De-Lamination Characteristics of Coated Conductor for Conduction Cooled HTS Coil

Jeong, Hwanjun; Park, Heecheol; Kim, Seokho; Park, Minwon; Yu, In-Keun; Lee, Sang-Jin; Park, Taejun; Sim, Kideok; Ha, Hong-Soo; Oh, Sang-Su; Moon, Seung‐Hyun

doi:10.1109/tasc.2011.2182331

Cited by 20 publications

(4 citation statements)

References 8 publications

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“…In the long term the manufacturers of CCs may succeed in developing tapes with improved bonding between the layers, but alternative techniques dealing with the impregnation process of the commercial tapes presently available have already been reported. For example, in order to avoid the thermal stress at the edge of the conductor, Hwanjun Jeong et al [89] suggested reducing the width of the RE123 layer of 30% with respect to the tape width, but this is applicable only to tape which are not slitted after deposition. In general delamination may best be avoided by reducing the adhesion between impregnating material and tape.…”

Section: Coil Impregnationmentioning

confidence: 99%

Progresses and challenges in the development of high-field solenoidal magnets based on RE123 coated conductors

Senatore

Alessandrini

Lucarelli

et al. 2014

Supercond. Sci. Technol.

247

136

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Recent progresses in the second generation REBa 2 Cu 3 O 7 − x (RE123) coated conductor (CC) have paved a way for the development of superconducting solenoids capable of generating fields well above 23.5 T, i.e. the limit of NbTi−Nb 3 Sn-based magnets. However, the RE123 magnet still poses several fundamental and engineering challenges. In this work we review the state-ofthe-art of conductor and magnet technologies. The goal is to illustrate a close synergetic relationship between evolution of high-field magnets and advancement in superconductor technology. The paper is organized in three parts: (1) the basics of RE123 CC fabrication technique, including latest developments to improve conductor performance and production throughput; (2) critical issues and innovative design concepts for the RE123-based magnet; and (3) an overview of noteworthy ongoing magnet projects.

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Section: Coil Impregnationmentioning

confidence: 99%

Progresses and challenges in the development of high-field solenoidal magnets based on RE123 coated conductors

Senatore

Alessandrini

Lucarelli

et al. 2014

Supercond. Sci. Technol.

247

136

View full text Add to dashboard Cite

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“…Thus, the parameter value k of 1.82 is adopted in this paper [34]. The transverse tensile test of the REBCO CC shows that the average mechanical delamination strength is about 10 MPa to 80 MPa [9,31,55,56]. Thus, the parameters are adopted as λ = 10 MPa, σ f n0 = 15 MPa and M = 23 MPa in the simulation.…”

Section: Weibull Distribution Of Interface Adhesion Strengthmentioning

confidence: 99%

“…First, we verify the effectiveness of the CZM used in the paper by the experimental data of the transverse REBCO CC delamination experiment. Figure 6(a) shows the simulation model based on the delamination experimental of REBCO CC from the reference paper [56]. And for validating the effect of the symmetry model on delamination behaviors simulation, we adopted the 1/4 REBCO CC model.…”

Section: Model Validationmentioning

confidence: 99%

3D numerical investigation on delamination behavior of the epoxy impregnated REBCO pancake coil

Shen,

Chen,

Peng

et al. 2023

Supercond. Sci. Technol.

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Superconducting coils made of Rare-Earth-Barium-Copper-Oxide (REBCO) coated conductor (CC) exhibit superior electromagnetic performance. Employing epoxy impregnation can improve the structural integrity and mechanical property of the superconducting coils. However, due to the extreme work environment and weak adhesion strength of REBCO CC, the delamination induced by radial thermal stress and electromagnetic force significantly affects the electromagnetic property and the reliability of the superconducting coil. This study proposes a three-dimensional (3D) thermal-electromagnetic mechanical delamination model that incorporates the cohesive zone model (CZM) to investigate the delamination mechanisms in epoxy impregnated REBCO pancake coils during the cooling and coil operation processes. The simulation employs a three-parameter Weibull distribution to account for the inhomogeneity of transverse tensile strength in the CCs. The delamination behavior and mechanisms of the coils under different conditions are analyzed. The simulation results show that the model considering random adhesion strength proves to be more effective in representing the delamination behavior of the coil. And large tensile radial stresses caused by thermal stresses and electromagnetic forces lead to the delamination behavior of the coil during cooling and operation. The main reason for the tensile radial stress is the mismatch in the thermal contraction among components of the coils during cooling process. Furthermore, we investigate the influence of the thermal expansion coefficient (CTE) and thickness of the mandrel, the CTE and prestress of the overband and the initial localized damage. The results indicate that these factors significantly affect the tensile radial stress and the extent of delamination in the windings. And the extent and distribution of delamination is related to the stress release caused by delamination to a certain degree.

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“…A key challenge is that, in certain configurations, they are vulnerable to delamination between the different tape layers, due to thermal and magnetic forces experienced during magnet operation [11][12][13]. REBCO tapes exhibit exceptional axial strength and can withstand up to 700 MPa of stress [14] in that orientation, however when put under a transverse tension, the tape can delaminate under 10-20 MPa of stress [15,16].…”

Section: Introductionmentioning

confidence: 99%

Characterization of edge damage induced on REBCO superconducting tape by mechanical slitting

et al. 2021

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Rare-earth barium-copper-oxide (REBCO) superconductors are high-field superconductors fabricated in a tape geometry that can be utilized in magnet applications well in excess of 20 T. Due to the multilayer architecture of the tape, delamination is one cause of mechanical failure in REBCO tapes. During a mechanical slitting step in the manufacturing process, edge cracks can be introduced into the tape. These cracks are thought to be potential initiation sites for crack propagation in the tapes when subjected to stresses in the fabrication and operation of magnet systems. We sought to understand which layers were the mechanically weakest by locating the crack initiation layer and identifying the geometrical conditions of the slitter that promoted or suppressed crack formation. The described cracking was investigated by selectively etching and characterizing each layer with scanning electron microscopy, laser confocal microscopy, and digital image analysis. Our analysis showed that the average crack lengths in the REBCO, LaMnO3 (LMO) and Al2O3 layers were 34 μm, 28 μm, and 15 μm, respectively. The total number of cracks measured in 30 mm of wire length was between 3000 and 5700 depending on the layer and their crack densities were 102 cracks mm−1 for REBCO, 108 cracks mm−1 for LMO, and 183 cracks mm−1 for Al2O3. These results indicated that there are separate crack initiation mechanisms for the REBCO and the LMO layers, as detailed in the paper. With a better understanding of the crack growth behavior exhibited by REBCO tapes, the fabrication process can be improved to provide a more mechanically stable and cost-effective superconductor.

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De-Lamination Characteristics of Coated Conductor for Conduction Cooled HTS Coil

Cited by 20 publications

References 8 publications

Progresses and challenges in the development of high-field solenoidal magnets based on RE123 coated conductors

Progresses and challenges in the development of high-field solenoidal magnets based on RE123 coated conductors

3D numerical investigation on delamination behavior of the epoxy impregnated REBCO pancake coil

Characterization of edge damage induced on REBCO superconducting tape by mechanical slitting

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