Finite-element assessment of damage to an aircraft windshield incurred by high-speed multiple bird strikes

In this work, a numerical model has been developed to predict the damage and failure of an aircraft windshield incurred by high-speed repeated bird impacts. Finite element (FE) simulations were performed by implementing the numerical model in explicit FE solver ANSYS AUTODYN. A rate-dependent elastoplastic material model with the maximum principal stress failure criterion and Mie-Grüneisen equation of state (EOS) model with the tensile failure criterion were adopted to model the damage of windshield and bird, respectively. The model successfully predicts the damage initiation and complete failure of windshield at different impact velocities. The maximum normal displacement and equivalent stress at different positions on the windshield were determined and compared for a single and multiple impacts. On the basis of numerical results, the limiting impact velocity, critical number of impacts, and the weakest portion on the windshield were also determined. The results show that at higher impact velocity, multiple impacts prove fatal to the windshield structure. The windshield that withstands a single bird impact is vulnerable to fail under successive impacts.