圧力技術
Online ISSN : 1347-9598
Print ISSN : 0387-0154
ISSN-L : 0387-0154
27 巻, 4 号
選択された号の論文の5件中1~5を表示しています
  • 河村 繁, 榎澤 誠, 野本 敏治
    1989 年 27 巻 4 号 p. 182-192
    発行日: 1989/07/25
    公開日: 2010/08/05
    ジャーナル フリー
    Design of bolted flange connections has been performed for only raised face flanges based on stress evaluations on them. New design method taking consideration not only stress evaluations but also sealing ability of the flanges was introduced into the Japanese Industrial Standards (JIS). Sealing ability was examined in terms of the variation in gasket load witch resulted from deflection of flange rings under both gasket seating and pressurized conditions.
    The maximum limiting pressures were calculated for each nominal size of steel full face flanges prescribed in JIS B 2220, by using above design method assuming soft full width gaskets. All variables in bolted flange connections, such as, dimensions and material properties of flanges, bolts and gaskets are included in the calculations.
    Calculated results revealed that the dimensions of flanges of nominal sizes ranging from 10A to 225A were almost reasonable in the view point of the rating pressures prescribed in JIS of 7kgf/cm2 (7kN/m2). In this range of nominal sizes, the calculated maxium limiting pressures increase with nominal sizes. There are some irregularities when bolt sizes or numbers of bolts change. In the flages of larger sizes than 250A, calculated maximum limiting pressures were far below the pressure required by JIS. Most of the limiting pressures for the flanges over 250A were limitied by the criterion of sealing ability because of low bending flexibility of the flanges, except the large size flange with extremely soft gasket, such as, rubber, in which stresses attain to the allowable stress under gasket seating condition
    It is shown that the maximum limiting pressure increases when thickness of gasket increases because of large allowance in compressed deflection of gasket at gasket seating to recovery at pressurized. The same tendency is also estimated remarkably as soft gaskets, that is, gasket with low Young's modulus are used. The maximum limiting pressures are also estimated on aluminium full face flanges, assuming A5083 alloy of allowable stress of 7kgf/mm2 (0.7MPa). The maximum limiting pressures, restricted by the criterion of sealing ability, on aluminium flanges with the identical dimensions to steel flanges decrease to 70% of those made of steel due to lower Young's modulus of aluminium alloy. In the case of stress limitation dominant, aluminium alloy flanges can be sustained to higher pressure than steel flanges due to short moment arms by larger flange ring deflection.
  • 南 起祐, 宮里 直矢, 安藤 柱, 小倉 信和
    1989 年 27 巻 4 号 p. 193-201
    発行日: 1989/07/25
    公開日: 2010/08/05
    ジャーナル フリー
    Fatigue life and crack through-thickness behavior was examined experimentally by using a large and small specimen. The material uesd was HT80 steel. The fatigue crack shape before through-thickness is almost semicircular, and the measured aspect ratio is larger than the value obtained by calculation using the K value proposed by Newman-Raju. It is found that the crack growth behavior on the back side after through-thickness is unique regardless of the specimen size and can be divided into three stages a, b and c. By using the K value proposed by the authors, remarkable crack growth behavior and the change in crack shape can be evaluated quantitatively. And also crack opening displacement can be evaluated quantitatively by using the model proposed by the authors.
  • 有限要素法による動的非線形解析
    山内 芳彦
    1989 年 27 巻 4 号 p. 202-209
    発行日: 1989/07/25
    公開日: 2010/08/05
    ジャーナル フリー
    Oil storage tanks are usually constructed directly on the earth foundations without anchors. In such a flat-bottom cylindrical tank subject to seismic excitaion, a part of the bottom plate adjacent to the shell will be lifted off the foundation due to overturning moment and it results in a failure of the shell-to-bottom junction. R. S. Wozniak and others treated the uplifted bottom plate as an elemental strip based on small deflection theory and assumed the development of two plastic hinges. Their investigations were summarized into API Standard 650 Appendix E as the seismic design provisions. But the nonlinear dynamic characteristics of this phenomenon are not yet clear.
    In this paper, calculations are carried out for a 9500kl oil storage tank under various conditions by the finite element code “CNCL-ND” developed by the author, and numerical results show dynamic effects on the uplifting behavior of tank bottom.
    As a result, it was found that the nonlinear relation exists between uplift height and uplift width of annular plate independently of excitation and it is also in good agreement with Wozniak's method. Furthermore, the ultimate strength of annular plate evaluated by Wozniak shows some conservative value in comparison with calculation results by FEM.
  • 松井 繁朋, 糸賀 興右, 緒方 隆昌, 平澤 英幸
    1989 年 27 巻 4 号 p. 211-220
    発行日: 1989/07/25
    公開日: 2010/08/05
    ジャーナル フリー
    The assessment of structural reliability of welded structures requires data on the reliability of NDT. To establish reliability of NDT, a lot of data are needed which relate kind, size, location and orientation of defect to test results of specific NDT methods. However, there is few data available. This is considered largely because it is difficult to fabricate a specimen with a defect of which real size and location are precisely known.
    The authors have developed specimens containing defects of which sizes and locations are known. The fabrication procedure of a specimen with simulated defect of controlled size and location by diffusion bonding is described. It was demonstrated that a planer defect as thin as 1μm is possible to be reproduced. Using specimens thus manufactured, reliability of ultrasonic testing was studied in terms of detectability and accuracy in defect sizing. It was shown that the detectability is affected more by defect orientation than by defect length or width. As for the accuracy, it was shown that ultrasonic testing in accordance with JIS Z 3060-1983 tends constantly to overestimate defect shorter than about 15mm. It was also demonstrated that indicated lengths fit fairly well to the normal distribution function. Mean values and standard deviations of indicated lengths were obtained for actual lengths ranging from 5 to 20mm where width and orientation of defect were taken as parameters.
  • 成田 圀郎
    1989 年 27 巻 4 号 p. 221-230
    発行日: 1989/07/25
    公開日: 2010/08/05
    ジャーナル フリー
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