27.01.16 - Ukrainian engineer Vladimir Tatarenko showcased an idea for a detachable aircraft cabin he believes could save lives during a crash landing. In the event of a crash, the plane’s cabin would detach from the rest of the plane and safely land on the ground or water using parachutes, boosters and rubber tubes which would automatically inflate on water. The design also includes a storage space that holds passengers’ luggage underneath the cabin to ensure no luggage is lost in the event the plane needs to detach. “Surviving a plane crash is possible,” said Tatarenko. “While aircraft engineers all over the world are trying to make planes safer, they can do nothing about the human factor.” I know this is his quote but maybe we can fix the grammar? According to Tatarenko, a critical component to making the design work is the use of composites. “The existing technology of using Kevlar and carbon composites for [the plane’s] fuselage, wings, flaps, spoilers, ailerons, tail will be used during the design,” said Tatarenko. “It allows to partly compensate the weight of parachute system.” Last year, Tatarenko received patents for a similar invention with an escape capsule system that would rescue passengers on board. The capsule, just like the new one, would be released through a rear hatch at the tail end of the plane within seconds of an emergency situation. However, the idea has plenty of critics. Some argue that the idea is not cost effective given how expensive the implementation of the technology would be to prevent a situation that is not common. Is it worth investing a lot of money in detachable technology if there were (according to Daily Mail) only 111 plane crashes in 2014? Others argue that the design itself still needs work, as it does not include a contingency plan for the pilots themselves. The post Engineer Designs Composite Aircraft with Detachable Cabin appeared first on materialsreview.
26.01.16 - The research team have developed the first demonstration of 3D printing of composite materials. Image courtesy Matt Sutton, Tom Llewellyn-Jones and Bruce Drinkwater. A team of engineers at the University of Bristol has developed a new type of 3D printing that can print composite materials. According to the study, published in Smart Materials and Structures, the team has demonstrated a method by which ultrasonic waves are used to carefully position millions of tiny reinforcement fibers as part of the 3D printing process. The fibres are formed into a microscopic reinforcement framework that gives the material strength. This microstructure is then set in place using a focused laser beam, which locally cures the epoxy resin and then prints the object. ‘We have demonstrated that our ultrasonic system can be added cheaply to an off-the-shelf 3D printer, which then turns it into a composite printer,’ said Tom Llewellyn-Jones, a PhD student in advanced composites who developed the system. In the study, a print speed of 20mm/s was achieved, which is similar to conventional additive layer techniques. The researchers have now shown the ability to assemble a plane of fibers into a reinforcement framework. The precise orientation of the fibers can be controlled by switching the ultrasonic standing wave pattern mid-print. To achieve this, the research team mounted a switchable, focused laser module on the carriage of a standard three-axis 3D printing stage, above the new ultrasonic alignment apparatus. New generation This approach allows the realisation of complex fibrous architectures within a 3D printed object. The versatile nature of the ultrasonic manipulation technique also enables a wide range of particle materials, shapes and sizes to be assembled, leading to the creation of a new generation of fibrous reinforced composites that can be 3D printed, according to the team of engineers. ‘Our work has shown the first example of 3D printing with real-time control over the distribution of an internal microstructure and it demonstrates the potential to produce rapid prototypes with complex microstructural arrangements,’ noted Bruce Drinkwater, Professor of Ultrasonics in the Department of Mechanical Engineering. ‘This orientation control gives us the ability to produce printed parts with tailored material properties, all without compromising the printing.’ ‘As well as offering reinforcement and improved strength, our method will be useful for a range of smart materials applications, such as printing resin-filled capsules for self-healing materials or piezoelectric particles for energy harvesting,’ added Dr Richard Trask, Reader in Multifunctional Materials in the Department of Aerospace Engineering. The post 3D printing composites with ultrasonic waves – Materials Today appeared first on materialsreview.
