Introducing a simple and reliable multi-objective optimization method to estimate hull dimensions of a semi-submersible rig

For optimal design of the hull dimensions of a semi-submersible platform, a method is required that calculates optimal answers in a short time according to the certain objectives. In this study, the grid search (GS) algorithm was introduced in the form of triple-objective function in order to minimize the hull weight and reduce the heave and pitch motion response. For this purpose, first the equations of the hull weight and heave and pitch motion response were discretized as the parametric equations. The design variables and constraints of the semi-submersible platform were considered. Then, this algorithm was implemented as a single-objective function with the objective of minimizing hull weight of a semi-submersible platform and its efficiency was evaluated by comparing the results with the results from previous studies. Subsequently, the GS algorithm was developed as the triple-objective function, which gives acceptable results in the shortest computational time. This study shows that the GS algorithm is an appropriate method for multi-objective optimization and can contribute to the more economical and efficient design of floating platforms.