Research On The Modeling And Simulation Of Engine Overhaul Strategy

Spare engine planning and maintenance decision-making have important relation with engine overhaul.Reasonable spare engine planning and maintenance decision-making can ensure the normal operation of aero-engine and the economic benefits of the airline company.Due to the complexity of engine structure and the diversity and randomness of fault modes,it is very difficult to establish and solve the spare engine and maintenance decision models by using the traditional analytical method.The discrete event simulation method is used to study the spare engine planning and maintenance decision-making in this paper.Based on the actual historical data of airlines,three common hardware damage forms of the blade of high pressure compressor,combustion chamber and the first stage blade of high pressure turbine are fitted by weibull distribution.Kolmogorov-smirnov test shows that logarithmic normal distribution is more suitable for performance degradation.Spare engine planning process is simplified into a queuing system,and the Arena simulation software is used to establish a spare engine model including two factors: hardware damage and performance degradation.Taking 3 years as a planning period,a certain A321 fleet is analyzed for the future 15 years,and the optimal number of spare engine is determined by considering the level and cost of guarantee.The results show that the number of spare engine obtained by this method is within the reasonable range of experience.Based on the eMMP,the engine module maintenance level decision logic is optimized,which proposes a concept of the threshold of the module heavy maintenance,and combined with the opportunity maintenance threshold based on the LLP,an engine full life cycle maintenance model is built by Arena simulation software.Taking the minimum maintenance cost per flight hour as the optimization objective,and considering the LLP utilization and engine reliability,the combined optimization values of the module heavy maintenance and opportunity maintenance threshold are generated,and the numbers of engine removal and repair levels of each module are also given,which provide a decision support for the airline company.