STP1220: The Effect of Crack Deflection and Surface Roughness on Constant and Variable Amplitude Loading Fatigue Crack Growth in Aluminum-Lithium Alloys

    Hull, A
    Research Engineer, Engineering Material Research, Downsview, Ontario

    Raizenne, D
    Research Officer, Institute for Aerospace Research, National Research Council, Ottawa,

    Pages: 16    Published: Jan 1995


    Abstract

    Aluminum-Lithium 2090-T8E41 and 8090-T8771 constant and variable amplitude fatigue crack growth rates were compared with an Aluminum-Copper 2024-T341. Specimen compliance data for inclined cracks up to 30 degrees were found to be similar. Compliance derived stress intensity expressions were developed for out-of-plane crack extension. Crack path deflection was explained by crystallographic cracking in textured plates. Variable amplitude loading significantly reduced crack path deflection. Closure mechanisms of plasticity and surface roughness were studied.

    Keywords:

    Aluminum-Lithium alloy, fatigue crack branching, roughness induced closure, texture, FALSTAFF


    Paper ID: STP14612S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP14612S


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