Abstract
As system components and their interactions become more and more complex, system reliability problems become increasingly prominent. In the reliability research, component importance measures have been widely used as an important decision-making aid index. Particularly, importance measures have been used in designing or selecting the optimal maintenance strategy. However, the practical factor of maintenance cost is not comprehensively considered in the existing importance analysis. This paper proposes new importance measures based on two types of maintenance costs under different maintenance strategies, including the failure-triggered replacement strategy that replaces damaged components, the age-based replacement strategy where a component is preventively replaced and when it has been used for a certain period of time, and the hybrid strategy that integrates the former two strategies. Methods for computing the proposed maintenance cost-based importance measures for series systems and parallel systems are given. A case study of a propeller plane system is provided to illustrate and validate the proposed method.