1,721,054 research outputs found
Mode jumping and attractive paths in multimode elastic buckling
No full textThis paper summarizes a part of the first author's Ph.D. Thesis(1) completely devoted to multimode elastic buckling within an FEM strategy. The theoretical arguments unfold among critical points on radial paths (the unique post-critical paths variationally defined), algebraic characterizations, proposition demonstrations and so on, by aiming to prove that the complexity of the phenomenon of multimode buckling (secondary bifurcations, post-critical attractive paths) can be theoretically explained
Finite Element formulation for nonlinear analysis of masonry walls
No full textThe work builds upon previous developments made by the authors in the context of the nonlinear, in-plane analysis of masonry walls. The structural behavior is characterized by phenomena, such as strain localization, damage, and friction, which need to be modeled at fine scales. Fine-scale modeling represents a significant challenge with regards to numerical simulations, due to its computational expensiveness and hard manageability. Generally, it requires sophisticated solution strategies, such as multi-grid techniques, as proposed in 2007 by the same authors, which cannot be effortlessly used in engineering softwares for structural analysis and design. In order to overcome such difficulties, we propose a coarse-scale model, to be employed in standard path-following techniques. based on an assumed stress Finite Element formulation in a context of non-associated plasticity. We obtain the nonlinear behavior by assuming a set of planes on the Element where frictional response can take place, together with tensile and compression limit stress. In this way, we capture the essential features of the nonlinear behavior as described by the more refined models developed in the past, exploiting algorithms widely adopted in elasto-plasticity, and therefore suitable for practical use in the analysis of full scale masonry structures
Sicurezza all'instabilità globale dei telai in acciaio.
No full textGiornate Italiane della Costruzione in Acciaio, C.T.A., Verona, 197
A numerical analysis of infinitesimal mechanisms
No full textThe paper presents a numerical algorithm, based on Koiter's theory of the elastic stability, for detecting the order of infinitesimal mechanisms, i.e. kinematically indeterminate systems of pin-jointed bars. In cases of one degree of indeterminacy the algorithm improves, in terms of computational simplicity and efficiency, an analogous algorithm proposed by Salerno in 1992. This is shown to be due to the vanishing of the terms higher than the third-order of the asymptotic expressions of the energy, owing to the use of the Green strain measure and a mixed (displacement and stress) formulation of the problem. Moreover, the proposed algorithm is able to provide a correct definition of mechanism in cases of several degrees of indeterminacy, mainly for structures like those first studied by Connelly and Servatius in 1994, which the paper will treat in depth
Sicurezza all'instabilità globale dei telai in acciaio.
No full textGiornate Italiane della Costruzione in Acciaio, C.T.A., Verona, 197
Schemi iterativi per l'analisi path-following di strutture reticolari in buckling multimodale
No full text
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