Nouveaux Matériaux Légers pour Airframers
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Beochien
Inscrit le 13/02/2007 |
# 17 novembre 2008 18:32 | |
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Tiens une méthode nouvelle "Multi punch" pour former des pannreaux Alu, plus vite et moins cher ... et qui nous vient de Chine ! ---------Extrait----------- http://kn.theiet.org/magazine/issues/0811/knockout.cfm After three years of research, a team of engineers and academics from around Europe are soon to unveil their first prototype for a new fast and flexible technology for producing aircraft panels. The basic idea of the ‘digitally-adjustable multipoint forming’ tool is to replace a solid die (the metal block used to shape panels) with a matrix of several punches that are height adjustable using software. This would mean the punches could change to produce a variety of shapes within a short timescale. The upshot of this, the researchers hope, will be that solid dies will no longer be necessary for panel making, leading to a significant reduction in costs and time. The project, known as DATAFORM, started in 2006 with backing from the European Commission. Partners include institutions and companies from Europe and China, and it is being coordinated by the Manufacturing Engineering Centre at Cardiff University. “This project focuses on forming metal panels, mainly aluminium ones, for the aeronautical industry,” says Katy Vanbrabant of SENER, a Spanish engineering consultancy that is involved in the DATAFORM project. “Even though the use of composites is increasing in the aeronautical industry, we believe that helping to reduce tooling costs and tool development time could help panel manufacturers supply aircraft panels faster and cheaper.” Multipoint forming (MPF) has already been used in China to produce body panels for highspeed trains, and the technique is also being used for the construction of columns with irregular angles for the national stadium for this summer's Olympic Games. The researchers say that the contribution of China’s Jilin University in MPF tooling methodology has been key to bringing the technology to the European aerospace industry. _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 17 novembre 2008 18:59 | |
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New ... Divinicell, c'est divin ! Garnitures thermiques et acoustiques, anti humidité pour l'aerospace ... et affinité Pré Peg en plus ! http://www.globalspec.com/FeaturedProdu ... re/78441/1 ------------------------------ Et si l'isolation acoustique n'est pas suffisante, une nouvelle méthode sponsorisée par EADS US ! Avec des nanotubes ... http://www.azonano.com/news.asp?newsID=7867 ----------- Extrait --------------- Noise from commercial and military jet aircraft causes environmental problems for communities near airports, obliging airplanes to follow often complex noise-abatement procedures on takeoff and landing. It can also make aircraft interiors excessively loud. A prototype microchanneled material composed of many metallic nanotubes was developed at the Georgia Tech Research Institute to validate acoustic absorption experiments designed to reduce noise in aircraft. Credit: Georgia Tech Photo: Gary Meek A prototype microchanneled material composed of many metallic nanotubes was developed at the Georgia Tech Research Institute to validate acoustic absorption experiments designed to reduce noise in aircraft. Credit: Georgia Tech Photo: Gary Meek To address this situation, engineers at the Georgia Tech Research Institute (GTRI) are turning to innovative materials that make possible a new approach to the physics of noise reduction. They have found that honeycomb-like structures composed of many tiny tubes or channels can reduce sound more effectively than conventional methods. "This approach dissipates acoustic waves by essentially wearing them out," said Jason Nadler, a GTRI research engineer. "It's a phenomenological shift, fundamentally different from traditional techniques that absorb sound using a more frequency-dependent resonance." The two-year project is sponsored by EADS North America, the U.S. operating entity of EADS. Most sound-deadening materials – such as foams or other cellular materials comprising many small cavities – exploit the fact that acoustic waves resonate through the air on various frequencies, Nadler explains. Just as air blowing into a bottle produces resonance at a particular tone, an acoustic wave hitting a cellular surface will resonate in certain-size cavities, thereby