Optimization of a Semi-Submersible Type Mega-Float Using a Risk Based Objective Function

Design requirements for a Semi-submersible Type Mega-float are safety and functionality, and it has been shown that solutions which satisfy the requirements exist. In this paper, in order to find the optimal configuration of a semi-submersible type mega-float, an efficient optimization procedure and an objective function based on concept of risk were proposed. This function unifies the structural weight and the requirements of safety and functionality such as motion and elastic response. To reduce heavy computational load, a simplified analysis model with sufficient precision and short computational time was developed and used for the optimization. The simplified analysis model was developed based on the theory of plate. Using this modeling and the objective function, the structure was optimized and more efficient configuration of a semi-submersible type mega-float was obtained.