aluminium in commercial vehicles - European Aluminium Association

84 EUROPEAN ALUMINIUM ASSOCIATION ALUMINIUM IN COMMERCIAL VEHICLES CHAPTER VI
mal radius of 450 mm to 350
mm. As illustrated, an increased
radius of 1000 mm will offer very
low stresses and demonstrates
simply the importance of smooth
transitions.
8.2.2. Perforation
The fixture of the supporting legs
to the chassis beam will normally
be located at the highest stressed
area of the chassis beam, i.e. in
the gooseneck area. Hence a per-
foration of the bottom flange by
boltholes must be avoided as
well as any welding on or near
the flange.
Figures VI.20 and VI.21 show the
consequence of perforating the
flange compared to the web in
this area.
The reduced relative lifespan will
be as much as >80% due to the
effect of stress concentration in
the perforated area of the flange.
For the situation with the perforation
through the web, the lifespan
will not be reduced. Both
examples show the importance
of a location away from the most
stressed area of the beam. If a
perforation through the flange is
inevitable, the location should be
as close as possible to the edge
of the flange (as far from the
web as possible). Note that
FIGURE VI.20
HOLE IN CHASSIS BEAM FLANGE, (ø = 20 mm): σ max = 102 MPa
‰
FIGURE VI.21
‰
σ =73MPa
σ max =102MPa
HOLE IN CHASSIS BEAM FLANGE, (ø = 20 mm): σ max = 73 MPa (on flange)
‰
‰
σ max =73MPa
σ =35MPa