Abstract: To solve the problem of that the failure rate of the weapon system is difficult to be described with time as an independent variable, a model is established by using the amount of intervally fired projectiles as the independent variable to describe the failure rate of the weapon system. Since the failures of weapon systems are closely related to the the amount of intervally fired projectiles, the preventive maintenance opportunity determined by the amount of intervally fired projectiles is easy to operate in practice, and the statistical data of the amount of intervally fired projectiles are retained easily. Based on the failure data of a weapon system, Ao (Operational availability) and EMC (Expected maintenance cost), which are two important objectives, are analytically expressed by the proposed failure rate model. For these two objectives, the optimized decision is made with MOPSO, and the satisfactory solutions meeting the requirements are obtained.

Key words: ordnance science and technology, Weibull distribution, preventive maintenance, maintenance cost, operational availability