Fatigue Assessment of Welded Structures

Fatigue assessment of welded structures centres on the prediction and evaluation of crack initiation and propagation under cyclic loading. Welding introduces microstructural heterogeneity, residual stress fields and geometric discontinuities that concentrate stress and accelerate fatigue damage. Design codes typically employ nominal stress approaches based on S–N curves and detail classifications to estimate fatigue life, while advanced methods incorporate notch stress, strain energy density and linear elastic fracture mechanics to capture local effects. Post-weld treatments such as mechanical grinding and high-frequency mechanical impact can improve fatigue performance by smoothing geometries and inducing compressive residual stresses. Corrosive environments introduce additional complexity through pitting and general metal loss, which further reduce fatigue life. Recent advances aim to integrate numerical simulation, high-resolution surface scanning and digital image correlation to link weld geometry and residual stress states with fatigue endurance, thereby enhancing the reliability and service life of welded components in infrastructure, offshore platforms and transportation applications.

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Fatigue Assessment of Welded Structures publication trend

The graph below shows the total number of articles in fatigue assessment of welded structures across all publications each year (not limited to Nature Index journals).

Technical terms

Fatigue life: Number of stress cycles a welded structure endures before crack initiation or failure.

S–N curve: Graphical relationship between applied stress range (S) and number of cycles to failure (N).

Weld toe: Edge region where weld face meets base material, prone to stress concentration and crack initiation.

Residual stress: Locked-in stresses in a welded joint resulting from thermal contraction and mechanical constraints.

Pitting corrosion: Localised metal loss creating pits that act as stress risers reducing fatigue performance.

FAT-class: Design classification denoting fatigue strength category of welded details under the nominal stress approach.

References

1. Effect of grinding on the fatigue strength of mild and high strength steel fillet weld joints. Results in Engineering (2024).
2. Impact of accelerated corrosion on weld geometry, hardness and residual stresses of offshore steel joints over time. Materials & Design (2025).
3. Analysis of fatigue test data to reassess EN 1993‐1‐9 detail categories. Steel Construction (2020).
4. Fatigue life extension of existing welded structures via high frequency mechanical impact (HFMI) treatment. Engineering Structures (2021).
5. Requirements for stress gradient‐based fatigue assessment of notched structures according to theory of critical distance. Fatigue & Fracture of Engineering Materials & Structures (2020).
6. Fatigue assessment of high strength welded joints through the strain energy density method. Fatigue & Fracture of Engineering Materials & Structures (2020).
7. Influence of pitting corrosion on the fatigue strength of offshore steel structures based on 3D surface scans. International Journal of Fatigue (2022).
8. Review of Fatigue Assessment Methods for Welded Steel Structures. Advances in Civil Engineering (2018).