Andrews, J.D., 2007. Component contributions to the failure of systems undergoing phased missions. IN: Proceedings of the 17th AR2TS, 17th Advances in Risk and Reliability Technology Symposium, Loughborough, UK, April, pp 155-168.
The way that many systems are utilised can be expressed in terms of missions which
are split into a sequence of contiguous phases. Mission success is only achieved if
each of the phases is successful and each phase is required to achieve a different
objective and use different elements of the system.
The reliability analysis of a phased mission system will produce the probability of
failure during each of the phases together with the overall mission failure likelihood.
In the event that the system performance does not meet with the acceptance
requirement, weaknesses in the design are identified and improvements made to
rectify the deficiencies. In conventional system assessments, importance measures
can be predicted which provide a numerical indicator of the significance that each
component plays in the system failure. Through the development of appropriate
importance measures this paper provides ways of identifying the contribution made
by each component failure to each phase failure and the overall mission failure. In
addition a means to update the system performance prediction and the importance
measures as phases of the mission are successfully completed is given.