STP969: Ductile Crack Bifurcation and Arrest in Pressurized Pipe

    Kobayashi, AS
    Professors, University of Washington, Seattle, WA

    Emery, AF
    Professors, University of Washington, Seattle, WA

    Love, WJ
    Professors, University of Washington, Seattle, WA

    Chao, Y-H
    Graduate students, University of Washington, Seattle, WA

    Johansson, O
    Graduate students, University of Washington, Seattle, WA

    Pages: 25    Published: Jan 1988


    Abstract

    This paper presents selected results on ductile crack propagation, curving and branching, and crack arrest from ten dynamic pipe rupture tests. Strain gage results adjacent to the crack path showed that a Dugdale-Barenblatt strip yield zone, of the order of eight pipe diameters in length, preceded the propagating crack tip and that the maximum principal strain direction changed from the hoop to the axial direction approximately 6 to 8 pipe diameters downstream of the crack tip. This change in principal strain direction constitutes the sufficiency condition for crack curving or branching prior to crack arrest in the absence of a crack arrester. The necessary condition for crack arrest is the sudden and sufficient increase in fracture resistance due to either increased apparent fracture toughness or a pipe opening restraint in the crack path.

    Keywords:

    dynamic fracture, crack bifurcation, crack curving, ductile fracture, axial pipe rupture, fracture mechanics


    Paper ID: STP33088S

    Committee/Subcommittee: E08.06

    DOI: 10.1520/STP33088S


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