STP743: A More Basic Approach to the Analysis of Multiple-Specimen R-Curves for Determination of Jc

    Carlson, KW
    Advanced engineer and senior engineer, Westinghouse Handford Co., Richland, Wash.

    Williams, JA
    Advanced engineer and senior engineer, Westinghouse Handford Co., Richland, Wash.

    Pages: 22    Published: Jan 1981


    Abstract

    Multiple specimen J-R curves were developed for groups of 25.4-mm-thick (1T) compact specimens with different a/W values and depth of side grooving. The purpose of this investigation was to determine Jc (J at the onset of crack extension) for each group. Judicious selection of points on the load versus load-line deflection record at which to unload and heat-tint specimens permitted direct observation of approximate onset of crack extension. It was found that the present recommended procedure for determining Jc from multiple-specimen R-curves, which is being considered for standardization, consistently yielded nonconservative Jc-values. A more basic approach to analyzing multiple-specimen R-curves is presented, applied, and discussed. This analysis determined Jc-values that closely corresponded to actual observed onset of crack extension.

    Keywords:

    J-integral, J, Ic, Jc, J-R curve, ductile fracture toughness, crack initiation, crack extension, crack-opening stretch, multiple-specimen R-curve


    Paper ID: STP28815S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP28815S


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