Fatigue strength assessment of laser stake-welded T-joints subjected to reversed bending

D. Frank*, P. Dissel, H. Remes, J. Romanoff, O. Klostermann

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

The paper investigates the fatigue strength of laser stake-welded T-joints subjected to reversed bending. The fatigue tests are carried out with the load ratio, R≈-0.8. The experimental data is firstly analysed using the nominal stress approach and then by the J-integral as the local fatigue strength parameter in the finite element (FE) assessment. The nominal stress approach demonstrated that the fatigue strength of the investigated T-joints is lower than encountered for any other steel joint under reversed tensile loading. The results also showed that the fatigue strength of this joint under the load ratio R≈-0.8 increases with respect to R=0 bending by 22.6% in the case of the nominal stress approach and 13% in the case of the J-integral approach. However, the slopes of the fatigue resistance curves for different load ratios appear very similar, suggesting that the load ratio has an insignificant influence to the slope. In contrast to the similar slopes, the scatter indexes were different. The nominal stress approach shows that the scatter index is 3.4 times larger for R≈-0.8 than R=0 bending. The J-integral approach showed that the scatter index for R≈-0.8 is only 67% larger than in the R=0 case because the weld geometry is modelled in the FE analysis.

Original languageEnglish
Pages (from-to)1272–1280
JournalFatigue and Fracture of Engineering Materials and Structures
Volume39
Issue number10
Early online date2016
DOIs
Publication statusPublished - 2016
MoE publication typeA1 Journal article-refereed

Keywords

  • Fatigue assessment
  • J-integral
  • Laser-welded joint
  • Load ratio
  • Local approach
  • Nominal stress

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