Optimal grouping preventive maintenance strategy for the multi-part series system under the extended warranty condition

Extended warranty (EW) is an optional contract that typically provides additional guarantee to users by the manufacturer after the initial warranty period of the equipment expires. To meet users' demand for minimizing the EW cost-availability ratio during the device's EW period and protect the manufacturer's profit, this article innovatively proposes a grouping preventive maintenance (GPM) strategy for multi-part series system, based on the consideration of user and manufacturer sharing warranty cost proportionally. This strategy can integrate the preventive maintenance (PM) of each individual component in the system, thereby reducing the total number of PM times and lowering the preparation cost for PM. The decision objective of the GPM strategy is to minimize the cost-availability ratio of the system's EW, and the decision variables are the PM interval and PM improvement factor. In the case analysis, taking the power system of electric vehicles as the research object, it was found that after adopting the GPM strategy, the EW cost-availability ratio of the system reduced by 16.6%, thus verifying the superiority of the GPM strategy proposed in this paper.