STP580

    Composite Matrix Fatigue Crazing—Detection and Measurement

    Published: Jan 1975


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    Abstract

    Crazing has recently become of interest in composite materials having organic matrices, and the development of crazes has been suggested as a failure criterion in the fatigue testing of susceptible composites.

    This paper reports the results of an experiment to find a practical means of detecting and monitoring the development of crazing during fatigue testing of fiber-reinforced epoxy matrix composite materials. A specimen of such material was strain-gaged with one 2-in.-long (0.051 m) foil gage, and with thirty 2/100-in.-long (0.508 mm) gages. The apparent strain of each gage was monitored during displacement control tension-tension fatigue testing.

    The experimental results demonstrated that the maximum difference between apparent strains as measured by the small strain gages provided a sensitive means of detecting crazing. It was concluded that thirty small strain gages with appropriate instrumentation could provide a practical means of automatically detecting crazing during such fatigue tests of composite materials.

    Keywords:

    composite materials, epoxy laminates, fiberglass reinforced plastics, reinforced plastics, fiber composites, tests, mechanical tests, tension tests, fatigue (materials), fatigue tests, failure, crazing, detection, strain gages


    Author Information:

    Schwabe, JE
    Senior research engineer, Babcock & Wilcox Co., Alliance Research Center, Alliance, Ohio


    Paper ID: STP32322S

    Committee/Subcommittee: D30.07

    DOI: 10.1520/STP32322S


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