Failure analysis of an engine fan and compressor blades

Four fan stator blades and three compressor rotor blades belonging to an aeroengine were sent to this laboratory for investigation. Examination revealed that all the four fan stator blades were in tact, while the rotor blades were severely damaged. The damages were in the form of loss of material by fracture and bending/curling. Study showed that the damages were caused due to impact of the blades with solid hard objects. From the shape and pattern of the damages, it was established that the foreign object was circular in cross section and it had threads on the surface. The damage pattern on the blades was found to have close resemblance to the threads on the screw (made of steel) that was provided for establishing the possible foreign object type. Analysis of the damaged regions on the rotor blades showed presence of elements such as iron in concentration as high as 29 wt%. Based on these laboratory findings, it is stated that the foreign object is similar to the screw that was provided for establishing the foreign object type