For the next generation of the A8, Audi is employing a mix of four materials – CFRP composites, aluminum, steel and magnesium, in the body structure, known as the Audi Space Frame (ASF). While most of the car will be made of different alloys, carbon fiber will be used to strengthen certain areas while keeping weight down, such as in the B-pillars and the rear panel of the vehicle. The CFRP rear panel is the largest component in the occupant cell of the A8.
“[Audi] consistently applies new material technologies and designs that are directly beneficial to the customer – and not only in terms of weight,” Audi wrote. “The upcoming flagship’s torsional rigidity – the critical parameter for precise handling and pleasing acoustics – surpasses its predecessor model’s rigidity value by up to 24 percent.”
According to Audi, the CFRP rear panel comprises 33 percent of the torsional rigidity of the total vehicle. In order to ensure the vehicle can absorb loads and shearing forces, between six and 19 fiber layers are placed on top of each other.
These individual fiber layers consist of tapes 50 millimeters (0.2 in) wide and can be placed individually in a finished layered panel, with any desired fiber angle and minimal trimming of the fibers. The OEM’s direct-fiber-layering process developed for specifically for this purpose eliminates the need to manufacture entire sheets of carbon fiber. Using another newly developed process, the layered panel is wetted with epoxy resin and cured within minutes.
This chassis technology and usage is very similar to the setup developed for the new 7 Series BMW, known as “Carbon Core.” According to BMW supplier SGL Group, Carbon Core technology “leads to substantial weight reduction and also helps to further enhance the driving dynamics by lowering the vehicle’s center of gravity.”
The new A8 will be fully unveiled at the Frankfurt Motor Show later this year.