25.01.16 - A carbon and hemp-fiber reinforced component such as this is a cheaper, greener hybrid composite that can do the job of pure carbon composites. Built in East Germany, the Trabant 601 was notorious for its many faults – not the least of which was a body made out of Duroplast, a hard plastic made of cotton waste and phenol resins that led those in the West to describe the car as being made of cardboard. However, it now looks as if the Trabant is getting the last laugh as scientists look at ways of making cars out of cotton and other botanical fibers formed into a new class of hybrid composites. New emission, safety, and mileage standards in Europe and North America call for vehicles that are ever stronger and lighter, which means that steel and aluminum are giving way to carbon composite materials. Basically, such carbon fiber-reinforced plastics (CFRP) are made up of carbon fibers reinforced by resins, which provides strength and durability, and by tweaking the materials put in, engineers can alter the composite to fit particular applications. These composites are light, strong, durable, and have proven their worth in everything from F1 racers to aircraft to surgical prostheses, but using them is a trade off. High-tech synthetic carbon composites may be marvelous materials, but they're also expensive and difficult to fabricate. Alternatives, such as glass fiber, can bring down the cost, but they tend to be heavier and not quite as strong. The Application Center for Wood Fiber Research of the Fraunhofer Institute for Wood Research, the Wilhelm-Klauditz-Institut WKI in Braunschweig is looking into a more natural alternative to CFRPs in natural botanical fiber composites made out of flax, hemp, cotton, or wood. As the Trabant, with its Duroplast cotton composite, shows, the basic idea isn't new, but how Fraunhofer is applying it is. The botanical composites don't seem like a very good choice at first. They aren't anywhere near as strong or durable as carbon composites, but they are as cheap as glass composites and lighter than glass. In addition, the botanicals burn cleanly without residues. The clever bit is to take a bio-based textile and carbon fibers and combine them. The idea is not for the botanical fibers to replace carbon, but to supplement them. For example, the strength and durability of a composite panel doesn't need to be the same across the whole unit. Instead, carbon composites can be used in areas that are subject to high strength and wear, while the botanical composites cover other areas. Blending the two together therefore results in a cheaper, greener hybrid composite that can do the job of pure carbon composites. Once explained, this hybrid composite seems fairly simple, but creating it isn't as straightforward. According to Fraunhofer, botanical fibers are usually made for use in textiles, which means they're treated so they'll run smoothly through spinners, looms, and other textile machines. However, composite engineers want fibers that are treated so they interact with the resins in a manner similar to roughening a wall so it will tightly grip the plaster. In the case of composites, properly treating the fibers can increase a material's durability by 50 percent. Such treatments are routine in carbon fibers, but Fraunhofer says that how to handle botanical fibers is still an unknown. In addition to this, the Fraunhofer team is also studying how to manufacture the hybrid composites on an industrial scale, how to recycle them, and how to recover the materials in the panels. The post Cotton cars to bring down costs of composites appeared first on materialsreview.
20.01.16 - Market research suggests that the glass fiber and special chemical fiber sector will grow annually by 6.47% from 2015 to 2020. Hyun-Dai Fiber.Co.Ltd. have been using their expertise and technical know-how to manufacture and supply various fibers - from superfine glass fiber to carbon fiber - in order to meet the demands of its customers. (Photo: Business Wire) Hyun-Dai Fiber.Co.Ltd is a well-established name in the composite materials sector, achieving mutual growth with customers and collaborating companies. This is based on the technology they use in the composite materials industry and long-time accumulated experiences. Glass fiber is a popular option for use in composite materials as a reinforced element due to its heat-resistance, high tensile strength, weather resistance, electric insulation, and dimensional stability. The products are sold after being coated with suitable resin to match the purpose, e.g golf shaft, pipes, protective clothing, fishing rods, reinforced materials for wall, and insulation. Carbon fiber possesses high elasticity, high heat resistance, and high strength. It exhibits superior functionality and property as an element for composite materials. By impregnating epoxy resin into carbon fiber textile, carbon fiber can be manufactured as prepreg state. The fiber is used widely in the aerospace sector, as it weighs less than plastic but is stronger than steel. The fiber can also be adapted to reinforce materials for industry and construction, and in sports and leisure, especially golf and skiing. HD Fiber is directly manufacturing and supplying fabric sheet which can be used for body or parts in auto, sports/leisure or bicycle by using glass fiber or carbon fiber. In case of carbon fiber, we will advance into the market by making splendid and various fiber pattern rather than focusing on lightweight and strength. The post Hyun-Dai Fiber Uses Glass/Carbon Fiber to Build Novel Composite Materials appeared first on materialsreview.
