RIASSUNTO
ABSTRACT
Needs for accurate analysis of dynamic behavior of moored offshore structure have been increasing in the shipbuilding industry, and there are many analysis codes for analysis of them. However, they cannot treat a detailed motion during offshore installation using floating barges and cranes. In this study, therefore, coupled behavior of the moored floating multibody body is analyzed. In here, multibody means the interconnected several bodies by joints. The equations of motions for multibody and mooring line are introduced, and input/output between multibody module and mooring line module are defined. The analysis results were validated by comparing with model test.
INTRODUCTION
Needs for accurate analysis of dynamic behavior have been increasing in many engineering fields, including the shipbuilding industry. There are several simulation tools which are focused on the traditional mechanical systems, such as car and machinery. In general, however, shipbuilding and offshore industry is different from conventional mechanical system in aspect of their purpose, size, and shape. Therefore, there are some limits to apply analysis tools, which are developed for conventional mechanical system, to the shipbuilding and offshore industry. Fig. 1 shows several kinds of the offshore operations in shipbuilding industry.
Due to these reasons, simulation tools are developed in several researches for the dynamic analysis of the shipbuilding and offshore operation process (Ku et al.; 2014, Roh et al., 2014). The simulation programs developed from these researches can deal with multibody system, so that more accurate dynamic analysis can be completed.
These programs define the mooring line as a linear spring, and the spring constants are determined with some assumption and linearization. However, in some offshore operation, such as installation and decommissioning, mooring analysis can be one of the most important analysis points.. Therefore, this paper presents about dynamic analysis for the moored floating multibody system. Dynamic analysis of mooring line is performed using non-linear finite element method(FEM).