TC4 Hollow Fan Blade Structural Optimization Based on Bird-strike Analysis

Bird strike event, from which fan blade of aero-engine frequently suffers, always poses a danger to life on board. In this work, crashworthiness under bird strike event is taken into consideration in structural optimization of hollow fan blade together with static strength. First bird strike simulation on plate is conducted with the ALE method in ANSYS/LS-DYNA to validate the modeling algorithm and the effect of parameters variation on stress and strain result in bird material model is discussed. The effect is not obvious, so further optimization of the parameters is ignored. Bird strike simulation on solid and hollow fan blade shows that large deformation can absorb energy and relieve direct damage to blade. At this point, hollow structure hinders large deformation of the blade, thus causes more material failure than the solid one. 3-level orthogonal experiment is designed for 4 key geometric factors of the hollow blade structural optimization with transient strength as the objective and static strength as the constraint. For further analysis, sensitivity analysis is conducted to figure out the most important factor. Final result for the optimization design is given.