Delamination Strengths of Different Types of REBCO-Coated Conductors and Method for Reducing Radial Thermal Stresses of Impregnated REBCO Pancake Coils

Miyazaki, Hiroshi; Iwai, Sadanori; Tosaka, Taizo; Tasaki, Kenji; Ishii, Yusuke

doi:10.1109/tasc.2014.2372048

Cited by 39 publications

(17 citation statements)

References 19 publications

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“…Operating DUDA assemblies at lower temperatures will offer considerably increased currents and magnetic fields. Magnetic fields comparable to experiments with trapped fields in stacks of 2G-HTS [6] seem to be achievable.…”

Section: Discussionmentioning

confidence: 64%

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New coil configurations with 2G-HTS and benefits for applications

Arndt

Holzäpfel

Noë

et al. 2021

Supercond. Sci. Technol.

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A scalable concept to prepare high current density windings with high-temperature superconducting material is introduced. The concept covers miniaturized high-current windings and large coils for applications in energy technology as well. The principle is based on a circular disk-up-down-assembly ('DUDA') and extended to rectangular coils. First measurements on the assemblies (≈40 turns) in liquid nitrogen are presented as a proof-of-concept. Centre fields of ≈40 mT and ≈340 mT are measured during steady operation and pulsed operation respectively. Operating the assemblies at lower temperatures will strongly increase the current and field performance. Lowering the contact resistance might lead to further improvements. Due to the homogenous structure in the radial direction, shear stresses are minimized and large winding heights can be realized in principle. The DUDA concept of coil windings can be used to build even more sophisticated magnetic arrangements, e.g. Halbach-arrays, or complex windings for new stator configurations of rotating machines. The optional miniaturization offers compact and powerful magnets, e.g. for accelerators too.

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Section: Discussionmentioning

confidence: 64%

“…Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. the sequence of different materials and CTE's in the radial direction [5,6]. To handle these stresses, a homogeneous architecture in the radial direction would be highly beneficial when building magnets.…”

Section: Introductionmentioning

confidence: 99%

New coil configurations with 2G-HTS and benefits for applications

Arndt

Holzäpfel

Noë

et al. 2021

Supercond. Sci. Technol.

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“…During operation, Lorentz forces distribution in such thick windings will also lead to large radial tensile stress. The solution proposed in [2] is to use non-stick material to separate the turns in several blocks in radial direction, or even separate all turns from each other. It was used successfully in recent magnets wound by Toshiba for HLFSM (High Field Laboratory for Superconducting Materials), where the insulation between turns is a co-wound thin polyimide tape with fluorine non-stick coating [3,4,5].…”

Section: Introductionmentioning

confidence: 99%

A High Performance Insulated REBCO Pancake With Conductive Cooling Capability

Vialle

Badel

Takahashi

et al. 2023

IEEE Trans. Appl. Supercond.

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REBCO Coated Conductors have high tensile strength along their length. They are however sensitive to delamination when traction force is applied on the tape surface, which in a pancake winding corresponds to radial tensile stress. For this reason, most REBCO magnets are dry-wound (not impregnated). One of the drawbacks of dry winding is that conduction cooling to low temperature (below 20 K) would be inefficient. Edge impregnation structures were developed to mitigate this problem but retaining a soft non-stick insulating layer in between the turn. In this paper, we propose an improved pancake structure with the benefits of edgeimpregnation but using Hastelloy tape with thin insulation coating to reinforce the winding. The mechanical behavior of such structure is first estimated then validated with high current tests under large background magnetic field. The insulation performance is then tested by rapid ramping and fast discharge.

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“…Despite the different adopted fabrication techniques that have been used, these CCs have multilayered structures because of the intrinsic brittle nature of superconducting ceramic, which makes it possible to subject the CCs to some deformation while carrying high currents. However, in practical utilization, thermal stress [5,6] and Lorentz forces [4,7], as major stress sources exerted on CCs in the transverse direction lead to critical current (I c ) degradation, these have been found in either epoxy impregnated coils during cooling [8] or paraffin impregnated coils after charging in a strong back magnetic field [9]. Results indicate that the layers between the Ag layer and the substrate layer delaminate and break, which then cause I c degradation.…”

Section: Introductionmentioning

confidence: 99%

A standardized measurement method and data analysis for the delamination strengths of YBCO coated conductors

Zhang

Sun

Liu

et al. 2020

Supercond. Sci. Technol.

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Of crucial importance for the application of high temperature superconducting coated conductors (CCs) is the delamination strength due to thermal stress and Lorentz force during their operation. This paper reports the mechanical delamination strengths of YBCO CCs at room temperature and 77 K, as well as the electro-mechanical delamination strength form a modified anvil tensile method. Compared to previous measurement setups, our anvil device only has one degree of freedom of transverse tension. Moreover, we use a vertical soldering technique to ensure the data reliability. Since we eliminate the influence of the measurement method on the experimental results, a naturally discrete property of the delamination strength is obtained. To describe these experimental data, a three-parameter Weibull distribution function has been suggested and a new criterion for determining delamination strength is proposed from the reliability function, which can be conveniently referred to for engineering design.

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Delamination Strengths of Different Types of REBCO-Coated Conductors and Method for Reducing Radial Thermal Stresses of Impregnated REBCO Pancake Coils

Cited by 39 publications

References 19 publications

New coil configurations with 2G-HTS and benefits for applications

New coil configurations with 2G-HTS and benefits for applications

A High Performance Insulated REBCO Pancake With Conductive Cooling Capability

A standardized measurement method and data analysis for the delamination strengths of YBCO coated conductors

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