Civil Engineering Reference
In-Depth Information
Phantom:
v = 215 m/s
Masse 20 t
Impuls 4400 MNs
Auftrefffläche 7 m
2
Fig. 14.5
Impact load-time function according to the RSK-LL for a fast flying military aircraft
based on a Phantom with an impact velocity v
¼
215 m/s
the involvement of different institutions. Impact speeds of up to 215 m/s were
reached. Extensive knowledge was gained about the impact load-time curve and the
behaviour of impacted structures. Among other researchers the author also exam-
ined the findings of the Meppen tests in the frame of his dissertation [
13
].
Figure
14.6
shows the experimental setup in Meppen. Using a special acceler-
ating device the approx. 6 m long steel pipes were shot at reinforced concrete slabs.
After the impact the deformed projectiles typically looked like the one shown in
Fig.
14.7
. Figure
14.8
schematically shows the failure pattern of a reinforced
concrete slab after an impact.
In a spectacular large scale test carried out in the USA in 1988 by the SANDIA
National Laboratories on behalf of Japanese institutions (cf. [
13
]) a full scale
verification of the theoretically determined load function for a Phantom was
realized for the first time. In the experiment a Phantom with a mass of nearly 20 t
and a speed of 215 m/s in accordance with the assumptions made in the RSK-LL
function was launched against a rigid target (3 m thick concrete slab), which was
suspended almost friction-free on an air cushion. During the experiment many
measurement signals were taken on the aircraft fuselage as well as on the target
body, which were then evaluated by Japanese and American teams. In addition, the
data were reevaluated by the German side in a joint research project lead by the
GRS and with the involvement of the author (cf. [
15
-
20
]). Through this many
valuable insights were gained about the processes of an airplane crash. The
resulting load function of the experimental data concurred relatively well with the
function according to the RSK-LL. Figure
14.9
shows a sequence of pictures during
the impact.
In addition to the test under realistic conditions performed with the Phantom
within the framework of the Sandia tests experimental studies were also performed
concerning the impact of jet engines and load functions determined accordingly.
