Dynamic Analysis of Mooring Dolphin System Considering Soil Properties

J. Ocean Eng. Technol. 1998;12(3):19-30.

Yi, Jin-Hak;Oh, Se-Boong;Yun, Chung-Bang;Hong, Sup;Kim, Jin-Ha;

지반의 강성특성을 고려한 지반-돌핀구조계의 동적해석

이진학;오세붕;윤정방;홍섭;김진하;

한국과학기술원 토목공학과;영남대학교 토목공학과;한국과학기술원 토목공학과;한국기계연구원 선박해양공학연구센터;한국기계연구원 선박해양공학연구센터;

Keywords: Soil-Pile Interaction, Mooring Dolphin Structure, Nonlinear Dynamic Analysis, Newmark B Method, Subgrade Reaction Method

핵심용어: 지반말뚝상호작용, 계류돌핀구조물, 비선형동적해석, Newmark B 방법, 지반반력법

Abstract

In this paper, the dynamic analysis of a dolphin system for mooring a floating structure such as barge mounted plant is studied. The characteristics of the soil-pile system are simplified by a set of equivalent spring elements at the mudline. To evaluate the equivalent spring constants, the finite difference method is used. Since the characteristics of the soil-pile system are nonlinear in case of soft foundation, the nonlinear dynamic analysis technique is needed. The Newmark $beta$ method incorporating the modified Newton-Raphson method(initial stiffness method) is used. A numerical analysis is performed on two mooring dolphin systems on soft foundation and rock foundation. In case of the rock foundation, the characteristics are found to be nearly linear, so the linear dynamic analysis may be sufficient to consider the foundation effect. But in case of soft foundation, the non-linearity of the foundation appears to be very signigicant, so the nonlinear dynamic analysis si needed.