Research On The Decision-making Method Of Maintenance Level For Application Of Engine Module

Before an engine is sent to repair,the suggested maintenance level should be provided by the airline for maintenance organization to confirm the maintenance margin.The maintenance level of the whole engine is determined through the maintenance level of each module.Besides,the performance degradation is the key factor to determine the maintenance level.Therefore,the decision-making of engine module maintenance level from the perspective of performance is studied to provide reference,and the engine performance degradation and performance recovery are taken as the core.Firstly,the factors which affecting the engine maintenance level are analyzed,including performance degradation,life limited parts,hardware damage,airworthiness directive /service bulletin and soft time.The analysis shows that the performance degradation is one of the main causes of engine shop visit.And then,the decision-making method of the engine module maintenance level from the view of performance degradation is studied.The state parameters which can effectively characterize the performance degradation of each engine module are analyzed from three aspects: engine principle,state parameter sensitivity and state parameter combination effectiveness.The initial maintenance level of each engine module is determined by the fuzzy comprehensive evaluation model,according to the change of state parameters.The validity of the model is verified by the example of the high pressure turbine module.In addition,engine module maintenance level optimization model is used to meet the requirements of multiple targets after the repair service.Performance recovery is taken as constraint condition,the lowest maintenance cost and maintenance time are taken as objective function.The linear weighted sum method is chose to transformed multiple targets into single objective.The model further optimizes the maintenance level,based on the initial maintenance level.That means an economy and the timeliness decision of engine module maintenance level is made,which provides a prerequisite to meet the performance requirements after repair the damage of the components.Finally,an actual case of engine shop visit is taken to verify the rationality of the model.