PSI - Issue 54

ScienceDirect Structural Integrity Procedia 00 (2023) 000 – 000 Structural Integrity Procedia 00 (2023) 000 – 000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ Available online at www.sciencedirect.com ^ĐŝĞŶĐĞ ŝƌĞĐƚ

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 54 (2024) 575–584

© 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 the scientific committee of the ICSI 2023 organizers Abstract The aim of this paper is to present a baseline-free method for the identification of slot edges in a square plate. The slots, created by reducing the plate thickness, have different geometries and are placed in several locations. We make use of Savitzky-Golay smoothing and differentiation filters for the computation of modal strains. These modal strains are computed by differentiating the modal displacements (mode shapes), which are obtained by the finite element method. A discussion on the set of Savitzky Golay filter parameters to obtain the best damage identifications is presented. The influence of noise on the quality of these damage identifications is also studied. The norm of modal strains is found to be very sensitive to the stiffness decrease, allowing the identification of single damage (one slot) and multiple damage (three slots). © 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 the scientific committee of the ICSI 2023 organizers Keywords: damage identification; plate; modal strains; noise; Savitzky-Golay filters 1. Introduction Damage identification in plate structures has been a subject of study by researchers over the last years and several methods have been proposed. Most methods are vibration-based and rely on the derivatives of mode shapes, which are computed with several differentiation numerical techniques (see e.g. Zhong and Yang (2016), Moreno-García et International Conference on Structural Integrity 2023 (ICSI 2023) Savitzky-Golay Smoothing and Differentiation Filters for Damage Identification in Plates J. V. Araújo dos Santos a *, H. Lopes b a IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal b DEM-ISEP, Instituto Politécnico do Porto, Porto, Portugal Abstract The aim of this paper is to present a baseline-free method for the identification of slot edges in a square plate. The slots, created by reducing the plate thickness, have different geometries and are placed in several locations. We make use of Savitzky-Golay smoothing and differentiation filters for the computation of modal strains. These modal strains are computed by differentiating the modal displacements (mode shapes), which are obtained by the finite element method. A discussion on the set of Savitzky Golay filter parameters to obtain the best damage identifications is presented. The influence of noise on the quality of these damage identifications is also studied. The norm of modal strains is found to be very sensitive to the stiffness decrease, allowing the identification of single damage (one slot) and multiple damage (three slots). © 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 the scientific committee of the ICSI 2023 organizers Keywords: damage identification; plate; modal strains; noise; Savitzky-Golay filters 1. Introduction Damage identification in plate structures has been a subject of study by researchers over the last years and several methods have been proposed. Most methods are vibration-based and rely on the derivatives of mode shapes, which are computed with several differentiation numerical techniques (see e.g. Zhong and Yang (2016), Moreno-García et International Conference on Structural Integrity 2023 (ICSI 2023) Savitzky-Golay Smoothing and Differentiation Filters for Damage Identification in Plates J. V. Araújo dos Santos a *, H. Lopes b a IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal b DEM-ISEP, Instituto Politécnico do Porto, Porto, Portugal

* Corresponding author. Tel.:+0-351-21-841-9463; fax:.+0-351-21-841-7915 E-mail address: viriato@tecnico.ulisboa.pt * Corresponding author. Tel.:+0-351-21-841-9463; fax:.+0-351-21-841-7915 E-mail address: viriato@tecnico.ulisboa.pt

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 the scientific committee of the ICSI 2023 organizers 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 the scientific committee of the ICSI 2023 organizers

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 the scientific committee of the ICSI 2023 organizers 10.1016/j.prostr.2024.01.121