STP937: Interlaminar Fracture Toughness and Real-Time Fracture Mechanism of Some Toughened Graphite/Epoxy Composites

    Hibbs, MF
    Research assistant and professor, Texas A&M University, College Station, TX

    Tse, MK
    Senior research engineer, The Dow Chemical Company, Resins Research, Freeport, TX

    Bradley, WL
    Research assistant and professor, Texas A&M University, College Station, TX

    Pages: 16    Published: Jan 1987


    Abstract

    Five graphite/epoxy composites containing toughened epoxies prepared at Dow Chemical and AS-4 graphite fibers from Hercules have been studied in Mode I, mixed mode, and Mode II to determine their delamination fracture toughnesses Gc and the controlling micromechanism of fracture. The Gc values were determined using split laminate specimens. The delamination fracture process was observed in real time in the scanning electron microscope. To increase delamination fracture toughness, both an improved interface as well as higher resin toughness were found to be required. Increasing Mode II loading, particularly of the more brittle systems, gives a significantly greater resistance to crack propagation as measured by the total energy release rate required to propagate the crack.

    Keywords:

    composite material, delamination, mixed mode, Mode I, graphite/epoxy, toughened, in situ fracture


    Paper ID: STP24374S

    Committee/Subcommittee: D30.06

    DOI: 10.1520/STP24374S


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