Abstract: Aiming to solve the problem of competing failure process of wartime equipment which is affected by natural degradation and random shocks, a condition-based preventive maintenance strategy is proposed. First， a reliability assessment model of a single-unit system is established, which considers the decrease of shock-threshold resulted from the accumulation of the system degradation. A reliability modeling method for equipment system under continuous shift-threshold is proposed. Then a condition-based preventive maintenance strategy is proposed for the equipment hidden function failure under the condition of the periodic detection and a cost rate function is constructed. Finally， a real example is used to analyze. The system’s reliability function and the optimal preventive replacement threshold are determined. The influence of different shock-threshold parameters on reliability is compared and analyzed. The results show that the proposed method can be adopted to achieve the reliability assessment for the equipment system under the condition of the competing failure, and provides an alternative approach to the optimal preventive maintenance threshold.

Key words: 战时, 竞争失效, 阈值连续变化, 预防性维修策略, 可靠性模型