Audi A8 2019 Service Training page 12

Safety cell
The occupant cell, also called the safety cell, is made of
aluminum and conventional hot-formed steel. The cell is
comprised of the lower area of the end wall, the side sills,
the B-pillars and the front area of the roof arch.
B-pillars
The B-pillars are specially formed to enhance rigidity and
meet crash requirements. They are produced using tailor
rolled blank technology. These are flexibly rolled blanks,
where variations in sheet-metal thickness are produced by
controlled opening and closing of the gap between the
rollers. These variations in sheet-metal thickness not only
save weight, but also create defined crumple zones which
provide protection in the event of a side impact. The sheet
metal thicknesses vary between 0.06 and 0.08 in (1.5 and
2.0 mm).
8
Some of these sheet metal blanks are produced with differ-
ent thicknesses (tailored blanks) and are also partially
tempered where necessary. This reduces the weight and
increases the strength in extremely safety-critical areas.
Partial tempering: The individual zones of the B-pillar are
cooled in the mold at different rates during hot working,
giving them different strength characteristics. During a side
impact, the bottom section of the B-pillar deforms in order
to absorb energy. However, less deformation takes place in
the upper section of the B-pillar (at head height).
0.07 in (1.7 mm)
0.08 in (2.0 mm)
0.07 in (1.7 mm)
0.06 in (1.5 mm)
662_194
662_193
Ultra-high-strength
High-strength
662_195