Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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MEAN LOAD EFFECT ON FATIGUE OF WELDED JOINTS USING STRUCTURAL STRESS AND FRACTURE MECHANICS APPROACH

  • Kim, Jong-Sung (Korea Power Engineering Company) ;
  • Kim, Cheol (Korea Power Engineering Company) ;
  • Jin, Tae-Eun (Korea Power Engineering Company) ;
  • Dong, P. (Center for Welded Structures Research, Battelle Memorial Institute)
  • Published : 2006.04.01
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Abstract

In order to ensure the structural integrity of nuclear welded structures during design life, the fatigue life has to be evaluated by fatigue analysis procedures presented in technical codes such as ASME B&PV Code Section III. However, existing fatigue analysis procedures do not explicitly consider the presence of welded joints. A new fatigue analysis procedure based on a structural stress/fracture mechanics approach has been recently developed in order to reduce conservatism by erasing uncertainty in the analysis procedure. A recent review of fatigue crack growth data under various mean loading conditions using the structural stress/fracture mechanics approach, does not consider the mean loading effect, revealed some significant discrepancies in fatigue crack growth curves according to the mean loading conditions. In this paper, we propose the use of the stress intensity factor range ${\Delta}K$ characterized with loading ratio R effects in terms of the structural stress. We demonstrate the effectiveness in characterizing fatigue crack growth and S-N behavior using the well-known data. It was identified that the S-N data under high mean loading could be consolidated in a master S-N curve for welded joints.

Keywords

References

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