dissipating its energy. An automobile muffler, for example, uses a resonance-dependent technique to reduce exhaust noise. The drawback with these traditional noise-reduction approaches is that they only work with some frequencies – those that can find cavities or other structures in which to resonate. Nadler's research involves broadband acoustic absorption, a method of reducing sound that doesn't depend on frequencies or resonance. In this approach, tiny parallel tubes in porous media such as metal or ceramics create a honeycomb-like structure that traps sound regardless of frequency. Instead of resonating, sound waves plunge into the channels and dissipate through a process called viscous shear. Viscous shear involves the interaction of a solid with a gas or other fluid. In this case, a gas – sound waves composed of compressed air – contacts a solid, the porous medium, and is weakened by the resulting friction. "It's the equivalent of propelling a little metal sphere down a rubber hose when the sphere is just a hair bigger than the rubber hose," Nadler explained. "Eventually the friction and the compressive stresses of contact with the tube would stop the sphere." _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 17 novembre 2008 20:28 | |
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Bonsoir Le papier de carbone nano tubes ... un futur élément pour l'aviation ! Enfin un vrai gap ?? Le avions de papier , un gag !! --------- L'Article ---------------- http://news.studentpilot.com/283future- ... %E2%80%9D/ Future airplanes could be made of carbon-fiber “paper” Posted by Peter Sachs on October 20, 2008 at 10:34 am The airplanes of the future could be far lighter than today’s and hundreds of times stronger thanks to a new use for carbon nanotubes. Researchers at Florida State University have figured out how to transform clusters of carbon molecules called buckyballs into extremely thin and strong sheets made up of millions of carbon nanotubes, the Associated Press reported. With grants from Lockheed, the researchers are now trying to stack those sheets together into stronger composite materials. And unlike other carbon-fiber composites, buckypaper conducts electricity and dissipates heat very efficiently. That means within a few years, the material could be certified to protect planes from lightning strikes and to shield components from electromagnetic radiation. Eventually, entire planes could be made out of the material, which is 10 times lighter than steel but 500 times stronger. The military is also interested in using the material in bulletproof vests and vehicle shielding. ---------- Et -------------- http://nanotechweb.org/cws/article/tech/35702 Nanotube paper flexes on demand Multiwalled carbon nanotubes (MWCNTs) reinforced with polyvinyl alcohol (PVA) are being tested by researchers in France as a step towards developing ultra-lightweight actuators for aviation applications. The team from Centre de Recherche Paul Pascal is busy optimizing the composite's electromechanical response and has already generated an actuation stress of 1.8 MPa by applying 10 V across a bimorph device dipped in liquid electrolyte. Multiwalled carbon nanotube device Bending behaviour "The porous nature of the CNT-PVA composite allows the ions of the liquid electrolyte to enter and swell the film when the device is electrically stimulated," Christèle Bartholome of Centre de Recherche Paul Pascal told nanotechweb.org. "The system expands at both positive and negative voltages, but the expansion is more pronounced when we apply a negative voltage." To prepare the bimorph, the researchers first oxidize a sample of MWCNTs, which encourages the structures to bind strongly with the host polymer. Next, the nanomaterial is dispersed in water and then mixed with various amounts of high molecular weight PVA. -------------- Et --------------- http://www.cnn.com/2008/TECH/10/17/buck ... ention.ap/ TALLAHASSEE, Florida (AP) -- It's called "buckypaper" and looks a lot like ordinary carbon paper, but don't be fooled by the cute name or flimsy appearance. It could revolutionize the way everything from airplanes to TVs are made. Florida State University researcher Ben Wang, whose computer screen shows a microscopic view of buckypaper. Florida State University researcher Ben Wang, whose computer screen shows a microscopic view of buckypaper. Buckypaper is 10 times lighter but potentially 500 times stronger than steel when sheets of it are stacked and pressed together to form a composite. Unlike conventional