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Influence of microcracking on shear localization / D. H. Warner in Journal of engineering mechanics, Vol. 137 N° 10 (Octobre 2011) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 137 N° 10 (Octobre 2011) . - pp.691-698 Titre : Influence of microcracking on shear localization Type de document : texte imprimé Auteurs : D. H. Warner, Auteur ; S. N. Mathaudhu, Auteur Année de publication : 2012 Article en page(s) : pp.691-698 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Microcracking  Shear  banding  Shear  localization  Micromechanics  Finite-element  modeling Résumé : This work examines the influence of microcracking on a material’s tendency to shear localize under compressive loading. A two-dimensional (2D) finite-element framework with explicit crack representation using cohesive-element methodologies is employed. The influence of microcracking is examined by taking the fracture toughness of the cohesive elements as a free parameter. The simulations suggest that an optimum fracture toughness exists for promoting shear localization. This value corresponds to the limiting mode I fracture toughness, below which microscopic material defects lead to brittle compressive failure, as opposed to shear localization. While in the presence of confinement, this value is shown to be close to zero; in the absence of confinement, it is computed to be 28% of the shear band toughness for the specific case of ultrafine-grained tungsten. More generally, it is found that the ratio of mode I fracture toughness to shear band toughness provides a crude indicator for predicting whether material defects are likely to lead to brittle failure or enhanced shear localization. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i10/p691_s1?isAuthorized=no [article] Influence of microcracking on shear localization [texte imprimé] / D. H. Warner, Auteur ; S. N. Mathaudhu, Auteur . - 2012 . - pp.691-698. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 137 N° 10 (Octobre 2011) . - pp.691-698 Mots-clés : Microcracking  Shear  banding  Shear  localization  Micromechanics  Finite-element  modeling Résumé : This work examines the influence of microcracking on a material’s tendency to shear localize under compressive loading. A two-dimensional (2D) finite-element framework with explicit crack representation using cohesive-element methodologies is employed. The influence of microcracking is examined by taking the fracture toughness of the cohesive elements as a free parameter. The simulations suggest that an optimum fracture toughness exists for promoting shear localization. This value corresponds to the limiting mode I fracture toughness, below which microscopic material defects lead to brittle compressive failure, as opposed to shear localization. While in the presence of confinement, this value is shown to be close to zero; in the absence of confinement, it is computed to be 28% of the shear band toughness for the specific case of ultrafine-grained tungsten. More generally, it is found that the ratio of mode I fracture toughness to shear band toughness provides a crude indicator for predicting whether material defects are likely to lead to brittle failure or enhanced shear localization. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i10/p691_s1?isAuthorized=no