Research On Interval Optimization Method For Imperfect Preventive Maintenance Task

It is an effective method to reduce cost of maintenance,improve reliability of the aircraft by optimizing the preventive maintenance task interval.It could also enhance the marketing competitiveness of the airlines.An aircraft system maintenance cost optimization model is established based on reliability theory,the preventive maintenance interval is determined,then replacement time and opportunity-group maintenance are studied.Firstly,the CA(Criticality analysis)importance analysis method is given to determine the optimal target which is called functional significant item.The standard includes 6 factors which have effect on maintenance activities,and a weight distribution is made by AHP.Then,maintenance task optimization model for a single component is established.For imperfect preventive maintenance,the maintenance improvement factor is introduced to describe the recovery status of system conditions.In combination with the improvement factor,the maintenance cost model is established.With the lowest maintenance cost rate as the optimal goal and the minimum equipment reliability as the constraint condition,an optimization model for imperfect preventive maintenance of single part is established.The maintenance interval in this model is variable.On the basis of variable interval,considering the opportunity-group maintenance of multi-task,the relationship of the failure rate is considered,the reliability threshold is used as an optimization variable,an opportunity-based maintenance model is established,and Quantum-behaved Particle Swarm Optimization(QPSO)is used to solve the function.Finally,an example of two established maintenance optimization models is verified.The real maintenance data is used to determine the failure mode and reliability parameters of the components,and the optimal maintenance interval and replacement timing of the carbon seal and the opportunity maintenance threshold of the relevant components are obtained.Compared with the traditional fixed maintenance intervals,variable intervals for parts with the characteristics of early failure or aging has better adaptability,it can also help the maintenance companies reduce costs.