Design Optimization Of Floating Production Storage And Offloading FPSO-Mid-Ship Section

We are at present in the midst of a gradual but profound change in the philosophy and practice of Ship Structural Design. The growing demand for more efficient marine transportation has already produced significant changes in ship sizes, types, and production methods. The design approaches are also transforming from Rule-Based to Rational-Based.This Rationally-based Design involves a thorough and accurate analysis of all of the factors affecting the safety and performance of the ship structure throughout its life, and a synthesis of this information, together with the goal or objective which the structure is intended to achieve, to produce that design which best achieves the objective and which provides adequate safety.The current research work is aimed at providing an Optimized Design of a popular offshore structure FPSO, in the light of this Rational-Based Design Approach.In this context a Finite Element Model of the structure was prepared and during the construction of this model the main idea of Optimization was kept in mind, so the model was not built-up using conventional modeling approach but the whole process was programmed using ANSYS (a popular Finite Element Analysis Program) built-in programming language called APDL (ANSYS Parametric Design Language).This programming language empowers the model to further harness the power of Design Optimization and a number of analysis under varying conditions are possible to be performed on the model, which is constructed using the programming paradigm. This APDL based model was then analyzed in the light of Rules specified guidelines-i.e. Load-Cases and the response of the model under typical loads was assessed.Finally on the basis of stresses developed into the model under different loading scenarios, the model was submitted to the Optimization Module in ANSYS and the Objective Function of Least Weight was set while obeying the constraints imposed on stresses, at the same time.It is observed that, there is a substantial weight saving (in the current case almost 9%) when the design is bases on Rational-Bases Approach rather merely relying on the Rule-Based Approach.