Design Flaw Enhanced by Improper Workmanship to Cause Fatigue Failure on Rotor Blade of Compressor Gas Turbine

Abstract:

Ten stages of Compressor Engine S/N 123 of X-Gas Turbine failed in service prior the schedule for overhaul at 40,000 hour. At the failure event the running hour was 29,600. The maintenance was normally done every 8000 hours including filter and gasket replacement, instrument re-calibration, and bore scope examination. Upon dismantling, it was found one blade at rotor stage #3 failed with facture surface strongly indicated a fatigue failure, defective on stator and rotor blades at downstream, no defective blades at upstream. Detail examination confirm Root Cause of failure on Compressor Blade of X-Gas Turbine were combination of a sharp radius of root chamfer as the major contributor and at lesser extent enhanced by “scratches” exist on root blade free surface. There was no evidences Foreign Objects or corrosion contributed to fail the compressor blades. Blade material was sound and did not contribute to fail the blade. The recommendations to avoid failure reoccurrences were all existing installed rotor blades shall be dismantled and examined for the existence of crack at their root area. Inspection on brand new blades for the existence of scratches on blade surface prior assembly shall be strongly imposed; blade with preexisting scratch shall be rejected. In a design stages, increase the sharp chamfer radius on blade root is worth-while to be analyzed further. Workmanship during blade assembly shall not develop any scratch on blade surface especially on its root surface. A procedure and schedule for inspection on the running blades shall be refined to be able to detect any crack on the operating blades; special attention shall be given on root area.

• Periodical: Applied Mechanics and Materials (Volume 660)
• Pages: 593-597
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.660.593
• Online since: October 2014
• Authors: Slameto Wiryolukito*
• Keywords: Compressor Blade of Gas Turbine, Design Flaw, Fatigue Failure, Improper Workmanship

References

[1] Internal communication with Oil & Gas company owner of the Compressor Engine unit.

[2] OEM Compressor Engine Manufacturer Bulletin.

[3] ASM Handbook, Failure Analysis and Prevention, Vol. 11, ASM International, 2002, ASM International, Materials Park, OH 44073-0002.