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Fraunhofer researchers have partnered with industry experts to develop highly durable thermoplastic foams and composites that make the blades lighter and recyclable

Offshore wind turbines are becoming ever larger, and the transportation, installation, disassembly and disposal of their gigantic rotor blades are presenting operators with new challenges.

The trend toward ever larger offshore wind farms continues with some rotor blades measuring up to 80 metres in length with rotor diameters of over 160 metres. Since the length of the blades is limited by their weight, it is essential to develop lightweight systems with high material strength.

The lower weight makes the wind turbines easier to assemble and disassemble, and also improves their stability at sea. In the EU’s WALiD (Wind Blade Using Cost-Effective Advanced Lightweight Design) project, scientists at the Fraunhofer Institute for Chemical Technology ICT in Pfinztal are working closely with ten industry and research partners on the lightweight design of rotor blades. By improving the design and materials used, they hope to reduce the weight of the blades and thus increase their service life.

These days, rotor blades for wind turbines are largely made by hand from thermosetting resin systems. These, however, don’t permit melting, and they aren’t suitable for material recycling. At best, granulated thermoset plastic waste is recycled as filler in simple applications.

Florian Rapp, the project coordinator at Fraunhofer ICT said;

In the WALiD project, we’re pursuing a completely new blade design. We’re switching the material class and using thermoplastics in rotor blades for the first time. These are meltable plastics that we can process efficiently in automated production facilities.

For the outer shell of the rotor blade, as well as for segments of the inner supporting structure, the project partners use sandwich materials made from thermoplastic foams and fibre-reinforced plastics. In general, carbon-fibre-reinforced thermoplastics are used for the areas of the rotor blade that bear the greatest load, while glass fibres reinforce the less stressed areas. For the sandwich core, Rapp and his team are developing thermoplastic foams that are bonded with cover layers made of fibre-reinforced thermoplastics in sandwich design. This combination improves the mechanical strength, efficiency, durability and longevity of the rotor blade.

The ICT foams provide better properties than existing material systems, thus enabling completely new applications – for instance in the automotive, aviation and shipping industries. In vehicles, manufacturers have been using foam materials in visors and seating, for example, but not for load-bearing structures.

The current foams have some limitations, for instance with regard to temperature stability, so they can’t be installed as insulation near the engine. Meltable plastic foams, by contrast, are temperature stable and therefore suitable as insulation material in areas close to the engine. They can permanently withstand higher temperatures than, for example, expanded polystyrene foam (EPS) or expanded polypropylene (EPP). Their enhanced mechanical properties also make them conceivable for use in door modules or as stiffening elements in the sandwich composite.

Yet another advantage is that thermoplastic foams are more easily available than renewable sandwich core materials such as balsa wood. These innovative materials are manufactured in the institute’s own foam extrusion plant in Pfinztal.

The process involves melting the plastic granules, mix a blowing agent into the polymer melt and foam the material. The foamed, stabilised particles and semi-finished products can then be shaped and cut as desired. In the area of foamed polymers, the ICT foam technologies research group covers the entire thermoplastic foams production chain, from material development and manufacture of extrusion-foamed particles and semi-finished products to process media and finished components.

The researchers will be presenting a miniature wind turbine made from the new foams and composites at the K 2016 trade fair in Düsseldorf from October 19 to 26.

The latest Airbus and Boeing passenger jets flying today are made primarily from advanced composite materials such as carbon fibre reinforced plastic — extremely lightweight, durable materials that reduce the overall weight of the plane by as much as 20% compared to aluminium-bodied planes. Such lightweight airframes translate directly to fuel savings, which is a major point in advanced composites’ favour.

But composite materials are also surprisingly vulnerable: While aluminium can withstand relatively large impacts before cracking, the many layers in composites can break apart due to relatively small impacts — a drawback that is considered the material’s Achilles’ heel.

MIT aerospace engineers have found a way to bond composite layers in such a way that the resulting material is substantially stronger and more resistant to damage than other advanced composites.

