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Evaluation of Mechanical Property and Fatigue Damage in A Practical Superconducting Cable for Magnet

초전도 마그네트용 실용 초전도 복합선재의 기계적 특성 및 피로손상 평가에 관한 연구

  • Published : 2000.03.01

Abstract

In order to investigate how the fatigue damage effects on the critical properties of superconductor, a fatigue test at room temperature and an Ic measurement test at 4.2K were carried out in this study, respectively, using a 9 strand Cu-Ni/NbTi/Cu composite cable. Through the fatigue test of a 9 strand Cu-NUNbTi/Cu composite cable, a conventional S-N curve was plotted even though there was a possibility of fretting among strands. It was found that the maximum stress corresponding to the inflection point on the S-N curve obtained was nearly the same value as the yielding strength of cable obtained from the static tensile test. However, the effect of cabling in multi-strands superconducting cable on the fatigue strength was not noticeable. The critical current(Ic) measurement was carried out at 4.2K in a NbTi strand out of the fatigued cable. It showed a degradation of lc at high stress amplitude regions over 380NTa, and the degradation became significant as the applied stress amplitude increased

Keywords

Superconducting Cable;NbTi Composite Wire;Mechanical Property;S-N Curve;Fatigue Damage;Critical Current

References

  1. Flukiger R., Drost E. and Speaking W., 1984, J. Appl. Phys., Vol. 504. p. 2869
  2. 福本將彦, 1986, 超傳導線材에 있어서 應力/變形率 效果와 安定性, 大板大學博士學位論文
  3. 박종철, 이규원, 류강식, 오상수, 권영길, 1997, 'Cu/Nb- Ti 초전도체의 임계전류 측정에 관한 연구,' 국립기술품질원보고서
  4. Iwasaki N., Hojo M., Ochiai S., et al, 1996, 'Fatigue Fracture Mechanisms and Superconducting Property of Nb-Ti Super- conducting Composite Wire,' Proc. of JSME MMD No. 96-1 pp. 677-678
  5. Taya M. and Arsenault R. J., 1989, 'Metal Matrix Composites,' Pergamon Press
  6. Hitotsuyanagi H., 1978, 'Stress Effects in Superconducting Nb-Ti Wires,' Cryogenic Engineering, Japan, Vol. 13, No. 3 pp. 114-129
  7. 이경수, 1998, 'KSTAR 과제:차세대 정상상태 초전도 Tokamak 실험,' 1998년도한국초전도저온 공학회 연차총회 및 국제심포지엄논문집, pp. 35-43
  8. Easton D. S. and Koch C. C, 1978, 'Mechanical Properties of Superconducting NbTi composites,' Advances in Cryogenic Engng., Vol. 24 pp. 453-462
  9. 신형섭, Katagiri K., 이해무, 1995,'극저온에서 실용 초전도 복합선재의 인장특성평가,' 대한기계학회 1995년도 추계학술대회 논문집(I) pp. 752-756
  10. Ekin J. W., 1978, 'Fatigue and Stress Effects in NbTi and Nb3Sn Multifilamentary Superconductors,' Advances in Cryogenic Engng., Vol. 24, K. D. Timmerhaus, R. P. Reed and A. F. Clark, eds., Plenum Press, New York, pp. 306-316
  11. For example; ASTM STP 1159, 1993, 'Standardization of Fretting Fatigue Test Methods and Equipment,' M. H. Attia and R. B. Waterhouse edited, Pliladelphia
  12. 박종철, 이규원, 홍계원, 이호진, 1996, '초전도 관련 표준의 현황과 대책연구,' 국립기술품질원 보고서
  13. 김상현, 1999, '한국에서의 초전도재료 및 전자소자 연구,' 초전도와 저온공학, 제l권, pp. 10-17