For bending problems of the general axisymmetric shell, the finite difference method has been widely used as well as the finite element method, and B.Budiansky and P.P.Radkowski have proposed a finite difference method based on Sanders' shell theory. In this paper, two numerical methods for statical bending and free vibration problems of the general axisymmetric shell are pressented. One of them is based on Flugge's shell theory, which is well used in our country, and the other is based on Mizoguchi's shell theory, the utility of which has been probed especially for various problems of cylindrical shells. The above-mentioned two methods are described by the equations of the same form as those by Budiansky and Radkowski, only the coefficients of which are different. These three methods are applied to some statical bending and free vibration problems at the same time, and it turns out that the results by these methods almost coincide with each other.

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This paper presents both the experiments and the explanations on the influences of hydrostatic pressure and the stress distribution upon the rupture of a marble cylinder in torsion. In the experiments coated and naked hollow and solid cylinders were twisted under hydrostatic pressure, and the following informations were obtained. (1) The yield point of a coated cylinder is remarkably influenced by hydrostatic pressure, and the stress at the yield point rises proportionally to hydrostatic pressure. A crack reaches near the center of the cylinder firstly at the yield point, and such a crack comes out successively as the shearing strain increases after the yield point. (2) The effects of hydrostatic pressure and the stress distribution upon the rupture of the coated cylinder are respectively accounted for by Nakanishi's theory on the rupture of brittle materials. (3) In a naked cylinder, pressure oil penetrates into the material, so the influence of hydrostatic pressure can not be recognized so much as in the coated cylinder.

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In order to examine the adaptability of the copper electroplating method to low temperatures, alternating torsion tests are made at temperatures between room temperature and -80°C. The specimens tested are cooled by vapourized liquid nitrogen. The relation between the limiting value of shearing strain which causes grain-growth in the deposited copper and the testing temperature is investigated, and the temperature range favourable for application of the method is studied. It is found that the present method has the same reliability at low temperatures as at room temperature. In the vicinity of -80°C, however, the limiting value of shearing strain is too high and the initial grown grains in the deposited copper become extremely fine, giving unavoidable errors in the measured values. It is concluded that the present method may be used down to -50°C in practice.

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Problems concerning the elastic deformation of a strip having an angular notch with a circular root under tension have been investigated by the elastic theory or the photoelasticity, and those concerning its plastic deformation have been analysed in the static equilibrium state by using the conventional plastic theory. In the usual deformation of actual materials, however, the stress distribution and the amount of deformation are affected by the deformation history in the transient period from the instant of loading to that state. Therefore, in order to analyse the actual deformation of real material precisely, the deformation should be investigated with the elastic-viscoplactic theory in which deformation history and time dependence are taken into account. In the present paper, the deformation of a softened celluloid strip having an angular notch with a circular root under constant compressive load is investigated by using the photorheologic method in the period from the instant of loading to the static equilibrium state 300 min after loading. The stress state in the strip is discussed comparing with the existing results in elasticity and the effect of viscoplastic property of real materials in the deformation is emphasized on the stress concentration.

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In a non-linear vibratory system subjected to several periodic external forces of different frequencies Ω₁, Ω₂…, Ω_M, so-called combination oscillations of frequency Ω=|m₁Ω₁+m₂Ω₂+…+m_MΩ_M|, (m_j=±1, ±2, …) can occur, if Ω is close to the natural frequency of the system. In this paper we first investigate the general characteristics of such oscillations in a system possessing some non-linear characteristics. To carry on the investigation further we then take up a typical case in which three forces act on a system having the non-linear characteristics of a cubic function of the displacement, and discuss in detail the characteristics of the combination oscillations of frequencies Ω=|Ω₁±Ω₂±Ω₃| induced in the system. Finally using an analog-computer we verify that these types of oscillations in fact occur.

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This problem has been studied on the assumption of a constant angular acceleration (Ω) taking account of the damping effect (D). The exact solution of this problem has been obtained by using error functions with complex variables but it is not suitable to understand characteristics of the transient vibration. In this paper, approximate solutions, which show the characteristics of the transient vibration in simple forms, are derived by using the series and the asymptotic expansion for the error functions. From this analysis it is found that when DΩ is larger than √(2), the characteristics of the transient vibration is simillar to that of the steady vibration. When DΩ is smaller than unity, and if √(1-D<SUP)2>+(1/Ω)√(2-D<SUP)3Ω²><τ(τ : nondimensional time) the approximate solution is written in the following form, e/X_G=√(π/2)(√(/1-D<SUP)2>)exp(-Ω²D(τ-√(1-D<SUP)2>cos(Ω²√(1-D<SUP)2>τ-Ω²/2+Ω²D²-π/4)+1/√(1/(τ<SUP)2-1)²+(2Dτ)²>cos(1/2Ω²τ²-β) where the first term represents a free vibration and the second term a forced vibration.

