The number of car models with carbon parts is growing at Porsche. In addition to the 919 Hybrid - recently the company announced - , the 911 GT3 RS street sports car trims several kilograms of vehicle weight by using CFRP to produce the boot lids, rear spoilers and wings. And the 918 Spyder puts a chassis on the road that is made entirely of carbon fibre and has a CFRP monocoque.
However, for larger production volumes, the lightweight car body of the future will presumably require an intelligent, requirements-based material mix of aluminium and steel supplemented by parts made of magnesium and fibre-reinforced polymer materials such as CFRP. Intelligent hybrid construction methods in particular – which combine the benefits of metals and fibre-reinforced polymer composites – have high potential for economic lightweight design, especially at medium to large production volumes. This much is certain: Porsche will still be adding a number of new chapters to the history of carbon fibre.
The use of CFRP - as Porsche remembers - was born in the aerospace industry. Starting in the 1950s, carbon fibres were woven into strips, soaked in resins and processed into very strong and lightweight molded parts. In the automotive industry, the fascinating material first appeared in the 1990s. At Porsche, carbon fibre made a fitting debut. In the 1998 race season, the 911 GT1 became the first Porsche to sport a carbon-fibre chassis. Designers saved a full 50 kilograms of weight compared to the previous model – and this promptly led to a magnificent first-second sweep at Le Mans. The street-car premiere of carbon fibre happened five years later – and it was reserved for an exceptional sports car: the Carrera GT.
But despite its excellent properties, carbon has not really revolutionised vehicle technology from the ground up. The once predicted triumph of carbon fibre has largely been restricted to the domain of super sports cars with smaller production volumes. The simple reason: the costs of CRFP parts are still very high compared to metal parts for the same production volumes.
The production of carbon fibre itself is very energy- and cost-intensive; processing it into an end product requires significantly more complex, time intensive production processes with less automation compared to metal materials. The key to reducing manufacturing costs and thereby making CFRP feasible for large-scale production is to shorten production times with faster curing resins or thermoplastic matrix systems.
28 December 2016