Study On Maintenance Interval Optimization Of Typical Engine Accessory Unit Based On Reliability

The implementation of reasonable and efficient maintenance management has always been an important research and application direction for airlines and government civil aviation management departments.The maintenance interval of civil aircraft is an important component of maintenance management,which has received great attention.Therefore,this thesis selects maintenance interval as research direction.The thesis bases on reliability analysis method to construct the maintenance model,and verifies the model by maintenance fault data to prove the feasibility and to provide reference plan for airlines.Current maintenance types and maintenance strategies are presented.According to MSG-3 analysis logic decision process,the fuel cooled oil cooler could be determined as maintenance significant item,the fault category should be determined to analyze its common failure mode and failure causes.When constructing a model for maintenance interval optimization.It's necessary to consider maintenance cost,reliability and availability.When only considering maintenance cost to construct the model,the maintenance cost should be minimized for unit time;Based on the previous model,the reliability is added,which means the average reliability should be maximized.Evaluation function method is chosen to combine the two decision objectives and to construct the multi-objective model.In the solving process,the simulated annealing algorithm is selected.This algorithm could find global optimal solution from local optimal solutions,but the solving speed is slow.Therefore,improvement measures need to be taken: by embedding Q learning algorithm in simulated annealing algorithm,annealing rate and control parameter get improved,which accelerates the convergence speed.With the fault data provided by an aviation company,the failure type and failure distribution function could be obtained after analysis.Necessary parameters and data will be brought into the built models for verification and to obtain calculation results for maintenance interval.Compared calculated results with the actual recommended maintenance interval value,the reason for difference is analyzed and explained to show that the constructed model is feasible to some degree.