Little attention has been paid to materials with different deformation responses to simple tension and compression, except to certain types, such as concrete. Yet, recently developed new materials, certain composites or high-polymers are said to exhibit more or less the avobe described behaviors. In this paper, as an example of analysis of plate or shell made of such materials, a circular cylindrical shell subjected to a uniform internal pressure is investigated. Since the elastic constants of these materials in a deformed body which depend on the sign of stress are unknown in advance, numerical analysis is performed by a successive approximation method, starting from an appropriately assumed stress state close to the desired solution. Results show that distributions of membrane force and bending moments in the circular cylindrical shell vary considerably with difference between tensile and compressive moduli of elasticity. Since precise experimental data on these materials are however still lacking, publication of such data is eagerly being waited for.

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In a nonlinear multidegree-of-freedom system subjected to harmonic excitation of frequency ω, a special type of oscillation is expected to occur when the linear combination (1/N)Σ^^k__(i=1)m_ip_i(N=2, 3, 4, ... ; m_i=±1, ±2, ...) constructed from the natural frequencies p₁, p₂, ..., p_k of the system is close to ω. This oscillation, if it occurs, contains several harmonic components with frequencies ω_i (i=1, 2, ..., k) satisfying ω_i≒p_i, ω=(1/N) xΣ^^k__(i=1)m_iω_i, and may be termed "super-division harmonic oscillation." Theoretical investigation on the occurrence of this type of oscillation is carried out for an important case of a two-degree-of-freedom system with nonlinear spring characteristic expressed by third order polynomials of the displacements and it is shown that the above type of oscillation really occurs in the system when 1/2(p₁ +p₂) is close to ω. Numerical calculations are performed and the theoretical investigation are checked against those of an analog-computer.

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As a roller chain possesses a high modulus of elasticity for elongation and its mean line density is comparatively large, the influences of the weight of the chain and of the fluctuation or tension during vibration on the frequency and the mode of natural vibration are remarkable. Hence the linear theory seems hardly to be valid. In this report, the forced vibration of the chain spanning vertically with boundary conditions where it is fixed at the one end while subjected to a harmonic forced displacement at the other end is investigated. It is shown that the properties of nonlinear forced oscillations reveal a typical hard spring type and vary with a shape parameter K of the link, a total link number N, a parameter p constructed of the ratio of (total weight of a chain /2) to tension T_m and a parameter λ composed of the amplitude of forced displacement A, modulus of elasticity E_d, tension T_m and total length l. The theoretical and the experimental results are compared. In order to estimate the influence of the friction in the bush parts, miniature bearings were inserted in these parts to remove friction.

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A two-degree-of-freedom gyroscope can't preserve its original direction when a housing on which the gyroscope is mounted oscillates. This problem has been dealt with by many people, but their works have been in want of universality in condition. In this paper, authors discuss the motion of a gyroscope mounted on a housing oscillating about an axis having arbitrary direction, and obtain the formulas of the drift rates by taking advantage of the fact that one can regard a two-degree-of-freedom gyroscope as a spherical quadric crank chain mechanism when the spin axis remains unchanged. And they investigate the effect of the dynamic unbalances of gimbals, the flexibility of a rotor shaft and frictions of bearings. And authors manufacture a gyroscopic vibration absorber for trial and examine its effect.

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An investigation was made into optimal control for automatic steering of a fork lift which is hard to maneuver on account of its rear-wheel steering. First, the vehicle motion was examined, and an optimal control law of the vehicle motion was studied as a linear regulator problem of modern control theory. Then, vehicle travel experiment and analogue simulation were performed. This experiment and simulation proved that an automatic steering mechanism designed after a simple manually operated model can hardly feed back all state variables in accord with optimal control law, but a favourable result was gained at travel velocities up to 3 m/sec. In a rear-wheel-steered fork lift, forward travel requires more severe specification for servo system than reverse travel does, which corresponds to front wheel steering.

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Rotation of a centrifugal impeller and blade curvature have much effect on the boundary layer flow along the blade surface. Since these effects do not appear in the flow of zero-order boundary layer approximation, in this analysis the perturbation method is used to obtain flows of higher orders in case of the laminar boundary layer. In the first place, a general theorem is presented for the effect of rotation on the laminar boundary layer on the surface of a two-dimensional body with arbitrary shape. In the second step, the laminar boundary layer on a rotating circular arc blade is analyzed as one of the simplest models of a centrifugal impeller blade. To consider the more general cases, effects of the main stream velocity and the blade geometry are taken into account. Further later in the present paper, results of the numerical calculation are shown for a thin logarithmic spiral blade in case that the main stream velocity changes linearly.

