Abstract
In this paper, we analyze the behavior of the chain for mooring offshore structures (M. A. Rahmen et al.2006，M. H. Kim et al.2005) by the analytical method of the multibody dynamics. For this system, there are two problems in the conventional method. One is the description of rotation for the rigid body. It leads to high nonlinearity and singularity caused by rotation. The other is the calculation efficiency due to the degree of freedom increases. In this research, in order to solve these problems, we introduces ”Rotation update equation”, which uses an incremental rotation for describing rotation matrix. This method doesn’t use the rotation angle in the equation, therefore the problems are mentioned improved. It can also reduce the calculation time, too. Moreover, this study introduces the normalization of the equation of rotation with the time step. It enables us to reduce the times of iteration procedure. This research compares the calculation results by the proroposed method and the results by the conventional method.
