Maintenance Planning Method Of Civil Aeroengine Fleet Under Discontinuous Use Strategy

Civil aero-engine is a complex equipment with high maintenance cost,long working life and requiring multiple maintenance during the whole life cycle.a reasonable maintenance planning from the perspective of civil aero-engine fleet can not only reduce the operation and maintenance costs,but also achieve the purpose of maintenance balancing.Therefore,the research on civil aero-engine fleet maintenance planning methods has important theoretical and economic value.At present,most of the research on the maintenance planning of civil aero-engine fleet is only based on the research of single engine,and there is a lack of a maintenance planning theoretical system based on the fleet.At the same time,the formulation of a fleet maintenance planning mainly relies on the experience of engineers.For the increasing number of engines,it is difficult to achieve an optimal maintenance planning.Aiming at the deficiencies of previous research,thi s paper comprehensively considers maintenance balance,operation and maintenance costs,establishes a fleet long-term maintenance planning model and a fleet short-term maintenance planning model,and uses particle swarm optimization and heuristic algorithms to solve the two models respectively.First,the content of fleet maintenance planning is described,and the factors that affect the operation and maintenance cost are analyzed;then combined with the characteristics of the engine whole life maintenance decision,the result of civil aero-engine whole-life maintenance decision is taken as constraint conditions,can be repaired in advance under the constraint conditions;then take advantage of discontinuous use strategy to establish a whole life cycle-oriented civil aero-engine fleet maintenance planning optimization model,which lays the foundation for realizing the civil aviation engine fleet maintenance plan optimization.Then using the known NP-hard problem,the three-division problem is reduced to the optimization problem of fleet maintenance planning,which proves that the optimization problem of aero-engine fleet maintenance planning is an NP-hard problem,and provides theoretical support for the optimization of aero-engine fleet maintenance planning.As the NP-hard problem is difficult to solve,it is impossible to find an effective method to solve it.Therefore,in order to reduce the difficulty of solving the problem of fleet maintenance planning,it is divided into two parts,the long-term maintenance planning and the short-term maintenance planning from the time dimension by referring to the practice of production planning.long-term maintenance planning of civil aero-engine fleet needs to determine the time when the engines in the fleet are sent for maintenance.Therefore,total ground inventory time between maintenances of civil aero-engine is used as decision variables,and maintenance balancing and the cost of operation and maintenance are optimization goals,in order to reduce the difficulty of solving the problem.Two optimization goals are added by the weight coefficient method as the optimization goal of the long-term maintenance planning model,and particle swarm algorithm is used to solve model of long-term maintenance planning.Finally,numerical experiments are used to verify that the method proposed in this paper is suitable for the formulation of long-term fleet maintenance planning.The short-term maintenance planning of the civil aero-engine fleet needs to determine when and which engine will be installed in each stand of the aircraft during planning period and how long it will be installed.When there is a lack of engines,lease out the aircraft in advance to avoid aircraft grounded due to lack of engines.In view of the particularity of the fleet’s short-term maintenance planning,two heuristic algorithms have been proposed.In view of the situation that multiple engines need to be replaced in the same day,a method of matching relationship between civil aero-engine and aircraft position is proposed.Finally,the results of the long-term maintenance plan obtained in Chapter 3 are used as experim ental data to verify that the method proposed in this paper can reduce number of days without civil aero-engine and cost of renting engines.Finally,based on long-term fleet maintenance planning methods and short-term fleet maintenance planning methods proposed in this article,combined with the actual needs of airlines for fleet maintenance planning,a prototype system for civil aero-engine fleet maintenance planning was designed and developed to provide maintenance planning for airlines,which provides technical support for the formulation of fleet maintenance planning of airlines.