Finite Element Modeling of a Bird Striking an Engine Fan Blade

Bird strike is a serious problem that affects both commercial and military aircrafts. Systematic modeling and simulation of bird strikes are severely lacking, especially for cases involving engine, fan blades, and casings. In the present investigation, explicit 3-D finite element analysis using LS-DYNA is carried out to study the nonlinear transient response of a bird striking a fan system. The bird strike is simulated using Lagrangian blade-bird formulations. The bird is modeled as a fluid jet with a homogenized fluidic constitutive relation, using the Brockman hydrodynamic model, which was found to be the most appropriate. The present simulations are validated using a benchmark test of a bird striking a rigid target that is reported in the literature. Following this validation, a reference case of a bird striking a flexible fan blade was set up and used as the reference case in a series of parametric studies. The effect of bird velocity and its size are examined and attention is given to strikes involving larger birds so as to address the lack of data in this area.