Abstract
Keywords - Aluminium, Lightweight Design, Sports Car, Audi Space Frame - ASF®, Magnesium
Audi enters the market with the R8 mid-engine sports car in the most ambitious segment and immediately takes over a leading position: Equipped with the Audi competence in motor sports and experience in production of sporty premium passenger cars the R8 stands for top level driving dynamics, technological leadership and fascinating design. The 420 hp V8 FSI Mid-Engine, permanent all wheel drive quattro, and the Aluminium space frame ASF® body assures an outstanding competitive position, as well as the high level of suitability for daily use and the Audi-typical perfection in quality and manufacturing.
For a high-performance sports car, a very light but at the same time extremely rigid body is essential for good driving dynamics and maximum motoring fun. The space frame technology with extruded aluminium profiles, castings and sheet metal elements, is an ideal way of achieving these objectives.
The mix of semi-finished elements used for the R8´s space frame is governed by the various functions that the body has to perform and by the number of cars to be built. The high proportion of extruded profiles, namely more than two third of the space frame´s parts, is explained by the fact that their cross-sections can be varied to suit every requirement or design preference. The vacuum pressure casting method enables to reduce the wall thicknesses for the aluminium casting parts, so that very light multi-functional parts can be produced. Another highlight of the R8´s space frame is the rear engine frame that reinforces the car´s rear end structure and is made of magnesium pressure casting.
The Audi R8´s body is hand-built, but none the less the very latest robot technologies and laser measuring techniques are used. The combination of different types of semi-finished elements requires an intelligent combination of different joining techniques. Next to MIG welding, mostly used to connect castings and cross sections, as well as structural sheet-metal parts is accompanied by self-piercing rivets and flow drill screws inserted by an automated process.
Body rigidity is an essential precondition for highly sporty but none the less comfortable road behaviour. Both static and dynamic characteristics of the bare body shell and the completely trimmed body were carefully examined using the very latest computer-aided methods such as topology optimisation.
All these efforts were made to design a top level sports car, unique in design and performance, especially in combination with every-day-suitability to uphold the Audi brand´s claims as a premium manufacturer.