Determination Of L/HIRF Inspection Intervals By Using The Theory Of Fuzzy Based On Grey Relational Degree

This article mainly concentrates on the L/HIRF protection analyzing made during the establishment of MRBR for modern civil aircraft and makes focal point for the method to determine the maintenance interval of L/HIRF protection systems, for the purpose of making the L/HIRF maintenance interval more reasonable and economic.The maintenance interval is one of the core missions during the establishment of MRBR and the L/HIRF maintenance interval is an important element in all sorts of intervals. In this article, the damage mechanism of L/HIRF is firstly studied, and different kinds of protective design are proposed aiming at these damages. Besides, the L/HIRF protection analyzing system in MSG-3 is studied and the L/HIRF maintenance interval determination model is built based on the MSG-3. According to the procedure given in this model, the L/HIRF protection objects are decided, the protection zones are divided and the influencing factors are given. The L/HIRF protection sensitivity is determined by using the comprehensive theory of fuzzy based on grey relational degree, and the weight of influencing factors is given via the expert decision based on AHP. Further more, 11 L/HIRF protection tasks are chosen from the AMM of one classical aircraft type to make the instance analysis. Questionnaires are designed and issued to collect experts’ opinions. The model is built with MATLAB and the maintenance intervals of these 11 tasks are calculated. In the end, The independent sample mean t test is applied on error analysis. The availability and accuracy of the model is verified and the cause of error is discussed.Nowadays, with the rapid development of civil aircraft manufacturing industry in China,the studying results in this paper can be a reference for the domestic research in MRBR establishment.