Search results for " scienza delle costruzioni"

Fractional calculus application to visco-elastic solid

2009

It is widely known that fractional derivative is the best mathematical tool to describe visco-elastic constitutive law. In this paper it is shown that as soon as we assume the creep compliance function as power law type, as in the linearized version of the Nutting equation, then the fractional constitutive law appears in a natural way. Moreover, using Nutting equation for the creep function, the relaxation modulus is also of power law type whose coefficients (intensity and exponent) are strictly related to those of the creep compliance. It follows that by a simple creep test (or relaxation test) by means of a best fitting procedure we may easily evaluate the parameters of Nutting equation a…

Seismic response of steel frames with reduced beam sections

2003

This study concerns the effectiveness of weakening on the beams of fully and partially restrained connection steel frames in order to locate plastic hinges far from the joints. Two types of non-linear analysis, for geometry and constitutive law are developed: static pushover analysis, in which the structure is subjected to constant vertical loads and to horizontal loads linearly increasing up to collapse; and incremental dynamic analysis, in which the structure is subjected to uniformly scaled ground motions. Applications for four-bay frames with three and nine stories designed according to the EC3 code and for Italian 1st-category seismic areas are developed in order to evaluate the influe…

Thermal and structural properties of a hemp–lime biocomposite

2013

Abstract The need to reduce greenhouse gases emission produced by the building sector leads to the research of renewable and less impacting materials that can replace traditional ones. This subject has encouraged new researches on biocomposite concretes with the aim to exploit renewable resources like vegetal fibres intended as materials whose production processes are generally characterized by low costs and energy demand. This biocomposite is obviously much lighter than concrete and, therefore, can be suitably used in such cases where a structure cannot be overloaded, for instance in the realization of a green covering on top of a preexistent building. In this work, a first analysis of the…

Cyclic Delamination Analysis: Experimental and Cohesive-Frictional interface Finite Element Modelling

2011

Prestress and experimental tests on fractional viscoelastic materials

2013

Creep and/or Relaxation tests on viscoelastic materials show a power-law trend. Based upon Boltzmann superposition principle the constitutive law with a power-law kernel is ruled by the Caputo’s fractional derivative. Fractional constitutive law posses a long memory and then the parameters obtained by best fitting procedures on experimental data are strongly influenced by the prestress on the specimen. As in fact during the relaxation test the imposed history of deformation is not instantaneously applied, since a unit step function may not be realized by the test machine. Aim of this paper, it is shown that, the experimental procedure, and in particular the initial ramp to reach the constan…

The restoration of the North-East corner columns of Santa Maria La Nova the cloister in Monreale, Italy

2022

Lo scopo della presente ricerca è quello di descrivere i risultati dello studio, con la rappresentazione tramite scanner laser 3D, e del restauro scientifico, che ha previsto anche una reintegrazione, del gruppo di colonne posto nell'angolo Nord-Est del famoso chiostro dell'Abbazia di Santa Maria La Nova in Monreale, vicino Palermo, Italia (ultimo quarto del XII secolo) The purpose of the present research is to describe the results of the study, with 3D laser scanner representation, and scientific restoration, which also included reintegration, of the group of columns located in the northeast corner of the famous cloister of the Abbey of Santa Maria La Nova in Monreale, near Palermo, Italy …

Ion Exchange Membrane deformation and its relevance in Reverse ElectroDialysis

2017

Reverse electrodialysis (RED) is an innovative electro-membrane technology for electric energy generation from two salt solutions with different concentration. This different concentration is the driving force to a selective movement of ions from the concentrate channel to the dilute one oriented by Ion Exchange Membranes (IEMs). Typically, RED stack are made by piling alternatively cation exchange membranes and anion exchange membranes with the aid of spacers or profiles built on the membrane surface. Two electrodic compartments are placed at the two ends of the stack, where the ion flux generated is converted into an electric current able to circulate through an external load connected to…

Fluid-structure interaction and flow redistribution in membrane-bounded channels

2019

The hydrodynamics of electrodialysis and reverse electrodialysis is commonly studied by neglecting membrane deformation caused by transmembrane pressure (TMP). However, large frictional pressure drops and differences in fluid velocity or physical properties in adjacent channels may lead to significant TMP values. In previous works, we conducted one-way coupled structural-CFD simulations at the scale of one periodic unit of a profiled membrane/channel assembly and computed its deformation and frictional characteristics as functions of TMP. In this work, a novel fluid&ndash

A novel 2D model for the assessment of deformation-induced flow redistribution phenomena in electrodialysis units

2022

A 2-D model of electrodialysis stacks including the effects of membrane deformation

2021

Abstract Membrane-based processes have gained a relevant role in many engineering applications. Much effort has been devoted to thoroughly understand the fundamental phenomena behind them. However, membrane deformation has been taken into consideration only recently, although much evidence has shown its impacts in many applications. This work presents a novel 2-D, multi-scale, semi-empirical process model able to predict the behavior and the performance of Electrodialysis (ED) systems in cross-flow configurations in the presence and absence of local membrane deformations. The model exploits the results and the simulation approaches of previous fluid-structure investigations performed by the…