Documents disponibles écrits par cet auteur

Sensitivity of seismic applications to different shape memory alloy models / Bassem Andrawes in Journal of engineering mechanics, Vol. 134 N°2 (Fevrier 2008) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 134 N°2 (Fevrier 2008) . - pp.173–183. Titre : Sensitivity of seismic applications to different shape memory alloy models Type de document : texte imprimé Auteurs : Bassem Andrawes, Auteur ; Reginald DesRoches, Auteur Année de publication : 2008 Article en page(s) : pp.173–183. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Shape  memory  effect  Elasticity  Earthquakes  Constitutive  models  Seismic  effects  Sensitivity  anlysis. Résumé : Shape memory alloys (SMAs) are known for their superelastic properties, which have been exploited in numerous applications in the biomedical, aerospace, and commercial fields. More recently, these materials have been evaluated for applications in the area of earthquake engineering. One key question that arises when using these materials is the appropriate constitutive material model to use to capture the highly nonlinear behavior of SMAs. This paper explores the effect of using different SMA constitutive models on the resulting response of systems using SMAs. A sensitivity analysis is conducted by using three SMA models with various levels of complexity. The models are implemented in a single-degree-of-freedom system and subjected to three groups of earthquake records with various characteristics. Considering a more accurate trend in modeling incomplete cycles in SMAs has little impact on the structural response. The strength degradation and residual deformation seem to be of more importance than the sublooping behavior. The response is more sensitive to the cyclic effects in the case of records with long durations or large intensities. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A2%2817 [...] [article] Sensitivity of seismic applications to different shape memory alloy models [texte imprimé] / Bassem Andrawes, Auteur ; Reginald DesRoches, Auteur . - 2008 . - pp.173–183. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 134 N°2 (Fevrier 2008) . - pp.173–183. Mots-clés : Shape  memory  effect  Elasticity  Earthquakes  Constitutive  models  Seismic  effects  Sensitivity  anlysis. Résumé : Shape memory alloys (SMAs) are known for their superelastic properties, which have been exploited in numerous applications in the biomedical, aerospace, and commercial fields. More recently, these materials have been evaluated for applications in the area of earthquake engineering. One key question that arises when using these materials is the appropriate constitutive material model to use to capture the highly nonlinear behavior of SMAs. This paper explores the effect of using different SMA constitutive models on the resulting response of systems using SMAs. A sensitivity analysis is conducted by using three SMA models with various levels of complexity. The models are implemented in a single-degree-of-freedom system and subjected to three groups of earthquake records with various characteristics. Considering a more accurate trend in modeling incomplete cycles in SMAs has little impact on the structural response. The strength degradation and residual deformation seem to be of more importance than the sublooping behavior. The response is more sensitive to the cyclic effects in the case of records with long durations or large intensities. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282008%29134%3A2%2817 [...]

Structural engineering with NiTi . II / Jason McCormick in Journal of engineering mechanics, Vol. 133 N°9 (Septembre 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°9 (Septembre 2007) . - pp.1019–1029. Titre : Structural engineering with NiTi . II : mechanical behavior and scaling Type de document : texte imprimé Auteurs : Jason McCormick, Auteur ; Jeff Tyber, Auteur ; Reginald DesRoches, Auteur Année de publication : 2007 Article en page(s) : pp.1019–1029. Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Shape  memory  effect,  Structures,  Material  tests,  Material  properties  Mechanical  properties  Cyclic  tests  Earthquake  engineering Résumé : This paper continues to address the overarching goal to provide a more unified understanding of NiTi shape memory alloys intended for use in structural applications by attempting to link standard processing practice and basic materials characterization to the deformation behavior of large diameter bars. Results from cyclic tensile tests performed on large diameter Ni-rich polycrystalline NiTi bars are presented. Coupon specimens taken from deformation processed bars with diameters of 12.7, 19.1, and 31.8mm are tested along with their respective full-scale specimens. The coupon tests results reveal small and highly variable differences between specimens taken from the different size bars. The full-scale specimen tests continue to show the presence of the R phase, but lack a Lüders-like transformation. A comparison of the results suggests that coupon specimens provide only limited information in terms of the full-scale behavior. Full-scale tests using an earthquake-type loading then show similar behavior to the tensile cyclic tests suggesting the ability to use NiTi in structural applications. Overall, this paper and Tyber et al. 2007 provide a multiscale analysis of NiTi shape memory alloys to be used by both material scientist and civil engineers in the development of applications for NiTi. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=1019&volume=133&issue=9&journalC [...] [article] Structural engineering with NiTi . II : mechanical behavior and scaling [texte imprimé] / Jason McCormick, Auteur ; Jeff Tyber, Auteur ; Reginald DesRoches, Auteur . - 2007 . - pp.1019–1029. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°9 (Septembre 2007) . - pp.1019–1029. Mots-clés : Shape  memory  effect,  Structures,  Material  tests,  Material  properties  Mechanical  properties  Cyclic  tests  Earthquake  engineering Résumé : This paper continues to address the overarching goal to provide a more unified understanding of NiTi shape memory alloys intended for use in structural applications by attempting to link standard processing practice and basic materials characterization to the deformation behavior of large diameter bars. Results from cyclic tensile tests performed on large diameter Ni-rich polycrystalline NiTi bars are presented. Coupon specimens taken from deformation processed bars with diameters of 12.7, 19.1, and 31.8mm are tested along with their respective full-scale specimens. The coupon tests results reveal small and highly variable differences between specimens taken from the different size bars. The full-scale specimen tests continue to show the presence of the R phase, but lack a Lüders-like transformation. A comparison of the results suggests that coupon specimens provide only limited information in terms of the full-scale behavior. Full-scale tests using an earthquake-type loading then show similar behavior to the tensile cyclic tests suggesting the ability to use NiTi in structural applications. Overall, this paper and Tyber et al. 2007 provide a multiscale analysis of NiTi shape memory alloys to be used by both material scientist and civil engineers in the development of applications for NiTi. ISSN : 0733-9399 En ligne : http://ascelibrary.org/action/showAbstract?page=1019&volume=133&issue=9&journalC [...]