composite materials, though, it conducts electricity like copper or silicon and disperses heat like steel or brass. "All those things are what a lot of people in nanotechnology have been working toward as sort of Holy Grails," said Wade Adams, a scientist at Rice University. That idea -- that there is great future promise for buckypaper and other derivatives of the ultra-tiny cylinders known as carbon nanotubes -- has been floated for years now. However, researchers at Florida State University say they have made important progress that may soon turn hype into reality. Buckypaper is made from tube-shaped carbon molecules 50,000 times thinner than a human hair. Due to its unique properties, it is envisioned as a wondrous new material for light, energy-efficient aircraft and automobiles, more powerful computers, improved TV screens and many other products. Don't Miss So far, buckypaper can be made at only a fraction of its potential strength, in small quantities and at a high price. The Florida State researchers are developing manufacturing techniques that soon may make it competitive with the best composite materials now available. "If this thing goes into production, this very well could be a very, very game-changing or revolutionary technology to the aerospace business," said Les Kramer, chief technologist for Lockheed Martin Missiles and Fire Control, which is helping fund the Florida State research. The scientific discovery that led to buckypaper virtually came from outer space. In 1985, British scientist Harry Kroto joined researchers at Rice for an experiment to create the same conditions that exist in a star. They wanted to find out how stars, the source of all carbon in the universe, make the element that is a main building block of life. Everything went as planned with one exception. "There was an extra character that turned up totally unexpected," recalled Kroto, now at Florida State heading a program that encourages the study of math, science and technology in public schools. "It was a discovery out of left field." The surprise guest was a molecule with 60 carbon atoms shaped like a soccer ball. To Kroto, it also looked like the geodesic domes promoted by Buckminster Fuller, an architect, inventor and futurist. That inspired Kroto to name the new molecule buckminsterfullerene, or "buckyballs" for short. For their discovery of the buckyball -- the third form of pure carbon to be discovered after graphite and diamonds -- Kroto and his Rice colleagues, Robert Curl Jr. and Richard E. Smalley, were awarded the Nobel Prize for chemistry in 1996. Separately, Japanese physicist Sumio Iijima developed a tube-shaped variation while doing research at Arizona State University. Researchers at Smalley's laboratory then inadvertently found that the tubes would stick together when disbursed in a liquid suspension and filtered through a fine mesh, producing a thin film -- buckypaper. The secret of its strength is the huge surface area of each nanotube, said Ben Wang, director of Florida State's High-Performance Materials Institute. "If you take a gram of nanotubes, just one gram, and if you unfold every tube into a graphite sheet, you can cover about two-thirds of a football field," Wang said. Carbon nanotubes are already beginning to be used to strengthen tennis rackets and bicycles, but in small amounts. The epoxy resins used in those applications are 1 to 5 percent carbon nanotubes, which are added in the form of a fine powder. Buckypaper, which is a thin film rather than a powder, has a much higher nanotube content -- about 50 percent. _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 25 novembre 2008 22:30 | |
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Un rapport sur le nouveaux matériaux, de septembre, refere aux présentations de Farnborough ! Noter la composition du Séries C de Canadair ! AL-Li oui ! Mais plastoc aussi ! Et pour 2-3 milliatrds seulement de développement annoncés, un compromis rentable ?? De Composites World ! http://www.compositesworld.com/articles ... eport.aspx _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 25 novembre 2008 22:36 | |
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Et une comparaison, concernant un départ manqué ... 350 Old, VS B787, vu il y à qq années ... Le AL-Li déjà présent  http://findarticles.com/p/articles/mi_h ... 88632/pg_3 _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 25 novembre 2008 22:38 | |
