STP748

    Random Spectrum Fatigue Crack Life Predictions With or Without Considering Load Interactions

    Published: Jan 1981


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    Abstract

    The validity of using constant amplitude crack growth rate data for the prediction of fatigue crack growth behavior and lives of center-cracked tension (CCT) specimens under random spectrum loadings was assessed. Analytical predictions obtained from the EFFGRO computer program were the results from two different approaches. One approach did not account for the load interaction effects to the fatigue crack growth, while the other approach considered both the tensile overload retardation and the compressive load acceleration effects as well as the reduction of overload retardation effect caused by the compressive load immediately following the tensile overload. This paper describes the fatigue crack growth rate equation, the load interaction model, the numerical procedure, and the cycle counting technique used in the EFFGRO program. Results from other studies, including the sensitivity of the overload shut-off ratio, the crack growth rate constants determination procedure, and the range-pair counting effects to the prediction accuracies, are also presented.

    Keywords:

    random spectrum loading, CCT specimen, 2219-T851 aluminum, fatigue crack life, load interaction effect, retardation, acceleration, life prediction


    Author Information:

    Chang, JB
    Program manager and technical staffs, North American Aircraft Division, Rockwell International Corporation, Los Angeles, Calif.

    Szamossi, M
    Program manager and technical staffs, North American Aircraft Division, Rockwell International Corporation, Los Angeles, Calif.

    Liu, K-W
    Program manager and technical staffs, North American Aircraft Division, Rockwell International Corporation, Los Angeles, Calif.


    Paper ID: STP28337S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP28337S


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