불규칙 효과를 고려한 모리슨 하중의 선형화에 관한 연구

Abstract

The Morison load includes nonlinear drag forces in velocity and inertia forces in acceleration. Therefore, it is difficult to apply the spectral fatigue analysis method based on the linearization assumption in fatigue analysis of members subjected to Morrison load. Furthermore, members located near the surface of the water are subject to the intermittent effect due to the change of the elevation of the free surface, and therefore the probability distribution of the load is significantly different from the fully submerged section. In order to facilitate the analysis of Morison loads, linearization coefficients are introduced to linearize the Morrison load in fatigue analysis. However, the previously proposed coefficients fit the fully submerged section and did not reflect the intermittent effect. In this paper, the probability distribution models of Morison force considering the intermittent effect have been reviewed. And the linearization coefficients for peak force of Morison force and fatigue damage considering the intermittent effect were proposed based on the probability distribution function. Finally, the fatigue analysis of the members subjected to the Morison load was carried out and the results were compared with the results of the time domain analysis