PSI - Issue 75

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 75 (2025) 184–192

Fatigue Design 2025 (FatDes 2025) Improving fatigue life assessment of scanned nuclear grade weld topologies using elastic-plastic FEA and advanced gradient based fatigue damage parameters Georg Veile * a , Daniel Klöss a , Julius Lotz b , Stefan Weihe a,b , Jürgen Rudolph c

a MPA – University of Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart, Germany b IMWF – University of Stuttgart, Pfaffenwaldring 32, 70569 Stuttgart, Germany c Framatome SA, Paul-Gossen-Straße 100, 91052 Erlangen, Germany

© 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 Fatigue life prediction of scanned weld geometries can be less accurate than prediction using an idealized weld radius. One possible solution is the use of elastic plastic material models. Furthermore, the accuracy can be improved by adjusting the material model retrospectively. However, this cannot be applied to fatigue life prediction in industry. An alternative solution is to introduce additional factors that consider stress, strain or shear gradients and geometric factors. Scanned weld topologies show radii down to 0.1 mm in the critical notches. These radii can be smaller than the grain size of the base metal. To investigate the difference in accuracy between scanned and idealized weld geometries, the effect of smoothing the scanned surfaces was examined. The accuracy of advanced gradient based FDP, such as FDP FGF or FDP FFS , was not affected. In contrast, common FDP, such as FDP FS or FDP SWT , showed more precise results with increase in smoothening local radii from up to 0.2 mm to up to 0.55 mm. In this work, gradients were also determined with different distances from the notch root. Thereby, the cause of the non-conservative fatigue life prediction in the FDP RM and FDP FFS was found. The subsequent effect on FDP FGF was also investigated. © 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 responsibility of the scientific committee of the Fatigue Design 2025 organizers Keywords: Fatigue; FEA; local concepts; weld topology; fatigue damage parameters

* Corresponding author. E-mail address: georg.veile@mpa.uni-stuttgart.de

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 responsibility of the scientific committee of the Fatigue Design 2025 organizers

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.2025.11.020