Search results for " scienza delle costruzioni"
showing 10 items of 496 documents
Active macro-zone approach for incremental elastoplastic-contact analysis
2013
The symmetric boundary element method, based on the Galerkin hypotheses, has found an application in the nonlinear analysis of plasticity and in contact-detachment problems, but both dealt with separately. In this paper, we want to treat these complex phenomena together as a linear complementarity problem. A mixed variable multidomain approach is utilized in which the substructures are distinguished into macroelements, where elastic behavior is assumed, and bem-elements, where it is possible that plastic strains may occur. Elasticity equations are written for all the substructures, and regularity conditions in weighted (weak) form on the boundary sides and in the nodes (strong) between cont…
Multidomain SBEM analysis of two dimensional elastoplastic-contact problems
2012
The Symmetric Boundary Element Method based on the Galerkin hypotheses has found application in the nonlinear analysis of plasticity and contact-detachment problems, but dealt with separately. In this paper we wants to treat these complex phenomena together. This method works in structures by introducing a subdivision into sub-structures, distinguished into macroelements, where elastic behaviour is assumed, and bem-elements, where it is possible for plastic strains to occur. In all the sub-structures, elasticity equations are written and regularity conditions in weighted (weak) form and/or in nodal (strong) form between boundaries have to be introduced, to attain the solving equation system.
The role of evanescent modes in Global-Local analysis of UGW in plates with varying local zone-scatterer relations
2023
In order to provide a reliable and robust SHM performance, Ultrasonic Guided Waves (UGWs) need to be analyzed and understood. Numerical modeling of UGW propagation and scattering by hybrid methods offers the possibility of simulating UGW interaction with waveguides of arbitrary cross-sections and discontinuities. Maximizing the accuracy of such methods is important to perform quantitative SHM, while maintaining minimum computational cost. This work investigates the role of evanescent modes in the numerical analysis of UGWs in aluminum and composite plates with defects, by the hybrid Global-Local method. The complex solutions to the UGW eigenvalue problem are found and the scattering spectra…
An explicit mechanical interpretation of Eringen non-local elasticity by means of fractional calculus
2009
If the attenuation function of strain is expressed as a power law, the formalism of fractional calculus may be used to handle Eringen non-local elastic model. Aim of the present paper is to provide a mechanical interpretation to this non-local fractional elastic model by showing that it is equivalent to a discrete, point-spring model. A one-dimensional geometry is considered; static, kinematic and constitutive equations as well as the proper boundary conditions are derived and discussed.
3D fractional viscoelasticity with applications to structural engineering
STRUMENTO MEDICO PER INSERIMENTI INTRALUMINALI
2018
La presente invenzione trova applicazione nel settore dei dispositivi medici inseribili all’interno del corpo umano ed ha particolarmente per oggetto uno strumento medico per inserimenti intraluminali, quali dispositivi per incannulazione o cateterizzazione del sistema vascolare.
Guided Wave Techniques for Damage Detection in Composite Aerospace Structures
2018
Composite materials make up an increasing portion of today’s aerospace structures (see, e.g. Boeing 787 and Airbus 380). These aircrafts’ fuselage, for example, is composed of a laminated composite skin connected to composite stringers and C-frames. Of primary importance is the detection of damage in these built-up structures, whether caused by the manufacturing process or in service (e.g. impacts). A related issue is the characterization of the composite (visco)elastic mechanical properties, that can also be related to the quantification of potential damage. Guided elastic waves propagating in the ~100s kHz regime lend themselves to provide the necessary sensitivity to these two conditions…
Sviluppo storico sino al 1998 della Scienza delle Costruzioni e della Tecnica delle Costruzioni nell'Ateneo Palermitano
2008
Nel contributo viene tracciata la storia della Scienza e Tecnica delle costruzioni dell'Università di Palermo a partire dalla Reale Scuola di applicazione per ingegneri e Architetti di Palermo, 1866, passando per il Gabinetto di Meccanica applicata alle Costruzioni, 1923, e per i successivi cambiamenti che portarono al Dipartimento di Ingegneria Strutturale e Geotecnica, 1985. Viene inoltre tracciata la storia dell'annesso Laboratorio di prove sui materiali da costruzione attraverso le attività svolte ed i macchinari acquisiti.
An Interface Model for the Analysis of Anisotropy of Friction and Wear of Contact Surfaces
2008
Effective reference and current integration for large displacement interface
2016
The most common interface formulations proposed in literature are generally based on the restrictive hypothesis of small strains and small displacements and, even though their application to geometrically nonlinear problems is of paramount interest, only few contributions are available in literature. Motivations are probably due to the difficulties encountered on such formulation, as already mentioned by several authors. A pioneering formulation is the finite displacement three-dimensional interface developed by Ortiz and Pandolfi in [1], where normal and tangential traction components are evaluated with respect to the middle surface in the current configuration, producing a non-symmetric g…