Fatigue strength assessment of TIG-dressed high-strength steel cruciform joints by nominal and local approaches

Peter Brunnhofer*, Christian Buzzi, Tobias Pertoll, Martin Leitner, Werner Mössler

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

According to the IIW recommendation, the fatigue strength of welded steel joints is defined as independent of the base material in case of the as-welded condition. However, post-treatment techniques can improve the fatigue performance of welded structures, especially for increased base material strengths. Therefore, this paper investigates the effect of TIG dressing, as common post-weld treatment method, on the fatigue strength of high-strength steel S700 cruciform joints. The statistically evaluated fatigue test results reveal a significant increase of the nominal fatigue strength from FAT 90 for the as-welded up to 182 MPa for the TIG-dressed state. The experiments are further compared to recommended and suggested design curves applying both nominal as well as local stress approaches. Focusing on the TIG-dressed state, the suggested increase in nominal stresses is well validated leading to a conservative assessment. In addition, the proposed slope in the finite life region with a value of m1 = 4 shows a sound fit to the statistically evaluated value of m1 = 4.7 for the test results. The local fatigue strength estimation is performed based on a recent proposal using the theory of critical distances. Therefore, linear elastic numerical analysis of the investigated specimens is performed. Again, the resulting S-N curves agree well to the experiments validating the proposed local design approach
Original languageEnglish
Pages (from-to)2585-2594
Number of pages10
JournalWelding in the World
Volume66
Issue number12
Early online date2022
DOIs
Publication statusPublished - Dec 2022

Keywords

  • Fatigue strength assessment
  • High-strength steel
  • Local approach
  • TIG dressing

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

Fields of Expertise

  • Mobility & Production

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