Research on an equivalent calculation method of the sealing structure of subsea pipeline connectors based on dimensionality reduction method

For the sealing structure of subsea pipeline connectors, it is crucial to understand the maximum equivalent stress of the sealing ring, the normal force generated by the pressure effect of the internal fluid acting on the contact area of the flanges and the sealing ring, and the displacement of the flange in the pre-tightening state and the working state. This paper proposes an equivalent calculation method (ECM) to quickly compute the values of these three variables. A theoretical model for the parallel contact of the axially symmetric object and an elastic foundation is proposed based on the dimensionality reduction method and Hertzian theory. Considering the contact and structural characteristics of the flanges and the sealing ring of the sealing structure, an equivalent hollow cylinder model is introduced. By combining these two models, along with the long hollow cylinder theory, theoretical formulas for the maximum equivalent stress, the normal force, and the flange displacement in the pre-tightening state and the working state of the sealing structure are derived. In addition, finite element simulations were conducted on the sealing structure of different sizes and working states. A comparative analysis was performed between the simulation results and the theoretical formulas results. The results show that, within the yield strength of the sealing ring, the maximum relative deviation of the three theoretical formulas is less than 10%. The theoretical formulas can be used for the design and engineering application of the sealing structure of subsea pipeline connectors.