As environmental pollution has become a global concern, regulations on carbon emissions from maritime activities are being implemented, and interest in using renewable energy as fuel for ships is growing. Hydrogen, which does not release carbon dioxide and has a high energy density, can potentially replace fossil fuels as a renewable energy source. Notably, storage of hydrogen in a liquid state is considered the most efficient. In this study, a 0.7 m³ liquid hydrogen fuel tank suitable for small vessels was designed, and a structural analysis was conducted to assess its structural integrity. The extremely low liquefaction temperature of hydrogen at −253 °C and the need for spatial efficiency in liquid hydrogen fuel tanks make vacuum insulation essential to minimize the heat transfer due to convection. A composite insulation system of sprayed-on foam insulation (SOFI) and multilayer insulation (MLI) was applied in the vacuum annular space between the inner and outer shells, and a tube-shaped supporter made of a G-11 cryogenic (CR) material with low thermal conductivity and high strength was employed. The material selected for the inner and outer layers of the tank was STS 316L, which exhibits sufficient ductility and strength at cryogenic temperatures and has low sensitivity to hydrogen embrittlement. The insulation performance was quantitatively assessed by calculating the boil-off rate (BOR) of the designed fuel tank. Structural integrity evaluations were conducted for nine load cases using heat transfer and structural analyses in accordance with the IGF code.

Hydrogen is a promising eco-friendly energy source, but its embrittlement effect on structural materials remains a significant challenge. This study investigates the notch sensitivity of 316L stainless steel under in situ electrochemical hydrogen charging, with a focus on mechanical degradation and fracture behavior. By examining the influence of notch geometry and hydrogen exposure, this research highlights the role of stress concentration in hydrogen embrittlement. The findings contribute to understanding hydrogen-induced material failure, offering insights for both industry practitioners in the energy sector and academic researchers. This study also underscores the need for further research on hydrogen-resistant materials and structural safety considerations in hydrogen applications.