Several experiments of micro-hardness have been performed on Al and Mg single crystal in order to clarify the effect of test conditions. The micro-hardness increased rapidly at first with the increasing of test load in the small load range, then decreased gradually and became finally independent of the test load. Such phenomena were observed in the test conditions. Firstly, it was supposed that the phenomenon of increasing micro-hardness in the small load range was caused by the external vibrations which originated from the experimental station. Secondly, it was verified that the load-dependency of micro-hardness which showed that the micro-hardness decreased with the increasing of test load was due to the heterogeneous deformation of indentation and the dissimilar indentation with respect to the indentation. So, for the micro-hardness testing it is recommended that the loading rate be kept at about 10μ/sec and the loading time of indenter kept below 10 sec.

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The plane bending plastic fatigue testing machine was developed for a further systematic study of the fatigue problem in the plastic range. A constrained strain test and a constrained stress test were carried out on the Ni-Cr-Mo steel. From the discussion of the results, it was concluded that the test under constant strain amplitude is the most basic one in the sense that it gives a fairly stable hysteresis loop throughout the test, and the data of the other tests under various conditions such as varying strain amplitude and constrained stress amplitude should be discussed in comparison with those of the test under constant strain amplitude. The treatment using the parameter ε_total, which is the total strain summed up from the beginning to the occurrence of a fracture regardless of the sign, seems to offer a method for further analysis.

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In measurements of residual stress by means of X-rays, there remains a question whether or not the stress measured by X-rays represents the macroscopic residual stress itself. In the present study, carbon steel plate specimens were heat-treated and the residual stress appearing in them was measured by both the X-ray method and the mechanical method, and the results were compared. The macroscopic residual stress in carbon steel caused by thermal stress can be accurately measured using the X-ray method when the specimen surface is treated by the electropolishing method. However, if such method of surface treatment which causes selective corrosion as etching by nitric acid is used, the relief of surface stress affectes the measured value of residual stress.

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The relation between the twisting fatigue strength and the bending fatigue strength varies with temperatures and specimen sizes, as well as with presence of notches, flaws, and environments. In the present paper, the size effect of fatigue strength is discussed by calculating the probability of flaws on the surface which affect the fatigue strength of materials by 1/(1+2μ) under bending and by 1/(1+μ) under twisting. And fatigue tests are carried out at elevated temperatures and at a low temperature for smooth specimens and also for notched specimens under bending and twisting moments. These results and the various past experimental results are applied to the calculation of the size effect discussed above, and the following explanation is given in a unified form : the relation of size effect under bending fatigue and under twisting fatigue, the size effect of smooth specimens and notched specimens, the effect of flaws, environments, and temperatures on the fatigue strength and notch factor, and the distribution of the fatigue strengths for various sizes of specimens.

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The bending stress concentration factors were investigated on the single throw steel crank specimens (solid), of which crankpin diameter was 80 mm. As the result of these investigations the empirical formula of the stress concentration factor of crankshaft is given as follows : α_k=Cf₁ (ρ/d) f₂ (ρ/d·δ/ρ·s/d) f₃ (b/d) f₄ (t/d) f₅ (t/d·s/d) C=4.84 f₁ (ρ/d)=0.420+0.160√(d/ρ-6.864) f₂ (ρ/d·δ/ρ·s/d)=1+81 [0.769-(0.407-s/d)²]·δ/ρ·(ρ/d)² f₃ (b/d)=0.285 (2.2-b/d)²+0.785 f₄ (t/d)=0.444 (d/t)^1.4 f₅ (t/d·s/d)=1-(s/d+0.1)²/(4t/d-0.7) (8⪈d/ρ⪈27, 0⪈δ/ρ⪈1, -0.3⪈s/d⪈0.3, 1.2⪈b/d⪈2.1, 0.36⪈t/d⪈0.56) where, α_k=πd³σ_m/32M_W, d : crankpin diameter, σ_m : maximum stress at crank fillet, M_W : bending moment at center of web thickness, ρ : fillet radius, δ : recessed depth at fillet, b : web breadth, t : web thickness, and s=(d-d_j)/2-r, d_j : crankjournal diameter, r : a half stroke. The limit of uncertainty of the above formula based on 95 percent confidence limits is 6 percent, and this value is enough for practical application.

