Volume 9, Issue 1 (January 1981)

    Chevron V-Notched Bend Specimen for KIc Measurement of Brittle Materials

    CODEN: JTEOAD

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    Abstract

    A chevron V-notched bend specimen is proposed for plane-strain fracture toughness KIc testing of brittle materials. This specimen has the following distinctive advantages over more conventional toughness specimens: (1) the simple geometry can easily be machined, (2) no fatigue precracking is required, (3) no crack length measurements are required (KIc can be calculated from knowledge of the peak load alone), and (4) the test can easily be conducted at elevated temperatures. The proposed specimen was calibrated with a 7079-T6 aluminum alloy of known fracture toughness. Subsequently, the fracture toughness of the ceramic material Pyroceram® 9606 was determined with the same specimen design. The reproducibility of KIc values was found to be excellent: 2.64 MPa·m1/2 ± 3% (2.39 ksi·in.1/2 ± 3%). The proposed specimen design is also recommended as an inexpensive toughness screening test for other structural materials. The chevron V-notch crack starter used in the bend bar specimen is also recommended for use in other specimen designs to improve the capability for both fatigue and stress corrosion threshold testing. In view of the tremendous cost- and time-saving potential associated with the chevron V-notch design, it is recommended that a detailed finite element analysis be performed on this configuration to further substantiate the applied stress and stress intensity conditions.


    Author Information:

    Shih, TT
    Senior engineerMember of ASTM, Westinghouse R & D Center, Pittsburgh, Pa.


    Stock #: JTE10647J

    ISSN: 0090-3973

    DOI: 10.1520/JTE10647J

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    Author
    Title Chevron V-Notched Bend Specimen for KIc Measurement of Brittle Materials
    Symposium , 0000-00-00
    Committee E08