A parametric study of bird strike on engine blades

Birds represent a major hazard to aviation. Especially bird ingestions by one or more engines, which can lead to significant power loss, are safety critical. Damage tolerant designs required by regulations should ensure the survivability of aircraft components under bird strike. At present, experiments and numerical simulations are used to aid design of bird strike resistant structures. These tests are very expensive and their number in the engine development process should be minimised. This is typically achieved through the use of numerical simulations, which provide an alternative to testing, and which can effectively support a significant part of the blade design process. However, bird strike tests still have to be performed in order to certify an engine for the bird ingestion. The simulation of bird strikes on engine blades, presented in this paper, was performed with an in-house Smoothed Particle Hydrodynamics (SPH) code coupled with a Transient Nonlinear Finite Element (Lawrence Livermore National Laboratory - DYNA3D) code. Treatment of contact between the bird (SPH particles) and the blade (FE mesh), was one of the key aspects in the bird strike analysis. The particle to node and the particle to surface contact algorithms, available in the code, were assessed and their performance compared. This was followed by a number of parametric studies including: influence of the bird shape; the bird impact location and impact timing. Simulation results from these studies were compared and validated against the final deformed shape of the blade recovered from the bird strike test.