Class 8 trucks are the workhorses of the freight sector. According to the U.S. Department of Energy (DOE), they haul 80% of U.S. goods and use 28 billion gallons of fuel annually, accounting for 22% of the country’s total transportation energy. As the trucking industry strives to increase fuel efficiency and reduce emissions, GFRP structures are emerging as a key part of the solution.
Trucks are typically built with stamped steel, aluminum or a metallic substructure. Replacing these metal structures with GFRP significantly improves fuel efficiency by reducing mass, enhancing aerodynamic performance and increasing thermal performance, says Todd Altman, senior director of automotive at Senvias™ Inc. (formerly TPI Composites’ automotive business unit).
These advantages are on display in a demonstration project, the International® SuperTruck II by Navistar. Senvias fabricated composite parts for the project, which is part of the DOE’s SuperTruck II public-private innovation program to develop technologies that improve the efficiency of Class 8 trucks.
Built in 2023, the International SuperTruck II features a GFRP and CFRP cab and GFRP cargo box, belly pan, axle pan and boat tail. It includes continuous fiber glass and vinyl ester parts, a PET core in the walls of the trailer box and CFRP A pillars. The International SuperTruck II also includes a balsa wood core in the trailer floor. The 230-foot trailer floor and trailer box were each fabricated as a single part.
Navistar’s truck has more than 45 composite parts that help increase aerodynamic efficiency by 58% and fuel efficiency by up to 20%, according to Altman. More than a third of the aerodynamic improvement results from the single-part GFRP trailer box.
“On traditional trailers those surfaces are not necessarily flat. They may have composite panels, but typically they have edges, rivets – all those items impact aerodynamic performance,” says Altman. “The trailer we developed with Navistar has soft, rounded edges and the sides are completely flat, so you get much better aero performance.”
In addition to increasing fuel efficiency, GFRP truck structures also enable significant part reduction and increased corrosion resistance and strength.
“You get a product that performs better because you don’t have a thin skin that is covering a skeleton. It’s a much stronger structure that is harder to damage,” Altman says.
Along with design benefits, composites manufacturing processes are less expensive than metal stamping. “Stamping is expensive,” says Altman. “You have the dies, you have automation. It can range anywhere from $50 million to $400 million dollars.” Comparatively, he says composites manufacturing production investments to make 5,000 trucks are a fraction of the cost.
Composite processes and tooling, including 3D-printed molds, also allow truck manufacturers to get to market quicker. For instance, Senvias helped Motiv Electric Trucks develop and begin production of an all-composite cab for its electric Class 6 Argo truck in one year.
Rapidly evolving technologies within the truck market continue to make composites an attractive option to metal.
“Composites offer a cost-effective opportunity for cab and aerodynamic surface optimization for a low-volume industry that continues to get fragmented by the technology walk from internal combustion engines to electric to autonomous,” says Dean Oppermann, chief technical engineer of advanced technology at Navistar.
Jim Castelaz, founder and chief technology officer at Motiv Electric Trucks, believes the truck industry is nearing an inflection point as more companies adopt composites.
“Other industries have moved from metallic to composite systems – look at planes, golf clubs or bicycles,” he says. “Eventually we believe composites will be the standard in the automotive and trucking industry.”
Melissa O’Leary is a freelance writer in Cleveland. Email comments to melissa@good4you.org.
A trailer box for the International® SuperTruck II by Navistar is removed from the mold.
Photo Credit: Navistar
