Hyundai: Using a CFRP Frame
Automakers like CFRP because of its weight (70 percent lighter than steel and 40 percent lighter than aluminium), high strength-to-weight ratio, stiffness and corrosion resistance. For its new Intrado crossover, Hyundai is using a rigid CFRP structure in combination with lightweight steel.
At the core of the Intrado’s frame are CFRP sections that begin life as beams containing overbraided carbon fiber and flexible foam cores. Hyundai says the composition makes laying-up and bending into shape easy – no pre-forming steps are necessary – while the enclosed foam reduces frame mass and cost. A vacuum-assisted RTM process is used to create the final material.
Precisely-shaped, continuous loops made from CFRP form self-contained modular frames for the roof, hood and door aperture on either side of the car. Hyundai bonded the carbon loops along their lengths, rather than at cross-sections, to make the frames stronger and reduce torsional stresses.
The seals of opening panels shut directly against these frames, further reducing weight and showcasing the CFRP whenever the doors, hood or trunk are opened. Body panels are made from advanced, super lightweight steel, but the strength and rigidity of the central CFRP frame structure means Hyundai could make them from any material.
A “floating” center console beam, also made of CFRP, runs the length of the Intrado. This beam provides the vehicle with its unique strength, connects the passenger areas and powertrain to the CFRP frame and serves as a mounting point for essential controls and protective padding.
Hyundai says the unique qualities of the Intrado make it more repairable than typical CFRP structures, as damaged sections or parts can be replaced without the use of expensive tooling or ovens. The Intrado’s minimalistic, self-supporting skeleton-like frame structure is highly stable and extremely lightweight, saving 70 percent weight compared to a conventional chassis and around 30 percent on the overall vehicle weight without compromising safety attributes, according to the company.
Ford: Bonding Composites with Aluminum
A CFRP passenger cell will anchor Ford’s new GT high-performance, limited-run supercar, scheduled for production in late 2016. The vehicle will include aluminum front and rear subframes encapsulated in structural CFRP body panels. The CFRP in the GT’s chassis tub and bodywork will be hand laid.