Research On Non-destructive Testing And Maintenance Strategy Of Aircraft Structural Parts Based On Reliability Measurement

Fault detection technology and maintenance strategies with high reliability are important ways to ensure continuous safety and airworthiness of the aircraft.To select non-destructive testing technology that satisfies the requirement of reliability and to make scientific preventive maintenance decision can not only keep the aircraft’s structural parts airworthy during the life cycle,but also provide theoretical and technical support for airlines to reduce operating costs.Therefore,it is of great practical value to study the testing technology’s reliability evaluation and maintenance decision of the aircraft’s structural parts.In the first part,the reliability evaluation method of fault detection technology of structural parts is studied.The evaluation index system of non-destructive testing reliability is given to improve the traditional evaluation method which only considers defect detection rate.The counting model and scoring model including missing and false detection rate are established,the systematic evaluation method of non-destructive testing reliability for aircraft structural parts is proposed and the validity of the method is verified by the real test data.In the second part,the perfect preventive maintenance strategy of structural parts is considered,and a stochastic programming model is established to minimize the sum of detection and renewal cost as well as aircraft on ground loss,to solve the optimal maintenance frequency and time interval to meet the reliability requirements of structural parts.The existence condition of the optimal solution is discussed and three important theorems are obtained.The corresponding iterative algorithm is constructed,and the effectiveness of the algorithm is verified by an example analysis.The third part demonstrates the discussion of the imperfect preventive maintenance strategy of structural parts.A nonlinear stochastic programming model with the objective function to minimize the expected cost rate in infinite time domain is established.Considering the complexity of the model,an iterative algorithm based on branch-and-bound golden section and quadratic interpolation is introduced to find the optimal maintenance period and times.The sensitivity analysis shows that the result of the model is consistent with the actual situation.