Affiliation:
1. Resilience Engineering Research Group, University of Nottingham, Nottingham NG7 2RD, UK
Abstract
A recent development in Fault Tree Analysis (FTA), known as Dynamic and Dependent Tree Theory (D2T2), accounts for dependencies between the basic events, making FTA more powerful. The method uses an integrated combination of Binary Decision Diagrams (BDDs), Stochastic Petri Nets (SPN) and Markov models. Current algorithms enable the prediction of the system failure probability and failure frequency. This paper proposes methods which extend the current capability of the D2T2 framework to calculate component importance measures. Birnbaum’s measure of importance, the Criticality measure of importance, the Risk Achievement Worth (RAW) measure of importance and the Risk Reduction Worth (RRW) measure of importance are considered. This adds a vital ability to the framework, enabling the influence that components have on system failure to be determined and the most effective means of improving system performance to be identified. The algorithms for calculating each measure of importance are described and demonstrated using a pressure vessel cooling system.
Funder
Lloyd’s Register Foundation
Subject
General Mathematics,Engineering (miscellaneous),Computer Science (miscellaneous)
Reference27 articles.
1. How Useful is Quantitative Risk Assessment?;Apostolakis;Risk Anal.,2004
2. A Time Dependent Methodology for Fault Tree Evaluation;Vesely;Nucl. Eng. Des.,1970
3. Andrews, J.D., and Moss, T.R. (2002). Reliability and Risk Assessment, Professional Engineering Publishing. [2nd ed.].
4. Element Importance and System failure frequency of a 2-State System;Zhang;IEEE Trans. Reliab.,1985
5. Interval Reliability for Initiating and Enabling Events;Dunglinson;IEEE Trans. Reliab.,1983