유한차분법을 이용한 해양부이 계류삭의 3차원 구조해석

Abstract

A mooring system is employed to prevent floating structures being carried away by a strong wind, wave or current and to make floating structures keep in a stable position.

This paper describes a mooring system in curvilinear coordinate system. The governing equations for a mooring line include the effects of geometric non-linearities and bending stiffness of cables.

In order to solve this problem, nonlinear differential equations are converted to algebraic equations by a finite difference method. An implicit method and Newton Raphson iteration are adopted for the time integration and nonlinear solutions.

The results show the typical characteristics of a mooring line along the length from bottom to top side. The tension response amplitude tends to be proportional to the amplitude of displacement applied to top side but tend to be inversely proportional to the time period applied to top side. Therefore, when a mooring line is designed, it has to be considered that the mooring lines tend to break under the huge and long period waves.

The amplitude of tension responses are large not only at top side but also at bottom side. So it is also essential to consider fatigue failure at both ends of cables.

The results of this study can contribute to the design of mooring system for a floating buoy.