Birdstrike: the Influence of the Bird Modelling on the Slicing Forces

Birdstrike is one of the most dangerous threats for flight safety. The consequences of a birdstrike can be dramatic and, therefore, the aircraft structure have to be certified for a proven level of bird impact resistance before being put into operational service. Since the experimental tests are expensive and troublesome, numerical techniques are usually used to develop high-efficiency bird-proof structures. In that, explicit nonlinear finite element codes have shown to be a rather convenient design tool. In this research, the influence of the bird modelling on slicing forces has been investigated with regard to different numerical bird models developed and validated referring to straight impact birdstrike tests. Two benchmark tests were eventually considered. Initially, a simple test case, the impact of a bird with a single fan blade, was considered in order to focus on the advantage and disadvantages of the different bird models. Hence, a test case consisting of the impact of two birds onto a complete rotating fan was considered. Event insights and guidelines for further investigation were eventually drawn.