PSI - Issue 52

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 52 (2024) 679–689

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2452-3216 © 2023 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 Professor Ferri Aliabadi 10.1016/j.prostr.2023.12.068 2452-3216 © 2023 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 Professor Ferri Aliabadi 2452-3216 © 2023 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 Professor Ferri Aliabadi © 2023 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 Professor Ferri Aliabadi Abstract In this paper, several baseline-free methods in realm of guided wave structural health monitoring (GWSHM), namely the virtual time reversal (VTR), the reciprocity-based and the instantaneous baseline (IB) techniques, are investigated and compared regarding the performance on damage localisation under varying temperatures and dual damage scenarios. Further experiments are carried out on an anisotropic composite plate with simulated damages. It is shown that the investigated baseline-free techniques are competent to localise single damages under 20℃ variations, while being able to localise dual damages despite overlapping pixels between the damages. Keywords: Baseline-free technique; Damage localisation; Composite structure; Guided wave 1. Introduction The structural health monitoring (SHM) aims to interrogate the health status of engineering structures with particular emphasis on the detection, localisation and characterisation of potential damages (Giurgiutiu, 2008) through continuous monitoring of structural responses in service. During the past decade the ultrasonic guided wave (UGW), as a non-destructive testing (NDT) technique, has been extensively utilised for the SHM on thin-walled structures considering its superiority in the long-range propagation with minimum energy losses (Cawley, 2018; Victor Giurgiutiu, 2002). In practice, the collection of guided wave signals is usually implemented by the piezoelectric (PZT) transducer arrays, either in a phased or sparse configuration (Giurgiutiu, 2014). The transducers transmit and sense guided waves in an active sensing manner, while operating as only a receiver in a passive setting where an external source is introduced (Aliabadi & Khodaei, 2017). Fracture, Damage and Structural Health Monitoring Investigation of Baseline-free Techniques for Damage Localisation on Anisotropic Composite Structures Hongmin Zhu a *, Zahra Sharif Khodaei a , M. H. Aliabadi a a Department of Aeronautics, Imperial College London, South Kensington Campus, London, UK, SW7 2AZ Abstract In this paper, several baseline-free methods in realm of guided wave structural health monitoring (GWSHM), namely the virtual time reversal (VTR), the reciprocity-based and the instantaneous baseline (IB) techniques, are investigated and compared regarding the performance on damage localisation under varying temperatures and dual damage scenarios. Further experiments are carried out on an anisotropic composite plate with simulated damages. It is shown that the investigated baseline-free techniques are competent to localise single damages under 20℃ variations, while being able to localise dual damages despite overlapping pixels between the damages. Keywords: Baseline-free technique; Damage localisation; Composite structure; Guided wave 1. Introduction The structural health monitoring (SHM) aims to interrogate the health status of engineering structures with particular emphasis on the detection, localisation and characterisation of potential damages (Giurgiutiu, 2008) through continuous monitoring of structural responses in service. During the past decade the ultrasonic guided wave (UGW), as a non-destructive testing (NDT) technique, has been extensively utilised for the SHM on thin-walled structures considering its superiority in the long-range propagation with minimum energy losses (Cawley, 2018; Victor Giurgiutiu, 2002). In practice, the collection of guided wave signals is usually implemented by the piezoelectric (PZT) transducer arrays, either in a phased or sparse configuration (Giurgiutiu, 2014). The transducers transmit and sense guided waves in an active sensing manner, while operating as only a receiver in a passive setting where an external source is introduced (Aliabadi & Khodaei, 2017). Fracture, Damage and Structural Health Monitoring Investigation of Baseline-free Techniques for Damage Localisation on Anisotropic Composite Structures Hongmin Zhu a *, Zahra Sharif Khodaei a , M. H. Aliabadi a a Department of Aeronautics, Imperial College London, South Kensington Campus, London, UK, SW7 2AZ * Corresponding author. E-mail address: h.zhu19@imperial.ac.uk. * Corresponding author. E-mail address: h.zhu19@imperial.ac.uk.