Aeroplanes have to meet a series of requirements regarding bird strike. Those requirements are defined basically in terms of structural resistance and the allowable degradation in flying qualities. One of the areas of the aircraft exposed to bird strike is the leading edge of the wing. The Eurofighter 2000 (EF-2000) is equipped with movable leading edge surfaces or "slats". The requirements for the slats in relation with potential bird strikes is that birds should not penetrate the leading edge of the skin or, in case of penetration, no critical damage should he induced to the structural elements behind the skin. For the EF-2000, the assessment of bird strike resistance of the slats has been based on numerical simulation of several impact scenarios covering a range of bird mass and velocity, points and sequences of impact and slat configurations. The method of analysis is based on finite element simulation using the commercial explicit integration code PAM-CRASH. The model of the structure includes a representation with shell elements of the slats, the fittings and actuators and the relevant areas of the fixed leading edge of the wing. The most relevant features are the use of adaptive meshing for the shell elements and a strain rate dependent plasticity model (Johnson-Cook) for the materials. The paper describes the basic assumptions of the analyses and the way in which the simulations have been carried out in an industrial environment. The paper also gives the main lines on how the results have been evaluated in order to assess the capacity of the slats to withstand the different impact scenarios.
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