STP868

    Crack Tip Plasticity of a Tearing Crack

    Published: Jan 1985


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    Abstract

    The effects of crack tip plasticity associated with rapid tearing under Mode I and stable crack growth under combined Modes I and II crack tip deformations are analyzed by a modified Dugdale model. The modification consists of an unloaded region immediately ahead of the crack tip. The wake of the extending crack is modeled by two equal and unequal tangential surface tractions acting at the crack tip for Mode I and combined Modes I and II loadings, respectively. The disposable parameters plus the higher order terms in the crack tip stress field associated with the modified Dugdale model are then determined by using the dynamic photoelasticity results of rapid tear and stable crack growth in thin polycarbonate sheets. The modified Dugdale model is justified by the good agreement between the computed and directly measured isochromatics. Crack tip opening displacement (CTOD) and crack tip opening angle (CTOA) obtained from the least-square fitted, modified Dugdale model remained nearly constant during ductile crack extension.

    Keywords:

    rapid tearing, crack tip plasticity, Dugdale model, mixed-mode fracture dynamic photoelasticity, crack tip opening displacement


    Author Information:

    Lee, OS
    Department of Mechanical Engineering, University of Washington, Seattle, WA

    Associate Professor, Inha University, Inchon,

    Kobayashi, AS
    Department of Mechanical Engineering, University of Washington, Seattle, WA


    Paper ID: STP34267S

    Committee/Subcommittee: E08.08

    DOI: 10.1520/STP34267S


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