Low-carbon strip steels 109A large force (typically 40 kN) is required to make the joint and this is provided
by means of a C-frame which is able to accommodate the rivet setter and the
upsetting die. When used to join two sheets of unequal thickness, it is preferable
for the thin material to be on the side that is fully pierced. It has been claimed
that the fatigue performance and energy absorption of self-piercing rivet joints
are equivalent to or better than spot welded joints. ~59
Use of adhesives in weldbonding, clinchbonding and rivbondingAdhesives may be used to join various components and are widely used to
join steel to dissimilar materials. Developments are still in progress, however,
concerning joints that are required to carry a structural load which are likely to be
subject to severe weather conditions in service. For potential applications in the
automotive industry, for example, the adhesive is generally considered for use in
combination with other joining methods such as spot welding, press joining or
riveting. These hybrid methods are known as weldbonding, clinchbonding and
rivbonding respectively.
Detailed studies l~ have shown that each method could be used under normal
automotive production conditions and that they could be used to join two, three
or four thickness combinations of steel together. It has been found that for simple
joints and arrays, each hybrid outperforms its parent method (without the adhe-
sive), but the extent of the improvement was markedly greater for shear- than
for peel-loading conditions. This can be attributed to the fact that adhesives are
significantly weaker in peel than in shear because of the reduced ability of the
steel to dissipate stress along the bond line under this mode of loading. The use of
the hybrid methods leads to an improvement in both the collapse resistance and
torsional stiffness of box hat structures. The extent of the benefit was, however,
greater for the former than for the latter loading regime. This was attributed to
the limited ability of the adhesive to withstand large deformations associated with
impact loading.
Strip steel in use
Fatigue
The load-bearing capability of any component manufactured from sheet steel
depends on its size and shape and on the thickness and strength of the steel used
to make the component. Most components are, however, joined together with
other components to form complete structures and the strength of any complete
structure clearly depends on the way the components are joined together as well
as on the strength of the individual components. Examples of such structures
would include the complete body shell of a motor car, the frame of a steel-
framed building or a cylindrical steel drum with each end connected to the side
wall in a suitable way (see below).
Many components and structures are subject to vibration in use. The compo-
nents and joints may, therefore, be subject to fatigue damage, whereby crack