PSI - Issue 79

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 79 (2026) 421–432

28th International Conference on Fracture and Structural Integrity - 3rd Mediterranean Conference on Fracture and Structural Integrity Fatigue Life Estimation of Thin-Walled Fillet-Welded Joints Under Constant Amplitude Loading

Martin Sladky´ a , Jan Papuga b , Martin Machacˇ b , Ivo Jeba´cˇek a a Faculty of Mechanical Engineering, Brno University of Technology, Technicka´ 2896, Brno 616 69, Czechia b Faculty of Mechanical Engineering, Czech Technical University in Prague, Technicka´ 4, Prague 160 00, Czechia

© 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 IGF28 - MedFract3 organizers Keywords: high cycle fatigue life prediction; thin-walled welded joints; nominal stress; hot-spot stress; notch stress Abstract This study evaluates the fatigue life estimation performance of nominal, hot-spot, and notch stress-based approaches for thin-walled fillet-welded joints made of steel subjected to constant-amplitude loading. The employed dataset comprised ten configurations with nearly identical wall thicknesses and load asymmetry ratios, which di ff ered mainly in their geometry and loading conditions. Assessing this dataset as a whole revealed that all three approaches exhibited a comparable average level of conservatism. However, the nominal and notch stress-based approaches exhibited pronounced scatter, leading to substantial configuration-to-configuration variations in the level of conservatism. The most consistent predictions, reflected by the lowest scatter, were observed for the hot-spot stress-based approach. Its performance could be further enhanced by extending the wall-thickness ranges over which the thickness corrections are derived from the actual wall thickness. The notch stress-based S–N data exhibited a clear tendency to separate into two approximately parallel curves corresponding to hollow section-based and plate-based configurations.

1. Introduction

The drive toward higher e ffi ciency in modern engineering has led to the advancement of thin-walled structures with complex geometries, where welding is widely employed as a joining method. These structures are often subjected to variable amplitude loading conditions, and welded joints, being inherently more susceptible to fatigue damage than the base material, frequently serve as the primary sites of fatigue crack initiation. Therefore, an accurate fatigue

∗ Corresponding author. Tel.: + 420 733 278 842. E-mail address: Martin.Sladky@vutbr.cz or sladkymartin97@gmail.com

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 IGF28 - MedFract3 organizers 10.1016/j.prostr.2025.12.353