Simulation Research On Engine Visit Shop Overhaul Strategy

The visit shop overhaul of the engine is a key issue for the management of the engine fleet.A reasonable engine visit shop overhaul strategy not only ensures the safe operation of the engine,but also improves the economic benefit of the airline.Due to the diversity of engine failure modes and the complexity of the maintenance system,it is extremely difficult to use the analytical method to study the engine visit shop overhaul strategy.Therefore,based on the Monte Carlo simulation method,the engine visit shop overhaul strategy is studied in this paper.By analyzing the historical data of the engine fleet,the life distribution functions of three failure modes: performance degradation,component damage and accidental damage are studied.Monte Carlo simulation model is established based on competitive failure to predict the law of time when the engine is first delivered.Combined with the actual data provided by the engine fleet,the Kolmogorov-Smirnov test is used to determine the distribution type of first delivery time.After analysis,the reliability error of the simulation results is small,between-1% and 2%,which verifies the rationality and feasibility of the method.According to the engine maintenance management outline,the process of determining the maintenance level of the engine is formulated and combining delivery time and the maintenance level determination process,the maintenance level is determined and evaluated.Through the visualization of the simulation results,the influence of the target on-wing time on the maintenance level is studied,and taking maintenance cost as the optimization target,the target on-wing time is optimized.After analysis,when the target on-wing time is 6500~7500cycle,it is the most optimal.The maintenance cost is lower at this time,and the target on-wing is longer meanwhile,which is in line with the ideal goal of engine maintenance.Based on the analysis of the failure causes of the engine's second delivery,the second delivery simulation model is established to study the impact of the engine's first delivery time on the second delivery.According to the simulation results,for a certain period of time,the longer the engine's first delivery time,the shorter the second delivery time,and due to the change of the maintenance level,at some point,the second delivery time may suddenly jump.In addition,the longer engine's first delivery time without the change of the maintenance level,the higher the accuracy of the second delivery time predicted by the simulation.Taking the first delivery caused by the performance degradation as an example to expand analysis,when the first delivery time is increased from 5000 cycle to 7000 cycle,for the prediction of the second delivery,the confidence interval under the confidence level of 68.26% is shortened by 890.89 cycle and the confidence interval under the confidence level of 94.55% is shortened by 1781.77 cycles.Finally,by analyzing the engine delivery time and the degree of component damage,the rationality of the simulation results is verified.