STP1131

    Application of the Weight-Functions Method to Three-Dimensional Cracks Under General Stress Gradients

    Published: Jan 1992


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    Abstract

    Recent advances in the weight-functions method have led to its application in determining stress-intensity factors (K) for corner and surface cracks. A major obstacle in accurately computing weight functions is that it not only requires the crack surface opening displacement (CSOD) fields, but also their rate of change with respect to the crack dimensions. In the present work, an approach similar to the two-dimensional Petroski and Achenbach method is developed and applied to determine the CSOD profiles as a function of threedimensional crack dimensions. Near-crack-tip details as well as crack-mouth opening displace-ment (CMOD) were considered along with the Newman and Raju K-solutions for finite geometry three-dimensional problems of elliptical corner, surface, and subsurface (embedded) cracks. The weight functions determined from a uniform stress loading were then applied to compute K solutions for general stress gradients. Comparison of the obtained results with the Newman and Raju bending stress K solutions have shown excellent agreements even for quite deep corner and surface flaws. Corner cracks at circular holes were also used to verify the method.

    Keywords:

    weight functions, stress-intensity factors, elliptical corner, surface and subsurface cracks, general stress gradients, crack surface, crack mouth opening displacement fields, fracture mechanics, fatigue (materials)


    Author Information:

    Malik, SN
    engineersenior materials engineer, Life Methods Development, General Electric Company, Aircraft EnginesU.S. Nuclear Regulatory Commission, CincinnatiWashington, OHDC


    Paper ID: STP23699S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP23699S


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