Birdstrike analysis on leading edge of an aircraft wing using a smooth particle hydrodynamics bird model
Birdstrikes on aircraft pose a major threat to human life and there is a need to devolop structures which have high resistance towards these structures. According to the Federal Aviation Regulation (FAR 25.571) on Damage-tolerance and fatigue evaluation of structure (Amdt.25-96), an airplane must be capable of successfully completing the flight during which likely structural damage might occur as a result of impact with 4-lb bird at cruise velocity at sea level or 0.85 cruise velocity at 8000 feet. The aim of the research is to develop a methodology which can be utilized to certify an aircraft for birdstrike using computational techniques since the physical testing of birdstrike is expensive, time consuming, cumbersome and for sanitary purpose. The simulations are carried out in the LS Dyna, non-linear finite element analysis code, in which the bird is modeled using the Smooth Particle Hydrodynamics (SPH) technique. Initially to validate the bird model in the LS Dyna, the birdstrike is carried out on rigid and deformable plates. The results including displacement, Von-Mises stresses, forces, impulse, squash time and rise time are obtained from the simulation. Then the non-dimensional plots of force, impulse and rise time are plotted and compared with results from experimental test data. The detailed CAD geometry of the leading edge is modeled in CATIA V5. Meshing, connections and material properties are then defined in the Altair Hypermesh 9.0. The validated SPH bird model is impacted at the leading edge. The results obtained from the simulation are compared with the data from the experiments, and the process is validated. The parametric studies are carried out by designing the leading edge for different values of nose radius and by vii assigning appropriate thickness values for leading edge components. Then the SPH bird model is impacted at varying impact velocites and results are compared with test data. It is proposed that the results obtained from simulation can be utilized in the initial design stages as well as for certification of an aircraft for birdstrike requirements as per federal regulations.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.