STP590

    Effect of Stress Ratio and Overload Ratio on Fatigue Crack Delay and Arrest Behavior Due to Single Peak Overloads

    Published: Jan 1976


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    Abstract

    In this investigation stress interaction effects on fatigue crack propagation following single peak overloads in 2024-T3 aluminum alloy were studied. The two parameters investigated were the overload stress ratio, ROL=Kmin/KOL, and the overload ratio, KOL/Kmax. Tests were run with quasi-constant stress intensity fatigue loading following the overload. The effect of overload on the crack growth rate through the overload plastic zone was observed. Additional tests were run to determine only whether or not crack arrest would occur. The delay effect due to single peak overloads was found to increase with overload stress ratio, ROL, and overload ratio, KOL/Kmax. The higher values of both ROL and KOL/Kmax produced nonpropagating fatigue cracks, and the delay/arrest boundary was defined.

    Keywords:

    crack propagation, fatigue tests, aluminum alloys, stresses, residual stress, stress ratio, loads (forces)


    Author Information:

    Himmelein, MK
    Mechanical design engineer, Aluminum Company of America, Pittsburgh, Pa.

    Hillberry, BM
    Professor, School of Mechanical Engineering, Purdue University, West Lafayette, Ind.


    Paper ID: STP33954S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP33954S


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