The researchers fastened the layers of composite materials together using carbon nanotubes — atom-thin rolls of carbon that, despite their microscopic stature, are incredibly strong. They embedded tiny “forests” of carbon nanotubes within a glue-like polymer matrix, then pressed the matrix between layers of carbon fibre composites. The nanotubes, resembling tiny, vertically aligned stitches, worked themselves within the crevices of each composite layer, serving as a scaffold to hold the layers together.


In experiments to test the material’s strength, the team found that, compared with existing composite materials, the stitched composites were 30% stronger, withstanding greater forces before breaking apart.

Roberto Guzman, who led the work as an MIT postdoc in the Department of Aeronautics and Astronautics (AeroAstro), says the improvement may lead to stronger, lighter airplane parts — particularly those that require nails or bolts, which can crack conventional composites.

More work needs to be done, but we are really positive that this will lead to stronger, lighter planes. That means a lot of fuel saved, which is great for the environment and for our pockets.

Today’s composite materials are composed of layers, or plies, of horizontal carbon fibres, held together by a polymer glue, which Wardle describes as “a very, very weak, problematic area.” Attempts to strengthen this glue region include Z-pinning and 3-D weaving — methods that involve pinning or weaving bundles of carbon fibres through composite layers, similar to pushing nails through plywood, or thread through fabric.

A stitch or nail is thousands of times bigger than carbon fibres. So when you drive them through the composite, you break thousands of carbon fibres and damage the composite.

Carbon nanotubes, by contrast, are about 10 nanometers in diameter — nearly a million times smaller than the carbon fibres. Researchers we’re able to put these nanotubes in without disturbing the larger carbon fibres, and that’s what maintains the composite’s strength.

Guzman and Wardle came up with a technique to integrate a scaffold of carbon nanotubes within the polymer glue. They first grew a forest of vertically aligned carbon nanotubes, following a procedure that Wardle’s group previously developed. They then transferred the forest onto a sticky, uncured composite layer and repeated the process to generate a stack of 16 composite plies — a typical composite laminate makeup — with carbon nanotubes glued between each layer.

To test the material’s strength, the team performed a tension-bearing test — a standard test used to size aerospace parts — where the researchers put a bolt through a hole in the composite, then ripped it out. While existing composites typically break under such tension, the team found the stitched composites were stronger, able to withstand 30 percent more force before cracking.

The researchers also performed an open-hole compression test, applying force to squeeze the bolt hole shut. In that case, the stitched composite withstood 14 percent more force before breaking, compared to existing composites.

The strength enhancements suggest this material will be more resistant to any type of damaging events or features. And since the majority of the newest planes are more than 50% composite by weight, improving these state-of-the art composites has very positive implications for aircraft structural performance.

This work was supported by Airbus Group, Boeing, Embraer, Lockheed Martin, Saab AB, Spirit AeroSystems Inc., Textron Systems, ANSYS, Hexcel, and TohoTenax through MIT’s Nano-Engineered Composite aerospace STructures (NECST) Consortium and, in part, by the U.S. Army.

Operating as an entity outside of the company’s headquarters in Sant’Agata Bolognese, the new facility will be responsible for unlocking new potential in carbon fibre. The research that takes place here will go on to influence developments in future Lamborghinis. The official grand opening of the new ACSL also marks the 30th anniversary of Lamborghini’s use of carbon fibre reinforced polymer in its vehicles.

Carbon fibre is a material that Lamborghini has a long history with. Starting with the Countach Quattrovalvole and continuing today, it is one of the most important keys to the success of our cars in the past, present and future.

Seattle is a strategic location for the company’s new research centre, particularly because of its collaboration with Boeing in working toward carbon fibre innovations that are beneficial in both automotive and aerospace applications.

Lamborghini see its Forged Composite technology as one of the most important developments to come from research within the ACSL which shortens the amount of production time required to form components by comparison the traditional labor techniques.

The technology made its debut in 2010 with the Sesto Elemento limited edition supercar where it served in a structural capacity and as proof of how capable the rapid-formed material is. Such continued refinements in the manufacturing process have allowed Lamborghini to enhance its finished product for structural and aesthetical application in 2013.

