STP1156

    Effect of Interleaves on the Damage Mechanisms and Residual Strength of Notched Composite Laminates Subjected to Axial Fatigue Loading

    Published: Jan 1993


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    Abstract

    The effect of interleaving on the fatigue damage mechanisms and residual tensile strength of two graphite/epoxy material systems subjected to cyclic axial loads is investigated. The two materials, AS4/985 and AS4/1808, have stacking sequences of [0/45/90/-45]s2 and [0/-45/90/45]s4, respectively. All specimens have centrally located through-holes. The 16-ply specimens are subjected to tensile fatigue loads, while the 32-ply specimens are subjected to fully reversed fatigue loads. Interleaving these laminates at every interface with a thin (on the order of 10% of the ply thickness), tough, thermoplastic film results in an expected increase in mass and decrease in laminate stiffness, but also in higher virgin tensile strengths, lower normalized residual tensile strengths, and slightly altered damage patterns and rates of damage growth in both laminate types. The presence of the interleaves alters the baseline virgin tensile load-to-failure and damage patterns to a greater extent in the 1808 material than in the 985 material.

    Keywords:

    composite material, fatigue, notch, damage, residual strength, toughness, interleaf


    Author Information:

    Swain, RE
    Graduate research associateSenior research engineer, Virginia Polytechnic Institute and State UniversitySmith & Nephew Richards Inc., BlacksburgMemphis, VATN

    Bakis, CE
    Assistant professor, Penn State University, University Park, PA

    Reifsnider, KL
    professor, Virginia Polytechnic Institute and State University, Blacksburg, VA


    Paper ID: STP24750S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP24750S


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