Documents disponibles écrits par cet auteur

In-plane nonlinear buckling analysis of deep circular arches incorporating transverse stresses / Tong Gengshu in Journal of engineering mechanics, Vol. 134 N°5 (Mai 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°5 (Mai 2008) . - pp.362–373. Titre : In-plane nonlinear buckling analysis of deep circular arches incorporating transverse stresses Type de document : texte imprimé Auteurs : Tong Gengshu, Auteur ; Yong-Lin Pi, Auteur ; Mark Andrew Bradford, Auteur Année de publication : 2008 Article en page(s) : pp.362–373. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Arches  Buckling  Elasticity  Nonlinear  analysis  Stress Résumé : Large discrepancies exist among current classical theories for the in-plane buckling of arches that are subjected to a constant-directed radial load uniformly distributed around the arch axis. Discrepancies also exist between the classical solutions and nonlinear finite-element results. A new theory is developed in this paper for the nonlinear analysis of circular arches in which the nonlinear strain-displacement relationship is based on finite displacement theory. In the resulting variational equilibrium equation, the energy terms due to both nonlinear shear and transverse stresses are included. This paper also derives a set of linearized equations for the elastic in-plane buckling of arches, and presents a detailed analysis of the buckling of deep circular arches under constant-directed uniform radial loading including the effects of shear and transverse stresses, and of the prebuckling deformations. The solutions of the new theory agree very well with nonlinear finite-element results. Various assumptions often used by other researchers, in particular the assumption of inextensibility of the arch axis, are examined. The discrepancies among the current theories are clarified in the paper. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=362&volume=134&issue=5&journalCo [...] [article] In-plane nonlinear buckling analysis of deep circular arches incorporating transverse stresses [texte imprimé] / Tong Gengshu, Auteur ; Yong-Lin Pi, Auteur ; Mark Andrew Bradford, Auteur . - 2008 . - pp.362–373. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°5 (Mai 2008) . - pp.362–373. Mots-clés : Arches  Buckling  Elasticity  Nonlinear  analysis  Stress Résumé : Large discrepancies exist among current classical theories for the in-plane buckling of arches that are subjected to a constant-directed radial load uniformly distributed around the arch axis. Discrepancies also exist between the classical solutions and nonlinear finite-element results. A new theory is developed in this paper for the nonlinear analysis of circular arches in which the nonlinear strain-displacement relationship is based on finite displacement theory. In the resulting variational equilibrium equation, the energy terms due to both nonlinear shear and transverse stresses are included. This paper also derives a set of linearized equations for the elastic in-plane buckling of arches, and presents a detailed analysis of the buckling of deep circular arches under constant-directed uniform radial loading including the effects of shear and transverse stresses, and of the prebuckling deformations. The solutions of the new theory agree very well with nonlinear finite-element results. Various assumptions often used by other researchers, in particular the assumption of inextensibility of the arch axis, are examined. The discrepancies among the current theories are clarified in the paper. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=362&volume=134&issue=5&journalCo [...]

Nonlinear analysis of composite beams with partial interaction in steel frame structures at elevated temperature / Amin Heidarpour in Journal of structural engineering, Vol. 136 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 968-977 Titre : Nonlinear analysis of composite beams with partial interaction in steel frame structures at elevated temperature Type de document : texte imprimé Auteurs : Amin Heidarpour, Auteur ; Mark Andrew Bradford, Auteur Année de publication : 2011 Article en page(s) : pp. 968-977 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Composite  beam  Elasticity  Elevated  temperature  Nonlinearity  Partial  interaction Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Flooring systems containing steel-concrete composite beams are common in steel frame structures and it is widely recognized that their behavior under fire loading is profoundly different to that of simply supported composite beams under fire loading. This difference in behavior is due to the presence of restraints provided by cooler members in a compartment fire in a composite frame structure and there is extensive evidence from fire tests that composite beams with unprotected steel components in steel frames perform much better than simply supported composite beams with unprotected steel components. In order to model the structural response of a composite beam restrained in this way at elevated temperature, recourse is needed to a geometric nonlinear formulation, since the transverse beam deflections are large and interact with the substantial axial compressive force in the member at the early stages of the fire. This paper presents such a formulation, which incorporates partial interaction between the concrete slab and steel component, as well as the degradation of the stiffnesses of the components of the composite beam prior to yield at elevated temperature. The generic technique that is developed is shown to agree with solutions reported elsewhere and provides a structural model for the response of a composite beam in fire with the potential for inclusion in prescriptive code rules for rational fire engineering based designs. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p968_s1?isAuthorized=no [article] Nonlinear analysis of composite beams with partial interaction in steel frame structures at elevated temperature [texte imprimé] / Amin Heidarpour, Auteur ; Mark Andrew Bradford, Auteur . - 2011 . - pp. 968-977. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 136 N° 8 (Août 2010) . - pp. 968-977 Mots-clés : Composite  beam  Elasticity  Elevated  temperature  Nonlinearity  Partial  interaction Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : Flooring systems containing steel-concrete composite beams are common in steel frame structures and it is widely recognized that their behavior under fire loading is profoundly different to that of simply supported composite beams under fire loading. This difference in behavior is due to the presence of restraints provided by cooler members in a compartment fire in a composite frame structure and there is extensive evidence from fire tests that composite beams with unprotected steel components in steel frames perform much better than simply supported composite beams with unprotected steel components. In order to model the structural response of a composite beam restrained in this way at elevated temperature, recourse is needed to a geometric nonlinear formulation, since the transverse beam deflections are large and interact with the substantial axial compressive force in the member at the early stages of the fire. This paper presents such a formulation, which incorporates partial interaction between the concrete slab and steel component, as well as the degradation of the stiffnesses of the components of the composite beam prior to yield at elevated temperature. The generic technique that is developed is shown to agree with solutions reported elsewhere and provides a structural model for the response of a composite beam in fire with the potential for inclusion in prescriptive code rules for rational fire engineering based designs. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v136/i8/p968_s1?isAuthorized=no

