STP1548

    Evaluation of Repaired Gas Turbine Engine Bearings Demonstrates Absence of Subsurface Fatigue Propagation in Appropriately Designed Applications

    Published: Oct 2012


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    Abstract

    Refurbishment of aerospace gas turbine engine bearings is a well established process regularly used to ensure asset availability. Repairs typically follow four well established basic levels. Level one generally requires detailed inspection in accordance with agreed criteria. Level two commonly involves replacement of rolling elements, refinishing of raceway surfaces and re-plating of bearing cages as appropriate. Level three involves the use of raceway grinding in the event that standard honing is insufficient to achieve required product quality. Level four is reserved for cases where one of the bearing rings is replaced. Results from detailed study of product following completion of full scale testing, repair per levels two and four, and continued testing is presented herein. Results demonstrate the absence of subsurface fatigue propagation. Test results conclude the commonly recognized acceptability of the repair methods noted and further support previously published theories regarding infinite fatigue theory. Reference to previously published findings describing expected symptoms of subsurface fatigue propagation are reviewed to support findings.

    Keywords:

    bearing repair, fatigue life testing, sub-surface fatigue propagation, infinite fatigue theory


    Author Information:

    Beer, Oskar
    Product Development Aerospace, FAG Aerospace GmbH & Co. KG, Schweinfurt,

    Streit, Edgar
    Product Development Aerospace, FAG Aerospace GmbH & Co. KG, Schweinfurt,

    Mirring, Patrick
    Product Development Aerospace, FAG Aerospace GmbH & Co. KG, Schweinfurt,

    Brock, Joe
    The Barden Corporation, Danbury, CT


    Paper ID: STP104601

    Committee/Subcommittee: A01.28

    DOI: 10.1520/STP104601


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