Analysis of wave induced vibration of a typical very large floating-type offshore airport platform

J. Ocean Eng. Technol. 1996;10(4):10-16.

초대형 부유식 해상공항의 파도에 의한 진동응답특성 해석

이현엽,전영기,신현경

홍익대학교 조선해양공학과,한국선급,울산대학교 조선 및 해양공학과

Keywords: Very Large Floating-type Offshore Structure, Offshore Airports, Wave Induced Vibration, Vibration Analysis, Modal Analysis

핵심용어: 초대형 부유식 해양구조물, 해상공항, 파도유기진동, 진동해석, 모델해석

Abstract

The vibration due to progressive ocean waves is analyzed for a typical footing-type offshore airport platform. The platform is modelled as a spring-supported Euler beam and buoyancy change due to wave is considered as excitation force, under the assumption that the wave propagates without distortion by the structure. The results show that the natural frequencies of this structure are distributed very closely and are little affected by boundary conditions and that the response charateristics due to ocean waves are quite different according to the wave frequency. In this study, the wave frequencies are divided into three regions; the resonance region at which the response is governed by the resonance between the natural mode at the wave frequency and the corresponding modal component of the wave excitation force, the bending governed region at which the response is governed by the bending stiffness, and the spring (buoyancy) governed region at which the response is governed by the spring constant ahd therefore is same as the incident wave form.