Force Simulation of Bird Strike Issues of Aircraft Turbojet Engine Fan Blades

Abstract

AbstractThe paper investigates the problem of simulation modeling of bird strike on the fan blades of an aircraft turbojet engine under operating conditions. Bird strike on the fan blades fan is modeled by an equivalent system of static forces and with an experimentally substantiated localization of impact points. The magnitude of these forces is determined with account for bird mass, size and speed. Such an approach, without conducting computation-intensive modeling of blade distortion and failure by using explicit dynamic analysis methods, allows assessing the stress-strained state of fan blades with much more accurate mathematical finite-element models with an admissible error level. The problem solution algorithm comprises the building of physical, mathematical and computational models with consideration for the design, mechanical characteristics of materials, operating conditions, as well as for the accepted assumptions and simplifications. The simulation modeling of fan blades yielded strains and stresses corresponding to several bird strike variants. The model was verified using several error estimate criteria, and the results were validated by comparison with bench test data. The approach suggested produces mathematical finite-element models with an admissible level of mesh discretization error and a least possible number of finite elements. Similar models can be reasonably used subsequently in analyzing the nonlinear dynamics of interaction of a flying bird with a rotating wheel impeller, whereas the results of quasistatic analyses can be used to verify models for explicit analysis methods.KeywordsGas turbine engineFan bladesBird strikeMathematical simulationEquivalent forces