The industry is evolving quickly to meet automotive lightweighting demands.
Deadlines are looming for CAFE fuel efficiency standards in the U.S. (54.5 mpg fleet average by 2025) and for Europe’s required reductions in CO2 emissions (40 percent decrease for fleets from 2007 to 2021). In response, automakers and OEMs are working more closely than ever with the composites industry to produce lighter, more efficient vehicles to meet the new requirements.
According to the U.S. Department of Energy (DOE) a 10 percent reduction in vehicle weight can improve fuel efficiency by 6 to 8 percent or increase the range of a battery-electric vehicle by up to 10 percent. Compared with steel, composites can offer a mass reduction ranging of 25 to 30 percent for glass fiber systems and 60 to 70 percent for carbon fiber systems. So it’s not surprising that Persistence Market Research predicts the global composites automotive market will more than double in size in the coming years, going from $3.06 million in 2014 to $7.01 million in 2022.
“The CAFE standards are really what’s been driving the growth of composites,” says Laura K. Gigas, senior product manager, Ashland Performance Materials. “Composites are lighter than steel, and they have other qualities like corrosion resistance and the ability to consolidate multiple steel parts into one composite part.”
Lightweight and cost effective
Although carbon fiber has grabbed much of the attention in the automotive world, OEMs today are using a wide range of composites in their vehicles.
Sogefi, working with Owens Corning, unveiled the first composite material coil springs for automotive suspension systems last fall. Audi will use the GFRP coil for its mass-produced A6 Avant 2.0 TDI ultra. The composite coils weigh 40 to 70 percent less than traditional springs made of steel and will reduce the weight of the vehicle by approximately 9.7 pounds. They also will reduce noise and decrease CO2 emissions up to 1.1 pounds per 0.62 miles.
Chevrolet will use Continental Structural Plastics’ TCA Ultra Lite SMC, a polyester-based Class A SMC with a specific gravity of 1.2, in 21 body panel assemblies in the 2016 Corvette. Components include doors, deck lids, quarter panels and fenders. The use of composites will save money, since tooling costs for composites for production volumes under 150,000 can be as much as 50 to 70 percent less than those for stamping steel or aluminum.
Ford researchers have been experimenting with both injection molding and compression molding for composite components made from chopped fibers. “The properties look very, very good for future applications,” says Matt Zaluzec, global materials & manufacturing research – VES Technical Advisory Board, Research & Advanced Engineering at Ford.
But random fiber composites provide less predictable, less reproducible results than composites made with continuous fiber. That’s not an issue in body panels, but it is essential in structural, safety-critical components. Ashland is working with resins and processes such as prepregs and high pressure resin transfer molding (HP-RTM) to improve the structural stability of both glass and carbon continuous fiber composites.