FEM Analysis and Simulation of Bird Striking Aircraft Structure

摘要

Bird-strike remains a major risk for the aircraft safety when landing and taking off. At sometimes, an impact of several birds at high velocity can cause severe damage to the aircraft structure. In this paper, finite element method was employed to investigate two birds impact on three curved plates with different materials (Aluminum, Titanium and 30CrMnSi) but with the same weight. Bird 1 hits the plate perpendicularly with the relative velocity of 200 m/s, while bird 2 hits the plate at the lower side at 25 degrees with the same speed. The Arbitrary-Lagrange-Euler (ALE) coupling algorithm is used to efficiently analyze the fluid (bird)-structure interface. Analytical results show the stress-time histories, strain-time histories of the three cases and the three-dimensional impacting process. Comparisons indicate that Aluminum plate has the longest plastics stage and failure time than other two plates, while the 30CrMnSi plate is the first to fail when impacted by birds. Also found in this analysis is that reasonable selection of the material can be assistance in the optimum design of survival aircraft structure when considering the weight constrains. Moreover, the FEA method can be applied to the determination of the critical thickness of aircraft skin for ensuring aircraft safety considering the relative impact velocity of birds with aircraft and the main impacting aspect by birds when aircraft landing or taking off. In sum, the results of numerical simulation offer a theoretical reference for engineering design of anti-bird aircraft structure in an effort to enhance the overall aircraft survivability when subjected to bird-strike.