Welding in the World

, Volume 59, Issue 5, pp 731–742 | Cite as

Fatigue assessment of welded joints using stress averaging and critical distance approaches

  • J. BaumgartnerEmail author
  • H. Schmidt
  • E. Ince
  • T. Melz
  • K. Dilger
Research Paper


This paper comprises a brief methodical analysis and practical application of both the stress averaging approach according to Neuber and the critical distance approach according to Taylor for a fatigue assessment on welded steel structures under axial loading. The stress averaging approach, as established theoretically by Neuber, is discussed and compared to the effective notch stress approach with a reference radius r ref = 1 mm and also to the r ref = 0.05 mm concept which is usually applied for thin-walled structures. Furthermore, both approaches are applied for an assessment of 38 individual test series. As a result of the evaluations, a microstructural length ρ* = 0.40 mm is recommended. For the critical distance approach, a distance a = 0.10 mm was derived. Fatigue design (FAT) values are recommended for the practical application. Compared to the notch stress approach with a radius r ref = 0.05 mm, it was possible to improve the assessment quality significantly. The non-local approaches should be preferred to the r ref = 0.05 mm concept, especially for welded components using thin sheets for which the radius of 1 mm cannot be applied.

Keywords (IIW Thesaurus)

Notch effect Fatigue strength Finite element analysis Elastic analysis 



The investigations presented here were supported by financial funding from the Federal Ministry of Economics and Technology (BMWi) via the Federation of Industrial Research Associations (Arbeitsgemeinschaft industrieller Forschungsvereinigungen “Otto von Guericke” e.V. = AiF e.V.) under grant 16.431. Technical and scientific support during the project was provided by the German Association for Research on Automotive Technology (FAT) and also by the German Welding Society DVS (Forschungsvereinigung Schweißen und verwandte Verfahren e. V.) in the working group FA9. The authors would like to thank the AiF, the FAT, the DVS, and the members of the AK25 and FA9 for their support. The authors are particularly grateful to Dr. Genbao Zhang for the valuable discussions.


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Copyright information

© International Institute of Welding 2015

Authors and Affiliations

  • J. Baumgartner
    • 1
    Email author
  • H. Schmidt
    • 1
  • E. Ince
    • 2
  • T. Melz
    • 1
  • K. Dilger
    • 2
  1. 1.Fraunhofer Institute for Structural Durability and System Reliability LBFDarmstadtGermany
  2. 2.Institute of Joining and WeldingTU BraunschweigBrunswickGermany

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