Journal of High Pressure Institute of Japan
Online ISSN : 1347-9598
Print ISSN : 0387-0154
ISSN-L : 0387-0154
Search
Advanced search
OR
Browse
Search
Volume 56, Issue 5
Displaying 1-4 of 4 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Original Paper
  • Study on Installation of Ring Stiffeners to Prevent Buckling of Aboveground Oil Storage Tanks under External Liquid Pressure of Tsunami
    Shoichi YOSHIDA
    2018 Volume 56 Issue 5 Pages 250-258
    Published: 2018
    Released on J-STAGE: October 28, 2018
    DOIhttps://doi.org/10.11181/hpi.56.250
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Powerful tsunami attacked to the northeast coast of Japan due to the Great East Japan Earthquake occurred on March 11, 2011. Some aboveground oil storage tanks (ASTs) were subjected to external liquid pressure of the tsunami. An effective method to prevent the buckling of existing ASTs under external liquid pressure is to install ring stiffeners on the shell plate. In this paper, the approximate minimum required number of ring stiffeners and their installed location of ASTs are determined. The optimum design method which repeats the procedure to increase the buckling liquid height by installing a ring stiffener at the peak location of buckling mode is used. This method was proposed in the author's previous paper. The bifurcation buckling analysis is the axisymmetric shell finite element method. As a result, the two ASTs of 10, 000m3 and 90, 000m3 require 14 ring stiffeners in each case when external liquid height is set to the same as the design internal liquid height.
    View full abstract
    Download PDF (480K)
  • Influence of Engagement Condition on Stress Distributions at Screw Thread
    Yuya OMIYA, Naoki TAMURA, Masahiro FUJII
    2018 Volume 56 Issue 5 Pages 259-267
    Published: 2018
    Released on J-STAGE: October 28, 2018
    DOIhttps://doi.org/10.11181/hpi.56.259
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The stress states in the bolted joint is extremely important in the field of bolt tightening and operation management. Furthermore, construction managers must take them with changes under the usage in actual environment into consideration. Therefore, in this study, the engagement condition of bolt-nut was focused on to investigate the influence of these changes on the stress state of bolted joints using finite element analysis. In case that the engagement length is smaller than the nut height, the stress at the root of the screw thread would become larger and plastic deformation would be likely to occur. In the shear fracture evaluation, in the case where the engagement length is shorter than the nut height, the calculation result of Alexander's formula could be evaluated on the safe side, however in the case where the thread height decreases, the calculation result of Alexander's formula could become dangerous side.
    View full abstract
    Download PDF (1674K)
  • KIc　Testing for Micro-void Coalescence Type Fracture with Small Specimens and Assessment of Plane Strain Condition
    Akira KIUCHI, Kenichi ISHIHARA
    2018 Volume 56 Issue 5 Pages 268-278
    Published: 2018
    Released on J-STAGE: October 28, 2018
    DOIhttps://doi.org/10.11181/hpi.56.268
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    In the previous report, we proposed a new validity criteria of KIc testing for micro-void coalescence type fracture. According to that, there is a possibility that we can obtain the valid KIc of high strength Al alloys, Ti alloys and extra high strength steels using small specimens, ligament size, W-a, and thickness,B , of which are less than 25mm. In this report, old KIc data obtained with the small specimens have been assessed according to the new validity criteria, and the plane strain condition for KIc testing has been assessed on the basis of our previous 3 dimensional elastic-plastic finite element analyses of CT specimens. As a result, it was found that size independent KIc is obtained using the small specimens with W-a-<25mm, and it was proposed for the micro-void coalescence type fracture that provisional fracture toughness KQ or KSQ is equivalent to the valid KIc defined by ASTM E 399, provided that W-a, B≥1. 1｛ (KQ or KSQ) ⁄σys}2.
    View full abstract
    Download PDF (602K)
  • Hydrogen trapping along grain boundary and its effect on fracture
    Yutaka TSUCHIDA
    2018 Volume 56 Issue 5 Pages 279-288
    Published: 2018
    Released on J-STAGE: October 28, 2018
    DOIhttps://doi.org/10.11181/hpi.56.279
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Hydrogen trapping along grain boundary is an important issue in the study of hydrogen embrittlement of steels, and it has been discussed on available published information of mainly pure iron. The desorption profiles of thermal desorption spectroscopy (TDS) , with the aid of peak separation by Gaussian distribution function, the amount of hydrogen trapped by grain boundary was qualitatively determined. It is also revealed that hydrogen trapping along grain boundary is enhanced by slow straining rate under hydrogen absorption. These findings are sufficiently visualized by tritium autoradiography (TAR) and hydrogen micro-print technique (HMP) . Recently in martensitic high strength steel, it is also visualized by HMP that hydrogen accumulates along grain boundary and it is intensified by prolonged straining. Further this hydrogen accumulation was found to cause micro-crack formation along grain boundary that leads to the grain boundary type fracture. Hydrogen segregation along grain boundary should be the dominant factor for grain boundary fracture type hydrogen embrittlement.
    View full abstract
    Download PDF (817K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top