Audi 2013 Annual Report Download - page 26

this configuration. The desired material properties can be only
be achieved when multiple plies of this material are cross-lami-
nated – similar to the steel belts of a car tire. Schauerte adds,
however : “Additional requirements with respect to such things
as fracture pattern, temperature resistance, surface quality,
contact corrosion behavior, acoustics or reparability can quickly
reduce a material’s initial high potential for lightweight
construction.” For example, if a very lightweight fiber-composite
component in the finished vehicle has such significant acoustic
disadvantages that a large amount of acoustic insulation is
required, this could oset the weight advantage. And nothing
would be gained.
As is so often the case, the solution is in the details. And in
industrialized, cost-eective manufacturing processes that keep
both weight and price down. Highly engineered, ecient, with
the focus on reduced energy consumption and nearly total
avoidance of waste, as the example of tailored fiber placement
shows. This involves stitching or embroidering carbon or glass
fibers to a substrate. Hardly any waste is produced, and the
fibers are perfectly oriented for the force curves and loads to
which the component will later be subjected.
There are a lot of things that need to be considered when
implementing the lightweight construction philosophy. But as a
pioneer of lightweight construction, Audi will accept nothing
less than an outstanding result. It isn’t the easiest way to go.
But we do our best to make light work of things.
Lightweight construction is one of Audi’s core competences.
“But lightweight construction requires heavy thought,” says
Dr.-Ing. Karl Durst philosophically. He is one of the experts
who make Audi lighter. “Unfortunately, it isn’t enough to
simply use the lightest material, since some lightweight mate-
rials hardly deform at all under load. And that goes against the
concept of safety in body design, since little crash energy would
be absorbed.” The passionate marathon runner, who ensures
that even his running shoes don’t weigh a single gram more
than is necessary, argues in favor of the smart use of composite
materials. “Each material has characteristic properties, advan-
tages and disadvantages. The art lies in combining lightweight
materials in a way that enhances the advantages of the individual
materials while compensating for their respective disadvantages.
We are always anxious to use the right amount of the right
material in the right place,” says Durst.
Audi is therefore increasingly using combinations of steel,
aluminum, magnesium and fiber-reinforced composites of
carbon and glass fibers in lightweight construction. Carbon-fiber-
reinforced polymer is up to 60 percent lighter than high-
strength steel, for example. “Elasticity, high strength and low
density result in above-average mechanical properties com-
bined with great design freedom,” says Dr. Oliver Schauerte,
Head of Technology and Properties Development for Fiber-
Composite Plastics. These materials initially only exhibit their
tremendous properties in the longitudinal direction of their
fibers, not in the lateral direction. Their use would be limited in
PHOTOS : AUDI AG, adidas AG
Fuel consumption and emission figures at the end of the Annual Report
THINK LIGHT
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