巻号一覧
36 巻 (1998)
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前身誌
36 巻, 6 号
選択された号の論文の13件中1～13を表示しています
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大坪 英臣, 矢尾 哲也, 角 洋一, 末岡 英利1998 年 36 巻 6 号 p. 366-376
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーIn the early morning of January 2, 1997, a Russian tanker, “Nakhodka, ” had broken into two in the Sea of Japan, and the coast of Japan was seriously polluted by the spilled heavy oil. Following this disaster, the committee for the investigation on causes of the casualty of Nakhodka was established. In this paper, the characteristics of structural strength of Nakhodka at the casualty are described, which could have been known through the research activities and discussions in the committee.
Structural characteristics of Nakhodka are described first, and the thickness reduction of structural members are estimated based on the measured results. The ultimate longitudinal strength of Nakhodka at the casualty is evaluated applying the so-called Smith's method, and the possibility of overall collapse is discussed. The mechanism of fracture at the bottom plating is also discussed according to the scenario based on the observed fracture surface of the cross-section. Finally, a numerical simulation of the break-up of the hull girder has been carried out. It is shown that buckling/plastic collapse took place at the deck plating near Fr. 153, which was followed by the successive collapse of side shell plating. At nearly the same time, the bottom plating was fractured just in front of the transverse bulkhead at Fr. 153.抄録全体を表示PDF形式でダウンロード (4247K) -
笠原 直人1998 年 36 巻 6 号 p. 377-382
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーIn the case of elevated temperature structural design, attention should be paid to inelastic behaviors of structures caused from creep deformation, which have much influence on failure modes. For consideration of these behaviors, elevated temperature design codes provide simplified structural analysis methods with design criteria.
Among these methods, precise ones tend to become too complex for design use. On the other hand, recent development of computer technology reduced computational time of inelastic finite element analysis. Such simplified methods are desirable for screening rule as simple procedure which can explain mechanisms of inelastic behaviors.抄録全体を表示PDF形式でダウンロード (742K) -
中澤 崇徳, 天藤 雅之, 小松 肇, 加口 仁, 古藤 廣之, 山口 弘二, 山崎 政義1998 年 36 巻 6 号 p. 383-392
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーThe effects of manganese, carbon, and phosphorus on elevated temperature properties of high nitrogen Mn-Ni-Cr austenitic steels were investigated from the view point of phase stability. Creep rupture and creep fatigue tests were conducted mainly at 550°C. Microstructures of these specimens and aged ones were examined with electron microscope. The effect of manganese on creep rupture and creep fatigue properties was small. Reducing carbon content from 0.010% to 0.003% caused decrease in rupture strength and ductility and, also creep fatigue life. 0.005% P steel showed lower rupture strength and ductility than 0.026% P steel, but had higher creep fatigue life. Time-temperature-precipitation diagrams were determined between 550°C and 650t for up to 10000h as a function of manganese, carbon, and phosphorus contents. Reducing carbon content accelerated precipitation of Laves and Sigma phases while reducing phosphorus content retarded these precipitation. Precipitation of Laves phase reduced solute molybdenum content and would result in loss of rupture stength at long time. Sigma phase caused grain boundary embrittlement and would reduce rupture ductility and creep fatigue life.抄録全体を表示PDF形式でダウンロード (7652K) -
寺本 徳郎, 斉藤 正克, 渡部 真式1998 年 36 巻 6 号 p. 393-398
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーThe mechanical properties and fracture mechanism of a clean Ti-6Al-4V alloy made of electron beam remelting method were examined at 77K and 300K as well as a dirty Ti-6Al-4V alloy with much addition of nitrogen was tested for comparison. The fracture toughness of clean alloy is much larger than that of dirty alloy especially at 300K. Using laser scanning microscope, the morphological examination on the fractured surface was made. The fractured surface of clean alloy was almost occupied with ductile equiaxial and elongated dimples at 300K. Besides, the intergranular crack of primary α was often found at 77K. On the other hand, the dirty alloy had a lot of cleavage facets at 300K and a lot of cleavage and groove facets at 77K.抄録全体を表示PDF形式でダウンロード (6753K) -
筧 勝行1998 年 36 巻 6 号 p. 399-415
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーA low pressure storage tank is equipped with anchoring devices to make the tank shell resist internal pressure. When the anchoring devices are freed from the tank shell by some events such as over pressure. big earthquake, fatigue failure of attachment for the anchoring devices or etc., the lower region with annular and shell plates of the storage tank are moved and lifted from foundation surface by internal pressure and/or overturning moment due to earthquake on the storage tank. These parts of the storage tank to be lifted from the foundation surface are subjected to extreme stress and deformation.
