Tesi di Dottorato
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Item Koiter's asymptotic numerical methods for shell structures using a corotational formulation(2009-11-30) Zagari, Giuseppe; Aristodemo, Maurizio; Casciaro, Raffaele; Garcea, GiovanniItem H-infinity optimal control of active dumpers for automotive suspension systems and civil structures(2014-06-09) Ezzine, Jamal; Vulcano, Alfonso; Aristodemo, MaurizioIn recent years the protection of structures against hazardous vibration has gained special interest. Structures such as buildings, bridges and vehicles are subject to vibrations that may cause malfunctioning, un-comfort or collapse. It is an extended practice to install damping devices in order to mitigate such vibrations. Furthermore, when the dampers are controllable, the structure acts as an adaptronic system. Adaptronic systems are characterized by their abil- ity to respond to external loading conditions and adapt themselves to these changes. These abilities can be exploited to solve the vibration mitigation problems through the installation of controllable dampers and the design of appropriate control laws for an adequate actuation. These modern systems in the case of vehicle suspension systems o®er improved comfort and road hold- ing in varying driving and loading conditions compared to traditional passive devices.Item Post-buckling behaviour of transversely stiffened plate girders(2014-05-28) Presta, Francesco; Aristodemo, Maurizio; Turco, EmilioMany investigations have been carried out to date into the behaviour of transversely stiffened web panels in bending and shear and many different theories have been proposed. Different code rules have been developed based on these theories. The British steel bridge code, BS 5400 Part 3, based its design rules for transverse stiffeners on the work of Rockey, while early drafts of Eurocode prEN 1993-1-5 were based on the work of Höglund. The former's tension field theory places a much greater demand on stiffener strength than does the latter's rotated stress field theory. Due to a lack of European agreement, EN 1993-1-5 was modified late on its drafting to include a stiffener force criterion more closely aligned to that in BS 5400 Part 3. The rules for stiffener design in EN 1993-1-5 are thus no longer consistent with the rotated stress field theory and lead to a greater axial force acting in the stiffener. The rules for the design of the web panels themselves in shear however remain based on Höglund's rotated stress field theory, creating an inconsistency. Recent investigations have suggested that the rules in BS 5400 Part 3 and, to a lesser extent, in the current version of EN 1993-1-5 can be unduly pessimistic. This thesis investigates the behaviour of transversely stiffened plate girders in bending and shear using non-linear finite element analyses. It considers slender symmetrical steel girders with and without axial force and also steel-concrete composite plate girders (which are therefore asymmetric). It discusses the observed web post-buckling behaviour, compares it with the predictions of other current theories and recommends modified design rules. It includes investigation into whether a stiffness-only approach to stiffener design can be justified, rather than a combined stiffness and force approach. The shear-moment interaction behaviour of the girders as a whole are also investigated aItem Rielaborazioni e sviluppi degli approcci per l'analisi di problemi dinamici nonlineari delle strutture(2014-05-19) Russo, Katia; Lopez, Salvatore; Aristodemo, MaurizioItem The implicit corotational method: general theory and FEM implementation(2014-03-12) Madeo, Antonio; Garcea, Giovanni; Casciaro, Raffaele; Aristodemo, Maurizio