1,721,332 research outputs found
Valeria Cavalloro – Gabriele Fichera – Damiano Frasca – Francesca Ippoliti – Alessandra Reccia – Maria Vittoria Tirinato (eds.), Scuola, la posta in gioco
Full text linkReview of the issue Scuola, la posta in gioco edited by Valeria Cavalloro, Gabriele Fichera, Damiano Frasca, Francesca Ippoliti, Alessandra Reccia, Maria Vittoria Tirinato (L’ospite ingrato, n° 9, 2021).
Critique de L’ospite ingrato, n° 9 (janvier-juin 2021).Recensione del numero monografico Scuola, la posta in gioco a cura di Valeria Cavalloro, Gabriele Fichera, Damiano Frasca, Francesca Ippoliti, Alessandra Reccia, Maria Vittoria Tirinato (in L'ospite ingrato, n° 9, 2021).
 
FE, DE and FE/DE models to investigate the non-linear behaviour of masonry walls: a critical comparison
No full textThe study of the non-linear behaviour of masonry panels is of great interest; in literature several approaches may be found, based on the adoption of continuous or discrete models [1][2]. In this work, three different models for the investigation of the non-linear analysis of in-plane loaded masonry walls are presented: a Finite Element (FEM) model (i), a Discrete Element (DEM) model (ii) and a combined Finite-Discrete Element (FEM/DEM) model (iii).
The FE model adopts a macro-modelling approach based on the smeared crack theory, where masonry, as a whole, is considered as a homogeneous material. Yield criterion is based on fracture energy taking into account the masonry softening response different for compression and tensile behaviour [3].
The DE and FE/DE models adopt a micro-modelling approach based on a discrete crack theory, where blocks are modelled as rigid bodies and mortar joints are modelled as zero thickness elasto-plastic Mohr-Coulomb interfaces. A comparison between DE and FE/DE approaches has been already proposed for the in plane non-linear analysis of masonry walls [4].
The FEM/DEM is here adopted with hypothesis of rigid infinitely resistant blocks and cracks may occur only in the mortar joints. However a triangular discretization of the domain with embedded crack elements, that activate whenever the peak strength is reached, is coupled with
DEM. In the FEM/DEM the use of FE allows to reproduce elastic strain into continuum, while the use of DE is suitable to model the frictional cohesive behaviour exhibited by masonry structures. Moreover, crack may occur everywhere, also inside blocks.
A comparison between the three different approaches is provided, in the aim to evaluate their applicability and reliability and the limit of application of each model.
References
[1] Addessi, D. and Sacco, E., “Nonlinear analysis of masonry panels using a kinematic enriched plane state formulation”, International Journal of Solids and Structures, 90, 194-214 (2016)
[2] Lemos, J. V., Discrete element modeling of masonry structures. International Journal of Architectural Heritage, 1(2), 190-213, (2007).
[3] Bello C.B.C., Cecchi A., Meroi E. and Oliveira D.V., Experimental and numerical investigations on the behaviour of masonry walls reinforced with an innovative sisal FRCM system, Submitted to Proceedings of MuRiCo5, Bologna, 28-30 June 2017, (under review).
[4] Baraldi, D., Reccia, E. and Cecchi, A., “In plane loaded masonry walls: DEM & FEM/DEM models. A critical review”, Sumbitted to Meccanica, S.I. New Trends Mech. Mason. (under review)
Three-leaf brick masonry walls: FE & DE models
No full textMost Europeans historical buildings are made by brick or stone masonry, often constituted by multiple leaves. A widespread multi-leaf typology is the three-leaf brick masonry wall, which presents two external brick leaves and one inner core consisting of different incoherent materials, with large presence of voids. Brick masonry behaviour tends to brittle failure mechanisms. By reference to solid masonry, multiple leaf walls present a more complex mechanical behaviour, with not simple, but combined collapse mechanisms: their interpretation remains a challenge [1-3]. The literature referred to modelling masonry interface behaviour considers mortar joints reduced to interfaces and internal block interfaces [4]. Here attention is focused on modelling interface between masonry layers: contact relationships between the inner core and the external leaves. This work develops interface models to describe the internal load distribution in a multi-leaf masonry wall, in addition to existing models already adopted for one-leaf masonry elements [5]. Compressive load results are evaluated with reference to experimental data recently obtained by the research group [6] by means of tests carried out at Laboratorio di Scienza delle Costruzioni IUAV (Labsco). This investigation aims to develop a suitable approach to predict the performance of historical masonry wall by FE & DE simulations. Here the two numerical modelling strategies on three-leaf brick masonry walls are presented and compared.
References
[1] Binda, L., Pina-Henriques, J., Anzani, A., Fontana, A., Lourenço, P.B., “A contribution for the understanding of load-transfer mechanisms in multi-leaf masonry walls: testing and modelling”, Engineering Structures, 28(8), pp. 1132–1148 (2006).
[2] Ramalho, M.A., Taliercio, A, Anzani, A., Binda, L. Papa, E., “A numerical model for the description of the nonlinear behaviour of multi-leaf masonry walls”, Advances in Engineering Software, 39(4), pp. 249-257 (2008).
[3] Milani, G., “3D upper bound limit analysis of multi-leaf masonry walls”, International Journal of Mechanical Sciences, 50(4), pp. 817-836 (2008).
[4] Lourenço, P.B., Rots, J.G., “A multi-surface interface model for the analysis of masonry structures”, ASCE Journal of Engineering Mechanics, 123(7), pp. 660–668 (1997).
[5] Baraldi, D., Reccia, E., Cecchi, A., “In plane loaded masonry walls: DEM and FEM/DEM models. A critical review”, Meccanica, 53, pp. 1613–1628 (2018).
[6] Boscato, G., Reccia, E., Cecchi, A., “Non-destructive experimentation: Dynamic identification of multi-leaf masonry walls damaged and consolidated”, Composites Part B: Engineering, 133, pp. 145–165 (2018)
Codice civile con la Costituzione, i Trattati europei e le principali norme complementari
No full textSi tratta di un codice civile, con la Costituzione e le principali norme complementari. Ciascuno degli autori ne ha curato una parte e l'attribuzione della curatela è indicata alla pagina 2. In particolare, la dott. Roberta Catalano si è occupata di curare i libri primo, terzo e quarto del Codice civile, nonché le sezioni intitolate "Diritti dell'Uomo e Libertà fondamentali", Trattati europei", Disposizioni sulla legge applicabile", "Adozione", "Consumatore", Famiglia e maternità", Informatica ed internet", Obbligazioni e contratti", Vendita e commercio"
Re: Incidental Detection of a Hodgkin Lymphoma on 18F-Choline PET/CT and Comparison With 18FDG PET/CT in a Patient With Prostate Cancer
No full textOn Dynamics of Elastic Networks with Rigid Junctions within Nonlinear Micropolar Elasticity
Full text linkWithin the nonlinear micropolar elasticity we discuss effective dynamic (kinetic) properties of elastic networks with rigid joints. The model of a hyperelastic micropolar continuum is based on two constitutive relations, i.e. static and kinetic ones. They introduce a strain energy density and a kinetic energy density, respectively. Here we consider three-dimensional elastic network made of three families of elastic fibers connected through massive rigid joints. So effective elastic properties are inherited from the geometry and material properties of fibers, whereas the kinetic (inertia) properties are determined by the both fibers and joints. Formulae for microinertia tensors are given
Nonlinear strain gradient and micromorphic one-dimensional elastic continua: Comparison through strong ellipticity conditions
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