Coupled Analysis of a Semisubmersible Platform with Two Types of Mooring Systems

摘要

Mooring system design selection of a semi-submersible platform whichworks in 1500m water depth of South China Sea was carried out. The3-dimension hydrodynamic finite element model of the semisubmersibleplatform is built firstly. The nonlinear time domaincoupled analysis between the semi-submersible platform and itsmooring system is calculated through numerical simulation. The waveforces are calculated under diffraction theory by boundary elementmethod, and the wind forces are obtained from the wind tunnel testwith the model scale 1:100, and the current forces are considered assteady. Two types of mooring system have the similar static restoringforce characteristics, the same mooring line number and anglearrangement. The single mooring line is respectively consisting ofchain-wire-chain and chain-polyester-chain. The polyester rope isadopted as the substitute for the wire while other conditions are keptunchanged. The mooring system is considered under intact anddamaged conditions. The influences of different mooring models on themotions of the semi-submersible platform and mooring line tension areinvestigated. The specific numerical simulation results would behelpful for the preliminary design of semi-submersible platform.