巻号一覧
53 巻 (2015)
- 6 号 p. 292-
- 5 号 p. 246-
- 4 号 p. 164-
- 3 号 p. 112-
- 2 号 p. 56-
- 1 号 p. 5-
前身誌
53 巻, 5 号
選択された号の論文の4件中1～4を表示しています
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論文
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屋嘉 広行, 中根 一起, 永田 徹也原稿種別: 論文
2015 年 53 巻 5 号 p. 246-254
発行日: 2015/09/25
公開日: 2015/10/27
ジャーナル フリーThe torispherical shell is a structure which is composed of a spherical, a toroidal and a cylindrical shell. When the internal pressure is loaded on a torispherical shell, hoop compression stress occurs around the junction between the spherical and toroidal shell, and this hoop compression stress can cause buckling.
The purpose of this study is to establish a evaluation method for the internal pressure buckling of the torispherical shell using FEM (Finite Element Method) . For the evaluation of the buckling pressure by the FEM, it is important to give appropriate initial imperfection setting to the analysis model. We investigated the effect of the magnitude and shape of the imperfections on the buckling pressure, and examined the method of evaluating the minimum buckling pressure. We estimated the minimum buckling pressure vs. the thickness relationship from the minimum buckling pressure at a certain thickness. This evaluation showed the same tendency of conventional studies.
We estimated the permissible pressure of the actual thickness based on the proposed FEM.抄録全体を表示PDF形式でダウンロード (2073K) -
吉田 聖一原稿種別: 論文
2015 年 53 巻 5 号 p. 255-265
発行日: 2015/09/25
公開日: 2015/10/27
ジャーナル フリーPowerful tsunami attacked to the northeast coast of Japan due to the Great East Japan Earthquake occurred on March 11, 2011. Some aboveground storage tanks (ASTs) were subjected to external pressure due to the tsunami. This paper presents the bifurcation buckling of shell plates in 1, 000m3 , 10, 000m3 and 90, 000m3 AST under both internal and external liquid pressure using the axisymmetric shell finite element method. The buckling of cylindrical shells which have the same diameter and thickness as ASTs has been also analyzed for the comparison. The buckling liquid height of an AST is less than that of a cylindrical shell. The reduction ratio of buckling liquid height of an AST from a cylindrical shell is proposed. The buckling liquid height of an AST can be simply obtained from that of a cylindrical shell using the reduction ratio.抄録全体を表示PDF形式でダウンロード (970K) -
土田 豊原稿種別: 論文
2015 年 53 巻 5 号 p. 266-273
発行日: 2015/09/25
公開日: 2015/10/27
ジャーナル フリーReported thermal desorption curves were subjected to peak separation by Gaussian distribution to evaluate numerically the state of hydrogen. The curves had been obtained on heavily cold rolled pure iron that was hydrogen-charged by cathodic polarization at different temperatures and current densities. All the curves were successfully decomposed into sub-peaks corresponding to lattice, dislocation, grain boundary, vacancy and vacancy cluster. The hydrogen partitioning among them were sophisticatedly depending on the charging temperature. Hydrogen in lattice or trapped by dislocation ever decreased with temperature until 363K;hydrogen trapped by vacancy type defects (vacancy or vacancy cluster) increased up to 363K. The amount of hydrogen trapped by grain boundary had a combined feature of these two types, presenting its maximum at 333K. As trap efficiency of all traps decreased monotonously with charging temperature, temperature dependence of trap densities is important. Density of dislocation trap was almost unaffected, that of grain boundary trap increases up to around 333K, and those of vacancy and vacancy cluster 363K. These features are useful for deciding hydrogen charging temperatures that is corporative to fracture mode;quasi-cleavage or inter-granular fracture which is relevant to vacancy type traps or grain boundary trap respectively. They are also useful in judging the temperature of hydrogen entry, through the straightforward relation between the amounts of hydrogen trapped by dislocation and grain boundary.抄録全体を表示PDF形式でダウンロード (468K) -
徳武 皓也, 西 晴樹, 笠井 尚哉, 岡崎 慎司原稿種別: 論文
2015 年 53 巻 5 号 p. 274-281
発行日: 2015/09/25
公開日: 2015/10/27
ジャーナル フリーA reasonable evaluation method is proposed based on an extreme value analysis for the appropriate management of a high-performance anticorrosion organic coating applying to the internal surfaces of the bottom plates of oil storage tanks. The analysis was applied to the values of constant-phase element (CPE) parameters extracted from the field impedance data obtained from the actual oil storage tanks. It was found that the representative degradation characteristics of the coating before the formation of visual defects can be evaluated by using the probability plots of the maximum values.
In addition, the comparative evaluation of the degradation degree of the coatings between oil storage tanks was performed using this method.抄録全体を表示PDF形式でダウンロード (403K)
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