http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Bautista, Zhierwinjay Mezona,Shin, Hyung-Seop Institute of Electrical and Electronics Engineers 2019 IEEE transactions on applied superconductivity Vol.29 No.5
<P>Delamination frequently occurs as a result of high transverse tensile stresses caused by fabrication and mechanical and thermal cycles during operation. It is generally known that transverse opening and peeling off are the primary delamination failure modes, and delamination strength is typically evaluated using anvil or peel tests. To avoid transverse openings that cause delamination failures in coated conductor (CC) tapes, the tape structure can be changed by developing or adding the fabrication process. Thus, in most studies, delamination strength has been characterized in REBCO CC tapes with Cu-edges and the slit-side one. In this study, the delamination strengths of 12-mm-wide CC tapes without a slit edge and a 4-mm-wide CC tapes without Cu-edges were experimentally measured under transverse tensile loading at 77 K. Results were compared to those obtained during the mechanical delamination of CC tapes with Cu edges. The delamination morphologies were also observed macroscopically.</P>
Bautista, Zhierwinjay,Shin, Hyung-Seop,Mean, Byoung Jean,Lee, Jae-Hun The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.4
The mechanical properties of REBCO coated conductor (CC) wires under uniaxial tension are largely determined by the thick component layers in the architecture, namely, the substrate and the stabilizer or even the reinforcement layer. Depending on device applications of the CC tapes, it is necessary to reinforce thin metallic foils externally to one-side or both sides of the CC tapes. Due to the external reinforcement of brass foils, it was found that this could increase the reversible strain limit from the Cu-stabilized CC tapes. In this study, the effects of differently hardened brass foil laminate on the electromechanical property of CC tapes were investigated under uniaxial tension loading. The tensile strain dependence of the critical current ($I_c$) was measured at 77 K and self-field. Depending on whether the $I_c$ of CC tapes were measured during loading or after unloading, a reversible strain (or stress) limit could be determined, respectively. The both-sides of the Cu-stabilized CC tapes were laminated with brass foils with different hardness, namely 1/4H, 1H and EH. From the obtained results, it showed that the yield strength of the brass laminated CC tapes with EH brass foil laminate was comparable to the one of the Cu-stabilized CC tape due to its large yield strength even though its large volume fraction. It was found that the brass foil with different hardness was mainly sensitive on the stress dependence of $I_c$, but not on the strain sensitivity due to the residual strain induced in the laminated CC tapes during unloading.
Bautista, Zhierwinjay M.,Shin, Hyung-Seop,Lee, Jae-Hun,Lee, Hunju,Moon, Seung-Hyun The Korea Institute of Applied Superconductivity a 2016 한국초전도저온공학회논문지 Vol.18 No.3
The enhancement of mechanical properties of coated conductor (CC) tapes in practical application are usually achieved by reinforcing through lamination or electroplating metal layers on either sides of the CC tape. Mechanical or electromechanical properties of the CC tapes have been largely affected by the lamination structure under various loading modes such as tension, bending or even cyclic. In this study, the influence of brass laminate volume fraction on electromechanical properties of RCE-DR processed Gadolinium-barium-copper-oxide (GdBCO) CC tapes was investigated. The samples used were composed of single-side and both-side laminate of brass layer to the Cu-stabilized CC tape and their $I_c$ behaviors were compared to those of the Cu-stabilized CC tape without external lamination. The stress/strain dependences of $I_c$ in laminated CC tapes under uniaxial tension were analyzed and the irreversible stress/strain limits were determined. As a result, the increase of brass laminate volume fraction initially increased the irreversible strain limit and became gradual. The corresponding irreversible stress limit, however, showed no difference even though the brass laminate volume fraction increased to 3.4. But the irreversible load limit linearly increased with the brass laminate volume fraction.
Bautista, Zhierwinjay,Diaz, Mark Angelo,Shin, Hyung-Seop,Lee, Jae-Hun The Korean Society of Superconductivity and Cryoge 2018 한국초전도저온공학회논문지 Vol.20 No.4
In this study, the electromechanical properties in Sn-Cu double layer stabilized GdBCO coated conductor (CC) tapes with and without external lamination under uniaxial tension were examined at 77 K and self-field. Their irreversible stress and strain limits were determined using a loading-unloading scheme based on different critical current ($I_c$) recovery criteria. The repeated tests were performed and statistical estimation was done to check the reproducibility depending on the criterion adopted in evaluating the electromechanical properties. From the results, it showed that the Sn-Cu double-layer stabilized CC tapes have the higher irreversible stress limit, but lower irreversible strain limit as compared to brass laminated ones. Through the repeated tests, it can be found that a small scattering of irreversible limits existed in both CC tape samples. Finally, similar strain sensitivity of $I_c$ in both CC tapes was obtained.
