International Catalogue

Basic Knowledge of Fastening Technology
Basic Knowledge of Fastening Technology
Dynamics
- predominantly
non-static loads in the fixing
technology
The general building authority approvals by the German Institute of Construction
Engineering in Berlin (DIBt) and the European Technical Approvals (ETA) are
generally exclusively for anchoring of predominantly static loads. However, in
contrast to these current permits, in practice a number of dynamic effects occur,
e. g. increasing and alternating stresses in swinging cranes, crane rails, guide rails in
elevator construction, machines, industrial robots and blast fans in tunnel construction.
This also includes anchorings for components susceptible to vibration like antennas and
masts.
Oscillating amplitude
durable oscillation strength
(durable capacity in case of fatigue)
Wöhler curve
statical strength
(statical capacity)
Number of cycles N
fatigue strength
(capacity in case of fatigue)
N = 2 ‰ 10 6
1 10 100 1.000 10.000 100.000 1.000.000 10.000.000 100.000.000
Action Run of the oscillation Possible cause
harmonic
periodic
period T
period T D
sinusoidal
optional,
periodical
Unbalances,
tumbling machines
Regularly abutting parts
(e.g. punching machines),
rail- and road traffic
transient
optional,
nonperiodical
Earthquakes
impulsive
optional,
with very short
time of influence
Impact, explosion
Dynamic effects
It is generally true that the anchoring of components with more than 10.000 load cycles
has to be carried out with fixings, which are tested and approved for this. The regular,
sub-sequent anchoring of these dynamically loaded items to be mounted still caused the
planning engineer big problems, even recently. Generally, the approvals for fixings only
apply for anchoring of predominantly static loads. The path through expert opinions and
“approvals for individual cases“ was difficult and tedious. Besides that, higher costs than
necessary often occurred due to the general planning uncertainty, since the anchors were
often oversized.
The bonded anchors fischer Highbond anchor FHB dyn and fischer UMV multicone dyn
are approved for dynamic loads. The approvals apply to anchoring of dynamic loads
with unlimited numbers of load cycles, for tension and for shear loads. In addition, the FHB
dyn is manufactured in anchor size M16 of highly corrosion-resistant steel, material no.
1.4529. Tests have shown that this material - in contrast to the usual standard stainless
steel types in the corrosion resistance class III, e.g. A4 - is suitable not only for use in humid
internal conditions and outside, but also for holding dynamic loads.
464