Carbon fiber composite subframe assembly replaces 45 steel parts with two molded and four metallic parts

Tier 1 Magna International Inc., in cooperation with Ford Motor Company, has developed a prototype carbon fiber composite subframe which reduces mass by 34 percent compared to a stamped steel equivalent. By replacing 45 steel parts with two molded and four metallic parts, the prototype subframe achieves a dramatic 87 percent reduction in the number of parts. The moldings are joined by adhesive bonding and structural rivets.

The carbon fiber subframe is the result of a research and development project between Magna and Ford to investigate potential mass-reduction benefits and technical challenges of using carbon fiber-reinforced composites in chassis applications. The subframe is a key part of a vehicle's structure, typically providing a place to attach the engine and wheels while also contributing rigidity and crash management.

"When we are able to work in close partnership with a customer at the beginning of their design and engineering processes, it's an opportunity to bring our full Magna capabilities to bear," said Grahame Burrow, President of Magna Exteriors, speaking at JEC World 2017 in Paris. "We are able to take a clean-sheet approach with design, materials and processing, collaborate with the customer and within our product groups, and deliver a solution with the potential to really move the needle in terms of aggressive lightweighting without sacrificing styling or performance."

Magna's engineering team – a collaborative effort between the company's body & chassis and exteriors product groups – combined its unique, full-vehicle knowledge on the design, materials and processing to address the challenge of reducing weight using composite materials and manufacturing processes.

The design has passed all performance requirements based on computer-aided engineering (CAE) analyses. The prototype subframes are now being produced by Magna for component and vehicle-level testing at Ford.

"Collaboration is the key to success in designing lightweight components that can give our customers fuel economy improvements without compromising ride and handling, durability or safety. We must continue to work hard to achieve these lightweight solutions at the most affordable costs. Magna and Ford working together on this carbon fiber composite subframe is a great example of collaboration on advanced materials," said Mike Whitens, Director of Vehicle Enterprise Systems within Ford Research and Advanced Engineering.

The testing phase will evaluate corrosion, stone chipping and bolt load retention, which aren't currently measured by CAE. The project team will also develop a recommended design, manufacturing and assembly process with the experience gained during the prototype build and subsequent testing.

"We've been a pioneer in the use of lightweight materials for many years now," added Burrow. "First we launched the CF hood for the Cadillac CTS/ATS-V series, followed by a carbon fiber grille opening reinforcement for the Mustang Shelby Cobra GT500. Applying our expertise now to a structural component like the subframe is another step forward as we continue to help our OEM partners meet their goals."