In-plane buckling may occur when internal pressure load acts on the U-bellows. In-plane buckling can be prevented by attaching an annular reinforcing member called“Reinforcing ring” that fills the valley of the bellow. U-bellows with “Hollow reinforcing ring” have no design formula that can consider the effect of reinforcement.
Authors performed detailed 3D-FEM analysis on the hollow reinforcing ring attached bellows to clarify the relationship between the buckling internal pressure and stiffness of the hollow reinforcing ring. The buckling internal pressure was proportional to the 1.4 power of the equivalent plate thickness which is derived by considering the bellows and the reinforcing ring as overlapping beams. In addition, In-plane buckling analysis was performed assuming that the bellows was deformed by the relative displacement at both ends. The buckling internal pressure was decreased by only 8% due to the influence of the maximum possible relative displacement.

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HPIS Z101-2, “Assessment Procedure for Crack-Like Flaws in Pressure Equipment - Level 2” provides the methodology for the evaluation of fitness-for-service for detected flaws in structural components during in-service inspection. The reference stress solutions for fundamental structures with surface flaws are prepared in the present standard for the assessment of the acceptability of the detected flaws. From the viewpoint of the comprehension of available solutions for excessive conditions, additional reference stress solutions for single edge flaws in plate, axially through-wall flaws in cylinder, circumferentially through-wall flaws in cylinder, and through-wall flaws in sphere are required. In this paper, the appropriate reference stress solutions to be adopted for the above structures were investigated by comparing the existing solutions in referable codes⁄standards.

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The purpose of this research is to establish a technique to predict weld distortion of large welded structures with practical accuracy and calculation time. The issue of the manufacturing process of large welded structures is improvement of productivity because it takes a lot of time to correct the weld distortion generated in the structure. Thermal elastic-plastic analysis has been applied as a tool to predict weld distortion, but calculation load is high and calculation time is extremely long. Thermal shrinkage technique is expected as a promising technology that can achieve both high accuracy and high-speed calculation. In this technique, shrinkage strain generated during the cooling process in the welding is applied to a specific region which is called shrinkage area, and then elastic-plastic analysis is performed. In this study, a parameter study was performed for the bead-on-plate welding in order to establish the setting method of shrinkage area, which is input data of thermal shrinkage technique. To evaluate effectiveness of thermal shrinkage technique, this technique was applied to inner surface buttering welding of cylindrical structure. The result of the thermal shrinkage technique was compared with the experimental result. In the bead-on-plate welding, the result of thermal shrinkage technique with rectangular shrinkage area consisting of width w and length (h +2d_h) was in good agreement with the experimental result (w: bead width, h: bead height, d_h: depth of heat affected zone). The thermal shrinkage technique with the established setting method was performed to the inner surface buttering welding of the cylindrical structure. The result of the thermal shrinkage technique was in good agreement with that of the experiment, suggesting that the thermal shrinkage technique had practical accuracy. The calculation time of the thermal shrinkage technique was 1⁄389 for bead-on-plate welding compared with thermal elastic-plastic analysis, which clarified that calculation time could be drastically shortened. In addition, the calculation time of the thermal shrinkage technique for cylindrical structure was about 30 minutes under given computing environment, which showed that the prediction of weld distortion for large structure could be performed with practical calculation time. It was concluded that the thermal shrinkage technique is effective to predict weld distortion of large welded structures with practical prediction accuracy and calculation time.

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In the damage evaluation (and analysis) of the bolted flange joints, it is most important to evaluate the reduction in the sealing performance. Although the marginal nut height found by Alexander’s theory serves as a value smaller about 20% than standard nut height, even if it becomes thin 20% or more on a track record and experience, leakage does not occur. In this study the effects of nut thinning due to corrosion on the sealing performance in 3-inch bolted flange joints under internal pressure by use of FEM calculations. The following results are obtained the relationship between stripping bolt load and nut height and width is developed, and the marginal nut height and width for the sealing performance is calculated.

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Hurricane Harvey made landfall late night on August 25, 2017 at the southeastern Texas Gulf Coast as a category 4. After striking land, Harvey was downgraded to a tropical storm on next day afternoon. Its moving became slow. Nevertheless, Harvey was producing heavy rain across the Greater Houston area, which had led to significant flooding. Crosby is 35 km northeast of Houston. The chemical plant of Arkema Inc. in Crosby produces a variety of organic peroxide products. Organic peroxides are unstable chemicals which continually decomposed with heat generation at a rate that depends on their temperature. They need to remain at a low temperature in cold storage. Arkema Crosby plant lost all power and refrigeration capability in the hurricane flooding. Organic peroxide products stored inside refrigerated trailers decomposed, causing the peroxide and the trailers to burn. The U.S. Chemical Safety and Hazard Investigation Board (CSB) released the final report on the cause of this incident on May 13, 2018. This paper describes this incident from a viewpoint of the emergency responding of hazard material storage facility due to flooding based on the CSB report.

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