Failure Analysis of an Inter-shaft Bearing of an Aero Gas Turbine Engine
- 393 Downloads
Failure of an inter-shaft bearing in an aero gas turbine engine is investigated to determine its root cause. Teardown inspections followed by metallurgical investigations are carried out on the parts of the failed bearing. None of the components of the bearing has shown any discolouration, wear, or overheating marks. But severe flaking is observed on one side of the outer raceway. It indicates progressive fatigue due to overload. Insufficient clearance due to differential expansion of inner ring and contraction of outer ring due to heating and cooling, respectively, can also result in this type of phenomena. Maintaining oil discipline and using correct grade of oil at proper frequency can address these issues. A comprehensive engine-bearing prognostic approach may be followed utilizing available sensor information on-board the aircraft such as rotor speed, vibration, lube system information, and aircraft maneuvers to predict bearing life and incipient bearing failure.
KeywordsFatigue failure SEM Spalling
The authors are very grateful to the Executive Director, Engine Division, Hindustan Aeronautics Limited and Chief Executive (Airworthiness), CEMILAC for their kind permission for publishing this paper.
- 3.J.L. Miller, D. Kitaljevich, In-line oil debris monitor for aircraft engine condition assessment, in 2000 IEEE Aerospace Conference Proceedings, vol. 6, pp. 49–56Google Scholar
- 4.P.J. Dempsey, N. Bolander, C. Haynes, A.M. Toms, Investigation of Bearing Fatigue Damage Life Prediction Using Oil Debris Monitoring, NASA/TM-2011-217117 (NASA, Washington, DC, 2011)Google Scholar
- 11.M.J. Roemer, G.J. Kacprzynski, Advanced diagnostics and prognostics for gas turbine engine risk assessment, in 2000 IEEE Aerospace Conference Proceedings, vol. 6, pp. 345–353Google Scholar
- 12.N.H. Forster, K. Thompson, A.M. Toms, S. Horning, Assessing the potential of a commercial oil debris sensor as a prognostic device for gas turbine engine bearings, in AFRL Presentation at IHSM Conference, Aug 11, 2005Google Scholar
- 13.H. Mao, P. Yang, S. Gai, Bearing condition evaluation and rule extraction. J. Comput. Inform. Syst. 8(18), 7433–7440 (2012)Google Scholar
- 15.R. Orsagh et al., A comprehensive prognostics approach for predicting gas turbine engine bearing life, GT2004-53965, in Proceedings of ASME TurboExpo 2004, June 14–17, 2004Google Scholar