Simulation on the relation of distribution of overall critical transport current to that of local one in bent-damaged Bi2223 superconducting composite tape

Ochiai, Shojiro; Fujimoto, Masahiro; Okuda, Hiroshi; Oh, Seungtae; Ha, Dong-Woo

doi:10.1063/1.3087782

Cited by 18 publications

(21 citation statements)

References 36 publications

(29 reference statements)

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“…)Ba 2 Cu 3 O 7¹¤ coated conductors (hereafter noted as REBCO conductors) are attractive for applications such as power cables, fault current limiters and current leads. 13) In fabrication and service, they are subjected to thermal, mechanical and electromagnetic stresses. When the superconducting layer is cracked by such stresses, the critical current I c is reduced (YBCO, 4,5) DyBCO, 69) SmBCO, 10,11) GdBCO 12) ).…”

Section: Introductionmentioning

confidence: 99%

Tape Length-Dependence of Critical Current and n-Value in Coated Conductor with a Local Crack

2014

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Tape length-dependence of voltagecurrent curve, critical current and n-value in a coated conductor with a local crack were studied by modeling analysis. In calculation, the specimen length was varied in the range of 1.5 to 18 cm where the influence of cracking of superconducting layer is sharply reflected in the voltagecurrent curve. The following results were obtained, which can be utilized for analysis and interpretation of the experimental results under applied tensile stress in laboratory scale of specimen length. The existence of a crack changed the critical current and n-value through the decrease in current-transportable cross-sectional area of the superconducting layer and the current shunting in the cracked cross-section for any specimen length and any crack size, while the extent of the change was dependent on specimen length and crack size. When the crack was large, critical current increased slightly and n-value decreased significantly with increasing specimen length due to the enhanced shunting current. On the other hand, when the crack was small, critical current increased slightly with specimen length due to the enhanced shunting current similarly to the case of large crack, but n-value decreased with increasing specimen length due to the enhanced shunting current but then it increased due to the enhanced voltage-development at higher voltage in the non-cracked part. Also, the features of the dependence of the relation of n-value to critical current on specimen length were revealed; the decrease in n-value with decreasing critical current became sharper for longer specimen.

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Section: Introductionmentioning

confidence: 99%

Tape Length-Dependence of Critical Current and n-Value in Coated Conductor with a Local Crack

2014

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“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Under no applied strain, the critical current is different from specimen to specimen and from position to position within a specimen. [18][19][20][21][22][23][24] Under applied strain, the damage evolution behavior is also different from specimen to specimen and from position to position within a specimen, resulting in wider distribution of critical current.…”

Section: Distribution Of Normalized Critical Current Of Bent Multifilmentioning

confidence: 98%

“…[18][19][20][21][22][23][24] Under applied strain, the damage evolution behavior is also different from specimen to specimen and from position to position within a specimen, resulting in wider distribution of critical current. [12][13][14][15][16][17] It is necessary to find a suitable function for describing the critical current distribution of the bend-damaged specimens. The first aim of the present work is to find a suitable function and to account for its validity from a physical viewpoint.…”

Section: Distribution Of Normalized Critical Current Of Bent Multifilmentioning

confidence: 99%

Distribution of normalized critical current of bent multifilamentary Bi2223 composite tape

Ochiai

Fujimoto

Shin

et al. 2009

Journal of Applied Physics

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The distribution of the normalized critical transport current (critical current normalized with respect to the original value) of Bi2223/Ag/Ag alloy composite tape under bending strain of 0%–0.833% was studied experimentally and analytically. The experimental results were analyzed by a modeling approach based on the relation of the heterogeneous damage evolution to the distribution of the critical current. The main results are summarized as follows. (1) The measured distribution of the critical current values varying with bending strain was described well by the present approach. (2) When all specimens were damaged at high bending strains (0.338%–0.833% in the present work), the distribution of the critical current of the bent-damaged specimens was expressed by the three-parameter Weibull distribution function, the reason for which was revealed. (3) The distribution of the irreversible strain was estimated, with which the influence of the increase in the fraction of damaged specimens on the variation of critical current distribution in the low bending strain range (0%–0.35%) was elucidated.

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“…This behavior could be attributed to the filaments buckling on the compression side and damage on the tension side. 5,7,9) Feature (1) is visible as the difference in the shape of the V-I curves on the logarithmic scale in Fig. 2.…”

Section: Introductionmentioning

confidence: 99%

“…The values of critical current (I c ) were obtained with an electric field criterion of E c = 1 µV/cm, corresponding to V c = E c L = 1 µV in this case, and the n-values were obtained as the n-index in V £ I n for the electric field range of E = 0.110 µV/cm, corresponding to the voltage range of V = 0.110 µV. The n-value given by @ ln(V )/@ ln(I ) refers to the slope of the V-I curve in the voltage range of V = 0.1 The data for Sample A under tensile stress 1) and bending strain 5) and those of Sample B under tensile stress 6) and bending strain 7) were taken from our previous work. + Graduate Student, Kyoto University Materials Transactions, Vol.…”

Section: Introductionmentioning

confidence: 99%

Relation between n-Value and Critical Current in Filamentary and Coated Superconducting Tapes with Tensile Stress-Induced Cracks

et al. 2015

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We have determined experimentally that the n-value of tension-damaged bismuth strontium calcium copper oxide (BSCCO, Bi2223) filamentary superconducting tape decreases very sharply with decreasing critical current, compared with bending-damaged tape. In this work, the sharp decrease in the n-value associated with decreasing critical current under applied tensile stress/strain was studied with a current shunting model that assumes cracks in filamentary and coated superconductors. In a filamentary conductor containing collective filament cracks, defined as cracks composed of successively cracked filaments in a transverse cross-section, the decrease in the cross-sectional area of the superconducting current transportable-filaments reduces the critical current, and the shunting current at the crack reduces the n-value. In addition, the decrease in the electrical resistance in the current shunting circuit increases the critical current slightly and decreases the n-value sharply. The experimentally measured relationship between the n-value and the critical current for two BSCCO samples from different manufacturers was described by the upper and lower bounds calculated with the current shunting circuit resistance as a variable. The experimentally measured relationship between the n-value and the critical current for two different coated conductors were described in a similar manner.

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Simulation on the relation of distribution of overall critical transport current to that of local one in bent-damaged Bi2223 superconducting composite tape

Abstract: Residual and fracture strains of Bi2223 filaments and their relation to critical current under applied bending and tensile strains in Bi 2223 ∕ Ag ∕ Ag alloy composite superconductor

Cited by 18 publications

References 36 publications

Tape Length-Dependence of Critical Current and <i>n</i>-Value in Coated Conductor with a Local Crack

Tape Length-Dependence of Critical Current and <i>n</i>-Value in Coated Conductor with a Local Crack

Distribution of normalized critical current of bent multifilamentary Bi2223 composite tape

Relation between <i>n</i>-Value and Critical Current in Filamentary and Coated Superconducting Tapes with Tensile Stress-Induced Cracks

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