Theoretical investigation on hub structure design of subsea connectors

Abstract

Subsea processing of oil/gas is performed by production system facilities, which are linked into a complete system by subsea connectors. High reliability and long service life of the connectors, defined by strict requirement of deepwater oil fields, raise the challenge of the design of the structure components to which the ASME-VIII code has been applied. The theoretical design problems of the main parameters of subsea connector's hub structure are detailed in this paper in comparison with the shortage of the ASME design method. Therefore, a new analytical model is developed, and is named stress analytical method (SAM). The hub structure is separated into two parts, i.e. a thick-walled cylinder and a hollow annular plate, and axisymmetric bending deformation problems of the thick-walled cylinder are proposed. The geometric equations, the constitutive equations, the physical equations and the equilibrium equations are developed to obtain the displacement analytical solution of the hub structure's thick-walled cylinder. The deformation continuity relationships between the thick-walled cylinder and the hollow annular plate are also established, and the analytical solutions of internal forces, displacements, rotation angles and stress components are acquired accordingly. The accuracy of SAM is investigated by comparing stress calculation results with Finite Element Method (FEM) results. A case study is carried out to compare SAM with ASME design method.