Numerical Simulation of Bird Strike Effect on a Composite Wing Leading Edge

Abstract

Birdstrike on aircraft is a major threat to human life and there is a need to develop structures which have high resistance towards birdstrike. This paper describes the numerical simulation of bird strike on the Aluminium Silicon Carbide (Al-SiC) metal matrix composite wing leading edge using LS-Dyna software. The metal matrix composite chosen has the composition of Aluminium 85% and Silicon Carbide 15%. At this composition the impact force of the material is high which means the material is more resistant to impacts which is suitable for the wing leading edge as it is subjected to events like birdstrike. For this simulation we have chosen the wing structure of Boeing 737 aircraft. The wing leading-edge section was designed using CATIA V5 with skin thickness of 2mm. Also, the ribs and the spar were designed for better results. A hemisphere cylindrical bird model is used for bird strike and is designed in LS Pre-Post V4.7.7 with length 196mm and diameter 98mm. The wing leading edge model was imported to the LS Pre-Post and was aligned properly for birdstrike analysis. The analysis of the birdstrike is carried out using the Lagrangian method. The required keyword input data such as Boundary Definition, Control, Contact Definition, Material properties for the bird and the wing leading edge section and Velocity for the bird are defined as per the requirements of the analysis. The simulation was run at different velocities ranging from 50-150m/s.  The results were obtained graphically as Pressure vs. Time, Effective Stress vs. Time, Effective Plastic Strain vs. Time, Rigid Body Displacement vs. Time, Internal Energy vs. Time and Kinetic Energy vs. Time graphs. Using these graphs, the graphs for the Effective Stress vs. Effective Plastic Strain & Rigid Body Displacement vs. Velocity were plotted. In this analysis, it was observed that the Effective Stress of the wing leading edge with Al-SiC material has been increased by approximately 100 MPa with respect to the traditional Al 7075 T6 material. Also, the pressure distribution over the wing leading edge surface is smoother during impact for wing section with Al-SiC material. The energy absorption of the wing section has been increased. The overall strength of the wing leading edge section with Al-SiC as the material has been increased when compared to the wing leading edge section with Al 7075 T6 material.