Research Of Fatigue Life Of Fuselage Skin Lap Joint With MSD

Widespread fatigue damage, revealed by the Aloha accident, is a new form of structural fatigue damage. Since widespread fatigue damage is a significant threat for the continued integrity of aircraft structure, it has become the research priorities of structure damage tolerance filed. In recent years, domestic and foreign airworthiness authorities have established new airworthiness regulation or amended existing airworthiness regulations to prevent widespread fatigue damage occurred in the fleet. In this paper, the existing airworthiness regulations for widespread fatigue damage have been discussed and analyzed exhaustively in the following contents: The background of amendments to the regulation, widespread fatigue damage evaluation method, the procedure of establishing and extending the limit of validity of the engineering data. Based on the analysis result of airworthiness regulation, a lot of work has been done on the fatigue life of fuselage skin lap area, which is a typical structure susceptible to widespread fatigue damage, including:Analysis the applicability of current damage detects methods for the multiple site damage occurs in the fuselage skin lap area: Based on the smallest crack size existing detecting methods to be able to detect, the applicability of current damage detects methods for the multiple site damage occurs in the fuselage skin lap area was discussed here;Compute the crack initiation life of aircraft skin lap using Monte-Carlo simulation method: A method based on Monte-Carlo simulation method, using the data of simple riveted specimen fatigue test to compute crack initiation life of aircraft skin lap using Monte-Carlo was introduced here;Analysis the effect of MSD cracks on the fatigue life of fuselage skin lap hole. The conclusion can be used to compute the remaining fatigue life of fuselage skin lap hole based on the crack size and initial fatigue life without and cracks exist.The contents of this paper give guidance on how to establish the inspection start point and structural modification point, which is important data in establishing LOV.