Search results for " COSTRUZIONE"

Inspection of additive-manufactured layered components

2015

Laser powder deposition (LPD) is a rapid additive manufacturing process to produce, layer upon layer, 3D geometries or to repair high-value components. Currently there is no nondestructive technique that can guarantee absence of flaws in LPD products during manufacturing. In this paper a laser ultrasonic technique for in-line inspection of LPD components is proposed. Reference samples were manufactured from Inconel and machined flaws were created to establish the sensitivity of the technique. Numerical models of laser-generated ultrasonic waves have been created to gain a deeper understanding of physics, to optimize the set-up and to verify the experimental measurements. Results obtained on…

Theoretical and Experimental Comparison between the Resistance Components of a fast Catamaran in different Configurations

2009

The investigation performed by the Authors represents the most recent development of a research presented in [1] and [2], in which the geometrical solutions of the hull have been obtained through an optimization process, made by using the CFD numerical methods. The most important result of this optimization was the wave resistance reduction, which arrived up to 20% of the total initial resistance. In this further process the hull catamaran model has been built and tested at the towing tanks of the Universities of Naples and Trieste. The results obtained in the numerical process have been compared with the experimental ones and the reliability of the numerical results will be proved. Then th…

An analysis of interface delamination mechanisms in orthotropic and hybrid fiber-metal composite laminates

2007

Abstract The onset and propagation of interlaminar defects is one of the main damage mechanisms in composite materials. This is even more the case when considering layered materials comprising metallic laminae (typically Aluminium) and FRP laminae. Propagation of delamination mainly depends on the initial crack extension and its loading mode. This work presents some results of a combined analytical–numerical–experimental study on the onset and propagation mechanisms regarding interlaminar defects. Two cases have been analysed in particular, the first consisting of a glass-fibre reinforced epoxy resin laminate, and the second consisting of a hybrid laminate where a lamina of aluminium is lay…

Speculazione ed empiria: la Deduzione generale del 1800

2012

STUDIO DEL COMPORTAMENTO DINAMICO DI UN MODELLO HALF CAR E CONFRONTO FRA AMMORTIZZAZIONE PASSIVA E SEMIATTIVA A FLUIDO MAGNETO-REOLOGICO

2010

Questo lavoro inizia con la progettazione di massima del pistone di un ammortizzatore a fluido magnetoreologico, effettuata con l’ausilio di Solid Works e del software di simulazione magnetica FEMM. Le dimensioni preliminari sono state assegnate facendo uso delle relazioni teoriche, mentre il software FEMM ha confermato il risultato. Sono state poi ricavate le equazioni della dinamica di un modello half car, sia in forma di sistema di equazioni differenziali che in forma di spazio di stato. Tramite l’interfaccia SimuLink di MatLab, è eseguito un confronto fra i risultati ottenuti dal sistema in condizioni di funzionamento passivo con quelli in funzionamento semi-attivo. Scelta la geometria …

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…

Thermal NDE of thick GRP panels by means of a Pulse Modulated Lock-In Thermography technique

2010

This work describes the development and implementation of an infrared thermal NDE procedure for the evaluation of subsurface defects. The approach is called Pulse-Modulated Lock-In Thermography (PMLT) and is based on the analysis of the frequency response of the measured temperature and comparison with the carrier frequencies launched by the external heat delivering source. The heat deposited on the object is in particular modulated as a train of square waves. This is easily achieved by periodically shuttering the heat source. The temperature is then sampled throughout the deposition of a few square waves. A lock-in algorithm is then implemented able to selectively filter out components at …

Topological optimization of a structural naval component manufactured in FDM

2019

In this paper, a topological optimization procedure has been applied on a real component of the deck of a sailing multi-hull in order to find the internal shape that best save the material used in the manufacturing process without a relevant loss of structural rigidity. The multi-hull boat is a 16 feet length catamaran equipped with an asymmetric foil on both centerboards and with a symmetric foil on both rudders. The task of the analyzed object is to act as a cylindrical support for the screw that drives the rotation of the centerboard. The process adopted to manufacture this object is the Fused Deposition Modeling (FDM) technique, because of its high versatility and its relative low-cost …

Architettura e costruzione delle “gallerie a pozzi” nella piana di Palermo

2014

Se la tutela dei Beni Culturali ed Ambientali “visibili” risulta spesso incentivata e promossa dall’opinione pubblica che percepisce in modo immediato nel degrado dei monumenti, delle opere d’arte o del paesaggio il rischio di una perdita irrimediabile, la salvaguardia di tutto ciò che è nascosto alla vista risulta spesso di più difficile attuazione: è il caso del vasto “Patrimonio Cavo” nascosto nel sottosuolo palermitano. In questo panorama rappresenta un’eccezione il “Corso Gesuitico Alto” a Palermo, una complessa architettura di cunicoli sotterranei destinati alla captazione e all'adduzione dell’acqua, uno dei pochi sistemi ancora attivi, non mutilato dagli scavi ciechi ed irresponsabil…

Injury Evaluation in Teenage Cyclist-Vehicle Crash by Multibody Simulation

2014

Information on impact locations, impact situations and cyclist and pedestrian dynamics in impacts with passenger cars is fundamental for the development of effective solutions to improve cyclist and pedestrian protection. Accidentology research shows that cyclists typically have a higher impact location than the pedestrian, with a larger share of injuries from the windscreen area. Majority of accidents in Palermo, in the last years, happens at urban street (84%) that involve teenager (6.4%). In this paper simulation study captures dynamics and injuries to head and chest for teenager between a generic bicycle and a car model that is suitable for pedestrian or cyclist safety. Multibody simula…