STP888

    Miniature Center-Cracked-Tension Specimen for Fatigue Crack Growth Testing

    Published: Jan 1986


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    Abstract

    A miniature specimen was developed to characterize the effects of neutron irradiation on the fatigue crack growth behavior of candidate fusion reactor first-wall materials. During the developmental effort, questions regarding thickness, buckling, excessive plasticity, accuracy of crack length measurements, length-to-width ratio, and proximity of welds to the notch (for welded specimens) were systematically addressed. This investigation led to the miniature center-cracked-tension specimen, consisting of a notched insert (nominally 0.61 mm thick by 25.4 mm wide by 12.7 mm long) which is irradiated, and two end grips (28.6 mm long) which are welded to the insert after irradiation. Fully assembled, the specimen has dimensions which are very similar to those of the standard center-cracked-tension specimen described in ASTM Test for Constant-Load-Amplitude Fatigue Crack Growth Rates Above 10−8 m/Cycle (E 647). The specimen is used with an electrical potential technique for monitoring the crack length, miniature high-temperature fatigue crack growth rate testing machines, and a computerized data acquisition system for unattended around-the-clock testing.

    Keywords:

    fatigue (materials), crack propagation, electrical potential, specimen design, test equipment


    Author Information:

    Ermi, AM
    Westinghouse Hanford Company, Richland, WA

    James, LA
    Westinghouse Hanford Company, Richland, WA


    Paper ID: STP33009S

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP33009S


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