Sensitivity-based multi-objective optimization of ship structures under ice impact

Ships navigating through icy waters face difficulties and dangers due to the rise in ice floes caused by glacier melting in Polar Regions. In this study, a structural optimization method is proposed to enhance the reliability of hull structures and to reduce its structural weight during ice-ship collisions. Firstly, a simplified model experiment based on an actual ship is conducted to validate the accuracy of the numerical method for ice-ship collision. Then, a numerical model of the real ship is established, and numerous structural dynamic responses under ice collision are obtained. Also, two mathematical formulae are derived from these results, and the structural reliability analysis is conducted considering the probabilistic characteristics of the ice impact as well as the structural dimensions. Finally, multi-objective optimization is performed using an improved non-dominated sorting genetic algorithm, focusing on enhancing structural reliability while reducing structural weight. This study provides a framework for the reliability-based lightweight design of ship structures in ice-ship collisions, integrating reliability optimization with lightweight design principles.