Documents disponibles écrits par cet auteur

Implications of the definition of the Φ function in elastic-viscoplastic models / T. M. Bodas Freitas in Géotechnique, Vol. 62 N° 7 (Juillet 2012) 

Public ISBD [article]  in Géotechnique > Vol. 62 N° 7 (Juillet 2012) . - pp. 643 –648 Titre : Implications of the definition of the Φ function in elastic-viscoplastic models Type de document : texte imprimé Auteurs : T. M. Bodas Freitas, Auteur ; D. M. Potts, Auteur ; L. Zdravkovic, Auteur Année de publication : 2012 Article en page(s) : pp. 643 –648 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Time  dependence  Creep  Constitutive  relations Résumé : A discrepancy has been identified in existing overstress theory based elastic-viscoplastic models regarding the definition of the Φ function, which determines the magnitude of the viscoplastic strain increment. Based on existing experimental data, some authors define the function Φ assuming that any given loading surface is a locus of constant volumetric viscoplastic strain rate. Others, instead, assume that a loading surface is a locus of constant Φ. This paper examines the implications of using either of the above approaches. It is shown that the two approaches yield very similar predictions for stress states far from failure (for stress levels up to approximately 0·6), however, critical-state conditions are reproduced only when the current loading surface is assumed to be a locus of constant Φ. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.10.P.053 [article] Implications of the definition of the Φ function in elastic-viscoplastic models [texte imprimé] / T. M. Bodas Freitas, Auteur ; D. M. Potts, Auteur ; L. Zdravkovic, Auteur . - 2012 . - pp. 643 –648. Génie Civil Langues : Anglais (eng) in Géotechnique > Vol. 62 N° 7 (Juillet 2012) . - pp. 643 –648 Mots-clés : Time  dependence  Creep  Constitutive  relations Résumé : A discrepancy has been identified in existing overstress theory based elastic-viscoplastic models regarding the definition of the Φ function, which determines the magnitude of the viscoplastic strain increment. Based on existing experimental data, some authors define the function Φ assuming that any given loading surface is a locus of constant volumetric viscoplastic strain rate. Others, instead, assume that a loading surface is a locus of constant Φ. This paper examines the implications of using either of the above approaches. It is shown that the two approaches yield very similar predictions for stress states far from failure (for stress levels up to approximately 0·6), however, critical-state conditions are reproduced only when the current loading surface is assumed to be a locus of constant Φ. ISSN : 0016-8505 En ligne : http://www.icevirtuallibrary.com/content/article/10.1680/geot.10.P.053