Failure-mode importance measures in system reliability analysis

To quantitatively estimate the contributions of component failure modes to system output, failure-mode importance measures have been proposed in this paper. This issue is discussed in two schemes: in Scheme 1, failure-mode importance is measured by the change in the characteristics of the system output after removal of the interested failure mode; and in Scheme 2, failure-mode importance is measured by the expected change in the characteristics of the system output after fixing the failure mode of interest at nominal values. Properties and the computational strategies of the failure-mode importance measures also are presented. Discussions with numerical and engineering examples demonstrate that the importance measures are of great significance for the purpose of system improvement.