Development of parametric equations for ultimate capacity of internally ring-stiffened tubular T/Y-joints under axial and moment load

ABSTRACT

Tubular joints in offshore structures is being designed using semi-empirical equations developed based on experimental and numerical studies and same were recommend for use in API-RP-2A and other codes. The parametric equation does not cover the tubular joints reinforced with internal ring-stiffeners. Hence, an attempt is made in the present study to develop parametric equations as a capacity enhancement factor (Q_r) to ultimate strength equation recommended for unstiffened joints by API-RP-2A. The development of Q_r for T/Y-joints under axial and moment load has been carried out using non-linear finite element. Numerical model has been validated using measured results from a scale model test conducted for this purpose and matches reasonably well. Parametric studies have been performed for various geometric non-dimensional parameters. The proposed parametric equations for ring-stiffeners in axial and moment load works well with the unstiffened equations specified in API-RP-2A enabling easy design procedure for ring-stiffened joints.

KEYWORDS:

• Ring-stiffened tubular T/Y-joints
• ultimate capacity
• internal ring-stiffener
• parametric equations
• offshore structures

Acknowledgements

The authors express their gratitude to High performance computing environment at Indian Institute of Technology Madras for access of super cluster using which the numerical simulations were carried out.

Disclosure statement

No potential conflict of interest was reported by the author(s).