SPH High Velocity Impact Analysis - A Birdstrike Windshield Application

This dissertation is the result of a research focused on the study, with the help of finite element analysis , of an aircraft windshield-surround structure with an innovative configuration, that satisfies the bird-strike requirement according to the EASA Certification Specifications 25.631 on the ”Bird-strike Damage” [CS25.631 (2003)]. The first step was the numerical analysis of a simplified, but realistic, square flat windshield model subjected to impact by a 1.8 kg bird model at 155m/s with an impact angle of 90?. The FE-SPH coupled approach was used to simulate the birdstrike by using the explicit finite element solver code LS-Dyna. The second step was the execution of a parametric analysis on the square model to estimate the influence of the target geometry, the impact angle, and the plate curvature on the impact response of the windshield structure. The goal of these numerical simulations was the evaluation of the windshield capability to absorb the impact energy, involving during a birdstrike event, in a safe and efficient way without any damage. Finally it was developed a numerical simulation of birdstrike event on a full-scale aircraft windshield-surround model. This FE numerical analysis showed the capability of the real innovative windshield to withstand to the impact force transferred by the bird during the impact and permitted the definition of some guidelines to execute a certification test simulation and to give an impact test article proposal, needed for a design of an airplane windshield structure able to resist to a birdstrike event in according with the conditions stated in the CS 25 standard requirements.