STP536: Influence of Sheet Thickness upon the Fracture Resistance of Structural Aluminum Alloys

    Sullivan, A. M.
    Metallurgist, Naval Research Laboratory, Washington, D. C.

    Stoop, J.
    Metallurgist, Naval Research Laboratory, Washington, D. C.

    Freed, C. N.
    Head, Naval Research LaboratoryEnvironmental Protection Agency, WashingtonWashington, D. C.D.C.

    Pages: 11    Published: Jan 1973


    Abstract

    Definition of fracture resistance for thin sheet material in terms of the linear-elastic fracture mechanics (LEFM) plane-stress parameter, Kc, continues to reveal aspects of its geometrical dependency. The effect of sheet thickness upon the Kc value of five structural aluminum alloys in current use has been determined over available thickness ranges of 1/32 to 1/4 in. Within this range, less thickness dependence than anticipated has been observed. The fact that both economy and convenience would be served if fracture resistance for all sheet thicknesses could be estimated from a limited number of specimens have given impetus to several models purporting to explain this dependency in terms of the relative contributions of a surface phenomenon, flat fracture, and a volume sensitive mechanism, shear lip development. Attempts to fit present data to the model disclose inadequacies for which there is no apparent immediate solution.

    Keywords:

    fracture properties, mechanical properties, stresses, aluminum alloys, failure, parameters, fatigue tests, crack propagation


    Paper ID: STP49649S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP49649S


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