Study on Foreign Object Damage Law of Titanium Alloy Blade of an Aero-Engine Impacted by Sandstone

Using ANSYS/LS-DYNA software and plastic follow-up hardening constitutive model, a simulation model of foreign object impact damage of the first stage TC4 titanium alloy rotor blade of an aero-engine low-pressure compressor was established. The correctness of the finite element model is verified by the impact test of flat specimens. Furthermore, considering the centrifugal prestress, the damage caused by sandstone impacting rotor blades during the taxiing of the aircraft is simulated. The damage assessment results are compared with those obtained without considering the centrifugal prestress. The main findings imply that for the blade inlet edge located 392.85 mm from the engine shaft, the critical condition for producing a notch is that the sandstone with a diameter of 1.1 mm hits the inlet edge at a relative speed of 442.5 m/s. With the increased gravel radius, the angle between the direction of gravel impacting blade and engine shaft, the relative kinetic energy, impact force, and notch depth all increase exponentially, while the impact duration grows via the quadratic law, and the maximum width of the notch increases linearly. For the sandstone radius between 0.55 and 2.4 mm, the notch depth is less than the notch width. These findings can guide the judgment of blade accident causes or symptoms and have theoretical significance for fatigue design of blades with the foreign object damage account.