When implementing Condition-Based Maintenance (CBM) for safety-critical systems such as aircraft, it is necessary to demonstrate the effectivity of the applied Condition Monitoring System (CMS) in detecting potential faults before failure. A quantitative fault detection reliability assessment for a given monitoring method and fault type, adapted from the field of Non-Destructive Testing (NDT), is proposed. It involves first modeling the relationship between the Condition Indicator values obtained with the CMS, for example vibration levels, and the corresponding fault severity in a signal response model. After defining an acceptable Probability of False Alarm (PoFA), the Probability of Detection (PoD) of the fault can be computed from the signal response model as a function of fault severity. Vibration monitoring presents particular challenges with regard to fault detection reliability, due to the high variability often encountered in vibration measurements. Further, a large number of individual Condition Indicators are typically computed from a vibration measurement and used for diagnostics. To systematically compare the detection performance of various indicators and to identify those indicators with the most significant response to a given fault, a discriminability measure derived from the signal response model is introduced. The fault detection reliability evaluation is demonstrated with vibration monitoring data from a series of Seeded Fault Tests (SFT) on helicopter tail rotor drive shaft bearings. Multiple bearings were first tested in an undamaged state, and then retested after the insertion of a local defect on the bearing inner ring race. The size of the defects was artificially increased in several steps, to obtain data over a range of fault severities. The evaluation shows that a Condition Indicator intended to detect bearing inner race faults indeed exhibits the most significant signal response, and achieves a high PoD at small defect sizes.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Evaluation of a condition monitoring method's fault detection reliability for condition-based maintenance applications


    Contributors:


    Publication date :

    2013


    Size :

    12 Seiten, 10 Bilder, 2 Tabellen, 13 Quellen



    Type of media :

    Conference paper


    Type of material :

    Storage medium


    Language :

    English





    From condition monitoring via condition based maintenance to condition based survey

    Rebel, Joerg / Behrens, Hans Peter / Langer, Klaus et al. | Tema Archive | 2007


    System reliability and condition based maintenance

    Banks, J. / Reichard, K. / Drake, M. | Tema Archive | 2008


    From condition monitoring via condition based maintenance to condition based survey

    Rebel, J. / Behrens, H.P. / Langer, K. et al. | British Library Conference Proceedings | 2007