The effect of loss of constraint on the Initiation of ductile fracture in a Mini-CT

    Research outputpeer-review


    As one of the most appealing miniaturized geometries for fracture toughness characterization, the miniature compact tension (mini-CT) geometry was demonstrated to provide reliable fracture toughness measurement in the ductile-to-brittle transition regime and Master Curve assessment. However, when using a mini-CT in the upper shelf (fully ductile) regime, the ductile crack initiation and the crack growth resistance tend to be underestimated for most of the investigated RPV steels. Previous experimental investigations have attributed the underestimation of the crack resistance properties to two concurrent processes related to loss of constraint and cold working occurring in the ligament ahead of crack tip during cracking, and gave an engineering size correction that mainly accounts for the thickness of the specimens. In this study, finite element simulations and two micromechanics-based approaches: the Rice-Tracey void growth model and Thomason void coalescence model are combined, aimed at investigating the role that the loss of constraint plays in the initiation of ductile fracture in a mini-CT and providing numerical evidence to support the proposal of the size correction on the critical fracture toughness. The final objective of this paper is to estimate the ductile crack initiation behavior that would be obtained from a standard 1T-CT specimen by applying appropriate size correction on a mini-CT. The results show that the method incorporating the finite element simulations and two micromechanics-based approaches can well describe the effects of loss of constraint for different materials, thus contributing to the size correction of critical fracture toughness of mini-CT in various conditions.

    Original languageEnglish
    Title of host publicationCodes and Standards
    PublisherASME - The American Society of Mechanical Engineers
    Number of pages10
    ISBN (Electronic)9780791887448
    StatePublished - Nov 2023
    Event2023 - ASME Pressure Vessels and Piping Conference - Atlanta
    Duration: 16 Jul 202321 Jul 2023
    Conference number: PVP 2023

    Publication series

    NameAmerican Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
    ISSN (Print)0277-027X


    Conference2023 - ASME Pressure Vessels and Piping Conference
    Country/TerritoryUnited States

    ASJC Scopus subject areas

    • Mechanical Engineering

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