造船協會論文集
Online ISSN : 1884-2062
ISSN-L : 0514-8499
1956 巻, 89 号
選択された号の論文の12件中1~12を表示しています
  • 花岡 達郎
    1956 年 1956 巻 89 号 p. 1-6
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    In this paper the author introduces, in the theory of wave resistance, the conception of the acceleration potential which has been profounded by L. Prandtl1) on the field of aerodynamics of a wing and shows a few fundamental investigations of the linearized theory. This investigation is made with the object providing such a general method of the theory of wave resistance that we can also treat a non-uniform fluid motion around a ship.
  • 其の一, 二次元流場
    花岡 達郎
    1956 年 1956 巻 89 号 p. 7-12
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    This paper shows a fundamental investigation concerning a non-uniform theory of wave resistance.
    The author applied to the theory the new method that he analysed in his other paper1) in the conception of acceleration potential. In this paper the author analysed a non-uniform fluid field. of surface wave that is caused by a ship moving with constant velocity describing harmonic oscillations and treated only two dimensional case, but it will be also developed in three dimensional case by the same process.
    The subject of this paper is a deduction of a velocity potential and an integral equation that determines a relation between motion of a ship and fluid pressure on the ship.
  • 田宮 眞
    1956 年 1956 巻 89 号 p. 13-22
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    According to the idea established in parts I and II of this paper, the author has investigated the following questions-that is-1, the variation of form effect due to the variation of Froude's No., 2. the frictional stresses and resistance of a ship model, 3, the effects of the propeller ac tion and 4, the calculation of the turbulent boundary layer around the solid of revolution. The results are:
    1. When Froude's No, increases or decreases the variation of form effect is small, but it has a little tendency to flatten the hollows of wave resistance curve.
    2. The calculated frictional resistance of a ship model is 4% lower than measured value, but if it is calculated in accordance with Froude's formula, the diff ernce from the experimental value will be 12%. The calculated value will vary considerably if the relation between ζ and Γ changes to some extent.
    3. The effects of propeller action are small, the augmentation of frictional resistance due to propeller is the order of 1%. The calculation has been worked out in the case of 2-dimensional flow, the propeller is represented by a single sink.
    4. Applying Buns' theory to the flow around a solid of revolution, the momentum equation has been integrated. The calculated frictional resistance shew good proximity to the results obtained experimentally by Amtsberg.
  • 笹島 秀雄
    1956 年 1956 巻 89 号 p. 23-32
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    The author proposes here a new vorticity transfer theory whose fundamental form is τR=-ζ/2D lα2v'd2u/dy2, where τR is Reynolds stress, l the mixture length, α2d2u/dy2 the circulation arround turbulent fluid particle and D the distance between the particle and its image refered to wall surface. Effect of viscosity is introduced as a loss of vorticity which appears in the expression of v'.
    As an application of the theory the flows through circular pipe are calculated, and the result shows a good coincidence with experiment especially in the neighbourhood of wall. The theory can also explain the reason for variation of coefficient of correlation.
  • 西山 哲男
    1956 年 1956 巻 89 号 p. 33-40
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    In this paper the author considered the mutual interference of ship hull and propeller in shallow water and restricted water, in particular, from the standpoint of wave-making.
    The main problems treated are as follows.
    (1) Expression for the wave resistance of a system, consisting of ship hull and sink propeller, in shallow water and restricted water is obtained.
    (2) The cause of wave resistance augumentation by the suction of sink propeller is clarified from the viewpoint of component wave, with special reference to shallow water effect and restricted water effect.
    (3) The wave resistance augumentation is divided into two components, and explained substantially.
    (4) The wave wake at the position of sink propeller in shallow water and restricted water is considered.
    (5) The variation of propeller performance in shallow water and restricted water is shown in the variation of thrust coefficient and advance constant.
  • 其の七, 三次元船型の場合
    菱田 敏男
    1956 年 1956 巻 89 号 p. 41-58
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    In this report, under one assumption the author proposes an equation for the wave-making resistance of the ship forms in three dimensions. One of the characteristics of the equation is that we can use the diagrams prepared in the Report No.3 and then a direct calculation without searching for the velocity potential will be possible.