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The stresses in cemented joints, especially those by scarf and butt bondings, were studied photoelastically. The photoelastic models were made of epoxy resin and epoxy rubber, or epoxy resin and metal, namely, each material had respective elastic constant. Tests were carried out under tension and bending on a bar bonded at various angles. Some results of experiments revealed that the stress concentrations were comparatively small on the scarf or butt bonding. The other results had revealed that the stresses on bonded boundary were not uniform under tension and bending, and that in the joints with a soft adhesive layer bonded to hard adherends, the stresses concentrations were found on the end of bonded boundary with an obtuse angle, and in those with a hard adhesive layer bonded to soft adherends, found on the end of bonded boundary with an acute angle.

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In the photoelastic apparatus of reflection type, a half mirror will be used sometimes in the light path to turn the polarized light at right angle, and in this case the polarization effect due to the mirror cannot be neglected usually. In the present paper, the conditions which must be satisfied to avoid the effect, have been considered theoretically and a new convenient method applicable to this case has been proposed. On the other hand, some attention is paid to the stress analysis in the homogeneous anisotropic material by the use of a birefringent coating, and a new method applicable to any bodies, which are in the state of plane stress and obey Hooke's law, has been presented.

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Numerical calculations of large deflection of circular ring plates subjected to uniform transverse force along the inner edge, are carried out for three edge conditions and some geometric configurations. Iterative procedure developed by H.B. Keller and E.L. Reiss is applied here, and a finite difference method is used to solve the set of differential equations, which appears in each step of iterative procedures. The purposes of this paper are mainly to reveal the limitations of small deflection theory and the limitations of the approximate solutions of large deflection theory. Experimental results are given for the case of the circular ring plates which are clamped along inner and outer edges. These results are quite satisfactory, and the Keller-Reiss method is also proved to be valid for this problem.

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A theoretical analysis is presented for the inlet region of the laminar, meridional flow in an arbitrarily shaped narrow gap between two axi-symmetrically formed walls. A series expansion method is used and the most general form of the exact solutions of the boundary layer equations is obtained. As an example, numerical calculations have been made for the radial flow in a gap formed by two parallel discs, by which the following important conclusions are confirmed. Separation of flow from the wall occurs, the separation point moving in downstream direction as the Reynolds number decreases. When the Reynolds number further decreases, reaching a value below a certain small finite value, separation does not occur. A result which is very important from the theoretical standpoint is that the separation point calculated in this work is not a mathematical singularity. This is the first theoretical example verifying actually the existance of a non-singular separation, which has already been predicted by S. Goldstein, K. Stewartson and others.

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In der vorliegenden Arbeit befassen sich die Verfasser mit dem Druckabfall, der Geschwindigkeit der Teilchen und der Geschwindigkeitsverteilung der Forderluft in der lotrechten Rohrleitung sowie dem Druckabfall und der Geschwindigkeit der Teilchen im Krummer. Von den Verfassern ist die empirische Formel fur den Druckabfall in der lotrechten Rohrleitung erhalten worden. Aus den Versuchsergebnissen stellte sich heraus, daβ der Druckabfall im Krummer von der Waagerechten in die Lotrechte nach oben groβer ist als der im Krummer von der Lotrechten nach oben in die Waagerechte, und daβ die Geschwindigkeit der Teilchen in der lotrechten Rohrleitung ganz anders ist als die in der waagerechten Rohrleitung. Bei kleiner Materialbeladung bewirken die im Gase enthaltenen Teilchen fast keinen Einfluβ auf die Geschwindigkeitsverteilung der Forderluft in der lotrechten Rohrleitung.

