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Search Results: 1 - 10 of 1597 matches for " Filippo Berto "
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Esistenza del modo O in piastre tridimensionali con fori circolari ed ellittici soggette a modo II
Filippo Berto,Christian Marangon
Frattura ed Integrità Strutturale , 2011,
Abstract: Il problema di una piastra criccata tridimensionale soggetta a modo II è stato affrontato in letteratura dimostrando che l’effetto del coefficiente di Poisson provoca l’insorgere di una nuova singolarità accoppiata al carico esterno applicato e non contemplata dalla soluzione piana di Williams. Recenti analisi teoriche e numeriche hanno evidenziato come questo effetto tridimensionale sia presente anche in piastre intagliate a spigolo vivo. Il nuovo modo (denominato modo O) rimane singolare anche per angoli di apertura dell’intaglio maggiori di 102.6° e cioè quando il modo II risulta essere non singolare. Tutte le analisi fino ad ora effettuate hanno riguardato piastre indebolite da cricche o intagli a spigolo vivo non considerando l’effetto di un raggio di raccordo diverso da zero all’apice dell’intaglio.L’obiettivo del presente contributo è quello di dimostrare che il modo O è presente anche in piastre tridimensionali indebolite da intagli raccordati e soggette a modo II. Si sono quindi analizzate piastre con fori circolari ed ellittici variando sia la geometria dell’intaglio sia il valore del coefficiente di Poisson.
A Review of Recent Results on 3D Effects
Filippo Berto, Relly Victoria V. Petrescu and Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2016, DOI: 10.3844/ajeassp.2016.1247.1260
Abstract: Three dimensions or three-dimensional or 3D are expressions that characterize the space around us, as perceived by our vision, in terms of width, height and depth. The term "3D" is also (and improperly) used to refer to the representation in synthetic (digital) images, the relief of stereoscopic images or other images in relief and sometimes even the simple stereophonic effect, which Can only render 2D (it is therefore only the calculation of the projected projections, the shadows, the renderings of materials). In mathematics, this notion corresponds to Euclidean geometry in space. The space is marked by three orthogonal axes, contrary to the plane composed of two dimensions. Since its origins and long before the appearance of colour, cinema has exploited stereoscopy, mainly through the processes of anaglyphs. During the 1950 s, the Hollywood studios exploited the polarized filter system and then, from the 2000 s onwards, with the adoption of digital formats, the rooms also equipped the electronic principle with alternating shutter ("active" glasses). Despite some anaglyphic experiments since the 1930 and 1950 s, the commercial success of 3D television became a reality from the end of the 1990 s to a real industrial development from the year 2000. Two principles and devices for Stereoscopic effects are commercialized: Of the "active" type with electronic bezels or of the "passive" type with polarized filter goggles. More complex and costly to industrialize in particular with regard to large screens, auto stereoscopy (relief effect without bezel) was introduced with Alioscopy since the late 1990 s, on the lenticular principle. Stereoscopic videoprojection intended for the general public requires electronic "active" glasses or a special screen (metallised or offering some refraction of light) associated with "passive" glasses with polarized filters. Three-Dimensional (3D) effects close to sharp corners of a hole in a plate with finite thickness are investigated in the present contribution. The results from detailed 3D finite element model are analyzed to investigate the stress intensity of various fracture modes caused by the presence of a finite thickness. The results expressed in terms of stressed are compared with some recent equations. The comparison between numerical and theoretical results shows a sound agreement.
Three-Dimensional in Bonded Joints: A Short Review
Filippo Berto, Relly Victoria V. Petrescu and Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2016, DOI: 10.3844/ajeassp.2016.1261.1268
Abstract: Distributions of stress 3D in the vicinity of the overlapping corners of joints with a single lap were investigated with accuracy at present the man. A (Fe), model accurately Finite Element 3D has been carried out in order to investigate the intensity of the stress of adjustments in the plan and outside of stress by the width of the plate. The influences of the thickness of the adhesive and the Poisson distribution have been taken into account. Numerical results showed the presence of modes engaged has been detected with precision a sudden rise in the way the out-of-plan is very close to the free surface side of the fitting.
