Static analysis and verification of flexible riser for underwater compressed air energy storage system with different boundary conditions

Abstract

ABSTRACT In an underwater compressed air energy storage system, fracture of the flexible riser often occurs. To solve this problem, we proposed a static analysis method for a flexible riser based on Cosserat theory. Bending and torsion deformation of a flexible riser were described. Using Euler parameters, static equilibrium differential equations were established. Finite element discretization, finite difference, and an improved Levenberg–Marquardt algorithm were used to perform the numerical calculations. Based on the similarity principle, experiments with three different boundary conditions were performed. Our static model and the OrcaFlex simulations were compared with experiments, and the average error of our static model was 2.9% smaller than that of the simulation. The results showed that the static model presented in this paper was more accurate than the OrcaFlex simulation calculation. This model is useful for estimating the mechanical characteristics and determining the strengths of flexible risers.