Outer-Brace Stress Concentration Factors of Offshore Two-Planar Tubular DKT-Joints

In the present paper, a set of parametric FE stress analyses is carried out for two-planar welded tubular DKT-joints under two different axial load cases. Analysis results are used to present general remarks on the effect of geometrical parameters on the stress concentration factors (SCFs) at the inner saddle, outer saddle, toe, and heel positions on the main (outer) brace. Then a new set of SCF parametric equations is developed through nonlinear regression analysis for the fatigue design of two-planar DKT-joints. An assessment study of these equations is conducted against the experimental data; and the satisfaction of the criteria regarding the acceptance of parametric equations is checked. Significant effort has been devoted by researchers to the study of SCFs in various uniplanar tubular connections. Nevertheless, for multi-planar joints covering the majority of practical applications, very few investigations have been reported due to the complexity and high cost involved.

Authors:

• Mohammad Ali Lotfollahi-Yaghin
• Hamid Ahmadi

Keywords:

• Offshore jacket structure
• Parametric equation
• Stress concentration factor (SCF)
• Two-planar tubular KT-joint

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