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

The Flying-V aircraft concept promises better fuel-burn performance over conventional tube-and wing configurations, integrating the passenger cabin and cargo volume into the lifting surface. However, 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 strikes. 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 objective is to propose a building block approach to design the Flying-V's leading edge bird strike crashworthiness that complies with the EASA's certification CS25.631 using a 4lb bird impacted at a sea level cruising speed of 70 m/s. An additional requirement by the authors is to keep the structure within the elastic deformation during the impact of a 4lb bird to avoid the need for repairs in the Flying-V fuselage. Plasticity generated in the structure is regarded as damage and is used as a comparative parameter. At the highest building block level, a sensitivity analysis is performed to identify the effect of the thickness 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. The critical case of a 133 m/s impact of a 4lb bird at the cruise altitude of 37000 ft is also evaluated, and the results show penetration.

Automated summary

This study investigates the dynamic load path and contribution of each structural element in the bird strike resistance of the Flying-V aircraft's leading-edge structures. The aim is to propose a modular design approach that complies with EASA's certification requirements and ensures elastic deformation during impact to avoid repairs. The results show that adjusting the thickness of structural elements significantly reduces plastic energy.