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In contrast to the single-phase flow, the gas-liquid two-phase flow is generally accompanied by violent pressure fluctuations. If the fluctuation is found to follow a certain law, the law may be useful in measuring the component flow in the two-phase mixture. From this view point, the pressure fluctuation was analyzed. This paper is the first report on the result of this analysis. A JIS orifice was fitted at the outlet of a vertical 1 inch bore pipe through which the airwater mixture flowed upward. The pressure at a point immediately before the orifice was recorded and analyzed. It was found that the pressure was either larger or smaller than the time-average pressure, and never stayed at the average amount. Therefore the time rate during which the pressure was larger than the average was definitely measurable. This quantity was named the liquid-phase time ratio, and its properties were examined. If the flow rate of each component of the gas-liquid mixture was given, the new quantity was found to have a definite amount.

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For the two-phase slug flow in the vertical tube, a simple flow model was proposed, by means of which the quantities defined in the previous report were theoretically correlated. A series of experiments was carried out, and it was proved that the actual slug flow could be fundamentally represented by the proposed flow model. Also the two-phase discharge coefficient of the orifice was defined and experimentally correlated with the component volume flow. It was found that the component flows could be estimated by measuring the average pressure drop across the orifice and the time ratio or the void ratio.

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The running resistance of a train is composed of two parts, i.e. mechanical resistance and aerodynamic one. The ratio of the latter to the former increases remarkably with train speed, so it is very important for the planning of high speed trains to estimate the aerodynamic drag accurately. We have, however, only insufficient knowledges about it so far. In the test using actual trains, only the total running resistance could be measured and aerodynamic drag could not be obtained separately. And also in the model test in a wind tunnel it was practically impossible, though possible in principle, to obtain quantitatively accurate data, because of the inevitable reduction of model size and of the difficulties of experiments using models with rolling wheels and moving ground. As such was the case, there was no way but to rely on unsatisfactory data. The author found that the aerodynamic drag is closely related with the pressure rise on the side surface of a train, when it rushes into a tunnel, and that the aerodynamic drag can be obtained from this pressure rise independently of mechanical resistance. The mean aerodynamic drag coefficient of streamlined trains obtained through this method can be expressed as follows : c_D=0.12+0.0075x where x is the length of a train measured in meters.

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To take out mechanical power from high pressure oil, an impulse type oil turbine of a construction similar to the Terry steam turbine was developed on the basis of the fundamental experiment and the study of the performance of a test turbine. The turbine mainly consists of a nozzle, a turbine wheel with many deflection grooves and several fixed deflection boxes. Comparing with a positive-displacement type oil moter, the oil turbine has such features as feasibility of high rotational speed, low idling resistance, simple construction etc. As the fundamental experiment, a static test of two-dimensional deflectors was carried out and design data for a deflector with minimum losses were obtained. Based on the data obtained from the above, a test turbine was built, and its performance was measured at different rotational speeds and also at different jet velocities. From this study the limit of performance of an impulse type oil turbine was clarified, and the necessary data for designing an efficient oil turbine were obtained.

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Experimental results are presented on the effectiveness of an insulating film formed by cold air injected through a preceding porous section of a flat plate covered with a fully developed turbulent boundary-layer and are correlated with an empirical equation. Also, some considerations are made to clarify the difference in the effectiveness of the present partially porous air injection from that of the tangential slot air injection.

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Considering the structure of turbulence in the mixing region of jets where the noise is mostly generated, the influence of the exit velocity profile (shear) on the jet-noise has been studied with the following results. Weakening the strength of shear makes the spectrum of the noise source per unit volume shift towards the lower frequency side. The spectrum of the noise as a whole is proportional to the second power of the shear strength in the higher frequency side and to the fourth power in the lower side. Total intensity of the noise varies with about the third power of the shear strength as long as the mixing layer contributes effectively to the noise generation. When it ceases to play such a role, the relation obtained is not always satisfied to show the limit of noise attenuation by means of weakening the strength of shear.

