Fatigue Life Estimation of ITER Conduits at 4 K

Part of the Advances in Cryogenic Engineering book series (ACRE, volume 44)


ITER superconducting magnets are designed to operate at 4 K under cyclic loading. The conduits of the magnets (e.g., central solenoid) are designed to support all the cyclic loads during operation. It is expected that fatigue fracture is the major failure mechanism for the conduits. In the present study, the fatigue life of the conduits for ITER and the model coil has been estimated by applying numerical integration of the Paris equation to a surface crack. The fatigue crack growth behavior of a 3D crack is analyzed. Discussion is given to three key factors of a 3D crack: crack type, crack aspect ratio, and the eccentricity of an embedded crack. It is found that the estimated fatigue life of the conduits for ITER or the model coil is acceptable based on the current ITER design criteria. In a thin plate, there is a linear-log relationship between the fatigue life and applied stress at given initial crack size. Either a surface or corner crack shows a shorter life than most embedded cracks. The fatigue life decreases as the crack eccentricity increases.


Fatigue Life Linear Elastic Fracture Mechanic Initial Crack Crack Depth Fatigue Crack Growth Behavior 
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  1. 1.
    ITER Superconducting Coils and Structures Division, “ITER Design Criteria, DDD 1.1, Appendix C,” N11DDD1996–11–21 W0. 1, Naka Joint Work Site, Naka (1996).Google Scholar
  2. 2.
    S. Suresh, “Fatigue of Materials,” Cambridge University Press, New York (1991).Google Scholar
  3. 3.
    K. Walker, The effect of stress ratio during crock propagation and fatigue for 2024-T3 and 7075-T6 aluminum, in: “Effects of Environment and Complex Load History on Fatigue Life,” ASTM STP 462 (1970), p. 1.Google Scholar
  4. 4.
    L.S. Toma, M.M. Steeves and R.P. Reed, “Incoloy Alloy 908 Data Handbook,” PFC/RR-94–2, PFC, MIT, Cambridge (1994).CrossRefGoogle Scholar
  5. 5.
    C.H. Jang and I.S. Hwang et al., Development of high toughness weld for Incoloy Alloy 908, in: “Advances in Cryogenic Engineering (Materials),” Vol. 40B (1994), p. 1323.Google Scholar
  6. 6.
    J. Feng and M.M. Steeves, “CS Model Coil, Fracture Mechanics Analysis of Incotoy Alloy 908 Conduits,” PFC/RR-95–4, PFC, MIT (1995).Google Scholar
  7. 7.
    A. Alekseev and Yu. Spirchenko, TF coil case fatigue life studies with CS hybrid, Tech report, MTM-13-R-4, RF home team, Efremov Scientific Research Institute, NAKA (1997).Google Scholar
  8. 8.
    J. Feng, Fatigue crack growth behavior and life estimation of an eccentrically embedded crack, Tech Report, PSFC, MIT, Cambridge (1997).Google Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • J. Feng
    • 1
  1. 1.Plasma Science and Fusion CenterMassachusetts Institute of TechnologyCambridgeUSA

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