PSI - Issue 18

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Procedia Structural Integrity 18 (2019) 570–576

25th International Conference on Fracture and Structural Integrity Acoustic Emission Entropy as a fracture-sensitive feature for real time assessment of metal plates under fatigue loading Danilo D’Angela * and Marianna Ercolino University of Greenwich, School of Engineering, Central Avenue, Chatham ME4 4TB, United Kingdom Abstract The paper presents the results of Acoustic Emission (AE) testing of fatigue fracture initiation and propagation in metal plates. The information Entropy of the AE data (i.e., AE Entropy ) is assessed as a fracture-sensitive feature for real-time assessment of metal plates under fatigue loading. Both Shannon and Kullback-Leibler formulations are found to be reliable for (a) detection of crack initiation/propagation, and (b) prediction of fracture failure. The reliability of the AE Entropy is also confirmed considering periodic monitoring (i.e., time-discontinuous detection/analysis of AE data), which is representative of structural health monitoring processes. The presented approach is promising for the application to real-time monitoring of metal structures undergoing fatigue loading such as bridges. 25th International Conference on Fracture and Structural Integrity Acoustic Emission Entropy as a fracture-sensitive feature for real time assessment of metal plates under fatigue loading Danilo D’Angela * and Marianna Ercolino University of Greenwich, School of Engineering, Central Avenue, Chatham ME4 4TB, United Kingdom Abstract The paper presents the results of Acoustic Emission (AE) testing of fatigue fracture initiation and propagation in metal plates. The information Entropy of the AE data (i.e., AE Entropy ) is assessed as a fracture-sensitive feature for real-time assessment of metal plates under fatigue loading. Both Shannon and Kullback-Leibler formulations are found to be reliable for (a) detection of crack initiation/propagation, and (b) prediction of fracture failure. The reliability of the AE Entropy is also confirmed considering periodic monitoring (i.e., time-discontinuous detection/analysis of AE data), which is representative of structural health monitoring processes. The presented approach is promising for the application to real-time monitoring of metal structures undergoing fatigue loading such as bridges.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. Keywords: Acoustic Emission testing; Fatigue fracture; Information Entropy; metal plates; Keywords: Acoustic Emission testing; Fatigue fracture; Information Entropy; metal plates;

1. Introduction Acoustic Emission (AE) testing (Grosse and Ohtsu, 2008) is among the most innovative techniques for structural health monitoring by means of non-destructive evaluation and passive testing. AEs are elastic waves spontaneously generated by localised structural damage within solids. The acoustic waves propagate within the bodies interacting with the structural discontinuities. AEs are detected by sensors coupled to the boundaries of the monitored components (Fig. 1.a). According to the most common approach, i.e., parameter-based approach, the direct/indirect analysis of the features of the AE waveform (i.e., AE features, Fig. 1.b) allows identifying the damage evolution. 1. Introduction Acoustic Emission (AE) testing (Grosse and Ohtsu, 2008) is among the most innovative techniques for structural health monitoring by means of non-destructive evaluation and passive testing. AEs are elastic waves spontaneously generated by localised structural damage within solids. The acoustic waves propagate within the bodies interacting with the structural discontinuities. AEs are detected by sensors coupled to the boundaries of the monitored components (Fig. 1.a). According to the most common approach, i.e., parameter-based approach, the direct/indirect analysis of the features of the AE waveform (i.e., AE features, Fig. 1.b) allows identifying the damage evolution.

* Corresponding author. Tel.: +44 (0) 7447156365 ; E-mail address: d.dangela@greenwich.ac.uk * Correspon ing author. Tel.: +44 (0) 7447156365 ; E-mail address: d.dangela@greenwich.ac.uk

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

2452-3216  2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo. 10.1016/j.prostr.2019.08.201