Documents disponibles écrits par cet auteur

Calibration of the SMCS criterion for ductile fracture in steels / A. T. Myers in Journal of engineering mechanics, Vol. 136 N° 11 (Novembre 2010) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 136 N° 11 (Novembre 2010) . - pp.1401-1410 Titre : Calibration of the SMCS criterion for ductile fracture in steels : specimen size dependence and parameter assessment Type de document : texte imprimé Auteurs : A. T. Myers, Auteur ; A. M. Kanvinde, Auteur ; G. G. Deierlein, Auteur Année de publication : 2011 Article en page(s) : pp.1401-1410 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Ductility  Cracking  Steel  Micromechanics  Parameters. Résumé : The stress modified critical strain (SMCS) criterion provides a local index for the initiation of ductile fracture in metals as a function of plastic strain and stress triaxiality. Previous research has confirmed the SMCS criterion to be an accurate index for fracture initiation in mild steels and demonstrated its application to civil/structural engineering. To facilitate practical implementation of the SMCS criterion, two key aspects of its calibration for steel materials are examined. The first pertains to the sensitivity of the measured SMCS material toughness parameter to the size of the test coupon. New results from 23 tests of cylindrically notched tension (CNT) specimens of various sizes and notch geometries indicate that the toughness parameter is relatively insensitive to calibration specimen size. This finding validates the use of miniature bar specimens to calibrate the SMCS model for thin plate steels and in-service structures, where extraction of larger coupons is impossible. The second aspect involves the development of closed-form expressions to determine directly the SMCS toughness parameter from CNT tests, thus avoiding the need for interpretation of the test data through finite-element simulations. Based on the results of 54 numerical simulations, encompassing a range of material constitutive properties, specimen geometries, and applied deformations, a semiempirical relationship (based in part on Bridgman’s solution for necked tension rods) is proposed to determine the toughness parameter directly from the CNT bar tests. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i11/p1401_s1?isAuthorized=no [article] Calibration of the SMCS criterion for ductile fracture in steels : specimen size dependence and parameter assessment [texte imprimé] / A. T. Myers, Auteur ; A. M. Kanvinde, Auteur ; G. G. Deierlein, Auteur . - 2011 . - pp.1401-1410. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 136 N° 11 (Novembre 2010) . - pp.1401-1410 Mots-clés : Ductility  Cracking  Steel  Micromechanics  Parameters. Résumé : The stress modified critical strain (SMCS) criterion provides a local index for the initiation of ductile fracture in metals as a function of plastic strain and stress triaxiality. Previous research has confirmed the SMCS criterion to be an accurate index for fracture initiation in mild steels and demonstrated its application to civil/structural engineering. To facilitate practical implementation of the SMCS criterion, two key aspects of its calibration for steel materials are examined. The first pertains to the sensitivity of the measured SMCS material toughness parameter to the size of the test coupon. New results from 23 tests of cylindrically notched tension (CNT) specimens of various sizes and notch geometries indicate that the toughness parameter is relatively insensitive to calibration specimen size. This finding validates the use of miniature bar specimens to calibrate the SMCS model for thin plate steels and in-service structures, where extraction of larger coupons is impossible. The second aspect involves the development of closed-form expressions to determine directly the SMCS toughness parameter from CNT tests, thus avoiding the need for interpretation of the test data through finite-element simulations. Based on the results of 54 numerical simulations, encompassing a range of material constitutive properties, specimen geometries, and applied deformations, a semiempirical relationship (based in part on Bridgman’s solution for necked tension rods) is proposed to determine the toughness parameter directly from the CNT bar tests. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v136/i11/p1401_s1?isAuthorized=no