Nonlinear thermoelastic buckling of pin-ended shallow arches under temperature gradient / Yong-Lin Pi in Journal of engineering mechanics, Vol. 136 N° 8 (Août 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 8 (Août 2010) . - pp. 960-968 Titre : Nonlinear thermoelastic buckling of pin-ended shallow arches under temperature gradient Type de document : texte imprimé Auteurs : Yong-Lin Pi, Auteur ; Mark Andrew Bradford, Auteur Article en page(s) : pp. 960-968 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Arches  Bifurcations  Buckling  Closed  form  solutions  Postbuckling  Temperature  effects  Nonlinear  analysis. Résumé : This paper presents a nonlinear thermal buckling analysis of circular shallow pin-ended arches that are subjected to a linear temperature gradient field in the plane of curvature of the arch. The linear temperature gradient produces axial expansion and curvature changes in the arch. The bending action produced by the curvature change and the axial compressive action produced by the restrained axial expansion may lead the arch to buckle suddenly in the plane of its curvature. The end reactions resulting from the restrained axial expansion also produce bending actions that are opposite to that produced by the temperature differential and tend to produce deflections on the convex side of the arch. A geometrically nonlinear analysis for thermoelastic buckling has been carried out based on a virtual work technique, and analytical solutions for the critical temperature gradients for the in-plane limit instability and bifurcation buckling are obtained. It is found that antisymmetric bifurcation is the dominant buckling mode for most shallow arches that are subjected to a linear temperature gradient. The limit instability is possible only for slender and shallow arches. It is also found that a characteristic value of the arch geometric parameter exists and that arches whose geometric parameter is less than this characteristic value show no typical buckling behavior. The formula for this characteristic value of the arch geometric parameter is derived. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Nonlinear thermoelastic buckling of pin-ended shallow arches under temperature gradient [texte imprimé] / Yong-Lin Pi, Auteur ; Mark Andrew Bradford, Auteur . - pp. 960-968. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 8 (Août 2010) . - pp. 960-968 Mots-clés : Arches  Bifurcations  Buckling  Closed  form  solutions  Postbuckling  Temperature  effects  Nonlinear  analysis. Résumé : This paper presents a nonlinear thermal buckling analysis of circular shallow pin-ended arches that are subjected to a linear temperature gradient field in the plane of curvature of the arch. The linear temperature gradient produces axial expansion and curvature changes in the arch. The bending action produced by the curvature change and the axial compressive action produced by the restrained axial expansion may lead the arch to buckle suddenly in the plane of its curvature. The end reactions resulting from the restrained axial expansion also produce bending actions that are opposite to that produced by the temperature differential and tend to produce deflections on the convex side of the arch. A geometrically nonlinear analysis for thermoelastic buckling has been carried out based on a virtual work technique, and analytical solutions for the critical temperature gradients for the in-plane limit instability and bifurcation buckling are obtained. It is found that antisymmetric bifurcation is the dominant buckling mode for most shallow arches that are subjected to a linear temperature gradient. The limit instability is possible only for slender and shallow arches. It is also found that a characteristic value of the arch geometric parameter exists and that arches whose geometric parameter is less than this characteristic value show no typical buckling behavior. The formula for this characteristic value of the arch geometric parameter is derived. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]