When calculating the stress generated in a flat-bottomed cylindrical liquefied hydrogen storage tank, it is considered appropriate to calculate the stress by FEM analysis as in the conventional flat-bottomed cylindrical storage tank. In this case, the slippage between the bottom plate of the inner tank and the insulation of the bottom was not considered, and the analysis was conducted under the fixed condition.
However, since the anchor strap is fixed to the inner tank not on the bottom plate but on the side plate, the sliding of the bottom plate due to the horizontal seismic load could not be completely restrained and some slippage occurred. It is undeniable that this slip affects the stress generated in the inner tank, and the analytical method considering the slip is desired to calculate the stress generated more accurately in order to evaluate the fracture toughness of the liquefied hydrogen storage tank. This paper describes a static analysis method for a flat-bottomed cylindrical liquefied hydrogen storage tank subjected to horizontal seismic load considering the sliding of the bottom plate.

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We have developed Low Transformation Temperature (LTT) welding material for large welded steel structures, including ship hull structures, and have been making efforts toward its practical application.
In our study, fracture toughness tests – including the V-notch Charpy impact test and the small size center notched wide plate tensile test – were conducted on weld metal of a welded joint produced using LTT welding material. The results indicated that, despite the low Charpy impact absorbed energy values, the weld metal exhibits satisfactory fracture toughness.
We proposed that the required toughness standard for welding materials used in large welded steel structures and ship hull structures should be defined based on the transition temperature (vTrE) corresponding to 50% of the upper shelf absorbed energy.

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