The effect of stress-strain curve on the deformation behavior of polycrystalline metal composed of anisotropic crystals is investigated from energy aspect. The constraint between grains is discussed in the cases that the stress-strain relations are represented by (1) combination of straight lines, and (2) exponential curve. It is pointed out that the mutual constraint between grains is affected by the shapes of stress-strain curves, as well as the anisotropy or the distribution of orientations of grains. It is also concluded that the deformation of polycrystals changes its mode from constant stress to constant strain as the total strain becomes greater and as the grain size becomes smaller.

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Although it is known that the fatigue strength of carburized steel is greatly influenced by the residual stress on the surface, it is very difficult to assess the effect quantitatively. In this report, the effect of mean stress on the fatigue strength of carburized steel is studied, and therefrom the effect of residual stress can be estimated. Following results are obtained. (1) The fatigue strength of a high hardness and brittle steel, is more sensitive to mean stress, as compared to those of medium and low hardness steels. (2) As the Tempering temperature of carburized steel is increased, the effect of mean stress on the fatigue strength decreases. (3) During the fatigue test little change was observed in the residual stress and half value breadth of X-ray diffraction line of carburized steel. On the basis of these results, the mechanism of fatigue failure of carburized steel was discussed.

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The wear of metals in the lubricating oil under mild conditions is considered to be due to surface fatigue, and some correlations are found between wear fragment and surface topography. Effect of small electric potential between the mating surface on wear behaviours are also examined. By using test pieces off annealed carbon steel, the most frequent value of diameter of wear fragments is found to be nearly equal to roughness pitch of worn surface and they vary in like manner with sliding distance. When the same metals are paired for the wear test and small electric potential is applied between the mating surfaces, wear rates of both the metals increase monotonously with voltage regardless of its polarity. When different metals are paired, wear rates of both are minimized under a voltage which is nearly equal to the voltage cancelling the contact electric potential. The diameter of wear fragments and also the roughness pitch are the largest at the voltages. These results are explained by the change of hardness and the lubricating condition in accordance with the change of surface energy which is in close relation to the electric potential of the surface.

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This paper discusses the optimum configuration of isolators for systems with stationary random excitations. Optimum control theory in frequency domain is applied to obtain an optimum isolating system that minimizes the response of the system to the excitations under certain conditions. A possible method of solving the optimization problems is presented for multi-degree-of-freedom systems and illustrated on a few typical systems. The optimum isolators thus obtained may in general be characterized by active elements rather than conventional spring-dashpot elements.

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A knowledge of the hydraulic resistance for tubular coils is required in connection with heat exchangers. Motion of liquid in curved tube coils is greatly influenced by their configurations, namely, by the ratio of radius of tube to radius of curvature of tube d/D₁ and spiral pitch of the coils, and also Reynolds number R_e. To investigate these effects, flexible vinyl tubes reinforced by steel wires were employed to facilitate the experiments and the hydraulic loss of curved tube coils was measured for 3.43≤D₁/d≤51.2, 1.7°≤ pitch angle θ≤70°, and 1.3×10³≤R_e≤5×10⁴. Flow patterns were also measured by a cylindrical Pitot tube. Except an extreme case of D₁/d=3.43, the hydraulic loss of coiled tubes can be estimated by modifying the results on curved tubes in one plane.

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In this paper, the authors deal with the pressure pulsations in a long delivery pipeline in consideration of the dynamic characteristics of the pipeline systems. The instantaneous parabolic delivery of a gear pump has been indicated as the sum of sine waves by being expanded into a Fourier series. The response of the delivery pressure in the long pipeline for it has been derived considering the internal leakage of the gear pump. The experiments have been performed in various line-conditions and speeds of the gear pump. It is shown that the theoretical solutions are in good agreement with the experimental results in various conditions.

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One-dimensional model analysis was made to investigate the effect of thermal factors of a heater upon the evaporation rate of a microlayer beneath the bubble. The evaporation rate was found to be markedly influenced by thermal factors such as heat capacity and thermal diffusivity of a heater. Quantitative analysis was also made about the corresponding behaviors of temperature and heat flux on the heater surface. The effect of heat capacity was really found by a careful inspection of the experimental data, which showed a considerable decrease of the bubble growth rate with a decreasing heat capacity. The thermal factors of a heater were found to influence the bubble growth rate through the mechanism of a microlayer evaporation.

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In the main fuel pipe (main nozzle) of the carburetor of gasoline engine, a little air is let into the fuel stream, in general. This two-phase flow streams into the venturi-tube. The author's experiments are made with simple models to elucidate the basic phenomena of the confluence of air and fuel in a small tube, that is, the flow pattern of a two-phase flow, the pressure drop caused by the confluence, the two-phase flow friction, and the relaxation oscillation. In 1st Report, experimental apparatus and flow pattern are described. Vertical tubes are 6, 3, 2 mm of diameter. Liquid is tap water in the most part of experiments, and in some part of them, is distilled water, gasoline, solvent, or surface active agents solution, Unless the air holes are large, stable fish-scale type slug flow appears in some range of air and liquid. This is attributed not to the effect of so-called entrance length but to that of the small diameter of tube.

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When air streams into a liquid flowing upward in a vertical small tube, two kinds of pressure drops occur ; that is, one is the pressure drop along the liquid stream line, and the other is that along the air stream line. After consideration of void fraction, a non-dimensional basic equation is obtained, using a simple model of confluence. For each flow pattern, semi-empirical equations of the former kind of pressure drops are obtained. An empirical equation which covers the whole region of flow pattern is obtained from these equations. An empirical equation of the latter kind of pressure drop which covers the whole region is also obtained.

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The measurement of air flows in internal combustion engines, such as occur in gas-exchanging or in the combustion chamber, is very difficult because of their great unsteadiness and complexity. The present paper treats of the availability and limitations of repetitive spark method in visualization and quantitative determination of such kinds of flows. The following are the results derived from the investigation. Although this method is absolutely accurate for a steady parallel flow, the acceleration produces considerable errors owing to the bouyancy of the hot zone heated by the discharges. The induced relative velocity caused by this effect is proved to be proportional to the equare root of the acceleration. Further, some applications of this spark method to evaluate the flow in the internal combustion engines are presented, of which one shows the flow patterns in the suction port and around the valve, and the other the swirls produced in the cylinder and in the swirl chamber.

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Synthesis of the mechanisms has been done with the angular displacements of the driving and the driven links given. However, the angular velocity and acceleration should very often be given arbitrarily by a designer in addition to the displacement curve and the mechanisms should be synthesized. The dynamic behaviour of the mechanisms is influenced by the values of the angular velocity and acceleration which were given in deciding the displacement curve, and it produces a deviation of the precision points from the displacement curve owing to the fluctuation of the input-torque, the deflection of the links, etc. In this paper, about the planner six-bar linkage, the displacement curves which satisfy the restricted values of the angular velocity and acceleration are decided and mechanisms are synthesized. And the fluctuation of the input-torque is analyzed and investigated.

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