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La Simulazione Fisica come Strumento di Progettazione di Prodotto e di Processo nella Tecnologia dello Stampaggio Massivo
No full textLa competitività tecnologica di un'azienda di forgiatura si misura oggi sulla capacità di avviare in tempi assai brevi la produzione di componenti nuovi dalla geometria complessa e di qualità elevata sia per l'accuratezza dimensionale e morfologica che per le caratteristiche meccaniche.
L'articolo illustra il ruolo, oggi spesso insostituibile, che la simulazione fisica, anche integrata con quella numerica, ha nell'assistere la progettazione del processo di fucinatura di un nuovo componente. Dopo una rassegne delle diverse tecniche di simulazione fisica oggi disponibili, sia quelle basate sull'impiego di materiali modello che quelle applicate ai materiali reali, vengono presentate le applicazioni più significative nelle aree :
• della qualificazione dei materiali (caratteristiche reologiche e di lavorabilità) e delle condizioni di interfaccia (attrito e scambio termico)
• dell'analisi delle modalità di riempimento delle cavità e deU'ottimizzazione della sequenza delle prefonne e
• dell'analisi e ottimizzazione dei parametri termici e meccanici nell'ambito dell'intero ciclo produttivo.
Nel presentare le applicazioni si fa riferimento a casi reali di aziende italiane di fucinatura
Complementary Aspects in Physical Simulation of Hot Forging Operations
Full text linkThe paper presents some recent applications at the DIMEG lab of physical simulation techniques
aimed at analysing and modelling hot forging operations. The applications concern (i) monitoring
of force-and-moment history over the forging cycle of complex parts, (ii) replicating on samples
local thermal/mechanical profiles that are predicted by FE codes and (iii) measuring interface
parameters such as heat transfer coefficients and temperature at the die surface
Determination of the Heat Transfer Coefficient in the Die-billet Zone for Nonisothermal Upset Forging Conditions
Full text linkA number of tests were conducted to measure the heat transfer coefficient between
billet and tool in non-isothermal upset forging conditions. Elastic deformation of cylindrical
specimens between flat punches was used to verify the proposed procedure, whose applicability to
large plastic deformation was verified in plane strain tests. This paper mainly insists on theoretical
aspects and on presentation of axis ymmetrica Itests.
A fixture consisting of two flat 304 stainless steel dies was instrumented with type-K thermocouples
to elastically deform 1100 Al cylindrical specimens at forging temperature, also instrumented with
thermocouples,
A procedure was designed to measure heat transfer coefficient. Inverse analysis based on comparison
between numerical and experimental data was applied. A fitting technique, based on adjustment of
input data, was aimed at (i) reaching a satisfactory agreement between experimental and analytical
results and (ii) determining a mean value for the heat transfer coefficient. Different operating
conditions were tested
Collaborative research work in cold and warm forging at University of Padova, Teksid and Carraro within the EUREKA-FAMOS “EFFORT” project
No full textTheongoing collaborative research work at the University of Padua and
the two companies Teksid and Carraro within the Eureka-Famos
"E.F.ForT. "project ispresented. Theproject is aimed at developing and
introducing tost-effective forging methods for precise and net- or nearnet-
shape forged products through the rea/isation at the companies of
novel forging environments where pilot-plant facilities for forging
(including cold, worm and hot forging) and tooling preparation are integrated with advanced software and simulation tools for product design,
process planning; as well as product quality management and assurance.
In the presentation particular emphasis will be put on the collaborative
effort between lridustry and university as well as on progress in developing
(i),the inteqrated CAO/CAE system for process design and! (ii)physical and numerical simulation of cold and warm forging operations
Some progresses in physical simulation of forging operations: replicating thermal/mechanical history and evaluating force components
Full text linkNew experimental facilities have recently been developed and installed at the DIMEG Lab
that are specifically designed for physical simulation experiments both on real and model
materials.
This paper illustrates some applications of these facilities and relevant simulative
techniques to the analysis of bulk metal forming operations such as hot forging of turbine
blades and hot rolling of steel plates. The presentation focuses on the most original aspects
of the simulations that concern (i) the evaluation of the force and torque components
applied to the dies during forging of complex parts and (ii) complementary aspects of
physical and F.E. simulation with particular emphasis on precise replicating, under
computer control, of local thermal-mechanical profiles that are predicted by F.E. codes
Characterization of Ti and Ni Alloys for Hot Forging:Setting-up of an Experimental Procedure
Full text linkThere is a growing interest in the application of Titanium and Nickel alloys forged
components in the aerospace and Hi-Tech industry.
Hot forging of these alloys requires a precise definition and control of operating parameters, such as
forging temperature, punch speed and lubricant.
A procedure is presented to obtain true stress true strain curves for Ti and Ni alloys at hot forging
conditions, that is especially designed to guarantee homogeneity at deformation and temperature in
the specimen during the overall compression test
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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