Bird strikes pose a significant threat to aircraft safety, yet accurately predicting their impact behaviour remains challenging due to many uncertainties, such as variations in bird properties, high impact velocities, and limited experimental data. While much research has focused on modelling the bird itself, understanding the structural response of materials, particularly aluminium alloys commonly used in aircraft structures, is just as important. This thesis investigates how different material model definitions in the plasticity regime affect the predicted response of aluminium 2024-T3 under bird strike conditions.
Moreover, it investigates the uncertainties that arise from limited quasi-static testing or usage of inconsistent material properties that can be found in the literature. The work aims to highlight the influence of modelling choices and identify key sources of uncertainty related to material characterisation. Using a surrogate model implementation for two chosen plasticity models, Ramberg-Osgood and Johnson-Cook plasticity models, the uncertainties are being assessed through one-factor-at-a-time sensitivity analysis together with Monte Carlo analysis. The results of this work contribute to improving the reliability of bird strike simulations and provide guidance for future model development.

Bird strike simulations require accurate information about the nonlinear material properties of the bird and structure, dynamic changes in contact between bird and structure, and large displacements and rotations of the structural elements. The soft-body nature of birds allows it to flow fluidly upon impact, making accurate simulation validation difficult. Setting up a model requires evaluating and considering a large number of parameters. To simplify the process of obtaining validated bird strike models, a set of guidelines for setting up the simulations, covering the major parameters that influence the validation of the models, is established. This was done for an EWVT-SPH (Element Weighted Voronoi Tessellation Smoothed Particle Hydrodynamics) bird model by following the building block approach laid out by the aerospace standards of SAE-G28 for both rigid and complaint target structures.