Failure analysis of compressor stator blades stage II & III of an aeroengine

Following an incidence in an aeroengine, two compressor stator blades belonging to stage II and III were forwarded to the laboratory for investigation. Fractographic study showed that both the blades have failed by fatigue. The fatigue crack in stage II blade (No. EE 256) had initiated at a stress concentrator at the hub-airfoil fillet. The stress concentrator was found to be in the form of a metallic bead that resulted during reworking of the blade. The fatigue crack in stage III blade (No. EEE 274) had initiated at a mechanical damage on the leading edge of the airfoil. Analysis shows that this damage was caused by the internal object generated due to failure in blade No. EE 256 sometime prior to Run No. 415. A detailed analysis of the failure is presented in this report and a few recommendations suggested