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Lattice dynamical finite-element method / Xiaohui Liu in Acta materialia, Vol. 58 N° 2 (Janvier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 510-523 Titre : Lattice dynamical finite-element method Type de document : texte imprimé Auteurs : Xiaohui Liu, Auteur ; Jianfeng Gu, Auteur ; Yao Shen, Directeur de thèse Article en page(s) : pp. 510-523 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Lattice  instability  Multiscale  modeling  Modulated  structure  Dislocation  nucleation  Phase  transformation Index. décimale : 669 Métallurgie Résumé : A lattice dynamical finite-element method (LDFEM) is proposed for multiscale analysis of stressed complex crystals. Interatomic potential is embedded into the constitutive relation within the hyperelasticity framework, and two energy-based lattice instability criteria, the Λ criterion and the soft phonon criterion, are incorporated into LDFEM for capturing stress-driven instabilities in a perfect crystal. The simulations of uniaxial loadings and a two-dimensional nanoindentation of B2-NiAl are performed using both LDFEM and molecular dynamics (MD). The good agreement of the simulated mechanical responses between the two methods validates the proposed method. Combination of the two criteria can provide a powerful tool for predicting lattice instabilities in complex crystals under load at zero or low temperatures. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...] [article] Lattice dynamical finite-element method [texte imprimé] / Xiaohui Liu, Auteur ; Jianfeng Gu, Auteur ; Yao Shen, Directeur de thèse . - pp. 510-523. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 510-523 Mots-clés : Lattice  instability  Multiscale  modeling  Modulated  structure  Dislocation  nucleation  Phase  transformation Index. décimale : 669 Métallurgie Résumé : A lattice dynamical finite-element method (LDFEM) is proposed for multiscale analysis of stressed complex crystals. Interatomic potential is embedded into the constitutive relation within the hyperelasticity framework, and two energy-based lattice instability criteria, the Λ criterion and the soft phonon criterion, are incorporated into LDFEM for capturing stress-driven instabilities in a perfect crystal. The simulations of uniaxial loadings and a two-dimensional nanoindentation of B2-NiAl are performed using both LDFEM and molecular dynamics (MD). The good agreement of the simulated mechanical responses between the two methods validates the proposed method. Combination of the two criteria can provide a powerful tool for predicting lattice instabilities in complex crystals under load at zero or low temperatures. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...]