Progress in Superconductivity and Cryogenics (한국초전도ㆍ저온공학회논문지)

The Korean Society of Superconductivity and Cryogenics (한국초전도저온학회)
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Procedural steps for reliability evaluation of ultrasonically welded REBCO coated conductor lap-joints under low cycle fatigue test condition

  • Michael De Leon (Department of Mechanical Design Engineering, Andong National University) ;
  • Mark Angelo Diaz (Department of Mechanical Design Engineering, Andong National University) ;
  • Hyung-Seop Shin (Department of Mechanical Design Engineering, Andong National University)
  • Received : 2023.12.13
  • Accepted : 2023.12.20
  • Published : 2023.12.31
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Abstract

This study presents a comprehensive procedure for the low cycle fatigue test of ultrasonically welded (UW) coated conductor (CC) lap-joints. The entire process is examined in detail, from the robust fabrication of the UW REBCO CC joints to the reliability testing under a low number of repeated cycle fatigue conditions. A continuous Ic measurement system enables real-time monitoring of Ic variations throughout the fatigue tests. The study aims to provide a step-by-step procedure that involves joint fabrication, electromechanical property (EMP) tests under uniaxial tension for stress level determination, and subsequent low-cycle fatigue tests. The joints are fabricated using a hybrid method that combines UW with adding In-Sn soldering, achieving a flux-free hybrid welding approach (UW-HW flux-free). The selected conditions for the low cycle fatigue tests include a stress ratio of R=0.1 and a frequency of 0.02 Hz. The results reveal some insights into the fatigue behavior, irreversible changes, and cumulative damage in the CC joints.

Keywords

Acknowledgement

This work was supported by a 2023 research grant from Andong National University.

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