PSI - Issue 75

ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2025) 000 – 000 Available online at www.sciencedirect.com

www.elsevier.com/locate/procedia

Procedia Structural Integrity 75 (2025) 467–473

© 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 © 2025 The Authors. Published by ELSEVIER B.V. 20 This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) 21 Peer-review under responsibility of the scientific committee of the Fatigue Design 2025 organisers 22 Keywords: Probabilistic fatigue modelling, Welded joints, Weld quality 23 24 Non-load-carrying welded details are often fatigue critical due to their geometric stress concentrations and 25 susceptibility to welding-induced residual stresses. High-strength steels such as S960 offer advantages in terms of 26 structural efficiency and weight reduction, yet the fatigue behavior of such materials under various loading histories, 27 including overload or preloading conditions, requires more characterisation. Preloading, or intentional early 28 overloading, can beneficially affect fatigue life by redistributing residual stresses and modifying local plasticity in the 29 Fatigue Design 2025 (FatDes 2025) 1 Experimental investigation of the preloading effect on S960 non- 2 load carrying circular flat studs 3 Mattias Clarin a , Gustav Hultgren b *, Rami Mansour b,c , 4 Torbjörn Narström b,d , Zuheir Barsoum b 5 a SSAB Special Steels AB, 781 84 Borlänge, Sweden 6 b KTH Royal Institute of Technology, Department of Engineering Mechanics, Material and Structural Mechanics, SE-100 44 Stockholm, Sweden 7 c Department of Mechanical and Production Engineering, Aarhus University, 8200 Aarhus N, Denmark. 8 d SSAB Special Steels AB, 613 31 Oxelösund, Sweden 9 10 Preloading, or potential overloading early in the fatigue spectrum, may redistribute the local residual stress at the weld 11 due to the stress concentration caused by weld geometry, thereby altering the joint's fatigue strength. This study 12 investigates the effect of preloading on the fatigue life of non-load-carrying circular flat studs made from S960 steel. 13 Nominal preloading up to the material's yield strength was applied to induce plastic deformation in the weld transition 14 area. The preloaded specimens were then subjected to constant amplitude fatigue testing, and the results were 15 compared with the fatigue life of specimens without preloading. The results indicate that preloading improves fatigue 16 life, demonstrating a clear relationship between preloading and fatigue strength, which also highlights the benefits of 17 high-strength steel in welded structures subjected to fatigue. a b c d Abstract 18 19 1. Introduction

* Corresponding author. E-mail address: gustavhu@kth.se

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.2025.11.047