The Micromechanics of Ambient Temperature Cyclic Fatigue Loading in a Composite of CAS Glass Ceramic Reinforced with Nicalon Fibers

    Volume 16, Issue 2 (April 1994)

    ISSN: 0884-6804

    CODEN: CTROAD

    Page Count: 12


    Rousseau, CQ
    Bell Helicopter/Textron Inc., Ft. Worth, TX

    Davidson, DL
    Southwest Research Institute, San Antonio, TX

    Campbell, JB
    Southwest Research Institute, San Antonio, TX

    Abstract

    The behavior of a Nicalon fiber reinforced glass ceramic composite cyclicly loaded has been evaluated at ambient temperature using high-resolution micromechanical test methods. On this basis, the events leading to fracture have been found to be similar to those accompanying fracture in unidirectional tension tests. Matrix strains were determined locally at the point of matrix fracture. Crack opening displacements (CODs) were measured as a function of loading cycles, and fiber strains were determined, in some cases. It is concluded that debonding of fibers begins at the point of matrix cracking and rapidly increases. Most of the cyclic lifetime of the material is spent with fibers debonded over large distances (fractions of a millimeter); these fibers are pulled out of the matrix on each loading cycle. Final debond length, as determined by fractography, is a function of the number of cycles to fracture, and of the applied stress level.


    Paper ID: CTR10401J

    DOI: 10.1520/CTR10401J

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    Author
    Title The Micromechanics of Ambient Temperature Cyclic Fatigue Loading in a Composite of CAS Glass Ceramic Reinforced with Nicalon Fibers
    Symposium , 0000-00-00
    Committee D30