A Wide Range Stress Intensity Factor Expression for the C-Shaped Specimen

    Volume 8, Issue 6 (November 1980)

    ISSN: 0090-3973

    CODEN: JTEOAD

    Page Count: 4


    Kapp, JA
    Mechanical engineer and materials engineerMembers of ASTM, U.S. Army Armament Research and Development Command, Benet Weapons Laboratory, Watervliet, N.Y.

    Newman, JC
    Research engineerMember of ASTM, NASA Langley Research Center, Hampton, Va.

    Underwood, JH
    Mechanical engineer and materials engineerMembers of ASTM, U.S. Army Armament Research and Development Command, Benet Weapons Laboratory, Watervliet, N.Y.

    Abstract

    A new expression has been developed to calculate the stress intensity factor K for the C-shaped specimen over a wider range of specimen parameters, namely, crack depth to width ratio a/W, load eccentricity X/W, and radii ratio r1/r2, than had previously been available. The rationale for the expression was to use known K solutions for short and deep cracks to develop a nondimensional form of K. This nondimensional form of K approaches the correct limiting values as a/W goes to both zero and one. Numerical K results from previous work were then nondimensionalized to this form and the dependence of K on a/W was determined by multivariable linear regression. The final expression agrees with the numerical K solutions within ±1.0% for 0.45 ≤ a/W ≤ 0.55 for all r1/r2 and X/W of either 0 or 0.5; within ±1.5% for 0.2 ≤ a/W ≤ 1 for all r1/r2 and X/W equal to 0 or 0.5; and within ±3% for 0.2 ≤ a/W ≤ 1 for all r1/r2 and 0 ≤ X/W ≤ 1. The accuracy of this expression will allow expanded use of the C-shaped specimen for crack growth resistance curve determination and fatigue crack growth rate testing.


    Paper ID: JTE10631J

    DOI: 10.1520/JTE10631J

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    Author
    Title A Wide Range Stress Intensity Factor Expression for the C-Shaped Specimen
    Symposium , 0000-00-00
    Committee E08