Abstract: Bird strike is one of the important factors threatening aviation safety. At present, most of the studies are about one-time bird impact on a single specimen or structure, while few are about secondary impact on the structure caused by penetrating the impact site of the bird body. To study this problem, a full-size model for helicopter tail with multi-Euler coupling is established based on the fluid-solid coupling algorithm. Considering the influence of air, the process of bird strike to the flat tail, damage forms of leading edge and front beam, displacement response of the flat tail, law of the bird impact load, the effect of impact load on the structure of flat tail root are analyzed in detail and are verified with the experimental results. The research shows that if the bird body does not disintegrate when penetrating the leading edge, its secondary impact load on the front beam will also be at high level. The design of flat tail structure needs to consider whether the bird strike will cause the root fracture of flat tail. The bird impact load has the characteristic of step function. The response time of the structure has obvious hysteresis effect compared with the impact load.

Key words: bird strike, helicopter, flat tail, damage, fluid-solid coupling