STP593: Threeui-Dimensional Solution for a Through-Thickness Crack with Crack Tip Damage in a Cross-Plied Laminate

    Wang, SS
    Research associates and professor, Massachusetts Institute of Technology, Cambridge, Mass.

    Mandell, JF
    Research associates and professor, Massachusetts Institute of Technology, Cambridge, Mass.

    McGarry, FJ
    Research associates and professor, Massachusetts Institute of Technology, Cambridge, Mass.

    Pages: 25    Published: Jan 1975


    Abstract

    A three-dimensional finite-element solution is given for the stress field of a 0/90 laminate containing a sharp through-thickness edge crack with crack tip damage consisting of subcracks parallel to the fibers of each ply. The solution is compared to that for a sharp crack with no subcracks given in an associated paper, and the introduction of the subcracks is shown to significantly alter the stress field. Outside of a core zone at the main crack tip, the two stress distributions are nearly identical. Inside of the core zone, the subcracks serve to relax the in-plane stresses in a manner similar to the action of a plastic zone in a metal; the mechanisms of stress transfer around the subcracks are identified. The results also indicate that the fundamental fracture mechanics concept of a zone of relaxed stresses near the main crack tip, surrounded by an undisturbed singular stress field, is preserved, and that the subcracks cause no shift in the singular stress field which would require a crack length correction.

    Keywords:

    fracture properties, composite materials, stress concentration, finite elements, stresses, crack propagation


    Paper ID: STP34792S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP34792S


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