    And by this method he examines systematically in ditail the effects of principal dimensions of ships, coefficients of fineness, height of the center of gravity, load conditions, and rolling period etc. upon the resistance, mainly for cargo ship-forms and fishing-boat-forms.
    Now this study, the author supposes, comes to a close and the summary of the study is appended at the end of this report.
  • 加藤 弘
    1956 年 1956 巻 89 号 p. 59-64
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    The natural period of roll of ships in any condition can in general be obtained by the well known formula T=2πK√<gm>, where K is the transverse radius of gyration of ship, m the metacentric height and g the acceleration due to gravity. The radius of gyration has hitherto been expressed by the breadth moulded and recently by the breadth and depth moulded, but these simple methods can not afford satisfactory results. After investigations of rolling materials of many vessels, new formulae for K have been found to give sufficiently accurate values. For merchant vessels the formula is written as
    (K/B)2=f[Cbcu+1.10Cu(1-Cb)(H/d-2.20)+H/B2].
    where B is the breadth moulded, Cb the block coefficient, Cu the upper deck area coefficient, H the effective depth, i e, the depth moulded plus mean height of projected areas on Profile of erections and deckhouses, d the mean draught and f the coefficient depending on the type of ship. The value of f is 0.125 for passenger, passenger and cargo, and cargo vessels. The formula for K of warships is of the same form as for merchant vessels. The errors of K-values obtained by the new formulae have been shown within the limits of about 3 per cent.
  • 秋田 好雄
    1956 年 1956 巻 89 号 p. 65-74
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    In the “plastic-elastic problem” the author showed a solution of general two-dimensional boundary value problem by small perturbation method. Using conjugate complex variables z=x +iy and z=x-iy the stress function φ is expressed as (21) in the case of plastic deformation theory and as (44) in flow theory, where A is a constant of strain hardening, τ2 is invarient of stress deviator tensor szj, and σzz is stress perpendicular to the stress field.
    The problems are divided into next four cases;
    (I-A) plane stress problem (σzz=0) in plastic deformation theory
    (I-B) plane strain problem (εzz=0) in plastic deformation theory
    (II-A) plane stress problem in plastic flow theory
    (II-B) plane strain problem in plastic flow theory
    Introducing parameter p the fundamental equation are expanded and successive approximation are obtained as (28) (29) (30) etc. The Oth approximation is elastic solution, and the first approximation coincides in two theories. The second approximation has difference in two theories. A solution having no difference in two theories was shown in Fig.1. or (66). Following to the example of stress field of infinite plate with a circular hole under uniform tension (author's last report), an example of stress and residual stress distribution of the same plate under inner pressure P at the hole was calculated as Fig2-Fig5.
  • 秋田 好雄, 田中 信治郎, 山崎 福太郎
    1956 年 1956 巻 89 号 p. 75-81
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    The effect of magnitude and gradient of pre-strain distribution on the notch-brittleness of steel plate for ships was studied. Test pieces were of 450×70×16mm size, centrally notched (Fig. 4), and tested by slow tension. The pre-strains were given by two ways. One is ordinary way (uniform distribution), and its magnitudes were 0% (A-series), 5%(B), 10%(C), 15%(D). Another way was the gradient pre-strain distribution, which are given with a perforated test piece without notch (Fig. 2), and its magnitudes at notch-bottom were 5% (E-series), 10%(F), and 15%(G)
    The results were obtained as follows:
    (1) The pre-strain of 5% raises the transition temperature and more pre-strain does not raise the transition temperature (Fig. 8). But the pre-strain lowers the energy level.
    (2) The gradient of prestrain distribution has little effect on the transition. (Fig. 9)
    (3) Comparing with the experiment of Prof. Boodberg, the transition curve are sharper, and a Japanese ship plate (rimmed) showed the transition temperature of the same order with Prof. Boodberg's “C”-steel (semi-killed) after correction of r/t (Fig. 10), where r, t are the radius and thickness of test piece.
