Fracture Toughness by Small Punch Testing

    Volume 23, Issue 1 (January 1995)

    ISSN: 0090-3973

    CODEN: JTEOAD

    Page Count: 8


    Foulds, JR
    Managing engineer, managing engineer, and senior engineer, Failure Analysis Associates, Inc., Menlo Park, CA

    Woytowitz, PJ
    Principal engineer, Engineering Mechanics Technology, Inc., San Jose, CA

    Parnell, TK
    Managing engineer, managing engineer, and senior engineer, Failure Analysis Associates, Inc., Menlo Park, CA

    Jewett, CW
    Managing engineer, managing engineer, and senior engineer, Failure Analysis Associates, Inc., Menlo Park, CA

    (Received 10 March 1994; accepted 27 June 1994)

    Abstract

    The small punch test, currently being used to empirically estimate the material fracture appearance transition temperature (FATT) of a range of components in fossil power plant service, has been further developed for direct estimation of KIc and JIc in a manner that is analytical, material-independent, and requires no prior knowledge of material mechanical properties. The procedure follows an approach that is based on the continuum material toughness concept wherein the criterion for fracture is defined and measured via the continuum stress-strain deformation properties of the material. The procedure specifically involves computing the “local” strain energy density accumulated at the location and time of crack initiation in the small punch test specimen using large-strain finite element (FE) analysis. Since the procedure also includes estimation of the material uniaxial tensile stress-strain behavior from the small punch load-displacement curve, both the fracture toughness and the uniaxial tensile behavior are determined from a single test. The procedure has been developed in order to take advantage of the miniature sample removal techniques that can be applied “nondestructively” to operating components. Results are presented on a range of steels.


    Paper ID: JTE10392J

    DOI: 10.1520/JTE10392J

    ASTM International is a member of CrossRef.

    Author
    Title Fracture Toughness by Small Punch Testing
    Symposium , 0000-00-00
    Committee E08