Parametric study of a SPH high velocity impact analysis – A birdstrike windshield application

During its life cycle an aircraft flies on the risk of impacting foreign objects. According to the aeronautical specifications, the term “birdstrike” indicates the collision between a bird and an aircraft front facing component, which includes windshield, nacelles, compressor blade, wing leading edge or even flaps, when extended.This paper is part 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 European and US aviation regulations 25.631 on the “Bird-strike Damage” [1] and [2].Firstly the paper provides a numerical analysis of a simplified, but dimensionally realistic, square flat windshield model subjected to impact by a 1.8 kg bird model at 155 m/s with an impact angle of 90°. The FE-SPH coupled approach is used to simulate the birdstrike by using the explicit finite element solver code LS-Dyna.The second step involves 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 is the evaluation of the windshield capability to absorb the impact energy of a birdstrike event, in a safe and efficient way which is compliant with the airworthiness rules.The aim of this work is to define a scientific and methodological approach to the study of the birdstrike problem. The collection of results and experiences achieved by the previous simplified realistic model can be applied to perform a certification test simulation and define possible guidelines for the design of a bird-proof airplane windshield.