Zhierwinjay Bautista,Mark Angelo Diaz,신형섭,이재훈 한국초전도.저온공학회 2018 한국초전도저온공학회논문지 Vol.20 No.4
In this study, the electromechanical properties in Sn-Cu double layer stabilized GdBCO coated conductor (CC) tapes with and without external lamination under uniaxial tension were examined at 77 K and self-field. Their irreversible stress and strain limits were determined using a loading-unloading scheme based on different critical current (Ic) recovery criteria. The repeated tests were performed and statistical estimation was done to check the reproducibility depending on the criterion adopted in evaluating the electromechanical properties. From the results, it showed that the Sn-Cu double-layer stabilized CC tapes have the higher irreversible stress limit, but lower irreversible strain limit as compared to brass laminated ones. Through the repeated tests, it can be found that a small scattering of irreversible limits existed in both CC tape samples. Finally, similar strain sensitivity of Ic in both CC tapes was obtained.
Bautista, Zhierwinjay,Diaz, Mark Angelo,Shin, Hyung-Seop,Lee, Jae-Hun,Oguro, Hidetoshi,Awaji, Satoshi Institute of Electrical and Electronics Engineers 2018 IEEE transactions on applied superconductivity Vol.28 No.3
<P>Transport properties of coated conductor tapes can be affected by stress and strain induced during fabrication, cool-down, and operation. Therefore, it is important to understand the strain/stress dependence of the critical current of the coated conductor tapes in the reversible region under magnetic field considering practical applications such as magnets and coils. In this paper, the strain characteristics of critical current, <I>I</I><SUB>c </SUB>, in high temperature superconducting (HTS)-coated conductor tapes fabricated using reactive co-evaporation by deposition and reaction reinforced with brass-foil laminate were investigated under external magnetic field at various cryogenic temperatures while applying uniaxial tension. Results show that <I>I</I><SUB>c</SUB> dependences on magnetic field and temperature were similar between brass-laminated coated conductor and Cu-stabilized tape. The irreversible strain limit and the irreversible stress limit of brass-laminated coated conductor tape increased as temperature decreased from 77 to 20 K. This behavior resulted from thermal hardening of the coated conductor tape at low temperature.</P>
Gorospe, Alking,Bautista, Zhierwinjay,Shin, Hyung-Seop IOP 2016 Superconductor science & technology Vol.29 No.10
<P>Coated conductor (CC) tapes utilized in high-current-density superconducting cables are commonly subjected to different loading modes, primarily torsion and tension especially in the case of twisted stacked-tape cable. Torsion load can occur due to twisting along the length or when winding the CC tapes around a former, while tension load can occur due to pre-tension when coiled and as a hoop stress when the coil is energized. In this study, electromechanical properties of single CC tapes under torsion load were investigated using a new test apparatus. The results could provide basic information for cable designers to fully characterize stacked cables. Copper-electroplated and brass-laminated CC tapes fabricated with different deposition techniques were subjected to pure torsion and combined tension-torsion loading. The critical current, <I>I</I> <SUB>c</SUB> degradation behaviours of CC tapes under torsional deformation were examined. Also, the effect of further external lamination on the <I>I</I> <SUB>c</SUB> degradation behaviour of the CC tapes under such loading conditions was investigated. In the case of the combined tension-torsion test, short samples were subjected to twist pitches of 200 mm and 100 mm. Critical parameters including reversible axial stress and strain in such twist pitch conditions were also investigated.</P>
Gorospe, Alking,Bautista, Zhierwinjay,Hyung-Seop Shin,Oguro, Hidetoshi,Awaji, Satoshi IEEE 2017 IEEE transactions on applied superconductivity Vol.27 No.4
<P>Superior mechanical and electromechanical properties of the coated conductor (CC) tapes made them a viable option for coil and magnet applications. In this study, investigation on the characteristics of I<SUB>c</SUB> under different B, T, and ε conditions were conducted. Tensile load was applied using the Katagiri type test rig under different high magnetic field and low-temperature conditions wherein irreversible strain, ε<SUB>irr</SUB> was determined. The I<SUB>c</SUB> behavior with magnetic field of both reactive co-evaporation by deposition and reaction (RCE-DR) and metal organic chemical vapor deposition (MOCVD) processed CC tapes at different T and B were obtained. The critical irreversible strain limit ε<SUB>irr</SUB> of Cu-stabilized REBCO CC tape increased with decreasing temperature from 65 K down to 20 K. This behavior was resulted from the increased yield strength of the CC tape due to thermal hardening effect.</P>