Generation of a detailed transport aircraft DRI-KRASH model and simulation of different crash scenarios

Kurzfassung

This paper describes the generation of a full-scale Aircraft DRI-KRASH model and presents the results of the simulations which were carried out for two different crash scenarios – impacts on a rigid surface and on a 10° slope. The work was a DLR contribution to the European consortium project CRAHVI (2001-2004) in which one of the major tasks was the generation of a cabin load database for different aircraft types in various crash scenarios. This load database can now be used for the design of innovative cabin safety features with the aim to improve passenger safety. The definition of the KRASH model geometry and the linear properties of the KRASH elements (masses, nodes, beams etc.) were derived from an NASTRAN model. A key feature in the DRI-KRASH modelling technique is the pre-definition of the non-linear force-deflection behaviour of larger structural areas. In the KRASH model, the definition of spring characteristics, plastic hinge moments and other non-linear properties were based on results of structural tests which were carried out on different fuselage sub-structures. With the use of nearly 900 beam elements, this model is one of the largest models that has been developed using DRI-KRASH up until now. The model size is still small enough to allow very short computation times, but is also detailed enough to represent the aircraft in a realistic manner. For each of the simulated crash scenarios, a detailed analysis of the occurrences during the course of the crash was carried out. Besides accelerations, velocities and displacements, other KRASH simulation results like the deformation and loading of the wings are shown. The behaviour of landing gears, engines and wings have been analysed with regard to their energy absorption contribution and their influence on the injury risk for the passengers. In order to judge the different calculated acceleration pulses, a modified ‘Eiband’ approach was developed. With this procedure, the fuselage regions with low and high injury risk can be clearly identified. The application of DRI-KRASH thus allows a better understanding of the events occurring within a crash landing.