Numerical analysis and discussion on the hot-spot stress concept applied to welded tubular KT joints

Ávila, Bianca; Correia, José A.F.O.; Carvalho, Hermes; Fantuzzi, Nicholas; Jesus, Abílio M.P. De; Berto, Filippo

doi:10.1016/j.engfailanal.2022.106092

Cited by 13 publications

(2 citation statements)

References 38 publications

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“…But the hot-spot stress approach cannot assess failures at the weld root. However, within the effective notch stress method, we can employ specific arc radii to represent notches at the weld toe and root of the weld seam (Wang et al, 2011;Sonsino et al, 2012;Pei et al, 2022;Avila et al, 2022). The effective notch stress method, as a localized analysis approach for evaluating welded structures, takes into account both the notch effect and the singularity of the weld seam, directly targeting the vulnerable notch regions of the weld (Zhu et al, 2020;Liao et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Research on fatigue curve fitting methods based on the notch stress approach

Xue,

He,

Chen

et al. 2024

IJSI

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PurposeThis study investigates the fitting techniques for notch fatigue curves, seeking a more reliable method to predict the lifespan of welded structures.Design/methodology/approachBuilding on the fatigue test results of butt and cruciform joints, this research delves into the selection of fitting methods for the notch fatigue curve of welded joints. Both empirical formula and finite element methods (FEMs) were employed to assess the notch stress concentration factor at the toe and root of the two types of welded joints. Considering the mean stress correction and weld misalignment coefficients, the notch fatigue life curves were established using both direct and indirect methods.FindingsAn engineering example was employed to discern the differences between the direct and indirect approaches. The findings highlight the enhanced reliability of the indirect method for fitting the fatigue life curve.Originality/valueWhile the notch stress approach is extensively adopted due to its accurate prediction of component fatigue life, most scholars have overlooked the importance of its curve fitting methods. Existing literature scantily addresses the establishment of these curves. This paper offers a focused examination of fatigue curve fitting techniques, delivering valuable perspectives on method selection.

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Section: Introductionmentioning

confidence: 99%

Research on fatigue curve fitting methods based on the notch stress approach

Xue,

He,

Chen

et al. 2024

IJSI

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“…Fatigue due to environmental and operational loads is the primary cause of failure in offshore structures, and it is critical to design for fatigue loading. The weld line at the interface tubular members is typically the most vulnerable to fatigue failure due to stress amplification caused by geometric variation [1,2], as illustrated in Figure 1. The failure of a joint causes additional load on the neighboring structural elements and can lead to the collapse of the entire structure [3].…”

Section: Introductionmentioning

confidence: 99%

Stress Concentration Factors in KT-Joints Subjected to Complex Bending Loads Using Artificial Neural Networks

Iqbal,

Karuppanan,

Perumal

et al. 2024

Civ Eng J

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Fatigue analysis of tubular joints based on peak stress concentration factor (SCF) is critical for offshore structures as it determines the fatigue life of the joint and possibly the overall structure. It is known that peak SCF occurs at the crown position for in-plane bending (IPB) and at the saddle position for out-of-plane bending (OPB). Tubular joints of offshore structures are under multiplanar bending, comprising IPB and OPB. When a joint is subjected to IPB and OPB loads simultaneously, the peak SCF occurs somewhere between the crown and the saddle. However, existing equations estimate SCF at the crown and saddle only when a joint is subjected to IPB or OPB. It was found that the position and magnitude of peak SCF under simultaneous IPB and OPB depend on the relative magnitudes of these uniplanar load components. The crown and saddle position SCF can be substantially lower than the cumulative peak SCF. Empirical models are proposed for computing peak SCF for KT-joints subjected to multiplanar bending. These models were developed through regression analysis using artificial neural networks (ANN). The ANN training data was generated through 3716 ANSYS finite element simulations. The empirical model was validated using models available in the literature and can determine peak SCF with an error of less than 1.5%. Doi: 10.28991/CEJ-2024-010-04-04 Full Text: PDF

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