The Influence of Additional Equipment to the Ultimate Strength of FPSO

Nowadays, there have many ship conversions, for example, from double hull tanker to Floating Production Storage Offloading (FPSO). The conversion is conducted due to the change function of the ship. On the other hand, due to the change function of the ship, some items of the ship, such as equipment, need to be evaluated because of those related to the ultimate strength of the ship. The objective of the present study is to analyze the influence of additional equipment to the ultimate strength of FPSO under vertical bending moment for hogging condition. The cross-section of FPSO is taken by considering one-frame space. The numerical method is used, and the Multi-Point Constraint (MPC) is applied to both sides of the crosssection, and it is assumed to have remained plane. The shell element type is used for modeling the crosssection. The material properties are set to be constant. As a simple calculation, the ship’s cross-section is analyzed in intact. The additional equipment is calculated and included in the analysis to know the influence of it. The analysis of the ultimate strength, including their influence of additional equipment, is conducted under longitudinal bending. To compare the ultimate strength obtained by the numerical method, the analytical method is adopted. It is found that the ultimate strength gained by the numerical method is almost identical to the analytical method. The behavior of the ship’s cross-section is also presented in terms of stress distribution and deformation.