STP1003

    Elastic-Plastic Stress Concentrations Around Crack-like Notches in Continuous Fiber Reinforced Metal Matrix Composites

    Published: Jan 1989


      Format Pages Price  
    PDF (328K) 15 $25   ADD TO CART
    Complete Source PDF (6.6M) 15 $59   ADD TO CART


    Abstract

    Continuous fiber silicon-carbide/aluminum composite laminates with slits were tested statically to failure. Five different layups were examined: [0]8, [02/±45]s, [0/90]2s, [0/±45/90]s, and [±45]2s. Either a 9.5- or a 19-mm slit was machined in the center of each specimen. The strain distribution ahead of the slit tip was found experimentally with a series of strain gages bonded ahead of the slit tip. A three-dimensional finite-element program (PAFAC) was used to predict the strain distribution ahead of the slit tip for several layups. For all layups, except the [0]8, the yielding of the metal matrix caused the fiber stress concentration factor to increase with increasing load. This is contrary to the behavior seen in homogeneous materials where yielding causes the stress concentration to drop. For the [0]8 laminate, yielding of the matrix caused a decrease in the fiber stress concentration. The finite-element analysis predicted these trends correctly.

    Keywords:

    metal matrix composites, yielding, stress concentrations, three-dimensional finite-element analysis, silicon-carbide fibers, aluminum matrix


    Author Information:

    Johnson, WS
    Senior research engineer and research engineer, NASA Langley Research Center, Hampton, VA

    Bigelow, CA
    Senior research engineer and research engineer, NASA Langley Research Center, Hampton, VA


    Paper ID: STP10031S

    Committee/Subcommittee: D30.07

    DOI: 10.1520/STP10031S


    CrossRef ASTM International is a member of CrossRef.