PSI - Issue 75

Per-Olof Danielsson et al. / Procedia Structural Integrity 75 (2025) 572–580 Per-Olof Danielsson et al. / Structural Integrity Procedia (2025)

580

9

The difference between the four positions (ID 1 – 4) becomes clear when comparing the amplitude and progression of the stress intensity factor. Positions 1 and 2 show higher levels of non-damaging stress contributions under ENS, leading to conservative life predictions. In contrast, SFM filters these out, capturing only the relevant crack-driving stresses. The time-resolved and equivalent stress intensity factors shown in Fig. 8a – d provide insight into the fatigue driving mechanisms at each location and explain the large improvement in fatigue life prediction accuracy. 6. Conclusions The Welded Structures 4 Tomorrow initiative has significantly advanced Volvo CE's ability to design and produce fatigue-resistant welded structures. By introducing the SFM approach, the company has moved beyond the limitations of traditional nominal and effective notch stress methods. The SFM approach enables more physics-based assessments that account for local crack-driving stresses and residual stress effects, while also simplifying the CAD and FE modelling processes. When combined with modern manufacturing techniques and digitized load simulations, the SFM approach supports faster, more informed design decisions and more efficient structural optimization. The integration of analysis, design, and production has proven effective in delivering lighter, more durable structures while reducing reliance on costly physical testing. Further development of the SFM approach will include expanded support for additional weld types. Ongoing work focuses on incorporating crack initiation modelling and fully verified stress relaxation models into fatigue life predictions. Integration of the SFM approach into the product digital twin is also under development, enabling even more accurate and predictive fatigue evaluations. Plans include scaling the model-based weld management system across product lines and increasing the use of automated TIG dressing and flexible 3D laser cutting to realize design intent geometries in production environments. 7. References [1] M. Andersson, P-O. Danielsson, A simplified fracture mechanics method for fatigue life analysis of weld roots, Elsevier B.V., 2023 [2] WEM Weld Evaluation Method for fillet weld roots M. Andersson, Volvo CE, 2023-12-31 [3] WEM Weld Evaluation Method for fillet weld toes M. Andersson, Volvo CE, 2023-12-31 [4] Boverkets handbok om stålkonstruktioner, BSK 07, Upplaga 4, 2007, https://www.boverket.se/globalassets/publikationer/dokument/2007/bsk_07.pdf [5] Recommendations for fatigue design of welded joints and components XIII-1823-07 IIW, A. Hobbacher (2008) [6] ANSA pre-processor - https://www.beta-cae.com/ansa.htm [7] BETA CAE Systems - https://www.beta-cae.com/meta.htm [8] Fatigue and Fracture of Weldments U. Zerbst, et al, Springer (2019), ISBN 978-3-030-04072-7. [9] On Digital Twins for the Construction Machine Industry , P-O. Danielsson, M. Andersson, J. Cramsky, M. Kumar, W. Löwe, L. Håkansson, 2024 [10] A simplified fatigue assessment method for high quality welded cruciform joints T. Nykänen, G. Marquis, T. Björk, Int. Journal of Fatigue (January 2009)

[11]

ASTM E 1049-85 Standard practices for cycle counting in fatigue analysis ASTM International (2005). Fracture Mechanics - Fundamentals and Applications T. L. Anderson, p 517, 2nd edition (1995). ABAQUS theory guide, version 6.13, Section 2.16.4 Prediction of the direction of crack propagation Dassault systems (2013).

[12]

[13]