Crashworthiness assessment of NASA CRM wing in single and multiple bird strikes scenarios

Numerous aircraft accidents involving bird flocks have occurred in aviation. Existing literature and the airworthiness certification standards are primarily focused on single bird-strike assumption. The present study addresses the possibility of bird flock incident and investigates the crashworthiness of NASA Common Research Model wing subjected to single and multiple bird strikes, using a coupled Finite Element Method and Smooth Particle Hydrodynamics approach. The numerical bird model is validated and the influence of equation of state (EOS) models, porosity and contact loads variation against the target structure’s shape, is reported. Two locations along the span i.e. towards the wing root and the wing tip, are considered for impact investigation, with emphasis on comparative penetration, energy absorption capability and potential damage to the main spar. Results revealed that the impact loads and impulse for the curved leading-edge section to reduce by more than half compared to the flat plate. The Gruneisen EOS provided a good correlation with experimental data, while adding porosity to the Polynomial EOS significantly reduced pressure peaks. Analyzing different flock orientation scenarios, the vulnerability of wing tip to multiple bird strikes was observed, leading to main spar damage. While single bird strikes may not cause critical damage, bird flocks pose a significant threat to aircraft safety, emphasizing the need for incorporating bird flock scenarios into aircraft design considerations.