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Et du plus récent ! L'électro acoustique in situ peut être, au service du contrôle des fibres ! Détection opto acoustique des défauts ! Application possible, pour l'aviation ! CFRP contrôles : https://dashlink.arc.nasa.gov/static/da ... -10-14.pdf _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 26 novembre 2008 17:57 | |
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Boulons, Vis, Fasteners divers pour l'aviation, en fibre de carbone continue … Merci Viking qui me l'a communiqué ! En évaluation, et pas mature today à son avis ! http://www.icotec.ch/ http://www.icotec.ch/newsletters/nl24/iconews_e_24.html http://www.icotec.ch/newsletters/nl24/I ... _large.jpg (Message édité par Beochien le 26/11/2008 18h01) _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 13 décembre 2008 14:12 | |
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Anecdotique ... Mais ... Les mâts et voiles de quille en carbone ... Principales causes d'avaries, et d'abandons, comme d'hab dans le vendée globe .. C'est un peu du style F1, mais quand même ! http://www.vendeeglobe.org/fr/actualite ... os-ii.html http://www.vendeeglobe.org/fr/actualite ... atage.html Un joli site ! JPRS Paris _________________ JPRS |
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pesawat
Inscrit le 06/01/2007 |
# 13 décembre 2008 16:09 | |
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Cela fait longtemps qu'on l'utilise en bateau et ça passe toujours pas. Un coup ça passe ,un coup ça casse alors pas pret le 787 pas étonnant et il ne sera pas certifié. |
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Beochien
Inscrit le 13/02/2007 |
# 22 décembre 2008 00:46 | |
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Tiens, une belle machine Basque qui pourrait arranger Boeing côté 787 ! http://www.sciencedaily.com/releases/20 ... 102843.htm _________________ JPRS |
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Beochien
Inscrit le 13/02/2007 |
# 24 décembre 2008 12:24 | |
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Une méthode de réparation du CFRP ! Sur une coque de bateau aprés impact ! On peut toujours penser que Boeing ou Airbus proposeront mieux ... mais pour l'instant, c'est pas simple ! Bon pour du cylindrique, (787) ce sera peut être plus simple -------------- Du Vendée Globe! Flash Info ! -------------- http://www.vendeeglobe.org/fr/depeches/ ... ation.html Hugo Boss en réparation Depuis son rapatriement le 29 novembre à Gosport (Sud Angleterre), Hugo Boss a commencé son chantier de réparation à Endeavour Quay. « La première chose que nous avons vérifiée a été la structure de la coque. Il y a eu deux impacts majeurs et nous avons utilisé pendant cinq jours un processus issu de l’échographie laser. Nous avons pu constater que le seul dommage qui a été détecté est localisé, autour de la zone abîmée. » La prochaine étape est désormais de réparer en pratiquant un large trou autour de l’impact sur cinq mètres et de réaliser une pièce dans le moule de coque. Cinq personnes travaillent au chantier dont le boat captain Ross Daniel et le constructeur Clifford Nicholson : Hugo Boss devrait remis à l’eau à la mi-février. _________________ JPRS |
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Viking
Inscrit le 18/10/2006 |
# 16 février 2009 19:53 | |
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RDV aux JEC! J'expose! http://www.jeccomposites.com/jec-paris-2009/visitors/ (Message édité par Viking le 16/02/2009 19h54) _________________ Merci de ne pas me citer ailleurs.... |
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Viking
Inscrit le 18/10/2006 |
# 16 février 2009 21:22 | |
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http://www.youtube.com/watch?v=_GDqxnahwbk c'est très joli ....ho la grande autoclave... _________________ Merci de ne pas me citer ailleurs.... |
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Viking
Inscrit le 18/10/2006 |
# 20 février 2009 09:35 | |
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Hansel Schnokeloch macht immer was er will? So what wickser? (Message édité par Viking le 21/02/2009 20h34) (Message édité par Viking le 23/02/2009 07h54) _________________ Merci de ne pas me citer ailleurs.... |
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Viking
Inscrit le 18/10/2006 |
# 24 février 2009 07:59 | |
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Vieux mais tres intéeressant pdf sur l'industrie composite UK http://www.aiaa.org/Aerospace/images/ar ... v06_PP.pdf _________________ Merci de ne pas me citer ailleurs.... |
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