Dynamic Analysis of Guyed Tower Subjected to Random Waves

J. Ocean Eng. Technol. 1987;1(1):57-64.

랜덤파랑하중에 대한 Guyed Tower의 동적 거동해석

유정선,윤정봉

한국과학기술원,한국과학기술원

Keywords: average stiffness method, equivalent linearization method, guyed tower, nonlinear drag force, nonlinear restoring force, random wave loading

핵심용어: 평균강도법, 등가선형법, 가이드 타워, 비선형저항력, 비선형 복원력, 랜덤파랑하중

Abstract

Methods of nonlinear stochastic analysis of guyed towers are studied in this paper. Two different kinds of nonlinearities are considered. They are the nonlinear restoring force from the guying system and the nonlinear hydrodynamic force. Analyses are carried out mainly in the frequency domain using linearization techniques. Two methods for the linearization of the nonlinear stiffness are presented, in which the effects of the steady offset and the oscillating component of the structural motion can be adequately analyzed. those two methods are the equivalent linearization method and the average stiffness method. The linearization of the nonlinear drag force is also carried out considering the effect of steady current as well as oscillatory wave motions. Example analyses are performed for guyed tower in 300m water. Transfer functions and the expected maximum values of the deck displacement and the bending moment near the middle of the tower are calculated. Numerical results show that both of the frequency domain methods presented in this paper predict the responses of the sturcture very reasonably compared with those by the time integration method utilzing the random simulations wave particla motions.