STP1114

    Development of Eta Factors in Elastic-Plastic Fracture Testing Using a Load Separation Technique

    Published: Jan 1991


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    Abstract

    A method for experimentally determining the eta (η) factor based on separation constants has been recently proposed. This method has two important implications for elastic plastic fracture toughness testing. First, the method can be used to determine the η factors for any new test specimen geometry which might be added to existing test standards. Such specimens as disk compact, arc bend, and arc tension are used in the KIc test standard. They can be added to the J based standards if the specimen calibrations are known, one being the η factor calibration. In this paper a step by step procedure is given describing η factor calibration for an arbitrary specimen geometry based on a series of blunt notched specimens.

    The procedure proposed in this paper was then applied to existing blunt notch data for the traditional test specimen geometries, the compact, and single edge notched bend specimens. The results of the study show different values for η from these in the existing standards both in magnitude and trend with a/W. In addition they show a slight material sensitivity. The consequences of having incorrect η factors in the test standards are explored in a sensitivity study. These results are used to evaluate the importance of having correct η factors and recommendations are made.

    Keywords:

    ductile fracture, eta factor, load separation, blunt notch testing, standard test method, J, -integral


    Author Information:

    Sharobeam, MH
    Graduate assistant, professor, and research associateprofessor, University of TennesseeNational University of Mar Del Plata, Knoxville, TN

    Landes, JD
    Graduate assistant, professor, and research associateprofessor, University of TennesseeNational University of Mar Del Plata, Knoxville, TN

    Herrera, R
    Graduate assistant, professor, and research associateprofessor, University of TennesseeNational University of Mar Del Plata, Knoxville, TN


    Paper ID: STP16850S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP16850S


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