Assessment of load history effects on ductile initiation fracture toughness by the Gurson-Tvergaard-Needleman model

A. P. Jivkov, J. K. Sharples, P. J. Budden

    Research output: Chapter in Book/Conference proceedingConference contributionpeer-review

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    Abstract

    Residual stresses may reduce the apparent ductile fracture toughness of structural steels. However, prior load excursions may alleviate this reduction. Effects of several load histories on ductile fracture initiation are investigated using finite element analyses of compact tension specimens. The Gurson-Tvergaard-Needleman micromechanical model is used, where void volume fraction in the crack tip vicinity measures local damage. Analysis without load history, with three tensile residual stress levels, and three tensile overload levels after each residual stress are performed. Evolutions of several global and local parameters with local damage are presented. Ductile fracture initiation is assumed when local damage attains a critical value. The reduction of fracture toughness is shown to increase with increasing residual stress levels. Departure from this trend is observed for high residual stresses and is explained by damage-band formation. Increasing overloads are shown to increasingly mitigate the detrimental effects of residual stress.
    Original languageEnglish
    Title of host publication12th International Conference on Fracture 2009, ICF-12|Int. Conf. Fract., ICF
    Place of PublicationCanada
    PublisherCurran Associates Incorporated
    Pages5903-5912
    Number of pages9
    Volume8
    ISBN (Print)9781617382277
    Publication statusPublished - 2009
    Event12th International Conference on Fracture 2009, ICF-12 - Ottawa, ON, Canada
    Duration: 12 Jul 200917 Jul 2009

    Conference

    Conference12th International Conference on Fracture 2009, ICF-12
    Country/TerritoryCanada
    CityOttawa, ON
    Period12/07/0917/07/09

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