STP1256: Experimental Application of Methodologies to Quantify the Effect of Constraint on Jc for a 3-D Flaw Geometry

    Porr, WC
    Materials Engineer, Senior Mechanical Engineer, and Mechanical Engineering Technician, Naval Surface Warfare Center, Annapolis, MD

    Link, RE
    Materials Engineer, Senior Mechanical Engineer, and Mechanical Engineering Technician, Naval Surface Warfare Center, Annapolis, MD

    Waskey, JP
    Materials Engineer, Senior Mechanical Engineer, and Mechanical Engineering Technician, Naval Surface Warfare Center, Annapolis, MD

    Dodds, RH
    Professor, University of Illinois, Urbana, IL

    Pages: 19    Published: Jan 1995


    Abstract

    In an effort to validate methodologies to quantify the effect of crack tip constraint on cleavage fracture toughness, a series of experiments were conducted to measure the cleavage fracture toughness, Jc, of an ASTM A515 Grade 70 steel utilizing large plate bend specimens containing semi-elliptical surface cracks, SC(B), (3-D flaw geometry). Jc was estimated with modified EPRI and Turner design curve schemes from load and remote strains measured at initiation. The cleavage toughness of the A515 steel used for this testing was previously characterized using a series of through-cracked single edge notch bend specimens, SE(B), (2-D flaw geometry) with various initial crack-depth to specimen-width ratios, a/W. The toughness values estimated for the surface cracked plate specimens were consistent with the toughness ranges predicted from the SE(B) results using the two parameter fracture mechanics (J-Q) methodology to account for differences in crack tip constraint. This result indicates the applicability of small specimen, constraint adjusted, results to engineering structural integrity predictions for the case of cleavage fracture.

    Keywords:

    A515 steel, J-Integral, fracture toughness, cleavage, surface crack, crack tip constraint, toughness scaling, two parameter fracture mechanics


    Paper ID: STP16381S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP16381S


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