STP995V1

    Fatigue Crack-Tip Mechanics in 7075-T6 Aluminum Alloy from High-Sensitivity Displacement Field Measurements

    Published: Jan 1988


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    Abstract

    The fatigue crack-tip deformation in the 7075-T6 aluminum alloy has been studied by moiré interferometry, which is a coherent optics technique for full-field in-plane displacement measurements in the submicrometre range. For constant-amplitude-loading conditions the local strain distributions and the crack-tip plasticity have been correlated with theoretical descriptions and models. The effects of a 60% overload on crack propagation has been investigated in terms of flaw profiles and the effective stress-intensity factor. Cyclic plasticity was originally found to depend qualitatively on crack length as much as on the overload-affected growth rate. The implications on crack closure of the moiré results are also discussed.

    Keywords:

    fatigue, crack propagation, fracture mechanics, overload effects, crack closure, stress-intensity factor, material plasticity, aluminum alloy, coherent optics, moiré interferometry, nonlinear fracture mechanics


    Author Information:

    Nicoletto, G
    Researcher/lecturer, University of,


    Paper ID: STP26786S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP26786S


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