Opportunistic Group Maintenance Optimization of Multi-unit System Considering Dependency

In view of the incomplete consideration to maintenance dependency in traditionally classified methods, a new method was put forward to judge maintenance correlation in a multi-unit system from four aspects such as time correlation, failure correlation, structure correlation and function correlation. An analysis of the impact caused by maintenance correlation on opportunistic group maintenance is conducted, on the basis of which, an opportunistic group maintenance optimization model is provided to minimize the system maintenance cost during unit available time. With the application of biogeography-based optimization (BBO) algorithm, the best opportunistic maintenance threshold sets about correlating components in the system can be defined. Furthermore, an existing example is analyzed in which oil transfer valve in marine fuel injection system can be opportunistically maintained with piston and needle valve. It is concluded that the proposed model in this paper provides a feasible method to group maintenance for multi-unit system.