September 29, 2010
Wheel In A Corset
Just imagine your car suddenly comes to a halt on a quiet country road, and it's only four years old. This is not a pleasant thought. A breakdown is expensive. Not to mention the safety risk to the occupants "“ because the breakdown was caused by the extremely light plastic wheels so highly praised by the car salesman. One of them has broken. "Such a scenario must, of course, never happen in reality," states Prof. Dr.-Ing. Andreas Bter from the Fraunhofer Institute for Structural Durability and System Reliability LBF in Darmstadt. The experts there specialize in operational strength testing of plastics in general and plastic wheels in particular.
To create the fundamentals for the production of lightweight and yet safe and reliable components they launched the High-Strength Plastic Structures project in cooperation with five other Fraunhofer institutes. "The aim was to provide the conditions and the tools for the operationally reliable design of extremely light safety parts made of SMC (sheet molding compound) material which could be produced on an ongoing basis in medium to large volumes. SMC is a fiber-reinforced composite material which mainly consists of inorganic constituents," explains project manager Professor Bter. "Up to now SMC has only been used for secondary parts of the bodywork such as the bonnet or doors," states Bter. "The purpose of our project was to clarify whether SMC is also suitable for safety-relevant primary parts." SMC is superior to metal in several ways. It is not only lighter but also exhibits an excellent mass-to-strength ratio. What's more, it is cheap to produce in medium to large quantities.
And what happens now? In cooperation with the industry the researchers would like to create a wheel based on the developed prototype which can withstand high stresses and loadings. It would feature a local reinforcement of continuous fibers. "That would act like a supporting corset for the wheel," the project manager adds, outlining his team's vision. A prototype of the lightweight wheel will be on display at the Composites Europe trade show from September 14 to 16 in Essen (Hall 12, Stand C33).
Image Caption: This wheel made of fiber-reinforced plastic is particularly light and exhibits high structural durability. Credit: Fraunhofer LBF
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