.1
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    • pp.6-9
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    • 2005
  • Aging characteristics of 0.2PMN-0.8PZT multilayer ceramic actuators (MCA) has been investigated by applying both triangular wave function for unpoled and unipolar wave for poling. P-E hysteresis loops of the MCA had been distorted after about 90 million cycles running in triangular wave function. Effective electromechanical coupling coefficient was calculated in resonant and anti resonant frequencies. And pseudo-piezoelectric constant $d_{33}$ was also estimated from the strain versus electric field characteristics. The crack growth of MCA was clearly observed along to the boundary between electrode and inactive area. That results were thought due to the internal tensile stress came from both actuation of $d_{33}$ mode and motion of Poisson ratio.

Performance Characteristics of Vibration Energy Harvesting Using [001] and [011]-Poled PMN-PZT Single Crystals ([001] 및 [011] 방향 분극의 압전 단결정 PMN-PZT 를 이용한 진동 에너지 수확 특성)

  • Sun, Kyung Ho;Kim, Young-Cheol;Kim, Jae Eun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.539-543
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    • 2014
  • This work investigated the electromechanical performance of a cantilevered vibration energy harvester incorporating the single crystal PMN-PZT, manufactured with the most recent technology of solid-state single crystal growth. Single crystal PMN-PZTs with two different crystallographic axes such as [011] and [001] were considered. For the [011] orientation, because material properties such as the stiffness, piezoelectric strain coefficients are not the same in the directions normal to the crystallographic axis, the effects of the transversely anisotropy on the magnitude and frequency bandwidth of output power were also analyzed.

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Analytical solutions to piezoelectric bimorphs based on improved FSDT beam model

  • Zhou, Yan-Guo;Chen, Yun-Min;Ding, Hao-Jiang
    • Smart Structures and Systems
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    • v.1 no.3
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    • pp.309-324
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    • 2005
  • This paper presents an efficient and accurate coupled beam model for piezoelectric bimorphs based on improved first-order shear deformation theory (FSDT). The model combines the equivalent single layer approach for the mechanical displacements and a layerwise modeling for the electric potential. General electric field function is proposed to reasonably approximate the through-the-thickness distribution of the applied and induced electric potentials. Layerwise defined shear correction factor (k) accounting for nonlinear shear strain distribution is introduced into both the shear stress resultant and the electric displacement integration. Analytical solutions for free vibrations and forced response under electromechanical loads are obtained for the simply supported piezoelectric bimorphs with series or parallel arrangement, and the numerical results for various length-to-thickness ratios are compared with the exact two-dimensional piezoelasticity solution. Excellent predictions with low error estimates of local and global responses as well as the modal frequencies are observed.