Research On Fatigue Reliability Analysis Method Of Aircraft Landing Gear

The landing gear of aircraft is one of the key parts for aircraft's flight safety, of which failure modes mostly behaves as fatigue failure under alternating load condition. As the aircraft design developing toward a higher, more reliable and technological level along with the developments of technology, it's meaningful to conduct the research on the fatigue reliability analysis of the aircraft landing gear. Based on the analysis of the fatigue reliability and the corresponding returns, the fatigue reliability analysis methods were studied, which meets the requirement of the project named fatigue failure control technology for landing gear funded by National Natural Science Foundation of China (NSFC).Two reliability models were studied based on the cumulative fatigue damage probability model and damage fatigue rating (DFR) method in this paper. This cumulative fatigue damage probability model, which puts the randomicity to the cumulative fatigue damage theory and makes a study to the random occurrence for the structure failure, can analyze the fatigue reliability characters under the multiplestage constant-amplitude load by using exiting fatigue data. And the analysis of fatigue reliability life using DFR was also discussed in this paper.Then taking as an example of one nose landing gear,an analysis model for landing gear was build, which was applicable for the engineering. Combining the structure characteristics of landing gear, the main idea of this model is to build the finite element modeling and conduct the stress and fatigue performance for the landing gear. After finite element modeling, the fatigue and reliability of landing gear were discussed via the two reliability analysis models.Finally a contrast analysis of the two reliability analysis methods was discussed and results indicate that both of the two methods can effectively analyze the reliability of the landing gear, and also easily apply to the engineering. Besides, comparative study of several existing factors, such as surface machining factor, stress concentration factor, for the efforts to the system reliability, was also discussed. Therefore, effective measures must be applied during the period of design, manufacture and usage to make sure that can enhance the fatigue performance and reliability for the landing gear.