19.01.16 - Some of the carbon fiber shapes, created out of polyethylene using Oak Ridge's new technique Thanks to research currently being conducted at the U.S. Department of Energy's Oak Ridge National Laboratory, our unwanted plastic bags may one day be recycled into carbon fiber. Not only that, but the properties of the fibers themselves could be fine-tuned, allowing different types of carbon fiber to be created for specific applications. The Oak Ridge team, led by materials scientist Amit Naskar, start with polyethylene-base fibers – these could conceivably come from waste plastic sources, such as shopping bags and carpet backing scraps. Using a “a multi-component melt extrusion-based fiber spinning method,” the surface contours of these fibers can be customized, and their diameter can be manipulated with submicron precision. It is also possible to control their porosity. Bundles of these fibers are dipped into a proprietary acid chemical bath. A process known as sulfonation causes the plastic molecules to bond with one another, transforming each bundle of fibers into one joined black fiber. When subsequently exposed to very high temperatures, these fibers won’t melt. The heat does, however, cause many of their chemical components to turn to a gaseous state. After these have off-gassed, what’s left behind is a fiber composed mostly of carbon. Many uses are envisioned for the plastic-derived carbon fiber – because of its tunable porosity, it may be particularly well-suited for applications such as filtration or energy harvesting. It is also hoped that the material could be used by the American auto industry, to make tough yet lightweight, inexpensive car parts. The post Tomorrow’s carbon fiber could be made from plastic bags appeared first on materialsreview.
18.01.16 - A research team has developed a carbon-fiber manufacturing method that uses half the energy consumed in the current process and could increase maximum output of the strong but lightweight material tenfold. The new process was announced on Jan. 14 by New Energy and Industrial Technology Development Organization (NEDO), which worked with the University of Tokyo, Toray Industries Inc., Teijin Ltd. and others in the development. The production process of carbon fiber has remained nearly unchanged since 1959, when the current method was conceived by Japanese researchers. Carbon fiber is now considered indispensable for reducing the weight of aircraft and automobiles. Typical carbon fiber has about 10 times the tensile strength of iron but with only one-fourth of the weight. However, the current carbon-fiber manufacturing method requires huge expenses and a large amount of energy to heat acrylic fibers at a high temperature for an extended period. The new formula dispenses with the prolonged heating process by using specially processed chemical fibers. Annual maximum output of carbon fiber is estimated at 2,000 tons per production line. The new process could bump up the amount to more than 20,000 tons a year, NEDO said. Some industry experts expect the global carbon fiber market to grow 15 percent annually by 2020 as demand rises for production of aircraft and automobiles. The new process could further expand the market. Three Japanese companies, Toray, Teijin and Mitsubishi Rayon Co., produce around 65 percent of the world’s carbon fiber. The post New carbon-fiber production method saves energy, slashes costs appeared first on materialsreview.
15.01.16 - Revolutionary Aluminum-Air Battery Travels 1,000 miles, Gas-Free! By now, most of you have heard about the big changes coming from the auto industry as carmakers move to military-grade aluminum alloys to achieve massive fuel efficiency gains. What’s gotten somewhat less attention is another major innovation coming from the aluminum industry that could move electric cars into the mainstream. To date, electric cars have achieved limited adoption partly due to “range anxiety” – consumer concern that their battery will die before reaching their destination. A recent announcement by Association member company Alcoa and clean technology firm Phinergy could change all that. Debuted during the Canadian International Aluminium Conference (CIAC), the companies showed off an electric car featuring an aluminum-air battery, which can extend the car’s travel distance by approximately 1,000 miles. The battery itself consists of 50 plates, each one of which can power a car for around 20 miles. When used as a supplement to a conventional lithium-ion battery, the aluminum-air battery can extend vehicle range enormously. The secret is in the vast amounts of energy stored within aluminum -- which is released using air and water. Commented Phinergy CEO Aviv Tzidon, “Compared to other batteries, the fundamental difference is energy density – the aluminum-air density allows you to do more with less weight. With greater energy density, you are creating electric vehicles with travel distances, purchase prices and life-cycle costs that are comparable to fossil-fuel cars.” Beyond electric vehicles, applications for the aluminum-air batteries are potentially endless – from generators for hospitals and data centers to defense applications to emergency first responder support. Much of the research and development on this project took place at the Alcoa Technical Center outside of Pittsburgh, which is the largest light metals research facility in the world. The post Go Further with Aluminum! appeared first on materialsreview.