Cyclic void growth model to assess ductile fracture initiation in structural steels due to ultra low cycle fatigue / A. M. Kanvinde in Journal of engineering mechanics, Vol. 133 N°6 (Juin 2007) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 133 N°6 (Juin 2007) . - pp.701–712. Titre : Cyclic void growth model to assess ductile fracture initiation in structural steels due to ultra low cycle fatigue Type de document : texte imprimé Auteurs : A. M. Kanvinde, Auteur ; G. G. Deierlein, Auteur Année de publication : 2007 Article en page(s) : pp.701–712. Note générale : Applied mechanics Langues : Anglais (eng) Mots-clés : Voids  Steel  Fatigue  Steel  structures  Earthquakes Résumé : A new model is proposed to simulate ductile fracture initiation due to large amplitude cyclic straining in structural steels, which is often the governing limit state in steel structures subjected to earthquakes. Termed the cyclic void growth model (CVGM), the proposed technique is an extension to previously published models that simulate ductile fracture caused by void growth and coalescence under monotonic loading. The CVGM aims to capture ultra low cycle fatigue (ductile fracture) behavior, which is characterized by a few (generally, less than 20) reverse loading cycles to large inelastic strain amplitudes (several times the yield strain). The underlying mechanisms of low-cycle fracture involve cyclic void growth, collapse, and distortion, which are distinct from those associated with more conventional fatigue. The CVGM represents these underlying fracture mechanisms through plastic strain and stress triaxiality histories that can be modeled at the material continuum level by finite-element analyses. Development and validation of the CVGM is substantiated by about 100 notched bar tests, with accompanying finite-element analyses, metallurgical tests, and fractographic examinations of seven varieties of structural steels. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A6%2870 [...] [article] Cyclic void growth model to assess ductile fracture initiation in structural steels due to ultra low cycle fatigue [texte imprimé] / A. M. Kanvinde, Auteur ; G. G. Deierlein, Auteur . - 2007 . - pp.701–712. Applied mechanics Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 133 N°6 (Juin 2007) . - pp.701–712. Mots-clés : Voids  Steel  Fatigue  Steel  structures  Earthquakes Résumé : A new model is proposed to simulate ductile fracture initiation due to large amplitude cyclic straining in structural steels, which is often the governing limit state in steel structures subjected to earthquakes. Termed the cyclic void growth model (CVGM), the proposed technique is an extension to previously published models that simulate ductile fracture caused by void growth and coalescence under monotonic loading. The CVGM aims to capture ultra low cycle fatigue (ductile fracture) behavior, which is characterized by a few (generally, less than 20) reverse loading cycles to large inelastic strain amplitudes (several times the yield strain). The underlying mechanisms of low-cycle fracture involve cyclic void growth, collapse, and distortion, which are distinct from those associated with more conventional fatigue. The CVGM represents these underlying fracture mechanisms through plastic strain and stress triaxiality histories that can be modeled at the material continuum level by finite-element analyses. Development and validation of the CVGM is substantiated by about 100 notched bar tests, with accompanying finite-element analyses, metallurgical tests, and fractographic examinations of seven varieties of structural steels. ISSN : 0733-9399 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%290733-9399%282007%29133%3A6%2870 [...]

Fillet weld groups loaded with out-of-plane eccentricity / A. M. Kanvinde in Journal of structural engineering, Vol. 139 N° 3 (Mars 2013) 

Public ISBD [article]  in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 305–319 Titre : Fillet weld groups loaded with out-of-plane eccentricity : simulations and new model for strength characterization Type de document : texte imprimé Auteurs : A. M. Kanvinde, Auteur ; J. Liu, Auteur ; X. Fu, Auteur Année de publication : 2013 Article en page(s) : pp. 305–319 Note générale : structural engineering Langues : Anglais (eng) Mots-clés : welding;  welded  connections;  finite  element  method;  simulation Résumé : The strength of fillet weld groups, loaded with an out-of-plane eccentricity, is controlled by complex interactions of weld yielding, as well as bearing between the connected parts. Current models that characterize connection strength, including those used in North American design specifications, are highly conservative, leading to oversized welds. These models are phenomenological, because the internal stress distribution within the welds is difficult to characterize experimentally. A new model is proposed for characterizing the strength of these connections. The model is based on insights developed from sophisticated finite-element (FE) simulations that feature accurate measurements of weld profiles, multiaxial plasticity, and simulation of contact and gapping phenomena that strongly influence connection response. The FE simulations reveal that current models do not reflect key aspects of force transfer within the connection, especially on the compression side. The proposed model incorporates these insights by using stress profiles and mechanisms consistent with those implied by the FE simulations. The model is evaluated against 79 experiments from three test programs. It is determined that the new model greatly reduces the conservatism of the existing models, resulting in an average test-to-predicted ratio of 1.01. This is in contrast to previous models, for which the average test-to-predicted ratios are in the range of 1.33–1.77. The efficacy of the proposed model is analyzed with respect to various parameters, and its limitations are outlined. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000641 [article] Fillet weld groups loaded with out-of-plane eccentricity : simulations and new model for strength characterization [texte imprimé] / A. M. Kanvinde, Auteur ; J. Liu, Auteur ; X. Fu, Auteur . - 2013 . - pp. 305–319. structural engineering Langues : Anglais (eng) in Journal of structural engineering > Vol. 139 N° 3 (Mars 2013) . - pp. 305–319 Mots-clés : welding;  welded  connections;  finite  element  method;  simulation Résumé : The strength of fillet weld groups, loaded with an out-of-plane eccentricity, is controlled by complex interactions of weld yielding, as well as bearing between the connected parts. Current models that characterize connection strength, including those used in North American design specifications, are highly conservative, leading to oversized welds. These models are phenomenological, because the internal stress distribution within the welds is difficult to characterize experimentally. A new model is proposed for characterizing the strength of these connections. The model is based on insights developed from sophisticated finite-element (FE) simulations that feature accurate measurements of weld profiles, multiaxial plasticity, and simulation of contact and gapping phenomena that strongly influence connection response. The FE simulations reveal that current models do not reflect key aspects of force transfer within the connection, especially on the compression side. The proposed model incorporates these insights by using stress profiles and mechanisms consistent with those implied by the FE simulations. The model is evaluated against 79 experiments from three test programs. It is determined that the new model greatly reduces the conservatism of the existing models, resulting in an average test-to-predicted ratio of 1.01. This is in contrast to previous models, for which the average test-to-predicted ratios are in the range of 1.33–1.77. The efficacy of the proposed model is analyzed with respect to various parameters, and its limitations are outlined. En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000641

