PSI - Issue 75

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia (2025) 000 – 000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia (2025) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 75 (2025) 85–93

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© 2025 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 the responsibility of Dr Fabien Lefebvre with at least 2 reviewers per paper Abstract Start-stop positions (intermittent welds) are known to cause significant variations in geometry, which can result in high stresses and, consequently, a reduced fatigue life. Based on 3D-Scans intermittent fillet welds specimen were related to different quality levels according to ISO 5817 (B, C and < D). Experimental fatigue test results showed that no significant differences in fatigue life were determined between specimen with start-stop positions that refer to different quality levels. A reverse engineering approach was used based on the translation of 3D-surface scans (point clouds) into 2D- and 3D-Finite Element Analysis (FEA) for the determination of local stresses. A combination of critical distance and linear elastic fracture mechanic approach was used to cover the effect of surface near variation of weld quality and stress concentrations. In addition, an assessment based on 2D-models and 3D-models was conducted. A local and a global 3D-effect are observed that lead to differences between 2D- and 3D-FEA. The results of 3D-FEA showed that this can be explained by different / -ratio during crack propagation and statistical size effects. Keywords: welded joints, weld quality, fatigue, reverse engineering, critical distance, linear-elastic fracture mechanics Nomenclature Weld toe radius in mm f Failure probability Weld toe angle in ° Tensile strength of the material in MPa Critical distance in mm FAT Fatigue class, stress range at =2×10 6 and = 2.3% ∆ th Threshold of cyclic SiF in MPa (m) -1/2 Stress ratio ∆ Stress range of the endurance limit in MPa T Plate thickness in mm 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 Fatigue Design 2023 organizers Fatigue Design 2025 (FatDes 2025) Assessment of stress concentration factors of welded joints based on 2D- and 3D-reverse engineering Xiru Wang a *, Jan Schubnell a , Jörg Baumgartner b a Fraunhofer Institut for Mechanics of Materials, Woehlerstr. 11, 79198 Freiburg, Germany b Fraunhofer LBF, Institut for Structural Durability and System Reliability, Bartningstr. 47, 64289 Darmstadt, Germany Abstract Start-stop positions (intermittent welds) are known to cause significant variations in geometry, which can result in high stresses and, consequently, a reduced fatigue life. Based on 3D-Scans intermittent fillet welds specimen were related to different quality levels according to ISO 5817 (B, C and < D). Experimental fatigue test results showed that no significant differences in fatigue life were determined between specimen with start-stop positions that refer to different quality levels. A reverse engineering approach was used based on the translation of 3D-surface scans (point clouds) into 2D- and 3D-Finite Element Analysis (FEA) for the determination of local stresses. A combination of critical distance and linear elastic fracture mechanic approach was used to cover the effect of surface near variation of weld quality and stress concentrations. In addition, an assessment based on 2D-models and 3D-models was conducted. A local and a global 3D-effect are observed that lead to differences between 2D- and 3D-FEA. The results of 3D-FEA showed that this can be explained by different / -ratio during crack propagation and statistical size effects. Keywords: welded joints, weld quality, fatigue, reverse engineering, critical distance, linear-elastic fracture mechanics Nomenclature Weld toe radius in mm f Failure probability Weld toe angle in ° Tensile strength of the material in MPa Critical distance in mm FAT Fatigue class, stress range at =2×10 6 and = 2.3% ∆ th Threshold of cyclic SiF in MPa (m) -1/2 Stress ratio ∆ Stress range of the endurance limit in MPa T Plate thickness in mm 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 Fatigue Design 2023 organizers Fatigue Design 2025 (FatDes 2025) Assessment of stress concentration factors of welded joints based on 2D- and 3D-reverse engineering Xiru Wang a *, Jan Schubnell a , Jörg Baumgartner b a Fraunhofer Institut for Mechanics of Materials, Woehlerstr. 11, 79198 Freiburg, Germany b Fraunhofer LBF, Institut for Structural Durability and System Reliability, Bartningstr. 47, 64289 Darmstadt, Germany

2452-3216 © 2025 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 the responsibility of Dr Fabien Lefebvre with at least 2 reviewers per paper 10.1016/j.prostr.2025.11.010