A Review of the Fatigue Strength of Load Carrying Shear Welded Joints
Filippo Berto, Abedin Gagani, Relly Victoria V. Petrescu, Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2017, DOI: 10.3844/ajeassp.2017.1.12
Abstract: In the study it is shown an overview of the latest results of two types of joints of the load carrying welded shear. Tests of fatigue have been carried out on the two solutions specific design features proposed and with the aim of improving the resistance of the joints under cycling loading. By hiring the 3D models, was determined Strain Energy Density (SED), in a volume of control which surrounds the lowest point of interest. All of the experimental results have been presented in short. The synthesis shows that all data are within the range of the scattering of the proposed previously in the specialized literature for steel construction welded.
Finite Element Analysis, 3d Model, Lap Joint, Notc h Stress Intensity Factors
Filippo Berto, Abedin Gagani, Raffaella Aversa, Relly Victoria V. Petrescu, Antonio Apicella and Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2016, DOI: 10.3844/ajeassp.2016.1269.1291
Abstract: Fatigue is a process (succession of mechanisms) which under the action of time-varying strains or deformations modifies the local properties of a material. These can lead to the formation of cracks and eventual rupture of the structure. Fatigue is in particular characterized by an extent of variation in stress which may be well below the yield strength of the material. The main stages of fatigue failure of an assembly are the initiation of cracks (if defects are not already present in the material), the propagation of cracks and the final rupture. The parameters often used to predict the fatigue behavior and thus the number of cycles at break of a structure is: The amplitude of the stress (loading or imposed strain), its average value, the surface state and the medium In which the structure will be used. Even if the study of fatigue is based on theoretical considerations (in particular the mechanics of the rupture), it is essentially an experimental field. The characterization of a material, a part, an assembly, a structure, requires numerous tests and measurements. The work deals with multiaxial fatigue power of specimens which are notched and all made of 40CrMoV13.9. Circumferentially V-notched specimens and semicircular notched were tested under combined tension and torsion loading, both, in phase or out of phase. Geometry of symmetric axis of V notched issues has been characterized of a notch radius constant from (1 mm) and V-notch opening angle of 90°. The semicircular specimens were characterized by a constant notch tip radius. For both situations the net diameter sectional area was 12 mm. The results from multi-axial tests are discussed together with those obtained being all under loading pure torsion and tension by the issues notched having the same geometry. Altogether more than 120 new fatigue data are summarized in the present work. All presented fatigue data are first in terms of nominal amplitudes stress and then reanalyzed in terms of the mean value of the strain energy density evaluated over a finite size semicircular sector surrounding the tip of the notch.
Key-Hole Notches in Isostatic Graphite: A Review of Some Recent Data
Filippo Berto, A. Gagani, Relly Victoria V. Petrescu and Florian Ion T. Petrescu
American Journal of Engineering and Applied Sciences , 2016, DOI: 10.3844/ajeassp.2016.1292.1300
Abstract: Fracture of the breakable isostatic graphite is concerned using the experimental and theoretically, the plates containing nicks holes key subject to varying degrees of mixed task. The main purpose of this work is a double one. In the first place, in order to offer a new set of experimental results on fracture of samples of graphite scored, with different values of the load mixed and radii notch and which may be helpful for researchers, as it enlarges the very limited data available; and secondly, to provide a criterion fracture of the polycrystalline graphite under the conditions mentioned above. The main purpose of this work is to offer a new set of experimental results (70 new data) on the fracture of the samples of the loose graphite of key holes, the different values of mixed loading, the tilt angle and radii notch and which may be of help as widens the very limited data available. By using the value of the average density of the stem of energy in a well defined, a criterion of fracture of the polycrystalline graphite under the conditions referred to above, it is proposed to predict the static resistance of the samples taken into account. The third part of the work deals with the analysis of the direction of initiation of fracture and spread of the crack in the early. The average value of the stem density of energy in a well defined is used to predict the static resistance of the samples taken into account. Good agreement is found between the experimental data for the tasks critical failure and the theoretical predictions based on average constant strain density of energy on the volume of the material.
