Bird-Strike Simulation on a Composite Wing Section

Bird strike represents a source of major risk for aircraft structures. Indeed an impact with a bird during cruise or during take-off and landing phases can lead to serious structural damages threatening passenger safety. Currently, certification tests are required to demonstrate that the airplane can safely operate after a bird strike event. For this reason, the need of accurate numerical models able to predict the structural response under a bird strike event can be of significant help in order to reduce the certification time and costs. In this paper, numerical simulations of a bird impact event on the leading edge of a composite wing section are presented. An approach based on Coupled Eulerian-Lagrangian (CEL) formulation has been adopted and, considering the high velocities of interest, the bird has been modelled as a soft body acting as a fluid on the target structure. The aim of this work is to assess the influence of the adopted numerical model in terms of finite element formulation and failure criteria on the bird-strike phenomenon including impact induced damage onset and evolution. The FE software ABAQUS/Explicit have been used to perform two different numerical simulations with different FE formulations. In the frame of the first simulation, the composite laminates have been simulated by using continuum shell elements and ABAQUS standard composite damage initiation and evolution criteria. In the frame of the second simulation, solid elements (C3D8R) have been adopted in conjunction with a user-defined material subroutine (VUMAT) based on Hashin and Puck damage criteria. The results obtained by means of the two proposed formulations have been compared in terms of damage extension in order to assess the robustness of numerical bird strike simulations and, hence, the dependence of the numerical outputs from the adopted FE formulation.