STP466

    Dynamic Tear Energy—A Practical Performance Criterion for Fracture Resistance

    Published: Jan 1970


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    Abstract

    The dynamic tear (DT) method of testing for fracture toughness is described. Design of specimens, impact test machines, and methods for energy measurement are presented. The relationship between DT energy and KIc values is presented for steel, and procedures for translating the energy values to design parameters such as critical flaw size and stress level are outlined.

    The current need for the use of the DT test in the development and selection of high-strength structural metals is illustrated by examples of conditions where the Cv test can be shown to be inadequate. Fracture toughness criteria defined by Cv and DT tests are compared for a high-strength titanium alloy, a 180-ksi yield strength steel, a 140-ksi yield strength steel weld metal, and a quenched and tempered 2¼ Cr-1 Mo steel of 90 ksi yield strength. In all of these examples the Cv test is shown to provide information in variance to that from the DT, DWT-NDT, and Robertson tests. It is concluded that the DT test method has desirable features for general industrial use, and it can provide broad-scope characterization of the fracture resistance of steels, titanium alloys, and aluminum alloys.

    Keywords:

    impact tests, fracture tests, toughness, performance evaluation, metals, tests


    Author Information:

    Lange, EA
    Head, Structural Metals Criteria Section, and research mechanical engineer, Naval Research Laboratory, Washington, D.C.,

    Loss, FJ
    Head, Structural Metals Criteria Section, and research mechanical engineer, Naval Research Laboratory, Washington, D.C.,


    Paper ID: STP32065S

    Committee/Subcommittee: E08.04

    DOI: 10.1520/STP32065S


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