Documents disponibles écrits par cet auteur

Application of exponential-based methods in integrating the constitutive equations with multicomponent nonlinear kinematic hardening / M. Rezaiee-Pajand in Journal of engineering mechanics, Vol. 136 N° 12 (Décembre 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 12 (Décembre 2010) . - pp.1502-1518 Titre : Application of exponential-based methods in integrating the constitutive equations with multicomponent nonlinear kinematic hardening Type de document : texte imprimé Auteurs : M. Rezaiee-Pajand, Auteur ; Cyrus Nasirai, Auteur ; Mehrzad Sharifian, Auteur Année de publication : 2011 Article en page(s) : pp.1502-1518 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Kinematics  Plasticity  Constitutive  models  Load  factors  Algorithms. Résumé : The von-Mises plasticity model, in the small strain regime, along with a class of multicomponent nonlinear kinematic hardening rules is considered. The material is assumed to be stabilized after several load cycles and therefore, isotropic hardening will not be accounted for. Application of exponential-based methods in integrating plasticity equations is provided, which is based on defining an augmented stress vector and using exponential maps to solve a system of quasi-linear differential equations. The solutions obtained by this new technique give very accurate updated stress values that are consistent with the yield surface. The classical forward Euler method is reformulated in details and applied to the multicomponent form of the nonlinear kinematic hardening in order to provide a comparison for the suggested technique. Moreover, a consistent tangent operator for the exponential-based integration strategy and also for the classical forward Euler algorithm is presented. In order to show the robustness and performance of the proposed formulation, an extensive numerical investigation is carried out. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i12/p1502_s1?isAuthorized=no [article] Application of exponential-based methods in integrating the constitutive equations with multicomponent nonlinear kinematic hardening [texte imprimé] / M. Rezaiee-Pajand, Auteur ; Cyrus Nasirai, Auteur ; Mehrzad Sharifian, Auteur . - 2011 . - pp.1502-1518. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 12 (Décembre 2010) . - pp.1502-1518 Mots-clés : Kinematics  Plasticity  Constitutive  models  Load  factors  Algorithms. Résumé : The von-Mises plasticity model, in the small strain regime, along with a class of multicomponent nonlinear kinematic hardening rules is considered. The material is assumed to be stabilized after several load cycles and therefore, isotropic hardening will not be accounted for. Application of exponential-based methods in integrating plasticity equations is provided, which is based on defining an augmented stress vector and using exponential maps to solve a system of quasi-linear differential equations. The solutions obtained by this new technique give very accurate updated stress values that are consistent with the yield surface. The classical forward Euler method is reformulated in details and applied to the multicomponent form of the nonlinear kinematic hardening in order to provide a comparison for the suggested technique. Moreover, a consistent tangent operator for the exponential-based integration strategy and also for the classical forward Euler algorithm is presented. In order to show the robustness and performance of the proposed formulation, an extensive numerical investigation is carried out. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i12/p1502_s1?isAuthorized=no

Automatic DR structural analysis of snap-through and snap-back using optimized load increments / M. Rezaiee-Pajand in Journal of structural engineering, Vol. 137 N° 1 (Janvier 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 1 (Janvier 2011) . - pp. 109-116 Titre : Automatic DR structural analysis of snap-through and snap-back using optimized load increments Type de document : texte imprimé Auteurs : M. Rezaiee-Pajand, Auteur ; J. Alamatian, Auteur Année de publication : 2011 Article en page(s) : pp. 109-116 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Numerical  models  Energy  Nonlinear  analysis  Structural  analysis  Load  factors Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, new schemes are presented for the dynamic relaxation (DR) method so that the snap-through and the snap-back regions can be traced automatically. These procedures are based on the minimization of the residual force (MRF) and minimization of the residual energy (MRE), and they are capable of updating the load factor in each DR iteration. The suggested techniques are perfectly automatic. Therefore, they do not require any additional parameters such as arc length, incremental displacement, etc. For numerical verification, some frame and truss structures, all possessing geometrical nonlinear behaviors, are analyzed. Tracing the statical path shows that both the MRF and MRE methods can be used successfully in structures with snap-through and snap-back regions. The numerical results indicate that the MRE scheme traces the statical path with a greater number of increments than the MRF. While the jumping probability of the MRE is less than that of the MRF, the analysis time may increase in the MRE. Also, a comparison between the proposed DR methods and arc-length approach shows that the MRF and MRE procedures can present the limit points with higher accuracy. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i1/p109_s1?isAuthorized=no [article] Automatic DR structural analysis of snap-through and snap-back using optimized load increments [texte imprimé] / M. Rezaiee-Pajand, Auteur ; J. Alamatian, Auteur . - 2011 . - pp. 109-116. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 1 (Janvier 2011) . - pp. 109-116 Mots-clés : Numerical  models  Energy  Nonlinear  analysis  Structural  analysis  Load  factors Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : In this paper, new schemes are presented for the dynamic relaxation (DR) method so that the snap-through and the snap-back regions can be traced automatically. These procedures are based on the minimization of the residual force (MRF) and minimization of the residual energy (MRE), and they are capable of updating the load factor in each DR iteration. The suggested techniques are perfectly automatic. Therefore, they do not require any additional parameters such as arc length, incremental displacement, etc. For numerical verification, some frame and truss structures, all possessing geometrical nonlinear behaviors, are analyzed. Tracing the statical path shows that both the MRF and MRE methods can be used successfully in structures with snap-through and snap-back regions. The numerical results indicate that the MRE scheme traces the statical path with a greater number of increments than the MRF. While the jumping probability of the MRE is less than that of the MRF, the analysis time may increase in the MRE. Also, a comparison between the proposed DR methods and arc-length approach shows that the MRF and MRE procedures can present the limit points with higher accuracy. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i1/p109_s1?isAuthorized=no