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Monitoring of fatigue crack growth in riveted aircraft structures by acoustic emission
Chlada, Milan ; Převorovský, Zdeněk
In principle, the acoustic emission (AE) represents one of NDT and structure health monitoring (SHM) methods for the detection and identification of growing material defects. Different types of signals detected by the AE method are supposed to correspond to different types of defects or operational noises. Monitoring of structures by acoustic emission 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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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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AE source location by neural networks independent on material scale changes
Chlada, Milan ; Převorovský, Zdeněk
The localization of acoustic emission (AE) sources by procedures using artificial neural networks (ANN) represents today highly effective alternative approach to classical triangulation algorithms. The main problems are in the collecting sufficiently extensive training and testing data sets together with the non portability of particular trained network to any other object. Recently, the ANN based AE source location method has been improved by using so-called signal arrival time profiles to overcome both limitations. This way of signal arrival time characterization enables ANN training on numerical models and allows the application of learned ANN on real structures of various scales and materials. In this paper, the method is upgraded and localization results are illustrated on experimental data obtained during pen-tests on a model roof I-beam and an aircraft structure part. General application possibilities of the method variations for different sensor configurations are also discussed.
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Application of Arrival Time Profiles to AE Source Location by Neural Networks
Chlada, Milan ; Blaháček, Michal ; Převorovský, Zdeněk
The localization procedures using artificial neural networks (ANN) represent today highly effective, alternative approach to classical triangulation algorithms. Nevertheless, their application possibilities are limited due to several reasons. The main problems are in the collecting of sufficiently extensive training and testing data sets together with the non-portability of particular trained network to any other object. In recent time, a new ANN-based AE source location method using so-called signal arrival time profiles was proposed to overcome both limitations. The new way of signal arrival time characterization provides the ANN training on numerical models and allows the application of learned ANN on real structures of various scales and materials. In the paper, this new method is illustrated on experimental data obtained at complex aircraft structure part testing, and its remarkable advantages concerning the considerable extension of ANN application possibilities are discussed.
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