Methods Of Scheduling And Condition Based Mainteance Decision Making In Civil Aero Engine Fleet

Because of the operating environment and seasonal factors, during a period of time the engine removal peak rate will be appeared in the airline when the engines of the airlines are not enough. While for another period of time there would give rise to low engine removal rate, a large number of idle inventory and a backlog of funds. If considering the single engine only, without taking into account the preparation of resources of the whole fleet, it easily make due to lack of aircraft grounded, the unbalanced rate of fleet removal, the large number of spare engines and the double loss of the economy and credibility. To address limitations of the maintenance decision-making based on the single engine, fleet maintenance decision-making theory is researched in this thesis. The main research content is as following:Firstly, a prediction method for the life of aero-engine based on the degradation data is researched by introducing the concept of performance reliability which linked the reliability and actual performance. The fleet performance reliability model based on Weibull distribution is established. The average expectancy life and performance reliability control method of the aero engine fleet are obtained under dynamic environment. And at the same time, a real-time reliability prediction method based on two time series analysis models is proposed applying on aero engine to predict the residual life of single aero engine on wings. The results indicate that the forecasting accuracy of the method based on. ARIMA model- is superior to the method-based on HOLT algorithm.Secondly, a wide range of information of the engine repair, use and stocks is covered in the scheduling scheme. Therefore, an evaluation method of the fleet maintenance cost to scheduling program is proposed, cost drivers such as the cost of the overhaul, sorting rules, echelon technology, engine life on the wings, the number of spare engines, length of plans and the protection rate. Compared with other assessment methods for aero engine fleet maintenance and support, the method proposed in this paper is more comprehensive, more systematic and better realization of the airline security and economic objectives. It can be used to guide the airline's specific engine maintenance management activities. Based on this, some researches are developed such as the genetic algorithm of aero engine fleet scheduling with constrain of parallel machine, a SSPT (shifted shortest processing time) method to smooth the removal rate of aero engine fleet, the optimization method the amount of spare engine. Examples of analysis were used to illustrate the effectiveness of these methods. Thirdly, according to the time and risk of functional failure based on single engine, the optimal timing of fleet maintenance decisions making under the overall cost can not be made. Therefore, to avoid the limit of single engine maintenance decision making, a random multi-objective decision making model of fleet maintenance and optimization method is studied based on conditions from practice. A concept about fleet maintenance decisions making is proposed based on contions. A decision-making method for the removal timing of aero engine and life limited parts is established by introducing the profomace condicong which resulted in a security risk and loss of machine performance and the materials cost of components. Applying the combination method based on rough set theory to estimate the cost of maintenance, the removal timing of engine and life limited parts is optimized by particle swarm method of immunization.Fourthly, based on the relevant methods of scheduling and software of home and abroad, combining Shanghai Airlines practical works, an aero engine scheduling system is developed by using the theory and methods of fleet maintenance decision.