Search results for " progettazione."
showing 10 items of 503 documents
Finite Element Method Analysis of a Spur Gear with a Corrected Profile
2007
The difference between the stress value calculated by a two-dimensional finite element model of spur gears and those obtained by the rules in ISO 6336 was evaluated. Hertz theory, which provides information on the extension of the contact area and the maximum value of the contact pressure, was used to choose the dimensions of the elements. The mesh was created using the stress analytical solution relative to a model consisting of two cylinders in contact. Analogous optimization was executed for the mesh of the teeth feet; a mesh of 15 elements was considered optimum, because it minimized the difference to 0.5 per cent in the bending stress calculation. Stress values, obtained using the fin…
Dalibor Vesely e la complessità culturale del progetto
2016
Dalibor Vesely ebbe una enorme influenza sulla cultura archiettonica inglese fino alla sua recente scomparsa, specialmente per la sua figura di docente. Con Rykwert insegnò in un famoso corso postlaurea all'Essex e successivamente a Cambridge. La sua concezione del progetto architettonico era fortemente influenzata dalla fenomenologia e dall'ermeneutica. The article outlines the outstanding relevance of Dalibor Vesely an architect and teacher who has recently disappeared. He was born and brought up in Czechoslovakia but, since the early Sixties, he has lived in London where he was considered an authority for his insightful approach to architecture. The article is focused on his conception o…
Defect Detection in Additively Manufactured Components: Laser Ultrasound and Laser Thermography Comparison
2018
Despite continuous technological advances in additive manufacturing, the lack of non-destructive inspection techniques during the manufacturing process is a limit for the industrial breakthroughs. Additive manufacturing is mainly used in industrial sectors where the zero defect target is crucial. The inclusion of the integrity assessment into the additive manufacturing process would allow corrective actions to be performed before the component is completed. To this end, the development of in-process monitoring and processing techniques is of great interest.This work proposes and compares two remote non-destructive inspection techniques: laser ultrasound and laser thermography. The two techn…
Evaluation of crack-closure by second harmonic thermoelastic stress analysis
2022
The work illustrates a new experimental approach to evaluate crack-closure in samples undergoing Fatigue Crack-Growing. Crack-closure leaves a peculiar signature on both amplitude and phase of the harmonic of the temperature signal at twice the loading frequency (Second Harmonic), due to the periodic nature of the internal elastic compression stresses. Thermoelastic Stress Analysis (TSA) is successfully applied to reveal such signatures on Single-Edge-Notched steel samples. A methodology is also proposed to evaluate the Crack-Opening-Load from temperature data. The work finally explores the influence of crack-closure on crack-tip identification and on the evaluation of the Stress Intensity …
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…
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 …
Formazione in servizio sulle competenze progettuali e valutative degli insegnanti: una ricerca esplorativa.
2018
Lo studio presentato è parte di un articolato progetto attuato all’interno di un’esperienza di formazione in servizio, durante un percorso formativo sulla progettazione e valutazione delle competenze. L’attività di ricerca è stata progettata per insegnanti di diversi ordini di scuola che hanno aderito al progetto: “percorsi e strumenti per progettare e valutare per competenze”. L’intero disegno progettuale è finalizzato ad avviare in maniera graduale la “messa a sistema” delle metodologie e degli strumenti che realizzano il ciclo virtuoso analisi-diagnosi-progettazione-elaborazione del piano di miglioramento della formazione professionale degli insegnanti.
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…