Our Universe
Relly Victoria Petrescu, Raffaella Aversa, Bilal Akash, Juan Corchado, Filippo Berto, MirMilad Mirsayar, Antonio Apicella and Florian Ion Tiberiu Petrescu
Journal of Aircraft and Spacecraft Technology , 2017, DOI: 10.3844/jastsp.2017.69.79
Abstract: It's hard to know ourselves and our role as humanity, without knowing our precise location first. In the universe where we find ourselves (what we know not much about), there are billions of galaxies. A galaxy is a large cluster of stars (suns), i.e., solar systems; on average an ordinary galaxy contains about two billion stars (suns), which may or may not have planets around them. A constellation is a group of galaxies that depend on each other. Virgo is a very famous zodiacal constellation. Her name comes from Latin, the virgin and her symbol is ?. The constellation of the Virgin is located between the Lion to the west and the Libra to the east, being the second constellation in the sky (after Hydra) in size. The constellation of the Virgin can easily be observed in the sky of the earth due to its sparkling star named Spica. So our universe contains about two billion galaxies and many constellations; a constellation comprises several galaxies and a galaxy has about 2 billion stars. Nowadays, thanks to modern telescopes, we know a great many galaxies, but only 88 constellations have been identified by humanity (for now).
What is a UFO?
Relly Victoria Petrescu, Raffaella Aversa, Bilal Akash, Juan Corchado, Filippo Berto, MirMilad Mirsayar, Antonio Apicella and Florian Ion Tiberiu Petrescu
Journal of Aircraft and Spacecraft Technology , 2017, DOI: 10.3844/jastsp.2017.80.90
Abstract: There is much talk about UFOs sometimes. Is there anyway? If so what are they? Here are some questions we want to answer them briefly in this paper. An unidentified flying object or UFO is defined as any apparent object in the sky that can’t be identified and classified as an object or phenomenon already known. But the name is generally widely used to refer to the alleged or actual observations of alien ships. Today, the vast majority of observed UFOs are later identified as conventional objects or phenomena (such as aircraft, meteorological balloons, clouds). However, some of them can not be identified, either due to lack of evidence or due to the lack of conventional explanations, despite extensive evidence. Some people believe that the latest cases represent possible observations of alien spacecraft craft. The issue of past observations is difficult to explain otherwise than through the existence of other civilizations more advanced than ours. UFO events in the last thirty years are hard to analyze and classify, as we now have intelligent ships with special capabilities that can easily be confused with an alien ship.
When Boeing is Dreaming – a Review
Relly Victoria Virgil Petrescu, Raffaella Aversa, Bilal Akash, Juan Corchado, Filippo Berto, Antonio Apicella and Florian Ion T. Petrescu
Journal of Aircraft and Spacecraft Technology , 2017, DOI: 10.3844/jastsp.2017.149.161
Abstract: Boeing is an aeronautical and aerospace manufacturer. Its head office is located in Chicago, Illinois. Its two largest plants are located in Wichita, Kansas and Everett, near Seattle. This aircraft manufacturer specializes in the design of civil aircraft, but also in military aircraft, helicopters and in satellites and rockets with its Boeing Defense, Space and Security division. In 2012, it ranks second in world military equipment sales. The company was born on July 15, 1916, thanks to its two fathers William E. Boeing and George Conrad Westervelt and is named "B and W". Shortly afterwards, his name became "Pacific Aero Products" and finally "Boeing Airplane Company". In 1938, Boeing commissioned the 307 Stratoliner; It was the first airplane with pressurized cabin; He was able to fly at a cruising altitude of 20,000 feet, so above most weather disturbances, making him the strongest aircraft in the Boeing