STP700: On the Equivalence Between Semi-Empirical Fracture Analyses and R-Curves

    Orange, TW
    Research engineer, National Aeronautics and Space Administration-Lewis Research Center, Cleveland, Ohio

    Pages: 22    Published: Jan 1980


    This paper examines the relationship between several semi-empirical fracture analyses (SEFA) and the R-curve concept of fracture mechanics. The conditions for equivalence between a SEFA and an R-curve are derived. A hypothetical (imaginary) material is employed to study the relationship analytically. Equivalent R-curves (ERC) are developed for real materials using data from the literature.

    For each SEFA there is an ERC whose magnitude and shape are determined by the SEFA formulation and its empirical parameters. If the R-curve is indeed unique, then the various empirical parameters cannot be constant, and vice versa. However, for one SEFA the differences are small enough that they may be within the range of normal data scatter for real materials.


    fracture properties, crack growth, resistance curves, residual strength, semiempirical analyses, crack propagation, fractures (materials)

    Paper ID: STP36987S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP36987S

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