Abstract
A structure optimization for the initial design of ship is under consideration in this paper. A bulk career is selected for the object of the optimization. Both the shapes and the plate thicknesses of a bottom structure of ship are taken as design variable simultaneously. Totally 66 design variables, 4 for shape and 62 for thickness, are considered here. Individual mesh sub-division technique and multi-point constrain method are introduced for making this optimization possible. In order for reducing computational effort, a sensitivity analysis is used instead of FEM, and the validity of using it is examined. Degree of influence for design variables to stress is introduced for reducing computational efforts. Computational results are compared with a real ship data and a great performance is observed for the optimal design with considering the size and the plate thickness of a ship structure. Multi Island Genetic algorithm is used for this optimization in this study.