13.01.16 - Fiber reinforced composites are common, but do you know how to select the different types of fiber and resin used? Comparing and Choosing Composite Materials Composite materials are broadly defined as those in which a binder is reinforced with a strengthening material. Here we take a look at the pros and cons of the components: the resins and the fibers used to strengthen them. Resins Most modern composites share a common bond – almost literally. The binding resins – the chemical matrix in which the reinforcing fibers are embedded – are relatively few in number. There are three main recipes: polyester, vinylester and epoxy. Various flavours of each are available, depending on whether they are strengthened with glass, carbon or aramid fibers, and the particular application. For example, high UV (sunlight) tolerance may be chemically engineered using additives. Common Issues The presence of volatile organic compounds(‘VOC’) is of concern both for health reasons and ‘greenhouse effect’ impact. Modern epoxies are VOC free, but polyester and vinylester compounds have high concentrations of VOC in the form of styrene. This means that fabrication using esters should take place in well ventilated space. Curing The epoxy compound is formed by mixing two different chemicals which react to form a ‘copolymer’. The curing rate is sensitive to temperature and the ratio of the two components, but curing is almost always assured. Some epoxy paste formulations will even cure underwater. Polyester and vinylester by comparison, cure with the use of a peroxide catalyst (usually known as MEKP). Vinylester is sensitive to temperature, and may not cure at all under certain conditions. Water resistance Epoxies are highly water resistant, with vinylesters also showing a high resistance.Polyester composites absorb water to a significant degree, and when used – say, in boat hulls – osmotic blistering occurs due to a reaction with water (hydrolysis) which results in chemical breakdown. Insoluble pthallic acid crystals damage the GRP laminate and acetic acid is a by-product. Chemical resistance Epoxies are very stable chemically, and offer excellent resistance to chemical attack. Polyesters are moderately resistant at room temperatures to most common chemicals, but vinylesters offer much higher resistance, though falling short of the protection that epoxies afford. The resistance of polyesters and vinylesters falls quickly at higher temperatures. Vinylesters may be used to provide a barrier coating to protect polyester, particularly in the marine environment. Shrinkage, Strength and Stiffness Polyesters and vinylesters typically shrink by 7% on curing, but epoxies shrink less than 2% and where dimensional stability is important, then epoxies are much to be preferred. Shrinkage can introduce stress into a structure, and designers much factor this in. Both for tensile strength and stiffness, polyester is lowest on the scale, with epoxy highest and vinylester just superior to polyester. Adhesion This is an important property when using composites. Adhesion has to be strong between the resin and the fiber strengthener. Vinylester is not the best in this respect. Cost Polyester is by far the cheapest of the three resin systems, much cheaper even than vinylester, weight for weight. Polyester is preferred for boats and bathtubs, but where strength/weight is important and budget less of an issue, then epoxies win – for example in motorsport and aerospace. Fiber Types There are three main families in use at present: glass fiber, carbon fiber and aramid fiber (more commonly known as Kevlar, a trademark of the DuPont Corporation). Glass fiber is by far the cheapest and most widely used, and works well with all three resin types, but it is relatively heavy. Carbon fiber is much lighter, as are aramid fibers. Glass fibers (either in chopped strand or woven cloth form) are most commonly used with a polyester resin, whereas carbon fiber, as a relatively high cost strengthener, is most usually combined with epoxy resins. Adhesion A resin has to ‘stick’ to the fiber strengthener, and it is important to select a resin/fiber combination (particularly with carbon and aramid fibers) so that there is good adhesion and the fibers are properly bonded within the resin. Composite Comparisons In general terms, Kevlar mechanical properties are good in strength (double that of glass fibers) but very poor in stiffness, whilst the glass composite is ten times as stiff and half the strength. Kevlar is very expensive compared to glass, so it is used where higher strength and elongation is needed. Both aramid composites and GRP are good at handling repeated flexing cycles (such as in a boat hull), but carbon fiber has an unpredictable life when subject to repeated flexing. GRP requires a considerably ‘heavier’ construction to achieve the strength of carbon fiber. Aramid fibers offer equivalent strength to fiberglass at a much lower weight, although abrasion resistance is lower. Summary When choosing a composite, there are many factors to take into account. Many users of advanced composites – for example in the premium boat building industry – will combine all three composites to tailor engineering properties and weight distribution. In fact, we now have structures which are composites of composites. The post GLASS FIBERS AND FIBERGLASS appeared first on materialsreview.
