PSI - Issue 37

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 37 (2022) 307–313

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Pedro Miguel Guimaraes Pires Moreira Abstract The integrity of the CORTEN steel exposed to corrosion agents is studied using Acousto-Ultrasonic approach. The Acousto Ultrasonic approach was tested before and after exposing the CORTEN steel to the corrosion agent. The waveforms recorded from the Acousto-Ultrasonic tests are analysed using Mel Spectrogram. The attenuation in the wave propagation due to the extent of corrosion and due to the geometrical configuration of the CORTEN steel test specimens is studied in time-frequency domain. The Mel scale is used for analysing the time-frequency characteristics of the recorded waveforms. A Deep Learning Neural Network is constructed for analysing the waveforms recorded from the Acousto-Ultrasonic test. Deep learning is used to classify the characteristic acoustic emission waveforms propagated through the CORTEN steel and attenuated due to the geometrical configuration and corrosion formation. The Convolutional Neural Network (CNN) is built in MATLAB® and is trained to classify the acoustic emission waveforms recorded from the Acousto-Ultrasonic test. © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Pedro Miguel Guimaraes Pires Moreira Keywords: acouso-ultrasonics; acoustic emission; deep learning; convolutional neural network (CNN); CORTEN steel; Mel scale 1. Introduction When stress waves/elastic waves generated in a material, they propagate through the material at an ultrasonic velocity. This phenomenon is commonly known as acoustic emission. The stress waves (or commonly referred to as acoustic waves) attenuate in their time and frequency domain during propagation. Several factors influence the attenuation of the acoustic wave propagation. Some of them are the geometrical boundaries, surface roughness, mechanical properties such as Young’s modulus, shear modulus and so on. Acousto-Ultrasonics is a technique in ICSI 2021 The 4th International Conference on Structural Integrity Designing a Deep Neural Network for an Acousto-Ultrasonic Investigation on the Corrosion behaviour of CORTEN Steel Claudia Barile a , Caterina Casavola a , Giovanni Pappalettera a , Vimalathithan Paramsamy Kannan a, * a Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Via Orabona, 70125 – Bari Italy

2452-3216 © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Pedro Miguel Guimaraes Pires Moreira

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Pedro Miguel Guimaraes Pires Moreira 10.1016/j.prostr.2022.01.089