An experimental study on the motion-structure coupled characteristics of multi-linked floating unit offshore structure with two different connection conditions

Abstract

With the recent intensification of climate change due to global warming, the importance of renewable energy has been highlighted, emphasizing the need for renewable energy development. In the case of renewable energy power generation, it is installed and operated on a large scale to meet energy demand, economic efficiency, and optimize local resources. Therefore, the number of cases of installation on water and sea with high space utilization is gradually increasing. When operating large-scale power systems, conservative design and review are necessary because damage to the structures can cause cascading failures, leading to major accidents. In particular, for photovoltaic systems, the method of expansion by connecting individual unit structures is commonly used. Therefore, it is necessary to analyze the characteristics of the unit structures and the connection methods. In this study, a fluid-structure coupled analysis was performed on the unit structures of a multi-linked floating offshore structures, which can be large-scale expansion, developed by the Korea Research Institute of Ships and Ocean Engineering. The characteristics were analyzed based on the connection method. The analysis results showed that when the connection method was a hinged condition, the pitch motion increased compared to the fixed condition, but since the peak occurred at a high frequency with a 4-s period, it is advantageous to avoid resonance. In particular, it was confirmed that the maximum stress was reduced by approximately three times, which is beneficial for structural integrity. Additionally, it was found that as the stress distribution moved from the center to the edges, it is also advantageous in terms of maintenance. In addition, the numerical method of the multi-linked floating offshore structures and the characteristics of hinged condition were verified through model tests.