Derivative-based component global importance measure for phased mission systems

Importance measures for system reliability analysis are used to estimate the relative importance of components to the system reliability, and further to provide useful information to improve system performance. Components in phased mission systems (PMS) may have unequal structural importance working in different phases with different reliability logics, and their reliability parameters also may vary from phase to phase caused by different phase environment. Thus, traditional importance measure based on fixed component structural importance and component nominal reliability are not suitable to be applied in these situations. This paper presents a derivative-based global sensitivity measure to evaluate the component importance of PMS. The proposed method can consider component with different structural logic in different phase task profiles, and variational reliability parameter caused by different work environment. Finally, a PMS example is given for illustration the effectiveness of the provided measure. Additionally, compared with the Birnbaum structural importance, the results show that the proposed measure displays reasonable component importance by considering component various reliability parameters and structural logics.