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A theoretical investigation about unsteady aerodynamic forces acting on a thin vibrating aerofoil with leading edge separation is presented on the assumption that unsteady component of velocity is small compared with velocity of uniform flow, and flow separates from the leading edge smoothly. In this theory is taken into consideration the effect of disturbance in the wake. But the unsteady aerodynamic forces due to the karman vortex street which has a close relation to a separated flow are neglected for the reason that the effect of Karman vortex street on the stall flutter can be separated from the effect of pure aerodynamic forces due to blade vibration in the greater part of angles of attack. Agreements between computational and experimental results are satisfactory for a relatively small reduced frequency.

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This paper presents an experimental study concerning the variation of the microscopic characteristics of a decaying turbulence generated in a closed vessel. The decaying process was analyzed on the assumption that the turbulence was able to be treated as steady during a short time interval along the decaying curve. That is to say, for such time interval, the relation between the fluctuating components as well as their time scales and the mean flow components was investigated. The time scales (mean-time-scale, micro-time-scale and energy-mean-frequency) were derived from the Eulerian correlation function and the spectrum function of the measured fluctuating velocities. The results are : (a) the difference between characteristic of turbulence in the pre-relaxation stage and the one in the relaxed stage (defined in the first report) was made clearer, and (b) the behavior of variation in characteristic values (fluctuating components and time scales of turbulence) was made known.

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The resonance tube is a cylindrical cavity, closed at the downstream end, which is excited to oscillation by a coaxial air-jet.This paper presents the experimental and the theoretical analysis on the unstable resonant phenomenon of the resonance tube with a secondary resonator. This phenomenon is explained by determining the characteristics of the acoustic impedance on this apparatus. Considering that the resonance tube and the secondary resonator are independent of each other, their acoustic impedances are calculated. And when they are set close, the acoustic mutual inductance yields due to the acoustic coupling, and then the impedance of the resonance tube increases. The unstable resonant phenomenon is explained by the calculation of the impedance on the coupling resonators.

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Experimental data are presented on the pressure drop, mean liquid film thickness, state of gas-liquid interface, droplet entrainment and its momentum, and heat transfer coefficient for downward annular and annular-mist two phase (two-component) flow in a vertical tube. From these data, the relation between the state of interface and the friction factor of gas stream in the core, and the relation between the liquid film flow rate and the mean film thickness are discussed. The characteristics of the mean film thickness with respect to the film Reynolds number are revealed comparing with the analytical predictions for laminar and turbulent films. On the basis of the experimental results of heat transfer coefficient, a correlation of the laminar sublayer thickness of liquid film is also presented for the mean film thickness.

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Experimental data are presented on the pressure drop, mean liquid film thickness, state of gas-liquid interface and droplet entrainment for upward annular-mist two phase flow in a vertical tube. Using these data, the relations between the shear stress at gas-liquid interface, the liquid film flow rate and the mean film thickness are investigated, and the characteristics of the mean film thickness with respect to the film Reynolds number are revealed by comparing with the analytical predictions for laminar and turbulent films. A heat transfer experiment is also performed and the results are compared with the analytical values of heat transfer coefficient for laminar and turbulent film flow. On the basis of the experimental data of heat transfer coefficient, the nondimensional thickness of the laminar sublayer of liquid film is calculated for both upflow and downflow, and correlated with the nondimensional film thickness. The result represents the difference in flow state between the upflow film and the downflow film.

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The characteristics of a cylindrical electrostatic probe inclined to the flow direction of a weakly ionized, high-density gas have been studied. The experiment was conducted by using potassium-seeded propane-air combustion gas flows. A brief theory for such a probe was developed also, and the results were compared with the experimental results. The ion current j₊ to the probe inclined at an angle φ to the flow direction was found to change with φ. The maximum and minimum ion currents were obtained at φ=90 and 0°, respectively. It was shown that the relation between j₊ and φ could be expressed as follows : j₊/j₊₉₀=sin^0.43φ, where j₊₉₀ is the ion current at φ90°. This relation agread well with the experimental results in the range 30°≤φ≤90°.

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In the thread grinding machine, it is desirable to align the lead-screw and the workpiece on a straight line in accordance with Abbe's principle. But this alignment requires a long space. When the leadscrew and the workpiece are paralleled as in a usual thread grinding machine, it is assumed that the pitch error of the ground workpiece screw is influenced by the tilting motion and out-of-straightness of the table traverse. It is the purpose of this paper to investigate fundamentally how the tilting motion and out-of-straightness of the table traverse change as running time goes by, and how they geometrically influence the pitch error of the ground workpiece screw. In practice, the tiliting motion and out-of-straightness of a certain thread grinding machine are measured over 1 m in length by the autocollimators and the electric level testers. As the result, it is found that the tilting motion of the table traverse much influences the accumulated pitch errors, and that the machine is thermally deformed by some heat sources and the accumulated pitch errors vary during the machine running. Furthermore, some considerations to reduce the accumulated pitch erors are made.

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