Dynamic Analysis of semi-Submersible in Time Domain

Offshore platforms are categorized according to the water depth in which installed. Regarding to
rising demand of deep water drilling and exploration, floating production system (FPS) is one of
the best alternative due to ease of installation and transportation. The main concern for FPS is
stability in wave motions. This report consists of dynamic analysis of semi-submersible both :in
fh:quency domain and time domain. Due to complexity of calculations, this· analysis is
accomplished by computer programming. This report mainly focused on analysis of semisubmersible
as a whole structure. ln literature review the types of platform are briefly described
including their similarities and differences. Our focus in this project is mainly draws to three
critical motions of platform, which are surge:, heave and pitch. These displacements are studied
under random waves. For random wave generation, P .. M is ·chosen. The forces on body are
calculated by Froude·-Krylov theory. ln this report the effect of water depth is investigated. Th·e
frequency domain analysis is done for two drafts and the results are compared together. For time
domain analysis one case is accomplished using Newmark's Beta method and the result is
compared with frequency domain method.