Numerical Analyses of Bird Impact on Aircraft Structures Undergoing Large Deformations and Localised Failures

Numerical analyses of birdstrike were performed on aircraft light structures made up in metallic, composite and polymeric materials, using the ESI/Pam-Crash solver code. The finite element models were developed calibrating the material models to take into account the different inelastic behaviours and failure modes. Three types of bird models were developed for the analyses, considering different combinations of porosity levels and shear strength of the bird materials. Adopting a Lagrangian approach featured with a numerical element elimination procedure, the computations were prosecuted also in presence of large distortions of the bird elements allowing to approximately analyse impacts with large deformations and perforations of the structures. The numerical-experimental correlations show that the developed finite element models were able to well represent the different failure mechanisms characterising the structural responses. The results also allow to evaluate how the severity of the load conditions experienced by the target in the numerical analyses depends on the porosity and the shear strength attributed to the bird material.