Out-of-autoclave prepreg enables concept sports car

After nine years and an investment of more than $1 million (Aus), the FR-1, a two-seat roadster concept car, hand built with carbon fiber composites, has made its debut. Conceived by a charitable foundation called Autohorizon (Melbourne, Victoria, Australia) to demonstrate the engineering, design and manufacturing expertise available in Australia today, the project was intended to inspire Australian students to become engineers and designers. Among the project’s 90 Australian sponsors were the Victorian Centre for Advanced Materials Manufacturing. (VCAMM, Knoxfield, Victoria) and four Melbourne-based participants: automaker Holden, Boeing Aerostructures Australia, the Automotive Centre of Excellence (ACE, where the concept car was built) and GMS Composites, which manufactured and supplied the GMS EP270 out-of-autoclave carbon-fiber prepreg system.

The FR-1’s design features include a lightweight carbon composite monocoque chassis — the first ever built in Australia. The ~2m by ~1.5m (~6.5 ft by ~4.9 ft) cockpit, designed by the VCAMM/Boeing team, weighs only 80 kg/176 lb but still provides high torsional rigidity, thanks to optimization of the number and orientation of plies.
The Autohorizon team looked at a number of epoxy prepregs before selecting GMS EP270. The cost-efficient, low-temperature material was available in small volumes and it provided the required strength and stiffness properties that would be required in the monocoque because the car would be powered by a Holden 6.0-liter V8 engine with a Ferrari 355 transmission. GMS EP270 met these requirements after low-temperature processing (70°C/158°F) under vacuum, on fiberglass tooling.

Jason Bonar, an 18-year veteran at Boeing Aerostructures Australia, worked with the team on the chassis layup, which included eight 16-hour cure cycles and a final postcure, all done out of autoclave. Bonar found that the 200 g/m2 3K carbon woven twill prepreg handled easily and conformed accurately to the tight, detailed tool geometry. The fabricated chassis laminate’s mechanical performance has been independently tested, correlated and analyzed using finite element analysis (FEA) by the Australia Future Fibres Research & Innovation Centre (AFFRIC) at Deakin University of Melbourne.

“FR-1 has been a fantastic engineering project,” says Sam Weller, managing director of GMS Composites. “We are thrilled to have been involved and to demonstrate the application performance that can be achieved with our ... prepreg system.”