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Nondestructive evaluation of corrosion damage of Al-alloys by in-situ AE monitoring and nonlinear elastic wave spectroscopy testing
Kober, Jan ; Převorovský, Zdeněk
This work investigates the possibilities of monitoring ongoing corrosion process by acoustic emission (AE) and of determining overall corrosion damage by the nonlinear wave modulation spectroscopy method (NWMS). Specimens made of Al-alloy L-beams simulating stringer reinforcements of airplane structure were studied. The samples were repeatedly immersed in sea salt solution. The acoustic emission activity was recorded in situ during corrosion process. Nonlinear parameters of the samples were measured in between corrosion tests by NWMS method. The current dynamics of a corrosion process was determined by AE, the amount of corrosion damage was corresponding to the nonlinear parameters obtained by NWMS.
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Detection of AE Sources During Long-term Fatigue Tests of Riveted Aircraft Wing Flange
Chlada, Milan ; Převorovský, Zdeněk
Fracture is the primary threat to the integrity, safety, and performance of nearly all highly stressed mechanical structures, e.g., aircrafts, building units or pressure vessels. Contemporary exacting demands on reliability and safety of material structures are not realizable without effective means of NDT and continuous state monitoring. AE monitoring of structures needs new robust and fast methods for emission source location and classification. Recently proposed AE source location method using so-called signal arrival time profiles and artificial neural networks (ANN) was applied for monitoring of growing defects during long-term fatigue testing of riveted aircraft wing flange. The potentialities of the method regarding the on-line monitoring of dangerous crack growth in selected critical parts of aircraft structures are discussed.
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