Since the ocean covers over 70% of the earth’s surface and marine transportation has many advantages, it is continuously increasing and shipbuilding is still considered as an important industry. This is constantly increasing the demands for ships as well as for the efficiency improvement of shipbuilding. Therefore, shipbuilding field is widely introducing advanced techniques including computer programs for ship design and shipbuilding to raise its modernization level.
Some processes such as seam landing of hull surface are carried out on computers, but they are mainly based on the skills and experiences of designers.
Seam or butt landing (simply seam landing) of shell plates in the hull lofting process which is the first step of shipbuilding plays an important role in raising the speed and quality of shipbuilding and lowering its cost. However, this work has not been modernized until now because of its complexity and it has been done manually on paper and on mold lofts by the skills and experiences of designers.
Some computer programs for ship design and shipbuilding such as AVEVA, Ship Constructor, Maxsurf, etc. give help with seam landing of shell plate. These programs contain some graphics processing functions for seam landing in ship surfaces. However, seam landing of hull surface by computers still depends on the skills and experiences of designers. Therefore, the result of seam landing of hull surface is dependent on designer’s ability and this work lacks scientific accuracy. The main reason for low scientific accuracy of this work is its complexity.
Pae Ho Rim, a researcher at the Faculty of Shipbuilding and Ocean Engineering, has proposed an optimization model for seam landing and a solving method by GA. On this basis, he has confirmed the validity of the proposed method.
First, for the optimum seam landing, he built an optimization model with the sum of cutting, shearing, forming and welding cost as an objective function. As obvious in the objective function, costs of cutting, shearing, forming and welding depend on seam landing.
Second, he proved that the optimization problem for seam landing of hull surface is a topological optimization one when the number and form of seams are design variables and it is a form optimization one when only the form is a design variable.
Finally, he demonstrated that optimization method using GA gives a better solution than the seam landing of an existing ship and that by Taguchi’s method.
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