Rotational stiffness of exposed column base connections / A. M. Kanvinde in Journal of structural engineering, Vol. 138 N° 5 (Mai 2012) 

Public ISBD [article]  in Journal of structural engineering > Vol. 138 N° 5 (Mai 2012) . - pp. 549–560. Titre : Rotational stiffness of exposed column base connections : Experiments and analytical models Type de document : texte imprimé Auteurs : A. M. Kanvinde, Auteur ; D.A. Grilli, Auteur ; F. Zareian, Auteur Année de publication : 2012 Article en page(s) : pp. 549–560. Note générale : Génie civil Langues : Anglais (eng) Mots-clés : Column  base  plates  Steel  connections  Earthquake  engineering Résumé : The rotational flexibility of column base connections is often ignored in structural simulation of moment frames in which the bases are assumed to be either fixed or pinned. Although structural response is sensitive to base flexibility, methods to properly characterize base flexibility are not readily available. Motivated by these issues, a new approach to characterize the rotational flexibility of exposed column base connections is presented in this paper. The method leverages existing design procedures for base connection design, such that the rotational stiffness may be calculated with modest effort once the design has been completed. The method is validated through comparison with nine experiments, which interrogate a range of parameters including base-plate size and thickness, level of axial load, anchor-rod strength, and concrete strength. The comparison between the test and the predicted values indicates that, on average, the method predicts the stiffness with accuracy, such that the average test-to-predicted ratio is 0.89. The method is particularly accurate for conditions in which the moment-to-axial-load ratio is large, whereas it overestimates the stiffness of connections with high axial load, relative to the applied moment. A detailed analysis of the results is presented, accompanied by a discussion of the limitations of the proposed approach. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000495 [article] Rotational stiffness of exposed column base connections : Experiments and analytical models [texte imprimé] / A. M. Kanvinde, Auteur ; D.A. Grilli, Auteur ; F. Zareian, Auteur . - 2012 . - pp. 549–560. Génie civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 138 N° 5 (Mai 2012) . - pp. 549–560. Mots-clés : Column  base  plates  Steel  connections  Earthquake  engineering Résumé : The rotational flexibility of column base connections is often ignored in structural simulation of moment frames in which the bases are assumed to be either fixed or pinned. Although structural response is sensitive to base flexibility, methods to properly characterize base flexibility are not readily available. Motivated by these issues, a new approach to characterize the rotational flexibility of exposed column base connections is presented in this paper. The method leverages existing design procedures for base connection design, such that the rotational stiffness may be calculated with modest effort once the design has been completed. The method is validated through comparison with nine experiments, which interrogate a range of parameters including base-plate size and thickness, level of axial load, anchor-rod strength, and concrete strength. The comparison between the test and the predicted values indicates that, on average, the method predicts the stiffness with accuracy, such that the average test-to-predicted ratio is 0.89. The method is particularly accurate for conditions in which the moment-to-axial-load ratio is large, whereas it overestimates the stiffness of connections with high axial load, relative to the applied moment. A detailed analysis of the results is presented, accompanied by a discussion of the limitations of the proposed approach. ISSN : 0733-9445 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000495