Quasi-static dislocation model around a crack tip with moving dislocations and the analysis of its stress concentration

Toshimitsu Yokobori, I. Joichi, T. Iwadate

    Research output: Contribution to journalArticlepeer-review

    Abstract

    With regard to fracture under dynamic load, an interaction model in the form of a fracture model of a crack and an inverse pile-up of dynamic dislocation groups at the tip of a dislocation-free zone was proposed. It was analyzed based on a coexisting model of static equilibrium and dynamic distribution of dislocation arrays. From these analyses, the following results were obtained. The stress concentration at a crack tip is reduced by the shielding effect of dislocation groups emitted from a stressed source near the crack tip. On the other hand, the stress concentration at the tip of the dislocation-free zone, due to the inverse pile-up of dislocation groups ahead of the crack tip, is induced by the effective stress distribution in a dislocation array which is a result of the dynamic dislocation distribution. Therefore, at the tip of the dislocation-free zone which exists ahead of the crack, stress singularity can be found, and the stress intensity factor can be defined. This result shows a theoretical foundation for the experimental result of the existence of a fracture trigger point under dynamic load.

    Original languageEnglish
    Pages (from-to)27-38
    Number of pages12
    JournalStrength, Fracture and Complexity
    Volume5
    Issue number1
    Publication statusPublished - 2007 Dec 1

    Keywords

    • Brittle fracture
    • Dislocation-free zone
    • Dynamic fracture toughness
    • Trigger point

    ASJC Scopus subject areas

    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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