By continuing to develop our patented Forged Composite materials, we are able to create a product that can enhance Lamborghini super sports cars in both their performance and their appearance.

Along with researching new advanced composite technologies, Lamborghini’s will also use its new Advanced Composite Structures Laboratory to find and recruit young, talented engineers from around the world.

The Wilhelmina Canal is an important water way in the south of the Netherlands, and a vital part of the transportation infrastructure. In order to keep up with the increasing water traffic and increasing size of the ships, the canal is being widened and deepened near the city of Tilburg.

As part of the larger project, the existing locks II and III are replaced by a single new lock. Also, new sheet piling is installed along the canal sides and a more environmentally banks are being developed.

While smaller composite lock gates have been installed in the past, so far the number of installations have been limited. The use of the large composite lock gates (size of each part 6.2 x 12.9 m) in the Tilburg project, means a major breakthrough in the acceptance of composite technology for this demanding application. The individual gate doors need to have very high strength and stiffness, and are required to resist water in continued contact for over 80 years, whilst surviving any potential impact of ships in that time.

“Lock gates in composite materials are highly competitive in terms of cost compared to traditional material solutions based on steel and wood”

The composite parts were designed, engineered and manufactured by FiberCore Europe using resins from Aliancys. The large parts have a relatively low weight (24 MT) which is significantly lower than comparable solutions in steel and wood (respectively 50% and 25% less). This makes the installation much easier, requiring simpler equipment and upfront preparation. Because the fact that the specific gravity of the gate material is fairly close to the one of water (unlike steel), the wear and tear on the pivoting points is greatly reduced.

Once the project is complete, larger vessels should be able to sail through this section much faster, which would mean less congestion and heavy traffic on main roadways. The improvements to the canal will also create additional economic opportunities in the south of the Netherlands, as businesses are increasingly using the canal network for delivery of products.

Built by ex-Koenigsegg engineer Leif Tufvesson, the design is based on the car from the Arkham knight video game but has been redesigned and manufactured with drivability and full functionality in mind. The wheelbase is 3.40 meters and the width of this special car is 2.5 metres. The special high rigid tubular frame is manufactured to provide good handling and offer a solid feeling.

Front and rear suspensions are fully independent and made with double wishbones connected to the coil over shock absorbers, up front through a special designed aluminium push rod. Under the bat hood sits a Lamborghini 560hp V10 engine connected to a paddle shift gear box affecting the 26″ wheels. To stop the car we have used ABS supported 8-pot Brembo calipers in front and 6-pot in rear all connected to big brake discs.

The complicated all carbon fibre body was made from full-scale moulds which are milled out from the CAD drawings. Inside, the interior is a combination of black soft leather and “see trough” fabric, all kept together by golden stitches. The interior lights up the seats, floor and pedals when the fully electric cockpit opens up.

BMW designers, working in close collaboration with Team USA athletes and coaches designed and developed the racing wheel chair which is set to make its competitive debut at the Rio 2016 Paralympic Games.

The new racing wheelchair features modernised aerodynamic efficiencies, carbon fibre material, a complete chassis redesign and a personalised approach for customised athlete fit.

Brad Cracchiola, Associate Director, BMW Group DesignWorks said;

Working on this project has been a truly rewarding experience for my team and we’re proud of what we’ve been able to accomplish in the last year and half with these athletes and their coaches, from fittings and immersion sessions, to data analysis and real-time testing, we had the unique opportunity to build a fully customised racing device. We’re eager to complete the final product and look forward to watching Team USA compete.

With the help of Team USA athletes, BMW will work over the next few months to continue to adjust and improve the wheelchair in the lead up to the Games. The final fleet of wheelchairs for use in the Rio 2016 Paralympic Games is slated to be delivered to the U.S. Paralympics track and field racers in the summer of 2016.

The company has been implementing its resources to advance the training and performance goals of Team USA since signing on as a sponsor in 2010. The BMW racing wheelchair is the company’s fourth technology transfer project, following the delivery of a two-man bobsled which helped Team USA overcome a 62-year medal drought at the Sochi 2014 Olympic Winter Games.

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