Design And Finite Element Analysis For Very Large Floating Structure Flexible Connector

With the depletion of land resources, people will pay more and more attention to marine resources development. South China Sea is rich in oil and gas and mineral resources, so it is bound to become a key area of resource exploitation in the future. However, in South China Sea, the big waves, flow urgent, islands and reefs being far from the mainland have restricted the exploitation of the South China Sea resources and the sovereignty protection of China. Very large floating structure(VLFS) is a kind of very large floating structures which can be deployed in offshore or international waters and be used as an offshore supply base or airport and be used for long-term personnel station. The scale of VLFS is over 1000 meters and it usually consists of multiple modules which are connected by connectors. The design of VLFS connector is a critical part of VLFS design process which relates to operational safety of the entire VLFS. So the design of VLFS connector is of great significance. Currently, the domestic and international research of VLFS connector mainly concentrates in the dynamic characteristics of the connector. The research on connector structure is primarily on conceptual design and there is few specific structure design.In this thesis, firstly, the current situation of researches on VLFS and VLFS connectors was introduced and the criteria of the design of VLFS connector was put forward. Secondly, the basic theories used in this thesis were introduced. Then hydrodynamic models of VLFS modules were built by using software Sesam / GeniE and the maximum loads of VLFS connectors of different stiffness in different sea conditions were calculated. The results showed that the loads of connectors and the movement amplitude of modules differ largely in different connector stiffness. Then the appropriate connector stiffness was selected. The connector loads of the selected stiffness in five different sea conditions at eight different wave incidence angles were calculated. The specific load in 7 level sea condition and in 45°wave incidence angle is chosen as the design load for VLFS connector. Last but not least, a design of flexible connector is presented. The connector structure consists of joints and rubber pads. By changing the thickness of the rubber pads, the stiffness of the connector can be changed. The rubber pads can be replaced, for easy maintenance of the connector. The finite element model of connector was established by using finite element software Abaqus. The strength analysis for the connector was done in different load cases. The result shows that the connector structure meets the strength requirements and the stiffness of the connector meets the design stiffness, which provides a reference for VLFS connector design.