Fatigue Failure of Erosion Strip of Rotor Blade of a Helicopter

摘要

To prevent damage from rain or sand erosion, metallic erosion strips are generally bonded to the leading edge of rotor blades of helicopters. An erosion strip [made of Ni-20%Co alloy] of Tail Rotor Blade of a military helicopter was found cracked in-service. Fractographic studies using Scanning Electron Microscope revealed features like beach marks and striations on the fracture surface of the erosion strip. This indicates towards failure of the erosion strip by fatigue. It was observed that fatigue failure had originated from one of the edges of the erosion strip. Further, physical damage was observed on the surface of the erosion strip at the failure origin. Thus, it was concluded that the physical damage on the surface of the erosion strip had acted as a stress riser and had caused failure of the strip by fatigue.