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The effects of the shape of nozzle exit, the size of nozzle exit, the multiple nozzle (jetinterference) etc. on the generation of noise and the mechanism of noise reduction of the widely used noise suppressors are investigated. With the change of the shape or the size of nozzle exit, the noise intensity per unit frequency increases proportionally to the second power of the characteristic length of nozzle exit at the lower frequencies and to the fourth power of that length at the higher frequencies. The interference between jets causes a change in the turbulent velocity field and reduces the strength of acoustic sources in the mixing region to the degree of the strength in the turbulent region. This accounts for the mechanism of noise reduction of tubular or lobed nozzles. The rate of associated noise-attenuation is evaluated on the basis of experimental results of the turbulent velocity field. The closer the ratio of the width of nozzle to the space between nozzles to unity on average, the more improved are the characteristics of noise reduction.

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In this paper, the author tried to investigate the relation between the profiles of velocity and temperature of the air flowing in a vortex chamber and the dimensions of the main tube, nozzle, cold-end orifice, etc. He obtained data for designing a standard type of vortex tube with high efficiency of energy separation. He also obtained formulae for the profiles of velocity, temperature and energy of the air flowing in a standard vortex chamber, considering the air flow in the annular region as a wall jet. Unlike the formulae represented hitherto, these formulae do not include factors such as radial velocity component or turbulent diffusivity and so may be used to predict the performance or efficiency of a standard vortex tube under any working conditions.

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The distributions of flow rate and mixing ratio are studied about a spray generated by two impinging jets which are generally used for bipropellant liquid rocket systems using hypergol. The propellant system was simulated by a water model. When two jets impinge together, the total mixing efficiency varies with the impinging angle ; it has a minimum value when the impinging angle is nearly 90°. When jets impinge together with different injection pressures from orifices of same sizes, the total mixing effciency decreases as the difference of the pressure increases. When the injection pressure is same and the dimentions of orifices are different, the total mixing efficiency varies with the increase of diameters, but the variation is small. When two jets are composed of immiscible liquids, the state of mixing is basically the same as that of miscible liquids.

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Many researchers have done some work on the analysis of shear spinning process. But their works are limited to a certain extent. This paper deals with the experiment on the shear spinning process of aluminium to find out the fundamental characters in detail. The influence of the following working conditions is discussed ; roller position angle, clearance between roller and mandrel, feed of roller, cone angle, speed of rotation of mandrel, roller corner radius, roller diameter, blank thickness and blank diameter. In addition, the deformation theory of simple shear which is derived from the observation of the experiments, is checked about tangential force P_θ. It is said that there is an optimum blank thickness t_s, of which the calculated values agree with the experiments, and if the blank thickness is smaller than t_s, the theoretical value is overestimated, but underestimated, if it is the other way round.

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This paper deals with a theoretical study of shear spinning process, which was clarified by the experiments described in the previous report. Assuming that the deformation in shear spinning is divided into the three parts, which are redundant bending at the start line of contact, shearing, and bending on the contact surface between the roller and the blank, tangential force is evaluated from the total work of deformation in an infinitesimal time interval. The calculated results are checked not only by the experimental results of the previous report, but the data of Spincraft, Cincinnati and S.Kobayashi's reports. The state of contact between the roller and the blank is indicated numerically for several working conditions by introducing the contact factor m. In addition, it is shown that axial and radial force components can be estimated approximately by the optimum angles of frictional components ν_θ and ν_θ.

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Two types of roughness testers using a "diaphragm type air-micrometer" were made for trial : "cylinder wall roughness tester" and "small portable roughness tester". The mechanism of this tester is as follows : The displacement of the tracer point which traces on the surface to be measured is changed into a pressure indicated by an air-micrometer and this pressure acts on air chambers. A small magnetic needle rotates correspondingly with an action of the air chambers. The torque of the magnetic needle is amplified by means of an air type torque amplifier coupled with the magnetic needle magnetically. Thus roughness is recorded with a recording pen operated by the air type torque amplifier. With the surface profile assumed to be sinusoidal, the characteristics of this tester were discussed. Various tests show that roughness can be accurately recorded by this tester.

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