Design for bird strike crashworthiness using a building block approach applied to the Flying-V aircraft

Abstract

The Flying-V aircraft promises better fuel-burn performance over conventional aircraft, integrating the passenger cabin and cargo volume into the lifting surface. The wing-fuselage and cockpit windows of the Flying-V are exposed to the flight direction, posing a new challenge to the design and certification of structures in terms of bird strike. This study is a first step towards understanding the dynamic load path and contribution of each structural element on the bird strike resistance of the Flying-V leading-edge structures. The goal is to comply with EASAs certification CS-25, while keeping the structure within elastic deformations during a 70 m/s impact with a projectile simulating a 4lb bird. A building block approach (BBA) is proposed for the design for bird strike crashworthiness. At the highest building block level, a sensitivity analysis is performed to identify the effect of each structural element on the plasticity and weight of the leading-edge structures. The trends are used to modify the baseline design and achieve a reduction of 80% of the plastic energy, without any optimization scheme. A critical case of a 133 m/s speed impact of a 4lb bird at 37000 ft cruise altitude shows that there is still penetration in the modified design.