STP460: The Role of Bond Strength in the Fracture of Advanced Filament Reinforced Composites

    Gatti, A.
    Metallurgist, General Electric Co., Philadelphia, Pa.

    Mullin, J. V.
    Material scientist, General Electric Co., Philadelphia, Pa.

    Berry, J. M.
    Mechanical metallurgist, General Electric Co., Philadelphia, Pa.

    Pages: 10    Published: Jan 1969


    Abstract

    A great number of studies have been made to establish the longitudinal strength characteristics of composites, with success being measured in many instances by the degree to which “rule of mixtures” predictions have been attained. Several investigators report good agreement for modulus and tensile strength in metallic filament reinforced composites. Agreement for strength predictions is less frequent in systems using continuous and discontinuous nonmetallic filament arrays. This lack of ability to predict strength of uniaxially reinforced specimens points up the need for further research on the factors contributing to premature and sometimes catastrophic failure of filament reinforced specimens. As a result of using single and multiple filament specimens of boron in epoxy novolac, methods for localizing the damage resulting from individual filament fractures were developed. Optimization of the bonding mechanism is one area of research which has yielded some very interesting results. Contrary to the concept that bond strength should be as high as possible, these studies show that, although a good bond is essential to the reinforcing mechanism, too high a bond strength may render the composite severely matrix limited. Further, it has been demonstrated in this work that varying the nature of the bond surface can be most effective in isolating the sudden energy release at a filament fracture.

    Keywords:

    fiber composites, boron, epoxy laminates, fracture properties, bonding strength, tests, evaluation


    Paper ID: STP49843S

    Committee/Subcommittee: D30.04

    DOI: 10.1520/STP49843S


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