STP1156: Meso-lndentation Testing of Composite Materials as a Tool for Measuring Interfacial Quality

    Lesko, JJ
    Graduate research assistant, research scientist, associate professor, and Alexander Giacco professor, Material Response GroupVirginia Polytechnic Institute and State University, Blacksburg, VA

    Carman, GP
    Graduate research assistant, research scientist, associate professor, and Alexander Giacco professor, Material Response GroupVirginia Polytechnic Institute and State University, Blacksburg, VA

    Dillard, DA
    Graduate research assistant, research scientist, associate professor, and Alexander Giacco professor, Material Response GroupVirginia Polytechnic Institute and State University, Blacksburg, VA

    Reifsnider, KL
    Graduate research assistant, research scientist, associate professor, and Alexander Giacco professor, Material Response GroupVirginia Polytechnic Institute and State University, Blacksburg, VA

    Pages: 18    Published: Jan 1993


    Abstract

    A unique application of indentation testing to composite materials is presented. The primary goal is to evaluate the sensitivity of conventional penetration techniques to fiber-matrix bond strength in laminated composites. The Vickers fixed-load hardness test and the continuous ball indentation test (CBIT) are employed for the penetration of continuous fiber-reinforced epoxy systems. These indentations are performed in the axial (fiber) direction of laminated unidirectional composites. Both techniques demonstrate significant sensitivity to fiber-matrix adhesion in graphite/epoxy systems which possess a systematic variation to their interfacial characteristics. The CBIT displayed the best opportunity for making quantitative measurements of interfacial strength. An innovative micromechanics model of the composite contact by a spherical indenter predicts trends and failure phenomena observed in the tests. Experimental and analytical results suggest that the ball penetration test is sensitive to the shearing characteristics of the composite. Preliminary results also reveal interrelationships between composite strength properties and hardness values.

    Keywords:

    Vickers hardness, continuous ball indentation testing, composite hardness testing, meso-indentation of composites, interfacial shear strength, interfacial adhesion assessment


    Paper ID: STP24742S

    Committee/Subcommittee: D30.05

    DOI: 10.1520/STP24742S


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