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Extension and Extrapolation of J-R Curves and Their Application to the Low Upper Shelf Toughness Issue

Technical Report ·
DOI:https://doi.org/10.2172/5876140· OSTI ID:5876140
 [1];  [2]
  1. US Naval Academy, Annapolis, MD (United States)
  2. David Taylor Research Center, Annapolis, MD (United States)
This document develops methods of measuring experimentally the limits of valid fracture mechanics data that can be obtained from small fracture mechanics specimens. The proposed technique generally shows that present ASTM limits are overly conservative and the new technique would allow almost a three fold increase in the amount of crack extension allowed in the testing of a surveillance specimen. Analytic relationships are then developed to allow use of the new experimentally measured limit to J controlled crack growth for design or failure analysis applications to pressure vessel structures. The new region of J controlled crack growth is shown to correlate best with the omega criterion which defines limits on both the maximum J level and the maximum crack extension allowable for a particular specimen size and material toughness combination. The final section looks at the problem of extrapolation of J-R curve data when needed for a structure fracture analysis. Several forms of extrapolation relationships are compared from the point of view of accurate and conservative extrapolation, particularly from the standpoint of tearing instability analysis of a growing, ductile crack on the material upper shelf.
Research Organization:
US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering; US Naval Academy, Annapolis, MD (United States); David Taylor Research Center, Annapolis, MD (United States)
Sponsoring Organization:
USNRC
OSTI ID:
5876140
Report Number(s):
NUREG/CR--5577; ON: TI91009862
Country of Publication:
United States
Language:
English