Development and validation of a local fatigue design concept for welded joints in offshore structures subjected to multi-axial and variable loading

Fatigue assessment of welded maritime structures is vital for safe, cost-effective offshore design. Conventional methods struggle with complex loading, variable amplitudes, and thick sections, often leading to overly conservative designs. In the joint industry research project SMATRA, a novel local approach combining notch stress analysis and fracture mechanics was developed, accounting for weld geometry, post-weld treatments, and multi-axial loading. By integrating 3D surface scans, automated FEM modeling, and a two-phase life prediction model (initiation and growth), prediction accuracy improved by 24–77% over IIW, Eurocode 3, and FKM standards. Validation on small-scale specimens and a full-scale double-Y-joint confirmed accurate crack initiation prediction. A practical design tool reduced assessment time by 80% and enabled seamless workflow integration. Material savings exceeded 25% in weld volume and plate thickness while maintaining safety. The project outcomes enable more efficient, safe, and sustainable offshore structures and establishes a foundation for industrial standardization of local fatigue assessment methods in the offshore industry.

Content

Subjects

Fatigue of welded maritime structures

notch stress concept

multi-axial loading

crack initiation

crack growth

3D scanning

finite element modeling

offshore wind energy plants

DDC Class

623: Military Engineering and Marine Engineering

Funding References

Funding(s)

Verbesserte Bewertung der Schwingfestigkeit geschweißter maritimer Tragstrukturen mittels skalierbarer Schwingfestigkeitsuntersuchungen

Files

Lizenz

https://creativecommons.org/licenses/by/4.0/

Publication version

publishedVersion

Download

Name

v003t03a004-omae2026-180656.pdf

Type

Main Article

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2.03 MB

Format

Adobe PDF