For example analysis of the storage tank, this paper reports the analysis of the stress, deformation, lift-off acceleration, left-off speed and etc. under lift-off condition of the lower region of the storage tank. When the anchoring devices are freed from the tank shell, the storage tank is designed by the following conditions such as maximum internal operation pressure, minimum stored liquid height, strength of the annular and shell plates, allowable deformation of nozzles and it's piping, attached devices of the sensor for instrument and etc. for the storage tank.抄録全体を表示PDF形式でダウンロード (1628K) -
二次元FEM解析を用いた極低サイクル疲労寿命の評価伊木 聡, 川原 正言, 河野 武亮, 関根 和喜, 日向 直之1998 年 36 巻 6 号 p. 416-424
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーIn recent years, the importance of safety management for steel structures subjected to severe earthquakes has much been recognized. Especially in oil storage tanks, the shell-annular joints are supposed to suffer from large cyclic Plastic strains caused by bending moments due to uplifting of wall plates. It is required to establish an estimation procedure of the ultra low cycle fatigue life and the criteria of maintenance of these joints so as to prevent fatal accidents.
Several papers have reported about the relationships between crack initiation life and cyclic displacements, including the effects of joint geometry in low cycle fatigue. However, the crack growth behaviors have not been much studied in these welded joints under low cycle bending loadings.
In the present study, a series of two-dimensional finite element analysis was conducted for a fillet joint model subjected to bending. J integral values were calculated in steps for different crack depths and bending displacements. Crack growth rates was estimated by a power-law of J integral and integrated to obtain the failure lives. A good agreement was confirmed with experimental results obtained in previous reports.抄録全体を表示PDF形式でダウンロード (943K) -
秋山 俊弥1998 年 36 巻 6 号 p. 425-432
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーMany investigations have been conducted to evaluate a crack propagating distance of running shear fracture propagation in high-pressure gas pipeline. Four important equations, which they were gas decompression behavior, the crack velocity-pressure relation, the pressure at a crack arrest and change of crack velocity, were presented by their efforts from the results of many full-scale burst tests or application of the fundamental formulae.
A combination of these equations made it possible to calculate a crack propagating distance of running shear fracture propagation in high-pressure gas pipeline. But, there are two remaining problems for the calculation used only design factors. One is the reconstruction of two constants in the velocity-pressure relation to evaluate the influence of pipe diameter, and the other is to give the initial distance and the initial time which could be calculated from design factors for the numerical calculation of a crack propagating distance.
Recently, author proposed an estimable method for each problem, and these methods may be possible to be taken in above combination for the calculation of a crack propagating distance.
In this paper, a calculation method was presented which used only a few of design factors such as a sort of gas, internal pressure, pipe geometry and the characteristics of the pipe material, and the calculated crack distances were compared with the results of the full-scale burst tests, which include five kinds of pipe diameters, conducted by AISI.
The results showed good coincidence, therefore, this calculation method by only a few of design factors would be successful for the evaluation of a crack propagating distance of running shear fracture propagation in high-pressure gas pipeline.抄録全体を表示PDF形式でダウンロード (944K) -
有持 和茂1998 年 36 巻 6 号 p. 433-441
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーThe recent progress in steel plates for low temperature storage tank such as LNG, LPG ones are described in this paper.
First, general safety criteria for storage tankage is introduced with the rational basis from the point of fracture mechanics consideration. Then, actual properties of the steels and their weldments for these storage tanks, that is, 9% Ni steel for LNG storage tank and Low temperature AI killed or low Ni type steels for LPG one. Attention is focused in low temperature toughness both in base metal and their welds, and metallurgical and also fracture mechanics background for attaining required toughness or degree of fracture safety level is especially high-lighted. Finally, the safety level of each steels are categorized according to the fracture safety criteria.抄録全体を表示PDF形式でダウンロード (2627K) -
石川 雄一1998 年 36 巻 6 号 p. 442-452
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーPDF形式でダウンロード (1254K) -
冨田 正吾, 佐々木 明美, 金山 宏明1998 年 36 巻 6 号 p. 453-459
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーElectron beam welding (EBW) is a high- power- density beam welding method generally recongnized as a useful production joining process. Recently, on the viewpoint of weight reduction of a vacuum chamber, stainless steels have been being taken their places by thick aluminum alloys. EBW are used to assemble it. This report summarizes the principle of EBW and current researches for weldability and structural and mechanical properties of welded thick aluminum alloy joints. Moreover, some examples of EB welded aluminum component are introduced as the industrial application.抄録全体を表示PDF形式でダウンロード (8728K) -
木谷 靖1998 年 36 巻 6 号 p. 460-465
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーDevelopment of high power CO2 (over 45kW) and NdYAG (over 5kW) lasers enabled to apply laser welding to welding of thick gage structural steel plates.
Laser weldments have different characteristics of hardness, strength and toughness from conventional arc weldments because laser welding process has lower heat input and higher cooling rate than arc welding process. Mechanical properties of laser weldments should be investigated and improved in order to put laser welding to practical use.
At present, applications of laser welding are limited to special uses in nuclear industries, steel makers, automotive manufacturers and so on. In order to expand applications of laser welding to general use of welding structural steels in the near future, it is necessary to solve some problems such as high initial cost, requirement of high accuracy in weld groove and difficulty to avoid welding failures in weld metal.抄録全体を表示PDF形式でダウンロード (3811K) -
田原 隆康1998 年 36 巻 6 号 p. 466-468
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーPDF形式でダウンロード (2488K) -
1998 年 36 巻 6 号 p. 469-489
発行日: 1998/11/25
公開日: 2010/08/05
ジャーナル フリーPDF形式でダウンロード (2742K)
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