| Fatigue failure is one of the main forms of aircraft structural failure, and the fatigue life of keycomponents representatives that of the whole aircraft. The event of fatigue crack will affect the flightsafety, and even cause flight accident. In addition, the cost of modern aircraft is very expensive, andpeople always find ways to tap the potential of each aircraft. If the residual life was calculatedaccurately and the duration of their service was extended, significant economic benefits would beobtained.Two kinds of life monitoring modes on single plane have been reviewed in this thesis. And amethod of physical prototype centered assessment for fatigue life of structures based on on-linemonitoring data was proposed. A possible complete realization of process was discussed and six keyproblems were analyzed. Two specimens with a centered hole under different loads were tested, thenthe fatigue life was estimated. The results show the feasibility and effectiveness of the proposedmethod.The test pieces of lug and corresponding fixtures were produced specially. Then11groups ofload inversion test and fatigue life test were carried out. Also, the fracture orientation and morphologyof the test pieces were analyzed. External load were inversed combined with the improved BP neuralnetwork, and fatigue life was calculated under this inversed load. The result shows that fatigue lifepredicted by the method proposed above was good agreement with the experimental results. |
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