A new calculation procedure is presented for the structural analysis of a steep wave riser (SWR) system. The equilibrium equation of the SWR is established based on Minimum total potential energy principle. The coupled equations are discretized by the finite difference method and then solved by Newton-Raphson technique. The accuracy of the numerical model is verified by Orcaflex software. Traditional parametric analysis of buoyancy factor, buoyancy section’s length, buoyancy section’s location and ocean current velocity are performed. An idea of engineering evaluation of the SWR’s working condition from the perspective of hang-off angle, tension, and bending radius is proposed. Through comparison, it is found that the hang-off angle is the main parameter affecting the installation safety of the SWR. And the allowable working water depth and installation span are determined. In addition, the optimization idea of the SWR’s configuration based on S-shape coefficient and hang-off angle is put forward, and the optimal configuration of a specific SWR is analyzed.
SeyedFBPatelMH. Mathematics of flexible risers including pressure and internal flow effects. Mar Struct1992; 5:121–150.
2.
CalvertSJBalashCChaiS, et al. Effects of buoyancy modules geometry on hydro-elastic and hydrodynamic performance of a steep wave riser in steady current. Proc Int Conf Offshore Mech Arct Eng OMAE. 2015; 5A: 1-11.
3.
NairAARajamanickamPSAnbuGA, et al. Analysis of deep sea umbilical in steep wave configuration. In: ASME international mechanical engineering congress and exposition. American Society of Mechanical Engineers2016, p.V04AT05A033.
4.
ZhaoHXuNLiY, et al. The effect of new steep wave riser configurations on the stability of the suspension cluster manifold based on Orcaflex. Ships Offshore Struct2021; 0: 1–10.
5.
PereiraPSDMourelleMMDe AguiarLL. Steel steep wave riser as an alternative configuration for Fpsos compliant risers. Proc Int Conf Offshore Mech Arct Eng OMAE2015; 5B: 1–8.
6.
QiaoHRuanWShangZ, et al. Non-linear static analysis of offshore steep wave riser. In: MATEC Web of Conferences. EDP Sciences 2016; 65: 01009.
7.
QiaoHRuanWShangZ, et al. Non-linear static analysis of 2D steep wave riser under current load. Proc Int Conf Offshore Mech Arct Eng OMAE, 2016; 5: 1–9.
8.
ChengYTangLJiC, et al. Nonlinear time-domain dynamic analysis of three-dimensional deepwater steep wave riser subjected to top motions with internal flow effects. Ships Offshore Struct2020; 0: 1–23.
9.
ChengYTangLJiC. Nonlinear analysis of bidirectional vortex-induced vibration of a deepwater steep wave riser subjected to oblique currents. China Ocean Eng. 2021; 35: 852–865.
10.
TangLChengYJiC. Time-domain nonlinear wave-current interaction with a steep wave riser considering internal flow effect. China Ocean Eng. 2021; 35: 410–421.
11.
GuHGuoHLiX, et al. Three-dimensional dynamic analysis of deep-water steel steep wave riser considering internal solitary wave. J Mar Sci Technol. 2021; 27: 452–466.
12.
RuffelsAZingoniA. On the accuracy of lumped mass models for free vibration of beams. In: Insights and innovations in structural engineering, mechanics and computation, 2016, pp.127–132.
13.
SeyedFB. On the Dynamics of Flexible Riser and Suspended Pipe Spans. Ph. D. Department of Mechanical Engineering, University of London, 1989
14.
O'BrienPMcNamaraJFGrealishF. Extreme bending and torsional responses of flexible pipelines. In: Proceedings of the 11th international conference on offshore mechanics and arctic engineering. ASME, 1992.
15.
ChaiYTVaryaniKSBarltropNDP. Three-dimensional Lump-Mass formulation of a catenary riser with bending, torsion and irregular seabed interaction effect. Ocean Eng2002; 29: 1503–25.
16.
TrapperPA. Feasible numerical method for analysis of offshore pipeline in installation. Appl Ocean Res2019; 88: 48–62.
TrapperPAMishalI. Numerical analysis of offshore pipe-lay subjected to environment-induced non-uniformly distributed follower loads. Appl Ocean Res2020; 100: 102149.
19.
TrapperPA. Static analysis of offshore pipe-lay on flat inelastic seabed. Ocean Eng2020; 213: 107673.
20.
TrapperPA. A numerical model for geometrically nonlinear analysis of a pipe-lay on a rough seafloor. Ocean Eng2022; 252: 111146.
21.
TrapperPA. A numerical model for geometrically nonlinear analysis of long free spanning offshore pipelines enhanced with buoyancy modules. Appl Ocean Res2022; 124: 103224.
22.
MorisonJRJohnsonJWSchaafSA. The force exerted by surface waves on piles. J Pet Technol1950; 2: 149–54.
23.
TanakaRLSilveiraLNovaesJ, et al. Bending stiffener design through structural optimization. In: International conference on offshore mechanics and arctic engineering, 2009,pp. 411–418.
24.
WitzJA. A case study in the cross-section analysis of flexible risers. Mar Struct1996; 9: 885–904.
25.
API SPEC 17J. Specification for unbonded flexible pipe. 2014.
26.
DentonN. Guidelines for Submarine Pipeline Installation. 2018.
27.
OhJJungDKimH, et al. A study on the simulation-based installation shape design method of steel lazy wave riser (SLWR) in ultra deepwater depth. Ocean Eng2020; 197: 106902.
28.
LiSNguyenC. Dynamics response of deepwater lazy-wave catenary riser. deep offshore technology international. Deep Offshore Technol Int Amsterdam2010; 2:1–20.
