The Efficiency of a New Vector form of Finite Eiement and Its Application to Offshore Structures

Abstract

A vector form intrinsic finite element (VFIFE) method of plane frame element is adapted and applied to the study of dynamic responses of offshore template platform under wave forces. The method adopted in this study is a scheme by updating the geometry of the structural system during the calculation of each time step, which is also called the coordinate moving frame approach, by avoiding the calculation of inverse matrix to improve the computational efficiency. In this study, in order to take the time-saving advantage during the dynamic analysis, a solution procedure by using VFIFE method is developed in cooperating with the interactions between wave motions and offshore structure. The efficiency of numerical computation compared against the traditional finite element method is also examined and then, a typical offshore template structure is analyzed for the dynamic behavior by utilizing the developed solution scheme. The motions in the horizontal and vertical direction at each joint of the structure are calculated and presented into figures. It is found from this study that the new developed VFIFE could be a promising method in analyzing the offshore template structures subject to wave motions in the ocean.