JEC COMPOSITES MAGAZINE - Issue #54 - January 2010 - 27

FEATURE “Wind Energy” Foam New PET foams for wind turbine construction Light weight and high mechanical strength in conjunction with residual flexibility and maxi-mum service life – these are the main material requirements for modern composite materials. I n recent years, PET foams have been able to secure an established place among the core materials for sandwich constructions. Due to their good technical properties and excellent value for money, polyethylene terephthalate foams are becoming more and more attractive for a wide range of applications. Armacell has succeeded in greatly improving the flexibility of PET foams, thus qualifying these materials for industrial applications. The central technical properties such as shear elongation, compression modulus and shear modulus were constantly optimized over the years. In 2006, Armacell produced ArmaFORM PET 100, a PET foam which has since become the state of the art in the field of composites. but also improves the position of PET foams in competition with other core materials such as PVC, SAN or balsa. Wide product range To better fulfil the specific requirements of such diverse areas of application as wind turbine construction, transport and shipbuilding, Armacell now offers a wider range of ArmaFORM PET foams: ArmaFORM PET AC is manufactured with densities of 80, 100, 115 and 135 kg/m³. ArmaFORM PET AC 80 directly competes with PVC core foams. PET foams have the advantage of high temperature resistance and withstand short-term curing temperatures of up to +180°C. This heat resistance leads to considerable savings in composite production methods, e.g. the prepreg procedure. ArmaFORM PET foams are also completely recyclable, they score well in the fatigue resistance test, and no toxic gases are generated in the event of a fire. More information: www.armacell .com New milestone in PET foam technology The new ArmaFORM PET AC foams display properties which have been further enhanced. In comparison with its predecessor, shear elongation (and therefore both damage tolerance and flexibility) has been optimized from 10 to 20% in ArmaFORM PET AC 115, in accordance with ISO 1922. At the same time, other important technical parameters such as the compression modulus have been kept at their usual high level. Armacell always aligns its compression modulus with ISO 844. Here, the company differs greatly from other manufacturers, who prefer to follow the DIN 53421 test, which leads to better but much less precise values. With the new material, Armacell not only has an advantage over other PET manufacturers, Focus Since 1980, the energy yield has been increased 500-fold. In order to enable the capacity of the turbines to be utilized efficiently, one focus of enhancements lies in the use of new materials. Today, a typical wind turbine has a nominal output of 2 MW. It consists of a nacelle, rotors, hub, generator and tower. The rotor blades are a central component of the turbine. They extract the wind’s energy from the air and transfer it to the generator. The span of the rotors usually ranges from 40 to 100 m. As the surface area of the rotor determines howmuch energy a wind turbine can generate, the trend is towards ever larger rotors. Enormous centrifugal forces act on the ends of the rotors: at 0.3 revolutions per second, the blade tips of 50-metre rotors reach a speed of 340 km/h. The centrifugal forces correspond to 18 times the acceleration of gravity. This makes great demands on the materials used. The rotors are the core element of the turbine. Modern rotor blades are made of composite materials. These are sandwich constructions in which a core material is laminated with a further material. Light weight, high mechanical strength and maximum service life are the main requirements for the core materials. No54 January 2010 / jec composites magazine

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JEC COMPOSITES MAGAZINE - Issue #54 - January 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #54 - January 2010