Determination of a Load Approaches for Aircraft Impacts - The Risks of Nuclear Energy Technology - page 262

Fig. 14.9 Pictures of the large scale experiment with a Phantom at the Sandia National Labora-
tories in the USA in 1988; the target body after the impact on the right

Sandia experimental data according to Fig. 14.10 . While the mass distribution can
be determined relatively well, there is a large degree of uncertainty concerning the
bursting load. It is determined by the strength and rigidity of the materials with
simultaneous consideration to the complex processes due to the crushing such as
stability, imperfections, the geometric non-linearity and the non-linearity of the
materials, temperature, etc. It turns out that the contribution of the bursting load to
the impact force is relatively low. The final result can therefore still be considered
reliable even with the uncertainties in the bursting load.
Figure 14.11 shows the resulting deformation of the nodes at specific points in
time as a result of the calculations. The deformation process is visible as a
compression of the nodal masses. At t 70 ms the fuselage is almost completely

compressed in the impact zone. The temporal development of the contact force is
shown in Fig. 14.12 and is compared with the impact load-time function according
to the RSK-LL. Due to a slightly lower gradient the maximum value of the impact
force of approx. 135 MN is slightly larger than the RSK-LL value. The analysis of
the Sandia experiments also resulted in slightly higher values (cf. [ 13 ]). It can be
seen that there is a fairly good agreement to the experimental results which shows
the applicability of the used mathematical model.

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14.4 Load Approaches for Large Commercial Aircraft

Load approaches for large commercial aircraft are not included in the general
nuclear facility technical guidelines. Only after the attacks on September
11, 2011 studies were carried out worldwide and load functions were determined
for various commercial aircraft classes. For the most part the information is not
publicly available and can therefore not be discussed in detail here. Contributions
to the determination of load approaches were presented in recent years, for example
at the SMiRT conferences, cf. e.g. [ 21 , 22 ]. The topic was also treated from
different perspectives within the framework of general scientific research amongst