A Simplified Approach for Modeling Fatigue of Unidirectional Ceramic Matrix Composites

    Volume 18, Issue 3 (July 1996)

    ISSN: 0884-6804

    CODEN: CTROAD

    Page Count: 12


    Robertson, DD
    Department head and assistant professor, Air Force Institute of Technology, OH

    Solti, JP
    Former AFIT Ph.D. student, United States Air Force Academy, CO

    Mall, S
    Department head and assistant professor, Air Force Institute of Technology, OH

    Abstract

    An analytical methodology is developed to model the response of unidirectional ceramic matrix composites (CMCs) under monotonic and fatigue loadings at room temperature. The analysis is presented as a first step toward analyzing the fatigue behavior of CMCs at elevated temperatures. The laminate is modeled using a modified shear-lag analyses in which the microstructural damage is estimated using simple damage criteria. Moreover, the damage mechanisms considered in this study are matrix cracking, fiber/matrix interfacial debonding and slip, fiber fracture, and fiber pullout. A simple criterion for estimating the average matrix crack density is developed and compared with classical fracture mechanics techniques. Additionally, a formulation for modeling the fatigue response of ceramic composites including stress-strain hysteresis and strain ratchetting is presented. The stress-strain response under monotonic tensile loading, and the fatigue life (S-N relationship) and stress-strain hysteresis under cyclic loading obtained from the present analytical methodology are compared with their experimental counterparts. They are in good agreement with one another.


    Paper ID: CTR10528J

    DOI: 10.1520/CTR10528J

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    Author
    Title A Simplified Approach for Modeling Fatigue of Unidirectional Ceramic Matrix Composites
    Symposium , 0000-00-00
    Committee D30