  • 金沢 武
    1956 年 1956 巻 89 号 p. 83-94
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    In order to explain the mechanism of brittle fracture of mild steel, flow stress surface and fracture stress surface are assumed as follows;
    Flow stress surface: J2=a2I21/2+A(dI1/220/dt)nes/T
    Fracture stress surface:
    σ11-1/2(σ33-|σ33|)=bI21/2+{B0-B1/2(σ-|σ|)}(dI1/220/dt)meU/T for σ11=Maximum principal stress σ33=Minimum principal stress ……etc
    Where J2, and I2=The 2nd order invariant of stress deviator tensor, and plastic strain deviator tensor, respectively
    σ=Mean of principal stresses, T=Absolute temperature
    A, B0, B1, S, U, m, n, a, and b=Material constants.
    S_??_170_??_180, U_??_65-75, n-m_??_0.02-0.04
    (B0/A)2(dI1/220/dt)2m-2n_??_{25(Statical tension) 10(charpy impact)
    dI1/220/dt=Total strain velocity, t=time
    I20=The 2nd order invariant of total strain deviator tensor.
    As the relation between transition temperature and r/t (r: notch radius, t: plate thickness) the following formula is obtained
    A2/B02e2(S-U)Tr=(3+e-2st/r)2(1+d2)+2d(e-4st/r-9)/12(3+e-2st/r)
    where A≡A(dI1/220/dt)n, B0=B0(dI1/220/dt)m d_??_{0.42(Statical tension) 0.09(charpy impact)
    Tr=Transition temperature (Absolute temperature), s=Constant.
    The calculated curves from this formula match very well with the experimental results by Mr. H.R. Thomas, etal., Mr. A.Boodberg, etal., and Mr. A.B.Bagsar.
    The data obtained by Mr. C.W.Macgregor etal., concerning with strain velocity and transition temperature are also explained by the above formula.
  • 林 毅
    1956 年 1956 巻 89 号 p. 95-103
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    According to the bending tests1) in still water of welded tanker “Neverita”, it was found that bending stress in the longitudinal bulkheads is very low and has great discrepancies from beam theory. The author thought that this phenomenon is due to shear-lag in bulkhead plate and analyzed by theory of shear field the stress distribution of the box-shaped beam with two longitudinal bulkheads (Fig.1) stiffened by stringers and especially, on the case which the bending rigidity of the box-beam is very large compared with that of longitudinal-bulkheads and the author obtained the general solution (22) of static equilibrium equation (3) or (20) for the boundary conditions of (4), (6) & k2_??_0 and the following results by the numerical example for the case of 11 stringers:
    (1) The inefficient action of longitudinal bulkheads is due to shear-lag.
    (2) The quantity K=(Gbt/EF) (L/H)2 has the great influence on the shear-lag phenomena, where Gbt, shear rigidity of the bulkhead; EF, extensional rigidity of stiffeners; L, H, length and depth of the bulkhead. When K is small, shear-lag occurs intensely, but when K is large, its stress distribution obeys approximately the usual beam theory as shown in Fig. 5 6, 7, 8
  • 小林 韓治, 石山 一郎
    1956 年 1956 巻 89 号 p. 105-112
    発行日: 1956年
    公開日: 2007/05/28
    ジャーナル フリー
    This report described the wire resistance strain meter which were designed by The Transportation Thechnical Reserch Institut, Ministry of Transportation and the measurement of stresses in The heavy derrick post.
    Accuracy of Reading; Observations can be made to an accuracy of 3×10-4mm which on a 30mm gauge length and corresponds a stress of 0.2kg sq. mm for mild steel.
    Time of Reading; It is possible to read one gauge in 10 seconds.
    Indicator: A 90-110 volt, 50-60 cycles, A.C. power Supply unit is avaiable for this instrument The proportional voltages due to the changes in the resistance produced by the Strains to the gauge fed into the two-stage amplifier operating two “magic eves”.
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