We studied the optimization method to reduce the amount of resin rope that used to fill the gap between the LNG tank and insulation panels while complying with the flatness criteria of the insulation panels.
The space between the thermal insulation panels and LNG tank hull should be reduced to minimize the use of resin rope. In this study, the corrugation of the inner side of the hull is measured, and the offset table of the corrugation is used to calculate the deformation of the LNG tank hull. To solve the optimization problem, an objective function with constraints is mathematically formulated and solved by using the genetic algorithm.
To check the applicability of the proposed method, we simulated thermal insulation panel installation and compared with an existing program. The results show that the proposed method can be effectively used for installation of the thermal insulation panels of the LNG tank.
As the importance of LNG carriers increases, it is needed to improve value-added and increase the competitiveness of LNG carriers. Design of the LNG tank is one of the most important factors in the design of the LNG carrier. Because the LNG carrier transports low-temperature LNG, the thermal insulation panel is used inside of LNG tank to maintain the temperature of LNG. But because the inside hull of the LNG tank is rugged, the resin ropes are used to equalize the height and flatten the slope of the insulation panel. A large amount of resin ropes is necessary to fill the gap between thermal insulation panels and LNG tank especially when the LNG tank hull's flatness is uneven, and this will increase the production cost of the LNG carrier (Chun et al., 2009; Kim et al., 2010). To decrease the amount of reins rope, there is a software that calculates the estimated amount of resin ropes while complying with the flatness criteria of the insulation panels made by GTT. The software tends to demand additional usage of resin ropes because the software is focused on the flatness of the thermal insulation panel and wouldn't reflect the recent change of LNG carrier and thermal insulation panel. In this study, the amount of resin ropes is reduced as a primary target while the flatness criteria of thermal insulation panel are satisfied.