Metro International is Up to No Good in Aluminum Warehousing Again – Steel, Aluminum, Copper, Stainless, Rare Earth, Metal Prices, Forecasting
13.01.16 - Metro International Trade Services — the dominant London Metal Exchange warehouse operator in Detroit but also with depots across the US, Italy, South Korea and Malaysia — was ever the stand out contrarian operator. Indeed, it was the fabulous profits the firm was generating that encouraged Goldman Sachs to buy the company in 2010, and it was the prospect of lower profits and regulatory oversight that probably prompted them to sell in 2014 to Swiss-based but British-owned investment house Reuben Brothers. Metro and Pacorini’s Load-Out Game It’s probably not unfair to say Metro, along with Glencore’s Paccorini, were the black sheep of the warehousing family in the years following the financial crisis, as they engineered massive load out queues, lasting up to two years, in order to generate vast rent profits from metal stuck waiting in the queue to be loaded out. Aluminum ingots, possibly waiting at a Metro International warehouse for load out. Consumers and processors put up with that for a while, but under threat of legal action the LME moved to tackle the problem in recent years and a number of rule changes have effectively forced warehouse firms to limit intake when queues are over a certain length. Increase load out rates and changes this year will force firms to reduce rent on metal in the load out queues. Open and Transparent Warehousing As a result, the warehouse business has been forced to operate on a more fair and open basis, charging rents on a competitive basis against other LME warehouses without the benefit of being able to offer massive incentives, in the form of secret discounts or up-front payments, to encourage firms to store metal in their sheds. The LME’s rule changes were expected to cause rents to rise, storing metal in a highly regulated and secure LME warehouse has costs (and benefits) attached that non-LME warehouse storage does not incur. Forcing LME warehouses to operate without these distorting incentives was always likely to incur an increase in rents, but according to Reuters the market has been taken by surprise this week when Metro announced their 2016/17 rent and Free on Truck (FOT) delivery charges for aluminum at levels way above those of any other LME warehouse company. Metro will charge $0.72 per metric ton per day to store aluminum in its sheds from April 1, up from $0.54 currently. The company has also raised its FOT charges in the US to $55.55 per metric ton from $39.95. By way of comparison, the average 2016/2017 rent charge for aluminum among competing operators of LME warehouses in Detroit is $0.535 per metric ton per day, up from $0.4683 in 2015/2016. The average FOT charge from competing operators will be $43.99 per mt, from $40.02 in 2015/2016. The LME has been typically understated in its response to the news, saying it has queried the economic rationale for the increases submitted, but behind the scenes must be demanding an explanation for such dramatic increases. The average of all warehouse rents for aluminum from April will be near 50 cents, and the LME has suggested it may consider rent capping but it’s unclear if it would run into legal challenges if it tried that route to resolve the situation. Metro’s Hand… Not All Trump Cards Metro may be the dominant LME warehouse operator in Detroit, its home base, but it is not the only one. There are four others holding aluminum, but Metro has 90% of the city’s LME aluminum stock. How much longer it will hold such a dominant position remains to be seen though, the firm can’t even make significant money out of the 200,00+ mt of metal sitting in its load-out queue. New rules such as queue-based rent capping due to be introduced by the LME in May mean the rent payable on metal stuck in a queue for longer than 30 days drops by half and is eliminated altogether after 50 days. Metro may find that it hemorrhages stock as customers switch to other operators. Or, more likely, this may be just be a negotiating stance and it fully expects to “respond to market pressure” and reduce the planned increases to something close to the industry norm, but achieve better than the average without having to fight a legal case. The post Metro International is Up to No Good in Aluminum Warehousing Again – Steel, Aluminum, Copper, Stainless, Rare Earth, Metal Prices, Forecasting appeared first on materialsreview.