fleet. In response to the concentration move in the US defense industry initiated by its competitor Lockheed in 1995, Boeing acquired Rockwell International's space and defense operations in August 1996 for $3.2 billion. Rockwell was the manufacturer of the seven US space shuttles (Enterprise, Pathfinder, Columbia, Atlantis, Endeavor, Discovery and Challenger). Then, Boeing bought the number two defense equipment behind Lockheed Martin that is McDonnell Douglas, for $13 billion in August 1997. McDonnell Douglas was the manufacturer of the Delta launchers. In 1999, the Boeing aircraft manufacturer sold 620 aircraft; in 2004, deliveries fell to 285 aircraft. It is now overtaken by its European competitor Airbus in orders since 2002 and in deliveries since 2004 (Source: Le Monde, 13 June 2005). In 2005, in a record market, the company announces 1,005 orders (of which 569 B737, 235 B787 and 154 B777) surpassed again by Airbus of about fifty aircraft. Boeing became the world's first aircraft manufacturer in 2006 with 1,044 orders versus 824 for Airbus. In 2008, Boeing is the world leader in the defense sector. In November 2016, Boeing announced a restructuring of its defense arm with the suppression of 500 positions, the closure of two plants in El Paso and Newington and the displacement of 2,000 employees.
About Northrop Grumman
Relly Victoria Petrescu, Raffaella Aversa, Bilal Akash, Juan Corchado, Filippo Berto, Antonio Apicella and Florian Ion Tiberiu Petrescu
Journal of Aircraft and Spacecraft Technology , 2017, DOI: 10.3844/jastsp.2017.162.185
Abstract: The Northrop Grumman (formerly Ryan Aeronautical) RQ-4 Global Hawk (known as Tier II during development) is an Unmanned Aerial Vehicle (UAV) used by the United States Air Force and Navy and the German Air Force as a surveillance aircraft. The Northrop Grumman B-2 Spirit (also known as the Stealth Bomber) is an American strategic bomber, featuring low observable stealth technology designed for penetrating dense anti-aircraft defenses; it is able to deploy both conventional and nuclear weapons. The bomber has a crew of two and can drop up to eighty 500 lb (230 kg)-class JDAM GPS-guided bombs, or sixteen 2,400 lb (1,100 kg) B83 nuclear bombs. The B-2 is the only aircraft that can carry large airto-surface standoff weapons in a stealth configuration. The BQM-74 Chukar is a series of aerial target drones produced by Northrop. The Chukar has gone through three major revisions, including the initial MQM-74A Chukar I, the MQM-74C Chukar II and the BQM-74C Chukar III. They are recoverable, remote controlled, subsonic aerial target, capable of speeds up to Mach 0.86 and altitudes from 30 to 40,000 ft (10 to 12,000 m). Northrop Grumman Corporation (NYSE: NOC) is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010 and the largest builder of naval vessels. Northrop Grumman employs over 75,000 people worldwide. Its 2010 annual revenue is reported at US$34 billion. Northrop Grumman ranks #72 on the 2011 Fortune 500 list of America's largest corporations and ranks in the top ten military-friendly employers. It has its headquarters in Falls Church, Virginia. Separate sectors, such as Aerospace Systems, produce aircraft for the US and other nations. The B-2 Spirit strategic bomber, the E-8C Joint STARS surveillance aircraft, the RQ-4 Global Hawk and the T-38 Talon supersonic trainer, are used by the US Air Force. The US Army uses Northrop Grumman's RQ-5 Hunter unmanned air vehicle, which has been in operational use for more than 10 years. The US Navy uses Northrop Grumman-built aerial vehicles such as the BQM-74 Chukar, RQ-4 Global Hawk based BAMS UAS, C-2 Greyhound, E-2 Hawkeye and the EA-6B Prowler. Northrop Grumman provides major components and assemblies for different aircraft such as F/A-18 Hornet, F/A-18E/F Super Hornet and the EA-18G Growler. Many aircraft, such as the F-5, T-38 Talon and E-2 Hawkeye are used by other nations.
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