Giorgio Barone

In the last decades, the research community has shown an increasing interest in the engineering applications of fractional calculus, which allows to accurately characterize the static and dynamic behavior of many complex mechanical systems, e.g., the nonlocal or nonviscous constitutive law. In particular, fractional calculus has gained considerable importance in the random vibration analysis of engineering structures provided with viscoelastic damping. In this case, the evaluation of the dynamic response in the frequency domain presents significant advantages, once a probabilistic characterization of the input is provided. On the other hand, closed-form expressions for the response statistics of dynamical fractional systems are not available even for the simplest cases. Taking advantage of the residue theorem, in this paper the exact expressions of the spectral moments of integer and complex orders (i.e., fractional spectral moments of linear fractional oscillators driven by acceleration time histories obtained as samples of stationary Gaussian white noise processes are determined.

This is a conference paper.The phenomenon of wave propagation through concrete materials is affected by dispersion\ud due to its intrinsic heterogeneous microstructure. Previous experiments have\ud shown an increase of phase velocity at high frequencies. This behaviour cannot be analytically described by the classical elasticity theory, due to its non-dispersive nature. Instead, enhanced theories can be adopted. In this work the dynamically consistent non local model, able to take into account the microstructural effects by two additional length scale parameters, is retrieved. The main subject of this contribution is the experimental identification of the dispersive behaviour of cementitious materials and the validation of the gradient continuum to predict the dispersion of the wave born out of the heterogeneity of the material. The proposed work extends the applicability of non-local theories from a purely heoretical/analytical domain to the laboratory territory

This is a conference paperThe potential of double-skin façade systems as distributed mass dampers to reduce\ud vibrations in tall buildings under seismic excitations is investigated in this paper.\ud The design problem consists of determining flexural stiffness of the outer skin, as\ud well as the stiffness of its links to the primary structure and its damping. These\ud structural parameters are estimated through two alternative optimisation procedures,\ud aiming at minimising the standard deviation of the displacements of the first storey\ud of the primary structure. Numerical results are presented for a set of recorded\ud accelerograms to take into account the effects of non-stationary excitations. A direct approach for the design of the stiffness link is also presented, based on observations deriving from the outcome of the optimisation problem

The evolution of naval vessels toward high-speed crafts subjected to severe sea conditions has promoted an increasing interest in lightweight high-strength materials. Due to its strength and weight characteristics, aluminum has been proven especially suitable as construction material for hull structures as well as other vessel parts. However, fatigue in aluminum naval crafts needs to be effectively addressed for the proper life-cycle assessment. Structural health monitoring systems constitute effective tools for measuring the structural response and assessing the structural performance under actual operational conditions. In this article, an approach for using structural health monitoring information in the fatigue reliability analysis and service life prediction of aluminum naval vessels is presented. The accumulated fatigue damage and the fatigue reliability are quantified based on structural health monitoring data acquired under different operational conditions, specified by the ship speeds, sea states, and heading angles. Additionally, an approach for estimating the reliability-based fatigue life under a given operational profile is presented. Seakeeping trial data of an aluminum high-speed naval vessel are used to illustrate the proposed approach.