Optimisation of hexagon-shaped floating units using the response surface method

A hexagon-shaped floating unit (HS-FU) was proposed, and the optimisation was performed with respect to the geometric dimension based on the response surface method (RSM). A multi-objective optimisation model considering the weight and heave response was established to achieve a satisfactory balance between economy and safety, constrained by the roll, initial metacentric height, freeboard, and collision issue. The results show that, opposite to the heave response, the structural weight is positively proportional to the side lengths of the water tank and living area; the stability can be improved by increasing the water tank height and the living area side length. The combination of weighting factors with a value of 0.4 for weight and 0.6 for heave was selected as one of the optimal designs. Compared with the initial design, the optimal design shows better performance, with the heave response decreasing by 22.51% and the initial metacentric height increasing by 28.30%.