The Research Of Synthetic Maintenance Policy Of Cycle Life For Complex System

Maintenance is important action to assure equipment performance and iprove and maintain its reliability in life cycle for complex equipment system. Along with the number of components and items in complex equipment system dramtically augmenting, there are various types of subsystem instructure is various leading to difficulty to make maintenance determination. Therefore defferent maintenance policy is applied to subsystem with defferent instructure, based on which the synthetic maintenance determaination is made.The development of maintenance theories is summarized. Reliabilty theory and reliability centered maintenance (RCM) theory are introduced in detail. The transformation of economic contraints to reliability constraints realize by establishing the function relation between economic indexes and reliability indexes, which insures that maintenance plan is economic.Based on lifecycle theory, the view is proposed that the equipment is synthetic utilized under multi-grades of work in its lifecylce. The model of revenue of a euipment in lifecycle under multi-grades of work is established and based on which the synthetic determination included the transit times of sequential two work grades and preventive maintenance (PM) times in a order of work grades is realized. PM times consist of many sets of preventive and each set of preventive maintenance times corresponds with a certian work grade.The two-stages policy is proposed for cold-standby system with reliability requirement for the acting unit. Under the policy, the operation period is partioned into two stages and the reliability requirement for equipment in different stage is different. It is testified that the optimum of miantenance plan is realized and at same time the reliability requirement of cold-standby system in operation period is assured under the policyThe unavailability models of safety instrumented system (SIS) are estblished based on various life distributions and the causes of electronic items. The synthetic determination model considered the number of items in redundancy and test and maintenance (T&M) policy is presented. The average unavailability modeles of safety redundant system with a set of determinant parameters combination are estblished. The determinant parameters include number of redundant items and T&M poloicy and T&M interval in operation periodFinally, the replacement policy of product with warrant item is research. In point of view of purchaser, the ideal of product investment cycle (PIC) is presented. The models of average cost in PIC with two common warrant polies are established and the determination about optimal maintenance period aiming to minimize the average cost in PIC is derived.