Record breaking cylinder will improve energy efficiency

APPLICATIf$,$@ European car makers turn to composites are once again finding .favour with European car makers, following several years in the doldrums because of recycling concerns. Stephane Guillon of Vetrotex, speaking at the AVK meeting in Baden Baden, Germany, in early October claims that 50% of European vehicles will have integrated front-ends by the year 2000, and 63% of these will be in composites. Today a quarter of cars have such front end systems with around one third being made from composites, He also expects composites to find increasing applications in body panels for niche vehicles and in door modules. A 10% growth in composites penetration of the automotive market between 1990 and 2000 means 4700 tonnes of new parts, says Guillon. Some 3000 tonnes of this will be in low profile applications including hatchbacks, wings and bonnets, the remaining 1700 tonnes will be for front ends. Other industry insiders generally support his forecasts. Hans Dieter Muller managing director of moulder Menzolit-Fibron and president of the European SMC Alliance told Reinforced Plastics that advances in US sheet moulding compound (SMC) technology now being transferred to Europe are behind the new interest from car makers. Developments include better paint technology, the ability to stick two parts together better, and the ability to make parts without ribs which cause shrink on the surface. COMPOSITES

Reinforced Plastics November 1997

Record breaking cylinder will improve energy efficiency breaking composite cyclinder could help improve the efficiency of energy storage systems in space and satellite structures, according the US National Laboratory at Oak Ridge, Tennessee. The laboratory’s Center for Composites Manufacturing says that it has fabricated a composite cylinder which it believes holds the record for the highest recorded hoop tensile strength for its class of material. The wet filament wound cylinder, formed from carbon fibre and a polycyanate resin, achieved an average hoop tensile strength of 4640 MPa, with a 4.3% coefficient of variation. Three of the ten test rings had individual strengths greater than 4826 MPa. The ultimate tensile strength of ultra-high strength steel, which is five times as dense, is just 2144 MPa. The measured hoop strengths are considered conservative. The true strength of the cylinder may actually be higher because of the additional bending stresses the fixtures impose on the ring during testing. Uses for strong, lightweight composite cylinders and rings include high-speed rotating’ hardware such as energy storage flywheels. Higher hoop strengths enable flywheels to be operated at high rotation speeds which increases the amount of energy that can be stored and recovered. A RECORD

Muller believes that predictions such as that made by Vetrotex are achievable providing the industry can make SMC parts which it can supply ready for a final paint coat on the manufacturer’s line. The technology exists, he says, but it needs to be developed to allow it to be used cost effectively. The demand for niche models is behind the car makers’ interest in SMC. Steel press tools are simply too expensive for the volumes required. Recyclability of SMC is no longer an issue for the car makers and concerns over crash behaviour have also been allayed. The ability to paint to a Class A finish at low cost is the only remaining hurdle. Composites successes at the moment include the SMC bodied Renault Espace. Now in its third model variant, some 300 a day are being built. A further 500-600 a day of the VW Sharan/Ford Galaxy/Seat Alhambra minivan are also being made; this features a SMC front end, noise shield and water box. Glass mat thermoplastics (GMT) also continue to find high profile, high volume applications. The new A Class city car from Mercedes uses 30 kg of the material on a range of body parts. This includes the

hatchback door which has a GMT inner, weighing 7 kg, bonded to an outer skin made from GE Plastics’ Noryl, modified polyphenylene oxide thermoplastic. Both components are moulded by Peguform. Swiss moulder Rieter is making GMT underbodies for the vehicle. Heinrich Ernst of press maker Dieffenbacher, says that a number of other car makers, including BMW and Rover, are looking at making more extensive use of SMC and GMT. Rover is said to have decided to use both mate. rials on its new minicars. VW, which uses composites for all its frontends, continues to pioneer new applications. Klaus-Uwe Broderson, chairman of MenzolitFibron, says that his firm is now making 2000 frontends a day (460 OOO/year) for the VW Passat using its long fibre reinforced (LFT) process. This uses a bulk moulding compound (BMC)-like material which is introduced into the mould over a plasticizer, thereby eliminating the need for a semi-finished product. Fellow German moulder Rufas is to set up a moulding operation in Brazil to make GMT front-ends for the VW models made there.

Bill Wilburn, Lockheed Martin Energy Systems; tel: + l-423-241493 7.