STP497: Impact Resistance of Unidirectional Fiber Composites

    Chamis, CC
    Aerospace technologists and section head, Lewis Research Center, National Aeronautics and Space Administration, Cleveland, Ohio

    Hanson, MP
    Aerospace technologists and section head, Lewis Research Center, National Aeronautics and Space Administration, Cleveland, Ohio

    Serafini, TT
    Aerospace technologists and section head, Lewis Research Center, National Aeronautics and Space Administration, Cleveland, Ohio

    Pages: 26    Published: Jan 1972


    Abstract

    Composite micromechanics and macromechanics and the miniature Izod impact test are used to investigate the impact resistance of unidirectional composites. Several composite systems are examined both theoretically and experimentally. The composites are classified theoretically with respect to their impact resistance for longitudinal, transverse, and shear modes. Experimental results are reported only for Izod impact with the fibers either parallel or transverse to the cantilever longitudinal axis. Impact resistance design criteria which evolved during this investigation are used to design hybrid composites with improved impact resistance. This is illustrated theoretically and demonstrated experimentally. The results show that in situ fiber and matrix elongation to fracture, matrix modulus, fabrication process, fiber and void volume ratios, and microresidual stresses are variables which affect the impact resistance. The ranking of composite impact resistance on the basis of measured and predicted results is in excellent agreement.

    Keywords:

    composite materials, fiber composites, fiber laminates, composite structures, epoxy resins, structural design, fractures (materials), failure, brittleness, residual stress, bonding, laminating, impact tests, impact strength, stress analysis, structural analysis


    Paper ID: STP27756S

    Committee/Subcommittee: D30.02

    DOI: 10.1520/STP27756S


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