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In a flow field without pressure gradient, wind tunnel measurements of the pressure distributions on two-dimensional normal plates were carried out by eliminating the blockage effects to correlate with the characteristics of a smooth-wall boundary layer in which they are immersed. The drag coefficients are found to be expressed as a logarithmic function of h/σ up to h/σ =1.20, whereσ is the thickness of the undisturbed boundary layer at the position where the plate is mounted. Further, a correlation is obtained between the variation of form drag and the plate height h, which is analogous in form to the law of the wall of a boundary layer velocity profile. A method of calculating the pressure distributions on the front surface of the normal plate is proposed to analyse with the aid of a free-streamline theory. The method involves four parameters, however, which must be determined experimentally. The velocity field is integrated to construct a flow pattern for the purpose of comparing with one obtainable by the present analytical method.

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Flow patterns of three two-dimensional parallel jets were investigated experimentally. In order to examine the effect of varying the ratio of the velocities in the central and outside jets on flow pattern, detailed measurements of the flow by a hot-wire anemometer and flow visualization by oil film were carried out. The results obtained are as follows. (1) The flow fields near the nozzles can be classified in three patterns of the flow according to the velocity ratio. 82) There is a specific velocity ratio at which the flow is unstable. (3) The flow patterns by means of visualization agree well with those of the streamlines, qualitatively.

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This paper presents the following two velocities in terms of nondimensional factors : (a) The mean suspension velocities of single freely-suspended spheres in a pipe v₁, (b) The terminal velocities of single spheres falling through still water in a pipe v₂ . The experiments were carried out with changes in sphere diameter d, specific gravity of sphere γ_s, pipe diameter D and inclination angle of pipe Θ. The results obtained are summarized as follows : (1) v₁ is not always identical with v₂, (2) v₁/v_t = 1.024 - 1.329In(d/D + 1.0), (1) (3) v₂/v_t = 1.0 - 2.130(d/D)^2.462 (2) for the spheres falling straighly along the pipe axis, or v₂ /v_t = 0.817 - 2.390(d/D)^2.462 (3) for the spheres falling with oscillation in the pipe, where v_t is the terminal velocity of single spheres in unbounded fluid, , (4) v₂/v₁ = 1.10 - 1.35, in the case of Eq . (2) and v₂/v₁ = 0.90 - 1.03, in the case of Eq . (3) .

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This paper deals with the waterhammer caused by closing the valves in a pipe line with two valves, one at the outlet end (discharge valve), another at the center of the pipe line (mid valve). Theoretical and experimental results indicate that the maximum head rise in the pipe line with two valves is lower than that produced by closing the discharge valve only, when the speed of closing the valve is the same. Moreover it is shown that when the mid valve is nearer to the reservoir or the mid valve is closed some time before the discharge valve, the head drop at the point just after the mid valve increases so much that the possibility of water column separation increases ; and when the mid valve is nearer to the discharge valve, the head rise at the point just before the mid valve increases.

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Transient temperature distribution in an infrared transmitting chalcogenide glass when this glass was heated by infrared radiation and a numerical solution by explicit difference equation of a combined radiation and conduction problem were investigated. In this explicit difference equation, the total reflection term that could not be neglected when the refraction took large value was considered, and in this consideration for wavelength dependence was investigated by the band model approximation. Thermal and optical properties of chalcogenide glass were measured out of necessity for the calculation of transient temperature distribution in glass using the explicit difference equation. Comparing the calculation result of chalcogenide glass with the result of soda-lime glass in the case of radiation heating, the special characters of chalcogenide glass as infrafed window glass were confirmed; for example, small temperature rise rate, and small temperature difference in glass.

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To verify the principle of the occurrence of the critical flow, a homogeneously dispersed two-phase flow is tactfully realized in an experiment. Air and water are used as fluids of the two-phase flow and water is blown into the gas stream as minute droplets. The concrete critical flow condition is carefully obtained by measuring the thrust of the two-phase flow outside the exit plane of the duct. The critical conditions obtained at the experimental result are well coincident with the theoretical ones. At the same time the factors governing the critical conditions of the homogeneously dispersed two-phase flow are also made clear.

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