A Novel FEM-DEM Adaptive Transfer Method for Bird-Strike Simulation

A bird strike is a major risk to aeroengines. It not only causes the damage of blades and casing due to impact, but also leads to an outage of the engine due to the deposition of bird fragments. A finite-element method–discrete-element method (FEM-DEM) adaptive transfer method has been proposed and developed to simulate a bird strike by transferring FEM elements of the initial intact bird to DEM elements of bird fragments, which is superior to that of smoothed particle hydrodynamics (SPH). The cohesion of bird fragments provided by blood and fat could be simulated by the DEM algorithm. The characteristics of deposition, agglomeration, and motion track of bird fragments are simulated by three specific cases with different impact sites of the bird at two different velocities of the bird and rotation speeds of the engine. It reveals that deposition and distribution of the bird fragments are highly affected by the impact sites and velocities. The most serious deposition of the bird fragments in the inner channel occurs when the bird impact direction points to the stator blade cascade with lower impact velocity of the bird and rotation speeds of the engine. The bird fragments distributed more dispersed in this case. This simulation method provides an economic and efficient simulation technique for the design and damage assessment of the engine.