Numerical analysis of bird strike events with the helicopter windshield

The aim of this article is to describe simulation results of a bird strike with a helicopter windshield. The simulation was performed based on LS-DYNA software by means of the SPH and Lagrangian methods. For the sake of the analysis, we selected a light helicopter, which is not covered by any certification requirements with regard to the windshield. The simulations were conducted for various bird shapes (sphere, cylinder, cylinder with hemispherical endings) for the cruising speed of Vc = 285 km/h. As a result of the simulations, we achieved comparative analyses of the methods at stake in the aspect of time curves of the kinetic energy, velocity and windshield deformation. The findings are depicted graphically and are presented in the form of charts. The deformations that were obtained as a result of the conducted tests may be referred to the data included in the AAIB report, which described the case of damaging the Agusta A-109C helicopter due to a collision with a seagull at the speed of approximately 278 km/h. The deformations obtained through numerical simulation do not make an accurate representation of this type of damage as in the case of a real one. Nevertheless, they reveal its character. While examining the test simulations from the quantity viewpoint, it is possible to observe slight discrepancies related to the applied approaches of bird modelling. In case of the kinetic energy, the slight discrepancies in the initial moment stem from rounding the mass of a single particle of the model, by means of the SPH method. The velocity curves of the accepted centre of the bird model vary considerably, depending upon its shape, which is linked with the deformation manner of the particular models.