PSI - Issue 77

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ScienceDirect

Procedia Structural Integrity 77 (2026) 11–17 Structural Integrity Procedia 00 (2026) 000–000 Structural Integrity Procedia 00 (2026) 000–000

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© 2026 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 ICSI organizers Abstract Accurate assessment of fatigue strength across di ff erent lifetimes traditionally requires conventional high-cycle fatigue (HCF) testing, a reliable but time consuming method. As an alternative, thermographic techniques (TT) o ff er a rapid estimation of fatigue strength, particularly for polymer matrix composites (PMCs) in the HCF regime. This study evaluates the e ff ectiveness of two common thermographic approaches, the temperature-stress ∆ T s − σ and heat dissipation rate-stress ˙ q − σ approaches for estimating fatigue strength ( σ TT ) in neat glass fiber-reinforced polymer (GFRP), GFRP with graphene nanoparticle reinforcement (GFRP GNPs), and GFRP with hybrid nanoparticle reinforcement (GFRP-HNPs). Classical fatigue tests were conducted at 40 Hz under fully reversed loading ( R = –1) and compared against thermographic predictions across multiple estimation methods: Bilinear (BL), Angular Change (AC), Minimum Curvature Radius (MCR), and Maximum Perpendicular Distance (MPD). Thermographic estimations showed strong correlation with fatigue strength σ S − N determined using S - N curveat 10 7 cycles, with the ˙ q − σ approach yielding an average relative error of only 0 . 6%. Among estimation techniques, the MPD method demonstrated the highest accuracy, with relative errors of − 5 . 2%for © 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of ICSI organizers. Keywords: thermographic technique; fatigue strength; polymer-matrix composite; fatigue life prediction; high-cycle fatigue International Conference on Structural Integrity Evaluation of fatigue strength of polymer-matrix composites based on thermographic data analysis Tomasz Rogala a, ∗ , Andrzej Katunin a , Jafar Amraei a a Department of Fundamentals of Machinery Design, Silesian University of Technology, Konarskiego 18A, 44-100 Gliwice, Poland Abstract Accurate assessment of fatigue strength across di ff erent lifetimes traditionally requires conventional high-cycle fatigue (HCF) testing, a reliable but time consuming method. As an alternative, thermographic techniques (TT) o ff er a rapid estimation of fatigue strength, particularly for polymer matrix composites (PMCs) in the HCF regime. This study evaluates the e ff ectiveness of two common thermographic approaches, the temperature-stress ∆ T s − σ and heat dissipation rate-stress ˙ q − σ approaches for estimating fatigue strength ( σ TT ) in neat glass fiber-reinforced polymer (GFRP), GFRP with graphene nanoparticle reinforcement (GFRP GNPs), and GFRP with hybrid nanoparticle reinforcement (GFRP-HNPs). Classical fatigue tests were conducted at 40 Hz under fully reversed loading ( R = –1) and compared against thermographic predictions across multiple estimation methods: Bilinear (BL), Angular Change (AC), Minimum Curvature Radius (MCR), and Maximum Perpendicular Distance (MPD). Thermographic estimations showed strong correlation with fatigue strength σ S − N determined using S - N curveat 10 7 cycles, with the ˙ q − σ approach yielding an average relative error of only 0 . 6%. Among estimation techniques, the MPD method demonstrated the highest accuracy, with relative errors of − 5 . 2%for © 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of ICSI organizers. Keywords: thermographic technique; fatigue strength; polymer-matrix composite; fatigue life prediction; high-cycle fatigue International Conference on Structural Integrity Evaluation of fatigue strength of polymer-matrix composites based on thermographic data analysis Tomasz Rogala a, ∗ , Andrzej Katunin a , Jafar Amraei a a Department of Fundamentals of Machinery Design, Silesian University of Technology, Konarskiego 18A, 44-100 Gliwice, Poland

1. Introduction 1. Introduction

Fatigue strength characterization is essential for assessing the durability of materials under cyclic loading. Tradi tional approaches for determining fatigue strength, such as the stress-life ( S - N ) curve, require extensive testing, which make them both costly and time consuming. This is particularly important for polymer-matrix composites (PMC) due to their heterogeneous and anisotropic nature, as well as their complex and unpredictable response to fatigue loading. The wide variability in composite structural designs further complicates fatigue behaviour. As PMCs are increasingly used in fatigue loading bearing structures, such as in aerospace and automotive structures, there is a growing need for rapid, reliable techniques to evaluate their fatigue performance. To address this need, e ff orts are underway to im plement accelerated fatigue testing methods including ultrasonic fatigue testing Backe and Balle (2016), Adam and Fatigue strength characterization is essential for assessing the durability of materials under cyclic loading. Tradi tional approaches for determining fatigue strength, such as the stress-life ( S - N ) curve, require extensive testing, which make them both costly and time consuming. This is particularly important for polymer-matrix composites (PMC) due to their heterogeneous and anisotropic nature, as well as their complex and unpredictable response to fatigue loading. The wide variability in composite structural designs further complicates fatigue behaviour. As PMCs are increasingly used in fatigue loading bearing structures, such as in aerospace and automotive structures, there is a growing need for rapid, reliable techniques to evaluate their fatigue performance. To address this need, e ff orts are underway to im plement accelerated fatigue testing methods including ultrasonic fatigue testing Backe and Balle (2016), Adam and

2452-3216 © 2026 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 ICSI organizers 10.1016/j.prostr.2026.01.002 ∗ Corresponding author: Tomasz Rogala Tel.: + 48-322-371-467 ; fax: + 48-322-371-360. E-mail address: tomasz.rogala@polsl.pl 2210-7843 © 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of ICSI organizers. ∗ Corresponding author: Tomasz Rogala Tel.: + 48-322-371-467 ; fax: + 48-322-371-360. E-mail address: tomasz.rogala@polsl.pl 2210-7843 © 2026 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of ICSI organizers.