07.01.16 - Researchers tested the force required to pluck a boron nitride nanotube (BNNT) from a polymer by welding a cantilever to the nanotube and pulling. The experimental set-up is shown in a schematic on the left and an actual image on the right. Credit: Changhong Ke/State University of New York at Binghamton Carbon nanotubes are legendary in their strength—at least 30 times stronger than bullet-stopping Kevlar by some estimates. When mixed with lightweight polymers such as plastics and epoxy resins, the tiny tubes reinforce the material, like the rebar in a block of concrete, promising lightweight and strong materials for airplanes, spaceships, cars and even sports equipment. While such carbon nanotube-polymer nanocomposites have attracted enormous interest from the materials research community, a group of scientists now has evidence that a different nanotube—made from boron nitride—could offer even more strength per unit of weight. They publish their results in the journal Applied Physics Letters. Boron nitride, like carbon, can form single-atom-thick sheets that are rolled into cylinders to create nanotubes. By themselves boron nitride nanotubes are almost as strong as carbon nanotubes, but their real advantage in a composite material comes from the way they stick strongly to the polymer. "The weakest link in these nanocomposites is the interface between the polymer and the nanotubes," said Changhong Ke, an associate professor in the mechanical engineering department at the State University of New York at Binghamton. If you break a composite, the nanotubes left sticking out have clean surfaces, as opposed to having chunks of polymer still stuck to them. The clean break indicates that the connection between the tubes and the polymer fails, Ke noted. Plucking Nanotubes Ke and his colleagues devised a novel way to test the strength of the nanotube-polymer link. They sandwiched boron nitride nanotubes between two thin layers of polymer, with some of the nanotubes left sticking out. They selected only the tubes that were sticking straight out of the polymer, and then welded the nanotube to the tip of a tiny cantilever beam. The team applied a force on the beam and tugged increasingly harder on the nanotube until it was ripped free of the polymer. The researchers found that the force required to pluck out a nanotube at first increased with the nanotube length, but then plateaued. The behavior is a sign that the connection between the nanotube and the polymer is failing through a crack that forms and then spreads, Ke said. The researchers tested two forms of polymer: epoxy and poly(methyl methacrylate), or PMMA, which is the same material used for Plexiglas. They found that the epoxy-boron nitride nanotube interface was stronger than the PMMA-nanotube interface. They also found that both polymer-boron nitride nanotube binding strengths were higher than those reported for carbon nanotubes—35 percent higher for the PMMA interface and approximately 20 percent higher for the epoxy interface. The Advantages of Boron Nitride Nanotubes Boron nitride nanotubes likely bind more strongly to polymers because of the way the electrons are arranged in the molecules, Ke explained. In carbon nanotubes, all carbon atoms have equal charges in their nucleus, so the atoms share electrons equally. In boron nitride, the nitrogen atom has more protons than the boron atom, so it hogs more of the electrons in the bond. The unequal charge distribution leads to a stronger attraction between the boron nitride and the polymer molecules, as verified by molecular dynamics simulations performed by Ke's colleagues in Dr. Xianqiao Wang's group at the University of Georgia. Boron nitride nanotubes also have additional advantages over carbon nanotubes, Ke said. They are more stable at high temperatures and they can better absorb neutron radiation, both advantageous properties in the extreme environment of outer space. In addition, boron nitride nanotubes are piezoelectric, which means they can generate an electric charge when stretched. This property means the material offers energy harvesting as well as sensing and actuation capabilities. The main drawback to boron nitride nanotubes is the cost. Currently they sell for about $1,000 per gram, compared to the $10-20 per gram for carbon nanotubes, Ke said. He is optimistic that the price will come down, though, noting that carbon nanotubes were similarly expensive when they were first developed. "I think boron nitride nanotubes are the future for making polymer composites for the aerospace industry," he said. The post Move aside carbon: Boron nitride-reinforced materials are even stronger appeared first on materialsreview.