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Improved accuracy in quantitative fault tree analysis
Author(s) -
Sinnamon R. M.,
Andrews J. D.
Publication year - 1997
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/(sici)1099-1638(199709/10)13:5<285::aid-qre109>3.0.co;2-3
Subject(s) - fault tree analysis , event tree analysis , binary decision diagram , event (particle physics) , event tree , tree diagram , computer science , fault (geology) , reliability engineering , failure mode and effects analysis , reliability (semiconductor) , algorithm , tree (set theory) , diagram , statistics , data mining , mathematics , engineering , posterior probability , mathematical analysis , bayesian probability , power (physics) , physics , quantum mechanics , seismology , geology
The fault tree diagram defines the causes of the system failure mode or ‘top event’ in terms of the component failures and human errors, represented by basic events. By providing information which enables the basic event probability to be calculated, the fault tree can then be quantified to yield reliability parameters for the system. Fault tree quantification enables the probability of the top event to be calculated and in addition its failure rate and expected number of occurrences. Importance measures which signify the contribution each basic event makes to system failure can also be determined. Owing to the large number of failure combinations (minimal cut sets) which generally result from a fault tree study, it is not possible using conventional techniques to calculate these parameters exactly and approximations are required. The approximations usually rely on the basic events having a small likelihood of occurrence. When this condition is not met, it can result in large inaccuracies. These problems can be overcome by employing the binary decision diagram (BDD) approach. This method converts the fault tree diagram into a format which encodes Shannon's decomposition and allows the exact failure probability to be determined in a very efficient calculation procedure. This paper describes how the BDD method can be employed in fault tree quantification. © 1997 John Wiley & Sons, Ltd.