COD Concepts in R-Curve Testing

  • D. E. McCabe
Conference paper


This report records the information that has been developed over many years of research on the effort to express the R-curve behavior of materials in a crack opening displacement (COD) format. In earlier tests, hinge rotation points were determined empirically and COD was inferred at the updated physical crack tip location (δt at ao+∆ap). Specimen geometry effects not seen in JR-Curve or KR-Curve representations had shown up at displacement levels of appreciable plastic deformation. The more recent suggestion of a COD measurement at the initial fatigue crack tip location has been shown to correlate well with modified J, and JM R-Curves. The commonality was demonstrated for a variety of cases where plane stress R-Curves were shown to be geometry independent, and where unique circumstances altered the basic geometry independent nature of R-Curve.


Plastic Hinge Crack Opening Displacement Stable Crack Growth Compact Specimen Hinge Point 
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Copyright information

© Springer-Verlag Berlin, Heidelberg 1986

Authors and Affiliations

  • D. E. McCabe
    • 1
  1. 1.Westinghouse R&DPittsburghUSA

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