STP1389

    Application of the Two-Parameter J-A2 Description to Ductile Crack Growth

    Published: Jan 2000


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    Abstract

    Typical ASTM fracture testing determines the J-integral resistance (J-R) curve or fracture toughness (JIC) based on specimens with high-constraint geometry such as those specified in ASTM E 1737-96. A three-term asymptotic solution with two parameters, J and A2 (a constraint parameter), has been developed for characterizing the constraint effect of various geometries. The present paper extends the J-A2 characterization of a stationary crack tip to the regime of stable crack growth. Similar to the concept of J-controlled crack growth, theJ-A2 description can be approximately used to characterize ductile crack growth under certain amount of crack extension. The region ofJ-A2controlled crack growth is much larger than that controlled by theJ-integral alone. From the relationships between A2 and the test data, JIC, and tearing modulus, TR, the coefficients used to define a J-R curve can be determined. for non-standard specimens or actual structures, once the constraint parameter A2 is determined, the J-R curves appropriate for these geometries can then be obtained. A procedure of transferring J-R curves determined from the standard ASTM procedure to non-standard specimens or flawed structures is outlined in the paper.

    Keywords:

    constraint effect, fracture toughness, tearing modulus, J-R, curve, J-A, 2, asymptotic solution, J, -controlled crack growth


    Author Information:

    Chao, YJ
    Department of Mechanical Engineering, University of South Carolina, Columbia, SC

    Zhu, XK
    Department of Mechanical Engineering, University of South Carolina, Columbia, SC

    Lam, P-S
    Westinghouse Savannah River Company, Aiken, SC

    Louthan, MR
    Westinghouse Savannah River Company, Aiken, SC

    Iyer, NC
    Westinghouse Savannah River Company, Aiken, SC


    Paper ID: STP14800S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP14800S


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