COMPOSITES IN CARS

Can you image a motor vehicle that has a fuel efficiency of 100 mpg and is not hybrid? In the near future, it may not be just a fantasy anymore. A vehicle with a composite body frame can easily have a fuel efficiency that is more than 100 mpg. Composites are a new category of materials that contain a high-performance fiber and matrix materials. Composite auto body frames are as strong as steel but with only 40% of the weight and do not rust.

“With composite materials, we get high strength-to-weight and stiffness-to-weight ratios, as well as excellent energy-absorbing capability per mass,” says Dan Adams, professor of mechanical engineering at the University of Utah, who specializes in automotive composites. Adams says composites are currently used in aerospace applications, which require a strong and stiff material that is also extremely light. One of the reasons that composites have not been adapted to the automotive industry is the cost. The processing of carbon fibers is too expensive and slow. This is because the current knowledge and developments in the carbon fiber have not reached the breakthrough point. As a result, carbon fiber composites cannot compete economically with steel in the auto industry.

Adams’ research focuses on designing sandwich composites that are low cost and highly damage tolerant. With the proper design, Adams says that composites can meet or even exceed safety requirements in a crash because they can be designed to absorb significantly more energy than traditional metallic metals when crushed. He says, “Energy is absorbed through repeated failure of the material. The ideal case would be the composite structure being broken into tiny pieces where the crush occurs, but everything else is intact. The materials have to be designed to fail in a controlled manner.”

Adams and his students’ sandwich composites have been used in the Chevrolet Corvette. Adams is continuing to develop crashworthiness of composites with organizations such as Oak Ridge National Laboratory (ORNL) and engineering consulting companies.

For more information about this news, please visit  http://www.coe.utah.edu/view_news/201