The science behind 
traveling light.

The science behind <br/>traveling light.
ASF® construction
There’s strength in numbers.
Crafting a vehicle that’s as light as it is strong is a longtime obsession of Audi. It began in 1983, when our engineers conceptualized the ASF®, with prototypes developed in 1987, and the first production ASF® chassis coming to fruition in the aluminum unibody A8, and since then, has been integrated into many of our production vehicles. The forthcoming A8, for the first time, sees an innovative combination of four materials —steel, aluminum, magnesium and carbon—to produce a lightweight vehicle.
What’s inside counts.
Nature inspired our engineers when it came to designing the next generation ASF®. Whereas a bee colony uses only the right amount of material to serve a specific function, we applied the same ideology to the A8. Joining the right materials in the right place with the optimal amount allows for greater understanding of a material’s potential and its intended purpose, which forms a foundation for greater performance and overall capability.
Abundant within the earth’s crust is iron, an element that, when melted down to raw iron, is made into steel. Known for its strength, steel can be formed into different alloys that are easily welded, cast, machined or forged into a variety of shapes or tempers unrivaled by other metals.
Many forms of transportation rely heavily on aluminum for its lightweight properties and strength. A vehicle made from aluminum can yield improved acceleration, braking and handling with its savings in mass.
The high strength-to-weight ratio of magnesium makes it lighter than other structural metals, like steel and aluminum. The damping properties make magnesium impact and fatigue resistant, allowing it to help absorb energy in case of an accident.
Carbon fiber-reinforced polymers are an integral component of the latest generation of ASF® construction. This flexible, fabric-like material, when combined with a resin to form a hard composite, can result in parts that are lighter and stronger in comparison to their metal counterparts.
A combination of high-strength, hot-formed and conventional steel components make up the front bulkhead, side sills, B-pillars and front section of the roofline of the A8 Audi Space Frame. By applying specialized tailoring technologies and partial heat treatment, sheet metal blanks are produced in varying thicknesses to help reduce weight and increase strength.
By and large, the 2019 A8 body is comprised mostly of aluminum components, with design features including heat-treated, ultra-high-strength cast alloy sheet metal, castings and sections that have high tensile strength.
Secured to the strut towers is a magnesium strut brace adding to the body's high torsional rigidity. In the event of a frontal collision, the forces generated are distributed to three impact buffers in the front end.
Carbon fiber polymer
A lightweight carbon fiber panel is joined to the rear wall of the passenger cabin to help increase torsional rigidity while absorbing vehicle loads and add stiffness to the Audi Space Frame.
14 joining processes
Trust the 
Creating the ASF® chassis requires 14 intricate processes to join lightweight materials together. The reason being, there are different rates of thermal expansion for each material. With “cold” mechanical technology connecting the side wall frame to the B-pillar, roof and door sills, or the “warm” process of remote laser welding, vehicle production becomes more streamlined in comparison to conventional means.
1 Laser welding, 2 Resistant spot welding (Al-Al), 3 Resistance spot welding (steel-steel), 4 Flow-drill screwing, 5 Friction-element welding, 6 MAG welding (steel-steel), 7 Roller hemming, 8 Clinch connections, 9 Grip punch-riveting, 10 Laser welding (steel-steel), 11 Semi-tubular punch-riveting, 12 MIG welding (Al-Al), 13 Bonding, 14 Laser welding
Working remotely has its benefits.
Using a remote laser welder is a more precise method of joining aluminum parts during the chassis assembly process. Positioning the laser beam exactly along the welding edge helps minimizes the risk of hot cracking and can control how deep the laser can penetrate. It also identifies the amount of gap between the parts being joined and can effectively control how the gap can be closed.
Flow-drill screwing is just one of the 14 specific techniques Audi engineers use to join lightweight materials to help create a stronger chassis.
The roller hemming method is used along the side sills of the Audi Space Frame design.
Other Uses of Lightweight Materials
See performance in a different light.
Beyond the innovative technology used to create the ASF® chassis, lightweight materials can also be used to help enhance vehicle performance in different ways. Audi engineers took what was developed originally for the track and instilled this technology into production vehicles that are enjoyable for everyday use.
Stay cool.
In addition to helping your vehicle to decelerate, ceramic brake discs can provide longer service life and motorsport aesthetics. The carbon composite discs feature ventilated grooves to help dissipate heat with little fading, even under repeated hard braking.
Select Audi models offer an available titanium exhaust system, a lightweight unit sporting larger diameter exhaust tips with carbon fiber accents and can deliver a more aggressive exhaust note.
Not all wheels are created equal.
Most wheels are typically cast—a process where molten aluminum is poured into a mold to create the wheel shape. Its heavier weight and porosity, however, can make it more susceptible to hair fractures. A forging process uses pressure to create a wheel that can be more structurally sound, lightweight and stronger than a cast wheel.