Documents disponibles écrits par cet auteur

Model uncertainty in finite-element analysis / T. Haukaas in Journal of engineering mechanics, Vol. 137 N° 8 (Août 2011) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 137 N° 8 (Août 2011) . - pp.519-526 Titre : Model uncertainty in finite-element analysis : bayesian finite elements Type de document : texte imprimé Auteurs : T. Haukaas, Auteur ; P. Gardoni, Auteur Année de publication : 2011 Article en page(s) : pp.519-526 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Probabilistic  models  Model  uncertainty  Finite  elements  Bayesian  updating Résumé : In this paper, probabilistic models for structural analysis are put forward, with particular emphasis on model uncertainty. Context is provided by the finite-element method and the need for probabilistic prediction of structural performance in contemporary engineering. Sources of model uncertainty are identified and modeled. A Bayesian approach is suggested for the assessment of new model parameters within the element formulations. The expressions are formulated by means of numerical “sensors” that influence the model uncertainty, such as element distortion and degree of nonlinearity. An assessment procedure is proposed to identify the sensors that are most suitable to capture model uncertainty. This paper presents the general methodology and specific implementations for a general-purpose structural element. Two numerical examples are presented to demonstrate the methodology and its implications for probabilistic prediction of structural response. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i8/p519_s1?isAuthorized=no [article] Model uncertainty in finite-element analysis : bayesian finite elements [texte imprimé] / T. Haukaas, Auteur ; P. Gardoni, Auteur . - 2011 . - pp.519-526. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 137 N° 8 (Août 2011) . - pp.519-526 Mots-clés : Probabilistic  models  Model  uncertainty  Finite  elements  Bayesian  updating Résumé : In this paper, probabilistic models for structural analysis are put forward, with particular emphasis on model uncertainty. Context is provided by the finite-element method and the need for probabilistic prediction of structural performance in contemporary engineering. Sources of model uncertainty are identified and modeled. A Bayesian approach is suggested for the assessment of new model parameters within the element formulations. The expressions are formulated by means of numerical “sensors” that influence the model uncertainty, such as element distortion and degree of nonlinearity. An assessment procedure is proposed to identify the sensors that are most suitable to capture model uncertainty. This paper presents the general methodology and specific implementations for a general-purpose structural element. Two numerical examples are presented to demonstrate the methodology and its implications for probabilistic prediction of structural response. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i8/p519_s1?isAuthorized=no

Probabilistic seismic loss assessment of a vancouver high-rise building / S. D. Koduru in Journal of structural engineering, Vol. 136 N° 3 (Mars 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 3 (Mars 2010) . - pp. 235-245 Titre : Probabilistic seismic loss assessment of a vancouver high-rise building Type de document : texte imprimé Auteurs : S. D. Koduru, Auteur ; T. Haukaas, Auteur Année de publication : 2011 Article en page(s) : pp. 235-245 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Performance-based  engineering  Seismic  effects  Reliability Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A seismic loss curve of a real-world building is obtained by means of state-of-the-art models for the impending ground motion, the structure, the damage of structural and nonstructural components, and the ensuing losses. In particular, the seismic hazard at the building’s location (Vancouver, Canada) is described by a comprehensive probabilistic model. It is argued that this ground motion model is particularly appropriate in reliability analysis compared with the more common utilization of a limited set of scaled ground motions. In this paper the probabilistic integrals are carried out by means of a reliability formulation, in which a series of probabilistic models enter. This is referred to as unified reliability analysis to contrast the unified format of the probabilistic models with alternatives, such as suites of ground motions and fragility curves that themselves are created by reliability analysis. A key contribution in this paper is the comprehensive numerical example, which entails an inelastic dynamic analysis of a finite-element model of a building located in Vancouver. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i3/p235_s1?isAuthorized=no [article] Probabilistic seismic loss assessment of a vancouver high-rise building [texte imprimé] / S. D. Koduru, Auteur ; T. Haukaas, Auteur . - 2011 . - pp. 235-245. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 3 (Mars 2010) . - pp. 235-245 Mots-clés : Performance-based  engineering  Seismic  effects  Reliability Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : A seismic loss curve of a real-world building is obtained by means of state-of-the-art models for the impending ground motion, the structure, the damage of structural and nonstructural components, and the ensuing losses. In particular, the seismic hazard at the building’s location (Vancouver, Canada) is described by a comprehensive probabilistic model. It is argued that this ground motion model is particularly appropriate in reliability analysis compared with the more common utilization of a limited set of scaled ground motions. In this paper the probabilistic integrals are carried out by means of a reliability formulation, in which a series of probabilistic models enter. This is referred to as unified reliability analysis to contrast the unified format of the probabilistic models with alternatives, such as suites of ground motions and fragility curves that themselves are created by reliability analysis. A key contribution in this paper is the comprehensive numerical example, which entails an inelastic dynamic analysis of a finite-element model of a building located in Vancouver. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i3/p235_s1?isAuthorized=no

Second-order sensitivities of inelastic finite-element response by direct differentiation / A. Bebamzadeh in Journal of engineering mechanics, Vol. 134 N°10 (Octobre 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°10 (Octobre 2008) . - pp.867–880. Titre : Second-order sensitivities of inelastic finite-element response by direct differentiation Type de document : texte imprimé Auteurs : A. Bebamzadeh, Auteur ; T. Haukaas, Auteur Année de publication : 2008 Article en page(s) : pp.867–880. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Sensitivity  analysis  Finite  element  method  Inelasticity  Computation Résumé : In this paper analytical equations are developed and implemented to obtain second-order derivatives of finite-element responses with respect to input parameters. The work extends previous work on first-order response sensitivity analysis. Of particular interest in this study is the computational feasibility of obtaining second-order response sensitivities. In the past, the straightforward finite difference approach has been available, but this approach suffers from serious efficiency and accuracy concerns. In this study it is demonstrated that analytical differentiation of the response algorithm and subsequent implementation on the computer provides second-order sensitivities at a significantly reduced cost. The sensitivity results are consistent with and have the same numerical precision as the ordinary response. The computational cost advantage of the direct differentiation approach increases as the problem size increases. Several novel implementation techniques are developed in this paper to optimize the computational efficiency. The derivations and implementations are demonstrated and verified with two finite-element analysis examples. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A10%288 [...] [article] Second-order sensitivities of inelastic finite-element response by direct differentiation [texte imprimé] / A. Bebamzadeh, Auteur ; T. Haukaas, Auteur . - 2008 . - pp.867–880. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°10 (Octobre 2008) . - pp.867–880. Mots-clés : Sensitivity  analysis  Finite  element  method  Inelasticity  Computation Résumé : In this paper analytical equations are developed and implemented to obtain second-order derivatives of finite-element responses with respect to input parameters. The work extends previous work on first-order response sensitivity analysis. Of particular interest in this study is the computational feasibility of obtaining second-order response sensitivities. In the past, the straightforward finite difference approach has been available, but this approach suffers from serious efficiency and accuracy concerns. In this study it is demonstrated that analytical differentiation of the response algorithm and subsequent implementation on the computer provides second-order sensitivities at a significantly reduced cost. The sensitivity results are consistent with and have the same numerical precision as the ordinary response. The computational cost advantage of the direct differentiation approach increases as the problem size increases. Several novel implementation techniques are developed in this paper to optimize the computational efficiency. The derivations and implementations are demonstrated and verified with two finite-element analysis examples. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A10%288 [...]