圧力技術
Online ISSN : 1347-9598
Print ISSN : 0387-0154
ISSN-L : 0387-0154
43 巻, 4 号
選択された号の論文の4件中1~4を表示しています
Original Paper
  • 第1報: 側板変形を考慮した浮き上がり解析および簡易解析法との比較
    石田 和雄, 茨田 高志, 山口 悟, 河野 和間, 関根 和喜, 丸山 裕章
    2005 年 43 巻 4 号 p. 190-199
    発行日: 2005年
    公開日: 2005/08/31
    ジャーナル フリー
    During intense seismic activity, strong horizontal excitation forces acting at the bottom of the unanchored oil tank shell can create an overturning moment and uplift displacement. To explore this, we carried out a nonlinear FEM static analysis to quantify the uplift displacement of an 110, 000m3 oil storage tank when subjected to the maximum response pressure load of the “Far-Off-Sanriku Earthquake” (1994) . A 3-dimensional shell model and maximum ground acceleration value of 293gal were used for the analysis.
    The maximum uplift displacement of the tank shell was calculated to be 188mm. For the circumferential distribution of this displacement, the first Fourier coefficient of cosine mode, a1, was about 40%; the second, a2, about 25%; a0 about 18% and the third, a3, about 14%. The Fourier coefficients for circumferential distribution of shell radial displacement were 30% respectively for cosine modes a1, a2 and a3. The analysis also showed that inward deformation of the shell occurred in the upper section of the tank at the uplift maximum part.
    A simple static model analysis showed that the maximum uplift displacement of the tank shell was about 100mm. However, no allowance was made for tank shell deformation in this analysis.
    A comparison of the uplift displacement of the 3D model with that of the simple model shows that the displacement simulated by the simple model corresponds to the summation of cosine modes a0 and a1 from the 3D shell model analysis. The a0 and a1 cosine modes are also regarded as rigid modes of shell plate.
    The ratio of total mode uplift displacement to (a0+a1) varies from 1. 2 to 1. 8 as the seismic load accelerates to full load (293gal) . This ratio is defined as the “mode correction factor of shell uplift”, and the real uplift displacement can be calculated by multiplying the value for uplift displacement obtained from the simple model by the “mode correction factor”.
  • 岩崎 和市
    2005 年 43 巻 4 号 p. 200-207
    発行日: 2005年
    公開日: 2005/08/31
    ジャーナル フリー
    Fuel cell vehicle (FCV) has already been put to practical use in 2002. FRP tank system has a important roll to spread FCV in commercialization. In order to realize the FRP tank system for 35MPa, we estimate the convenience of this system, and evaluate the characteristic of A6061-T6 liner of FRP tank system. MH (Metal hydride) tank system (effective hydrogen storage capacity: 31. 25m3) was prototyped, and filling test was also conducted. Basing on evaluated 35 MPa FRP tank system, we estimated the hybrid hydrogen storage vessel, which consisting Al-CFRP composite vessel and a small amount of MH. Next generation MH with more than 4 mass% capacity has also considered in this paper.
  • 大城戸 忍, 林 眞琴, 皆川 宣明, 森井 幸生, 安藤 柱
    2005 年 43 巻 4 号 p. 208-215
    発行日: 2005年
    公開日: 2005/08/31
    ジャーナル フリー
    Residual stress is known to be redistributed as a result of crack extension. The neutron diffraction method was used to evaluate this residual stress redistribution, using a specimen consisting of a butt-weld-jointed pipe made of type-304 austenitic stainless steel (inner diameter φ=97. 1mm, thickness t=8. 9mm) . Half-elliptical cracks were introduced by an electrical discharge machining at the inner surface of a heat-affected zone. The ratios of at, for crack depth a and specimen thickness t, were 0. 25 and 0. 5, with aspect ratios ac, for crack half-length c, of 0. 1 and 0. 5. Comparing the residual stress distribution before and after the crack introduction showed that although the residual stress distribution along the line of the ligament at the deepest point of the crack changed slightly in front of the crack tip, it did not change throughout the ligament. This result shows that residual stress redistributes throughout in the whole crack tip region, including the width of the crack.
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