Credit: DLR (CC BY-NC-ND 3.0).
In the LuFo project CREVAD (2012-2014), the Institute of Structures and Design jointly worked together with the project partners Airbus and EADS-Innovation Works. The research activities were funded by the German Luftfahrtforschungsprogramm (LuFo IV) with the aim to develop an alternative crash concept for composite transport aircraft of the second generation.
Compared to metallic designs, fuselage structures fabricated from composite material typically require a specific crash design to compensate the generally brittle failure behaviour of composites.
In previous research projects a crash concept for composite transport aircraft fuselages was developed which provides a stiff cargo floor cross beam. In this concept, a large amount of kinetic crash energy is absorbed by crushing the sub-cargo floor structure according to the crumple zone principle of Béla Barényi. However, for typical fuselage architectures of transport aircraft this crash design resulted in a significant structural mass penalty.
In the project CREVAD, an alternative approach was chosen utilizing tension loads for energy absorption. For typical crash landing conditions, the cylindrical fuselage section impacts the ground surface and tends to an ovalization which induces tension loads in the cabin and cargo floor cross beams. These tension loads can be used for energy absorption without an unfavourable loading of the structure that would lead to a structural mass penalty.
For the development of these novel crash concepts meta-model based optimization methods were used which were coupled with a parameterized and automated model generation. Optimized crash designs could be derived with requirements for the individual crash devices and an optimal design of the fuselage structure. In contrast to the previously developed concepts with a crumple zone in the sub-cargo area, improved passenger safety in combination with a significantly reduced structural mass penalty could be achieved.