Steel and Composite Structures

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Research on stress distributions around welds of three-planar tubular Y-joints under out-of-plane bending moment

  • Shiliu Bao (College of Civil and Transportation Engineering, Hohai University) ;
  • Wenhua Wang (Faculty of Infrastructure Engineering, Dalian University of Technology) ;
  • Jikai Zhou (College of Civil and Transportation Engineering, Hohai University) ;
  • Xin Li (Faculty of Infrastructure Engineering, Dalian University of Technology)
  • Received : 2023.02.11
  • Accepted : 2023.10.12
  • Published : 2023.10.25
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Abstract

Marine structures including offshore wind turbines (OWTs) always work under cyclic loads, which arouses much attention on the fatigue design. The tripod substructure is one of the typical foundation forms for fixed OWTs. The three-planar tubular Y-joint (3Y joint) is one of the important components in fatigue design as it is most likely to have cracks. With the existence of the multiplanar interaction effect, calculating the hot spot stress (HSS) of 3Y joints is complicated. To assist with fatigue design, the distributions of stress concentration factor (SCF) and multiplanar interaction factor (MIF) along weld toe curves induced by the out-of-plane bending moment are explored in this study. An FE analysis method was first developed and verified against experimental results. This method was applied to build a numerical database including 1920 FE models covering common ranges of geometric parameters. A parametric study has been carried out to reveal the distribution patterns of SCF and MIF. After multidimensional nonlinear fittings, SCF and MIF distribution formulas have been proposed. Accuracy and reliability checking prove that the proposed formulas are suitable for calculating the HSS of 3Y joints.

Keywords

Acknowledgement

The National Natural Science Foundation of China (Grant No. 52101311), Fundamental Research Funds for Center Universities (Grant Nos. B220202008), and Jiangsu Postdoctoral Research Funding (Grant No. 2021K286B) are all acknowledged for their financial support, which is much appreciated by the authors. We take this opportunity to thank the insightful opinions given to the drafts of this paper by anonymous reviewers.

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