In a previous paper, it was shown that stresses arising in a floating roof subjected to sloshing are significantly underestimated if the nonlinearity of the sloshing is neglected. In this paper, dependence of the nonlinear responses of the stresses on the slope of the pontoon is examined. Numerical results show that the decrease in the slope of the top and bottom of the pontoon results in decrease of the out-of-plane stresses and increase of relatively small in-plane stress components. Furthermore, the validity of the present nonlinear sloshing analysis is confirmed by conducting numerical calculations for the cases in which the pressure under the pontoon becomes negative and the free liquid surface oscillates with finite amplitude. It is confirmed that the results for the negative pressure and the surface displacement are in good agreement with results presented in past works.

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The 2003 Tokachi-Oki earthquake caused severe damage to oil storage tanks due to liquid sloshing. Seven single-deck floating roofs had experienced structural problems as evidenced by sinking failure in large diameter tanks at the refinery in Tomakomai, Japan. The pontoons of the floating roofs might be buckled due to circumferential bending moment during the sloshing. The content in the tank was spilled on the floating roof from small failures which were caused in the welding joints of pontoon bottom plate by the buckling. Then the floating roof began to lose buoyancy and submerged into the content slowly. The authors had reported the buckling strength of the pontoons subjected to circumferential bending load and to both circumferential and radial bending load in the previous papers. This paper presents the buckling strength of the pontoons subjected to both circumferential bending load and circumferential compressive load. The axisymmetric shell finite element method is used in the analysis. Linear elastic bifurcation buckling analysis is carried out and the buckling characteristics of the pontoon both with and without ring stiffeners are investigated.

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A model was proposed to estimate temperature change during filling or discharging hydrogen into a tank by authors. It verifies to be a good agree-ment between the measured and estimated temperatures of hydrogen. Seven non-dimensional parameters, which govern the temperature change, are derived from the governing equations and are constituted from 14 parameters concerned with this process. One of them is a controlled one related to the pressure change or mass flow rate. Some case studies have been done based on a corresponding filling test using actual tanks. The effect of these parameters on the temperature characteristics has been clarified for the actual vessel during charging hydrogen up to 35MPa and 70MPa.

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Neutron diffraction method is very much effective for measurement of residual stress and texture in the engineering materials. Now a new neutron science facility named as Japan Proton Accelerator Research Complex (J-PARC) is under constructing in Nuclear Science Research Institute of JAEA. In this paper, an outline of J-PARC and Ibaraki Prefecture's Materials Design Diffractometer to be installed in J-PARC are introduced. In addition, present situations of industrial application of neutron scattering are reviewed.

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A standard draft of ”Fitness-For-Service assessment “for oil storage tanks was completed by TSM Committee in HPI, sponsored by JOGMEC, in 2007 March. This paper presents the outline of the standard which was completed to keep safe operation against long term material deterioration and⁄or disaster such as corrosion and earthquake.
The object components of FFS assessment are shell plate, annular plate, and bottom plate of oil storage tanks. As to failure mode, general metal loss, local metal loss, pitting corrosion, and crack-like flaw are taken into consideration. The assessment procedure is classified into three levels, from “level one” to “level three”, in order to promote tank users, such as operators and maintenance engineers in oil stock piling terminals, to use this standard by themselves. This standard is prepared to put emphasis on “level one” procedure in which simple calculation formulas are adopted.

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