Search results for "cienza"

Visco-elastic behavior through fractional calculus: an easier method for best fitting experimental results

2011

In capturing visco-elastic behavior, experimental tests play a fundamental rule, since they allow to build up theoretical constitutive laws very useful for simulating their own behavior. The main challenge is representing the visco-elastic materials through simple models, in order to spread their use. However, the wide used models for capturing both relaxation and creep tests are combinations of simple models as Maxwell and/or Kelvin, that depend on several parameters for fitting both creep and relaxation tests. This paper, following Nutting and Gemant idea of fitting experimental data through a power law function, aims at stressing the validity of fractional model. In fact, as soon as rela…

Filter equation by fractional calculus

2014

Aim of this paper is to represent a causal filter equation for any kind of linear system in the general form L=f(t), where f(t) is the forcing function, x(t) is the output and L is a summation of fractional operators. The exact form of the operator L is obtained by using Mellin transform in complex plane.

On the numerical implementation of a 3D fractional viscoelastic constitutive model

2015

The aim of this paper is the implementation of a 3D fraction al viscoelastic constitutive law in a user material subroutine (UMAT) in the finite element software Abaqus. Essential to the implementation of the model is access to the strain history at each Gauss point of each element in a constructive manner. Details of the UMAT and comparison with some analytical results are presented in order to show that the fractional viscoelastic constitutive law has been successfully implemented.

Mechanical properties of basalt fiber reinforced composites manufactured with different vacuum assisted impregnation techniques

2016

Abstract This work describes an experimental mechanical characterisation campaign on composites made out of a quasi-unidirectional basalt fabric. In order to evaluate the ability of commercial basalt fabrics and their composites to meet the potentials of basalt fibers, the work has used raw materials from commercial catalogs with no further modification. Two common manufacturing techniques for medium performance composites have been adopted: vacuum assisted resin infusion, and hand-impregnated vacuum bagging. Two panels, one for each technique, have been fabricated, able to provide a sufficient number of samples for a comprehensive stiffness and strength characterization through Tensile, Fl…

Inter-Element Crack Propagation with High-Order Stress Equilibrium Element

2021

The present contribution proposes a formulation based on the use of hybrid equilibrium elements (HEEs), for the analysis of inter-element delamination and fracture propagation problems. HEEs are defined in terms of quadratic stress fields, which strongly verify both the homogeneous and inter-element equilibrium equations and they are employed with interfaces, initially exhibiting rigid behavior, embedded at the elements’ sides. The interface model is formulated in terms of the same degrees of freedom of the HEE, without any additional burden. The cohesive zone model (CZM) of the extrinsic interface is rigorously developed in the damage mechanics framework, with perfect adhesion at the pre-…

Il contributo di Francesco Scaduto alla scienza giuridica

2009

The Economics of Freedom. Theory, Measure and Policy Implications

2012

What is freedom? Can we measure it? Does it affect policy? This book develops an original measure of freedom called 'Autonomy Freedom', consistent with J. S. Mill's view of autonomy, and applies it to issues in policy and political design. The work pursues three aims. First, it extends classical liberalism beyond exclusive reliance on negative freedom so as to take autonomous behavior explicitly into account. Second, it grounds on firm conceptual foundations a new standard in the measurement of freedom that can be fruitfully coupled with existing gauges. Third, it shows empirically that individual preferences for redistribution and cross-country differences in welfare spending in Organisati…

True V or not True V, That is the Question

2016

In this paper we intend to argue that: (1) the question `True V or not True V' is central to both the philosophical and mathematical investigations of the foundations of mathematics; (2) when posed within a framework in which set theory is seen as a science of objects, the question `True V or not True V' generates a dilemma each horn of which turns out to be unacceptable; (3) a plausible way out of the dilemma mentioned at (2) is provided by an approach to set theory according to which this is considered to be a science of structures.

Vibration mitigation of the Silver Madonna during the procession in Palermo: preliminary study

2010

The role of friction in the 3ENF and 4ENF delamination tests: an analytical solution

2018

In composite structures, the presence and growth of delamination mechanisms in static or fatigue loading conditions is of paramount interest and the American Society for Testing and Materials (ASTM) has adopted the three-points bend end-notched flexure test (3ENF) as the standard for measurement of mode II toughness. The drawback of the 3ENF test is the unstable crack growth and a modified version of the test, namely the four points bend end-notched flexure test (4ENF), has been proposed. The main advantage of the 4ENF over the 3ENF is that crack growth is stable under displacement control, but it can be strong influenced by the interlaminar frictional effects. The effect of frictional cont…