Preventive Maintenance Period Research of series-parallel Systems Based on Optimal Policy

Preventive Maintenance can reduce failure rate and improve system performance,but with the increase of Preventive Maintenance times,the maintenance costs will go up.Based on the dynamic changing rules of failure rate,an optimal Policy research model for series-parallel system was presented about Preventive Maintenance Period.The cost function of a maintenance policy was minimized under given reliability constraint,and the recursion relationship of failure rate before and after preventive maintenance was built up concerning with the concept of age reduction factor.Genetic algorithm was utilized to obtain optimization solution,and some practical methods and improvements of using parallel operation and preserving excellence individual were proposed.A special case was presented;the result shows that the optimization method is feasible.Starting from the results obtained for series-parallel system,this approach can be extended to more complex systems.