STP945

    Growth of Parabolic Fatigue Cracks from Flaws at Fastener Holes

    Published: Jan 1988


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    Abstract

    A crack of parabolic shape, emanating from corner and embedded flaws at a hole in a plate of finite width, was analyzed by the slice synthesis. In contrast with other crack shapes, equilibrium solutions for a parabolic crack are finite and continuous as the crack passes the bottom of the hole and starts to propagate along the rear surface. Fracture parameters derived were KI for predicting fatigue crack growth along the plate surfaces and down the bore of the hole, and GI for residual strength. The two cases studied were a flaw emanating from the corner of the hole and a flaw embedded in the side of the hole at the mid-depth, each case being either remotely loaded, or loaded at the hole. Fatigue crack curves were calculated with the aid of the derived fracture parameters, and fatigue crack curves were compared with experimental data and with calculated results obtained assuming an elliptically shaped crack. The parabolic crack analysis resulted in superior correspondence with measured data. Tables of constants for evaluating the fracture parameters are provided.

    Keywords:

    fracture mechanics, stress intensity factor, crack shape, crack propagation, open holes, lugs, aluminum alloys, fatigue crack growth, fatigue (materials)


    Author Information:

    Berkovits, A
    Associate professor, Technion-Israel Institute of Technology, Haifa,

    Prinz, D
    Department of Defense,


    Paper ID: STP23289S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP23289S


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