STP1220: Experimental and Analytical Studies of Crack Initiation and Arrest in Hot Pressed Silicon Nitride

    Gorelik, M
    Research associate and professor, University of Illinois at Chicago, Chicago, IL

    Calomino, AM
    Materials research engineer, Fatigue and Fracture Branch, NASA Lewis Research Center, Cleveland, OH

    Chudnovsky, A
    Research associate and professor, University of Illinois at Chicago, Chicago, IL

    Pages: 15    Published: Jan 1995


    Abstract

    A recently developed experimental procedure enables stable crack growth in high modulus material. Significant scatter of critical parameters such as critical crack length, energy release rates at crack initiation and crack arrest, length of dynamic crack increments has been observed in a hot pressed silicon nitride. There is a consistent difference in the values of the energy release rates at crack arrest and initiation. Fractographic studies suggest existence of the process zone in the subcritical crack growth region. A new statistical model is proposed. It is based on Statistical Fracture Mechanics approach combined with the Monte Carlo technique. The model provides the means to explain all essential features of fracture behavior. A computer simulation of the fracture process is performed. Good agreement between statistics of observed and simulated critical fracture parameters has been achieved.

    Keywords:

    silicon nitride, brittle fracture, stochastic, subcritical crack growth, process zone, Monte Carlo method, scatter


    Paper ID: STP14586S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP14586S


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