Study on Optimum Design of FPSO Spread Mooring System

J. Ocean Eng. Technol. 2009;23(6):61-66.

Lim Yu-Chang,Kim Kyung-Su,Choung Joon-Mo,Kim Jae-Woo,Kim Jin-Tae,Yeo Seung-Hoon

Dept. of Naval Architecture & Ocean Engineering Inha University,Dept. of Naval Architecture & Ocean Engineering Inha University,Dept. of Naval Architecture & Ocean Engineering Inha University,Dept. of Naval Architecture & Ocean Engineering Inha Un

FPSO 다점 계류 시스템의 최적 설계 연구

임유창,김경수,정준모,김재우,김진태,여승훈

인하대학교 선박해양공학과,인하대학교 선박해양공학과,인하대학교 선박해양공학과,인하대학교 선박해양공학과,대우조선해양(주) 구조기본그룹²,인하대학교 선박해양공학과

Keywords: Spread mooring system, Mooring line length, Mooring line stiffness, Catenary equation, Quasi-static analysis, Time domain analysis

핵심용어: 다점 계류 시스템, 계류 라인 길이, 계류 라인 강성, 현수선 방정식, 준정적 해석, 시간 영역 해석

Abstract

For a spread-moored FPSO (Floating Production, Storage, & Off-loading) subjected to environmental excitation from waves, current, and wind, a procedure to determine optimum length and stiffness of mooring lines is suggested using quasi-static frequency domain response analyses. Coupled relations between design parameters are closely examined. In consideration of this, optimized design parameters are proposed based on minimum weight condition. The initial design parameters for numerical analyses are calculated using the static catenary equation of mooring lines. It is demonstrated the line tension and vessel's offset are influenced by the mooring line length and stiffness. Accordingly it is suggested the optimum vessel's offset range should be determined considering line fatigue damage. The availability and limitation of the application of quasi-static analysis method for spread mooring system are explained by comparing the result of time domain analysis with one of frequency domain analysis.