Documents disponibles écrits par cet auteur

Evaluation of force-based frame element response sensitivity formulations / Michael H. Scott in Journal of structural engineering, Vol. 138 N° 1 (Janvier 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 1 (Janvier 2012) . - pp. 72-80 Titre : Evaluation of force-based frame element response sensitivity formulations Type de document : texte imprimé Auteurs : Michael H. Scott, Auteur Année de publication : 2012 Article en page(s) : pp. 72-80 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Sensitivity  analysis  Frame  elements  Reliability  Optimization  Numerical  analysis Résumé : The direct differentiation method (DDM) has been shown to be an accurate and efficient approach to computing the sensitivity of structural response to uncertain parameters of constitutive models and finite-element formulations. Although it is well-known that the DDM should be consistent with the numerical time stepping procedure at the structural level, it is possible for element-level numerical instabilities to arise when the response sensitivity equations are inconsistent with the equations that govern the element response. Two existing formulations of DDM force-based element response sensitivity are shown to be mathematically equivalent in exact arithmetic; however, only one is consistent with the force-based response equations and possesses a low condition number for finite arithmetic. On the other hand, the inconsistent formulation has a high condition number that is equal to the product of the largest singular values of the section and element stiffness matrices. Representative examples show that the high condition number of the inconsistent formulation is innocuous for sensitivity with respect to section-level parameters but can lead to round off errors for sensitivity with respect to element-level geometric parameters. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i1/p72_s1?isAuthorized=no [article] Evaluation of force-based frame element response sensitivity formulations [texte imprimé] / Michael H. Scott, Auteur . - 2012 . - pp. 72-80. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 1 (Janvier 2012) . - pp. 72-80 Mots-clés : Sensitivity  analysis  Frame  elements  Reliability  Optimization  Numerical  analysis Résumé : The direct differentiation method (DDM) has been shown to be an accurate and efficient approach to computing the sensitivity of structural response to uncertain parameters of constitutive models and finite-element formulations. Although it is well-known that the DDM should be consistent with the numerical time stepping procedure at the structural level, it is possible for element-level numerical instabilities to arise when the response sensitivity equations are inconsistent with the equations that govern the element response. Two existing formulations of DDM force-based element response sensitivity are shown to be mathematically equivalent in exact arithmetic; however, only one is consistent with the force-based response equations and possesses a low condition number for finite arithmetic. On the other hand, the inconsistent formulation has a high condition number that is equal to the product of the largest singular values of the section and element stiffness matrices. Representative examples show that the high condition number of the inconsistent formulation is innocuous for sensitivity with respect to section-level parameters but can lead to round off errors for sensitivity with respect to element-level geometric parameters. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v138/i1/p72_s1?isAuthorized=no

Krylov subspace accelerated newton algorithm / Michael H. Scott in Journal of structural engineering, Vol. 136 N° 5 (Mai 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 5 (Mai 2010) . - pp. 473-480 Titre : Krylov subspace accelerated newton algorithm : application to dynamic progressive collapse simulation of frames Type de document : texte imprimé Auteurs : Michael H. Scott, Auteur ; Gregory L. Fenves, Auteur Année de publication : 2011 Article en page(s) : pp. 473-480 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Algorithms  Collapse  Nonlinear  analysis  Progressive  failure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : An accelerated Newton algorithm based on Krylov subspaces is applied to solving nonlinear equations of structural equilibrium. The algorithm uses a low-rank least-squares analysis to advance the search for equilibrium at the degrees of freedom (DOFs) where the largest changes in structural state occur; then it corrects for smaller changes at the remaining DOFs using a modified Newton computation. The algorithm is suited to simulating the dynamic progressive collapse analysis of frames where yielding and local collapse mechanisms form at a small number of DOFs while the state of the remaining structural components is relatively linear. In addition, the algorithm is able to resolve erroneous search directions that arise from approximation errors in the tangent stiffness matrix. Numerical examples indicate that the Krylov subspace algorithm has a larger radius of convergence and requires fewer matrix factorizations than Newton-Raphson in the dynamic progressive collapse simulation of reinforced concrete and steel frames. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i5/p473_s1?isAuthorized=no [article] Krylov subspace accelerated newton algorithm : application to dynamic progressive collapse simulation of frames [texte imprimé] / Michael H. Scott, Auteur ; Gregory L. Fenves, Auteur . - 2011 . - pp. 473-480. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 5 (Mai 2010) . - pp. 473-480 Mots-clés : Algorithms  Collapse  Nonlinear  analysis  Progressive  failure Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : An accelerated Newton algorithm based on Krylov subspaces is applied to solving nonlinear equations of structural equilibrium. The algorithm uses a low-rank least-squares analysis to advance the search for equilibrium at the degrees of freedom (DOFs) where the largest changes in structural state occur; then it corrects for smaller changes at the remaining DOFs using a modified Newton computation. The algorithm is suited to simulating the dynamic progressive collapse analysis of frames where yielding and local collapse mechanisms form at a small number of DOFs while the state of the remaining structural components is relatively linear. In addition, the algorithm is able to resolve erroneous search directions that arise from approximation errors in the tangent stiffness matrix. Numerical examples indicate that the Krylov subspace algorithm has a larger radius of convergence and requires fewer matrix factorizations than Newton-Raphson in the dynamic progressive collapse simulation of reinforced concrete and steel frames. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i5/p473_s1?isAuthorized=no