STP1330: An Approach to Include Interfacial Wear Effects in Modeling Fatigue Crack Growth of Titanium Matrix Composites

    Ward, GT
    Senior project engineerresearch assistant, Allison Engine CompanySchool of Mechanical Engineering, Purdue University, IndianapolisWest Lafayette, ININ

    Hillberry, BM
    Professor, School of Mechanical Engineering, Purdue University, West Lafayette, IN

    Pages: 21    Published: Jan 1998


    Abstract

    An approach has been developed that includes the effects of interfacial wear on the fiber-bridging behavior of titanium matrix composites during fatigue crack propagation. This approach uses a Coulomb friction-based fiber-bridging model in which the effect of fiber surface roughness on the clamping stress between the fiber and matrix is included. A previously developed wear model has been incorporated into this bridging model as a means to determine the reduction of the fiber surface roughness amplitude during fatigue cycling. As the roughness decreases, its contribution to the clamping stress also decreases, resulting in a lower interfacial shear stress. In order to include this effect in model fatigue crack growth rates, the combined Coulomb friction and wear models have been applied to a discrete composite model formulation. Crack growth predictions were then performed using a single set of input parameters by allowing the fiber surface roughness to decrease due to wear over a discrete increment of fatigue crack geometry based on bridging conditions determined by the composite model. These predictions correlated very well with experimental results for different loading conditions, especially those at relatively high crack growth rates.

    Keywords:

    titanium matrix composites, silicon-carbide fibers, fiber bridging, wear, fiber/ matrix interface, fatigue crack growth


    Paper ID: STP13266S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP13266S


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