Documents disponibles écrits par cet auteur

Adaptive Configuration Tuned Mass Damper for Mitigation of Rotational Vibrations / R. Mohammadi-Ghazi in Journal of engineering mechanics, Vol. 138 N° 8 (Août 2012) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 138 N° 8 (Août 2012) . - pp.934–944 Titre : Adaptive Configuration Tuned Mass Damper for Mitigation of Rotational Vibrations Type de document : texte imprimé Auteurs : R. Mohammadi-Ghazi, Auteur ; A. K. Ghorbani-Tanha, Auteur ; M. Rahimian, Auteur Année de publication : 2012 Article en page(s) : pp.934–944 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Adaptive  configuration  Mass  moment  of  inertia  Semiactive  vibration  absorber  Adaptive  tuned  mass  damper  Variable  stiffness  Transient  vibrations Résumé : An innovative design for an adaptive configuration tuned mass damper (ACTMD) is proposed. An ACTMD is a semiactive dynamic vibration absorber by which the undesirable rotational vibrations of a structure can be greatly suppressed. It can also be used to attenuate translational vibrations that are converted into rotation by means of an appropriate mechanism. Retuning the absorber with the instantaneous excitation frequency is accomplished by changing the configuration of the ACTMD. The device consists of both fixed and moving parts. To readjust the absorber with the new condition, the position of the moving parts should change. As a result, the device’s mass moment of inertia (MMI) alters and the ACTMD adapts to the new condition in real time. However, the device may not cover all frequency bands, because the moving parts cannot be located in all desirable places. After determining the governing equations, the other effects of alternation in the device’s configuration, such as the attenuation-amplification coefficient, are interpreted. Then, the performance of the absorber is evaluated by controlling a transient rotational vibration through numerical simulation. Finally, a sensitivity analysis is carried out to identify a suitable range of MMI for designing an ACTMD. ISSN : 0888-5885 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000400 [article] Adaptive Configuration Tuned Mass Damper for Mitigation of Rotational Vibrations [texte imprimé] / R. Mohammadi-Ghazi, Auteur ; A. K. Ghorbani-Tanha, Auteur ; M. Rahimian, Auteur . - 2012 . - pp.934–944. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 138 N° 8 (Août 2012) . - pp.934–944 Mots-clés : Adaptive  configuration  Mass  moment  of  inertia  Semiactive  vibration  absorber  Adaptive  tuned  mass  damper  Variable  stiffness  Transient  vibrations Résumé : An innovative design for an adaptive configuration tuned mass damper (ACTMD) is proposed. An ACTMD is a semiactive dynamic vibration absorber by which the undesirable rotational vibrations of a structure can be greatly suppressed. It can also be used to attenuate translational vibrations that are converted into rotation by means of an appropriate mechanism. Retuning the absorber with the instantaneous excitation frequency is accomplished by changing the configuration of the ACTMD. The device consists of both fixed and moving parts. To readjust the absorber with the new condition, the position of the moving parts should change. As a result, the device’s mass moment of inertia (MMI) alters and the ACTMD adapts to the new condition in real time. However, the device may not cover all frequency bands, because the moving parts cannot be located in all desirable places. After determining the governing equations, the other effects of alternation in the device’s configuration, such as the attenuation-amplification coefficient, are interpreted. Then, the performance of the absorber is evaluated by controlling a transient rotational vibration through numerical simulation. Finally, a sensitivity analysis is carried out to identify a suitable range of MMI for designing an ACTMD. ISSN : 0888-5885 En ligne : http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29EM.1943-7889.0000400

Methods to improve infilled frame ductility / M. Mohammadi in Journal of structural engineering, Vol. 137 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of structural engineering > Vol. 137 N° 6 (Juin 2011) . - pp. 646-653 Titre : Methods to improve infilled frame ductility Type de document : texte imprimé Auteurs : M. Mohammadi, Auteur ; V. Akrami, Auteur ; R. Mohammadi-Ghazi, Auteur Année de publication : 2011 Article en page(s) : pp. 646-653 Note générale : Génie Civil Langues : Anglais (eng) Mots-clés : Engineered  infill  Cyclic  tests  Steel  frames  Cracking  Stiffness  Strength  Ductility  Frictional  sliding  fuse Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : An experimental investigation was conducted to achieve engineered infilled frames in two stages. The first stage was aimed at discovering methods to raise infilled frames’ ductility, through testing six single-story single-bay infilled steel frames; three general techniques were studied, disregarding their manufacturing details. Results show that supplying a sliding fuse in the infill highly efficiently increases ductility; however, this presents some problems that can be avoided by improving fuse configuration. The second stage of the testing was conducted with two specimens with an improved sliding fuse configuration, in which the influences of fuse sliding strength on the behavior of the infilled frames were studied. On the basis of these results, the infills, provided with frictional sliding fuses, can be considered to be engineered elements of high ductility, of transversal stability, and capable of being adjusted for desired strengths. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i6/p646_s1?isAuthorized=no [article] Methods to improve infilled frame ductility [texte imprimé] / M. Mohammadi, Auteur ; V. Akrami, Auteur ; R. Mohammadi-Ghazi, Auteur . - 2011 . - pp. 646-653. Génie Civil Langues : Anglais (eng) in Journal of structural engineering > Vol. 137 N° 6 (Juin 2011) . - pp. 646-653 Mots-clés : Engineered  infill  Cyclic  tests  Steel  frames  Cracking  Stiffness  Strength  Ductility  Frictional  sliding  fuse Index. décimale : 624 Constructions du génie civil et du bâtiment. Infrastructures. Ouvrages en terres. Fondations. Tunnels. Ponts et charpentes Résumé : An experimental investigation was conducted to achieve engineered infilled frames in two stages. The first stage was aimed at discovering methods to raise infilled frames’ ductility, through testing six single-story single-bay infilled steel frames; three general techniques were studied, disregarding their manufacturing details. Results show that supplying a sliding fuse in the infill highly efficiently increases ductility; however, this presents some problems that can be avoided by improving fuse configuration. The second stage of the testing was conducted with two specimens with an improved sliding fuse configuration, in which the influences of fuse sliding strength on the behavior of the infilled frames were studied. On the basis of these results, the infills, provided with frictional sliding fuses, can be considered to be engineered elements of high ductility, of transversal stability, and capable of being adjusted for desired strengths. DEWEY : 624.17 ISSN : 0733-9445 En ligne : http://ascelibrary.org/sto/resource/1/jsendh/v137/i6/p646_s1?isAuthorized=no