Volume 15, Issue 2 (June 1993)

    Mechanical Properties of Triaxially Braided Composites: Experimental and Analytical Results


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    This paper investigates the unnotched tensile properties of two-dimensional (2-D) triaxial braid-reinforced composites from both an experimental and an analytical viewpoint. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. Specimens were cut from resin transfer molded composite panels made from each briad. There were considerable differences in the observed elastic constants from different size strain gage and extensometer readings. Larger strain gages gave more consistent results and correlated better with the extensometer readings. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0°, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations.

    The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement, but none adequately matched the experimental results for all the braids.

    Author Information:

    Pastore, CM
    Assistant professor, North Carolina State University, Raleigh, NC

    Masters, JE
    Staff engineer, Lockheed Engineering and Science, NASA Langley Research Center, Hampton, VA

    Foye, RL
    Adjunct professor, North Carolina A&T State University, Greensboro, NC

    Gowayed, YA
    Assistant professor, Auburn University, Auburn, AL

    Stock #: CTR10362J

    ISSN: 0884-6804

    DOI: 10.1520/CTR10362J

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    Title Mechanical Properties of Triaxially Braided Composites: Experimental and Analytical Results
    Symposium , 0000-00-00
    Committee D30