By Rhoda Miel, Plastics News Staff
San Antonio, Texas -- Making a concept composite floor structure for sedans is one thing, but the engineers and companies involved with the Automotive Composites Consortium also wanted to make sure the concept could fit into existing auto-manufacturing lines.
"Our goal is to develop manufacturing methodologies that each [automaker] would then take forward for their use," said Libby Berger, a staff researcher in General Motors llc's research and development centre.
So as part of the nearly six-year project to develop a structural composite automotive underbody, the members of the consortium also developed a process to attach it to a steel body structure.
Berger discussed the underbody project during the Society of Plastics Engineers Thermoset TopCon conference 24-25 Jan in San Antonio. Detroit-based GM, Ford Motor Co. and Chrysler Group llc were all part of the cooperative investigation along with Continental Structural Plastics Inc., Multimatic Inc. and the Department of Energy's Oak Ridge, Tennessee, laboratory, as part of the US Council for Automotive Research programme to investigate new technology.
With the composite underbody, the group focused on one part of the body, rather than the entire vehicle - the centre flooring structure of a current-model large sedan.
The current centre underbody, or floorpan, is made of 14-16 individual steel components. ACC focused on replacing that with one composite part that could be produced in a two-and-a-half-minute cycle. Berger admitted the team did not quite hit the cycle target, but the final component was more than 20 lb (9 kg) lighter and still met extensive crash and structure requirements.
The team looked at a variety of processes and materials for the composite part before landing on a multilayer, sheet moulded compound fabric, using long-glass-fibre reinforcement for most of the part and a chopped structural SMC (sheet moulding compound) for reinforcing ribs.
There is no guarantee that the concept will ever make it into production, although there is interest. The coalition focuses on developing projects to a pre-production state. It is then up to individual automakers to decide whether to take the project further. If the concept does move forward, though, Berger warned it could take three to five more years of development.
"If you're going to develop a new material, you've got to plan on it taking a long time," she warned. "At this point, the technology has gone back to the [carmakers] and it's up to them to take it further."
The full version of this article first appeared on our sister publication, Plastics News