TY - JOUR

T1 - Enhanced local fatigue approach for welded tubular joints using 3D digital scans and implicit gradient model

AU - Brömer, Tim

AU - Widerspan, Viktor

AU - Shojai, Sulaiman

AU - Ghafoori, Elyas

N1 - Publisher Copyright: © 2025 The Authors

PY - 2025/5/12

Y1 - 2025/5/12

N2 - The design of jacket structures in offshore wind turbines (OWTs) is driven by fatigue, crucial due to dynamic loads from operational movements, waves, and wind. This study aims to develop a digital framework for fatigue analysis of tubular welded joints in jacket OWT, incorporating real 3D scanned geometries and imperfections through their digital images. Numerical analysis has been conducted using finite element method to predict the experimental results, in which the effect of micro-support has been taken into account using an implicit gradient model (IGM). Furthermore, 4R method has been used to account for mean stress corrections due to residual stresses and imperfections. Digital Image Correlation (DIC) was employed during the high-cycle fatigue experiments to detect the initiation and progression of a technical crack, providing precise measurements of strain distribution and crack size development. The results have shown that the proposed numerical framework based on the IGM can successfully determine the lifetime and location of crack initiation in the 3D scanned welded details. The proposed framework significantly improves the accuracy of high-cycle fatigue life predictions and offers a scalable solution for structural health monitoring, facilitating lifetime extension across a wide range of industries, including construction, automotive, aerospace, and renewable energy.

AB - The design of jacket structures in offshore wind turbines (OWTs) is driven by fatigue, crucial due to dynamic loads from operational movements, waves, and wind. This study aims to develop a digital framework for fatigue analysis of tubular welded joints in jacket OWT, incorporating real 3D scanned geometries and imperfections through their digital images. Numerical analysis has been conducted using finite element method to predict the experimental results, in which the effect of micro-support has been taken into account using an implicit gradient model (IGM). Furthermore, 4R method has been used to account for mean stress corrections due to residual stresses and imperfections. Digital Image Correlation (DIC) was employed during the high-cycle fatigue experiments to detect the initiation and progression of a technical crack, providing precise measurements of strain distribution and crack size development. The results have shown that the proposed numerical framework based on the IGM can successfully determine the lifetime and location of crack initiation in the 3D scanned welded details. The proposed framework significantly improves the accuracy of high-cycle fatigue life predictions and offers a scalable solution for structural health monitoring, facilitating lifetime extension across a wide range of industries, including construction, automotive, aerospace, and renewable energy.

KW - 3D digital images

KW - Digitalization

KW - High-cycle fatigue assessment

KW - Lifetime extension

KW - Notch stress approach

KW - Offshore wind turbines

KW - Residual stresses

KW - Sustainability

KW - Welded tubular joint

UR - http://www.scopus.com/inward/record.url?scp=105005745548&partnerID=8YFLogxK

U2 - 10.1016/j.ijfatigue.2025.109060

DO - 10.1016/j.ijfatigue.2025.109060

M3 - Article

VL - 199

JO - International journal of fatigue

JF - International journal of fatigue

SN - 0142-1123

M1 - 109060

ER -