Documents disponibles écrits par cet auteur

Computational post failure analysis with Cosserat continuum / Panos Papanastasiou in European journal of environmental and civil engineering, Vol. 14 N° 8-9 (Septembre 2010) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 14 N° 8-9 (Septembre 2010) . - pp. 1051-1065 Titre : Computational post failure analysis with Cosserat continuum Type de document : texte imprimé Auteurs : Panos Papanastasiou, Auteur Année de publication : 2011 Article en page(s) : pp. 1051-1065 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Cosserat  model  Plasticity  theory  Finite  elements  Stability  Bifurcation  Localization  of  deformation  Scale  effect  Borehole  Perforations Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : We present computational analysis of geomechanics problems in the post failure regime based on a Cosserat material model The introduction of internal length (related to grain size) in the Cosserat model improves the computational stability and allows for robust progressive localization modelling. The model is capable of predicting advanced deformation modes such as surface buckling and localization of deformation in shear bands that may cause failure in a structure. The obtained results show clearly a progressive failure mechanism and the computed modes are in a good qualitative agreement with laboratory and field observations. As illustration we present results of two applications from petroleum engineering: the modelling of failure in thick walled cylinder test and the stability of elliptical shape perforations. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/resnum.jsp [article] Computational post failure analysis with Cosserat continuum [texte imprimé] / Panos Papanastasiou, Auteur . - 2011 . - pp. 1051-1065. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 14 N° 8-9 (Septembre 2010) . - pp. 1051-1065 Mots-clés : Cosserat  model  Plasticity  theory  Finite  elements  Stability  Bifurcation  Localization  of  deformation  Scale  effect  Borehole  Perforations Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : We present computational analysis of geomechanics problems in the post failure regime based on a Cosserat material model The introduction of internal length (related to grain size) in the Cosserat model improves the computational stability and allows for robust progressive localization modelling. The model is capable of predicting advanced deformation modes such as surface buckling and localization of deformation in shear bands that may cause failure in a structure. The obtained results show clearly a progressive failure mechanism and the computed modes are in a good qualitative agreement with laboratory and field observations. As illustration we present results of two applications from petroleum engineering: the modelling of failure in thick walled cylinder test and the stability of elliptical shape perforations. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/resnum.jsp

Computational post failure analysis with a second gradient theory / Antonis Zervos in European journal of environmental and civil engineering, Vol. 14 N° 8-9 (Septembre 2010) 

Public ISBD [article]  in European journal of environmental and civil engineering > Vol. 14 N° 8-9 (Septembre 2010) . - pp. 1067-1079 Titre : Computational post failure analysis with a second gradient theory : Gradient elastoplasticity Type de document : texte imprimé Auteurs : Antonis Zervos, Auteur ; Panos Papanastasiou, Auteur Année de publication : 2011 Article en page(s) : pp. 1067-1079 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Gradient  plasticity  Gradient  elastoplasticity  Post-bifurcation  modelling  Finite  elements  Numerical  modelling  Microstructure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This article presents a theory of Gradient Elastoplasticity for strain-softening materials, in which internal length scales are present in both the elastic and the elastoplastic regime. A numerical discretisation based on the displacement formulation and a C1 finite element is used. It is shown that the formulation enables robust modelling of the post-peak material behaviour leading to localisation of deformation, spontaneously tracking emergent instabilities and quantitatively capturing details of the final localised failure mechanism. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/resnum.jsp [article] Computational post failure analysis with a second gradient theory : Gradient elastoplasticity [texte imprimé] / Antonis Zervos, Auteur ; Panos Papanastasiou, Auteur . - 2011 . - pp. 1067-1079. Génie Civil Langues : Anglais (eng) in European journal of environmental and civil engineering > Vol. 14 N° 8-9 (Septembre 2010) . - pp. 1067-1079 Mots-clés : Gradient  plasticity  Gradient  elastoplasticity  Post-bifurcation  modelling  Finite  elements  Numerical  modelling  Microstructure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : This article presents a theory of Gradient Elastoplasticity for strain-softening materials, in which internal length scales are present in both the elastic and the elastoplastic regime. A numerical discretisation based on the displacement formulation and a C1 finite element is used. It is shown that the formulation enables robust modelling of the post-peak material behaviour leading to localisation of deformation, spontaneously tracking emergent instabilities and quantitatively capturing details of the final localised failure mechanism. DEWEY : 624 ISSN : 1964-8189 En ligne : http://ejece.revuesonline.com/resnum.jsp