Since cementite particles have great influence upon the mechanical properties of the steel, it is very important to know internal stresses on the cementite phase. The cementite diffraction lines available to stress measurement are too weak and exist in low angle region, so that a new measuring system (Lucas method) must be adopted. X-ray elastic constants of the cementite (121) plane were measured on a high carbon (1.4 wt. per cent) tool steel containing spheroidal cementite particles. After tensile plastic deformation, it was detected that tensile residual stresses in the cementite phase and compression in the ferrite phase were generated. During the first few per cent of plastic deformation, residual stresses in the cementite phase rapidly increased and were balanced by the stresses of the opposit sign in the ferrite phase. According to the broadness of diffraction lines, deformation of the ferrite phase advances more rapidly than the cementite phase, and a remarkable dependency of the reflecting plane was observed in the early stage of the deformation.

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Transmission electron microscopy has been used to study the structure changes in polycrystalline aluminium fatigued at very high repetition frequency (17.7 kc/sec). A number of small dislocation loops and voids were observed frequently and sometimes large loops on {012} planes. These are thought to be formed as the result of the condensation of vacancies. Rough estimation is made of the number of vacancies generated in the fatigue-process. The effect of vacancies on the fatigue life is briefly discussed.

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Changes in surface residual stress during fatigue process of annealed specimen are investigated adopting X-ray stress measurement. It is found that in torsional fatigue a tensile residual stress appears in the early stage of fatigue process, which is insensitive to the alternation of applied stress range. Meanwhile in bending fatigue, the residual stress produced during stress alternations is fairly dependent on the range of applied stress. For instance, in the case of completely reversed bending fatigue, compressive residual stress is produced at the early period of fatigue process. Considerations are made on the mechanism of the changes in residual stresses, in connection with the behavior of microscopic lattice defects during fatigue process. The effect of residual stress on fatigue life is also discussed.

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This investigation was carried out to estimate the effect of mean stress on behaviour of the crack which was initiated at the edge of a hole and propagated on the surface of specimen with a transverse-circular hole under the fluctuating twisting moment. It was concluded that the life to the crack initiation did not depend on the mean stress, but only on the alternating stress and the relation between the rate of crack propagation and the stress could be expressed by : logΔl/ΔN=Aσ_a+Bσ_m-C, where A, B, and C are positive constants, σ_a, the alternating stress, σ_m, the mean stress and that the effect of the alternating stress on the rate of crack propagation was larger than that of the mean stress.

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According to the experiments on the bursting of the rotor with a rim, a boss, and blades, there are two modes in the bursting of the rotor depending on the magnitude of a boss. For instance, when the thickness of a boss varies widely and its diameter is constant, the bursting of the rotor occurs as follows ; - (i) The rotor bursts in the diametral section until the boss thickness reaches a certain value, and the bursting speed increases as the thickness increases in this range. (ii) The rotor bursts in the section around a boss and the bursting speed keeps a constant value when the boss thickness increases over this value. Therefore, the certain value is considered to be the critical thickness of a boss, and it is meaningless to increase the thickness of a boss over this critical value. These experimental data on the bursting of the rotor are accounted for considering individual effects of a rim, a boss, and blades on the bursting strength of a uniformly thick disc, and the practical dimensions on the critical thickness of a boss can be suggested.

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This paper describes an analytical method of the stresses and deformations of the rotating finite hollow cylinders using the method suggested in Ref. (5). Particularly, the studies on the effect of the wall-thickness on the stress distributions and deformations of rotating finite hollow cylinders were made in detail with the aid of the computer. The obtained results are as follows : (1) With the value of a/b increased to 1.0, the stress distributions are almost similar to the well-known two-dimensional results, where a/b is the ratio of the inner to the outer diameter. (2) The shear stress reaches its maximum in the middle of the inner surface, and increases slightly when the ratio of a/b becomes greater. (3) In the case of a stick cylinder of a/b=1/8, the wall-thickness increases by rotation, but on the other hand in the case of a thin cylinder, it decreases.

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An analysis of inherent stresses in an elastic solid is described assuming inherent strain to be a stress-source. General solutions for two- and three-dimensional cases are obtained and applied in some examples. Theory of inherent stresses has been established using the concept of incompatibility of strain and the results are expressed in terms of "incompatibility tensor" in most cases. In this paper, stress functions including the incompatibility of inherent strain are integrated by parts and stress formulas are presented in terms of "inherent strain". In the inherent stress problems in engineering, the distribution of inherent strain is assumed to be known. The results in this paper may be conveniently applied to practical cases.

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This paper deals with the measurement of rigidity G and the shear stress-strain relations by means of the twisted square plate, which is a square plate subjected to four vertical loads of the same intensity, two of them acting downward at the ends of one diagonal, and the remaining two holding upward at the ends of the other diagonal. In this type of loading the two principal bending moments have equal and opposite signs and the deflection becomes anticlastic. And there exists an instability limit in transit from anticlastic to synclastic deformation of square plates. The authors have made a study of the effects of shapes and sizes of specimens on the instability limit and shown some typical examples of measurement of G and τ-γ relations in half-hard aluminium plates. It has been revealed that the limits of such instability initiation are to be used as basic data for determination of the limit of application of this method.

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In this investigation three different experiments on the cylinder vibration caused by the wake force are undertaken. Namely, in the first place on the elastically supported cylinder in a wind tunnel and in the second place on the oscillated cylinder in a model basin experimental studies are undertaken. And in the third place on the oscillated cylinder in a wind tunnel an experimental research is made in which a fluctuating pressure on the cylinder surface is measured. According to these experimental results it is concluded that the exciting mechanism is a selfinduced vibration. In other words the exciting force is caused by the cylinder vibration itself under the special flow velocity, say, the nondimensional velocity of about 5. In addition, the theoretical analysis under this consideration is shown to be able to explain these test results well.

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In this paper, the mechanism of air-leakage between contact surfaces was studied. The mechanical properties of modeled surface irregularities in a shape of truncated cones were assumed to be ideally plastic or elastic. The results obtained can be summarized that the theoretical values of equivalent gap between contact surfaces agree with those obtained from experiments within an error of about 7%.

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Although many studies on journal bearings have been reported as regards eccentric rotating cylinders, there is no frictional moment (torque) measurement which has been done for various eccentricity ratios and radius ratios in condition that there is sufficient fluid to fill the clearance in journal bearing. Recently, Oguro, Coles and Van Atta reported that under certain conditions a pattern of alternating helical stripes of laminar and turbulent flow could be observed in the gap between concentric rotating cylinders, with the outer cylinder rotating. However the critical Reynolds number has not been investigated in detail. In this paper the torque acting on the inner cylinder in eccentric rotating cylinders is measured over the range from the laminar flow to the fully developed turbulent flow, with the outer cylinder rotating. Torque measurements are done using water, glycerine-water solution and spindle oil, and increasing the fluid pressure in order to prevent the occurrence of cavitation. And we studied experimentally the relation between torque coefficient and a few parameters, such as rotating Reynolds number R_ω, eccentricity ratio etc., and obtained R_ω at which transition to turbulent flow occurs.

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We previously investigated the pressure drop in an annulus with a rotating inner cylinder under fully developed conditions and reported that there is a noticeable increase in axial resistance associated with the onset of Taylor vortices for laminar flow of axial-flow Reynolds number above 100. On the other hand, in the case with no axial flow, it has been reported that the flow between eccentric cylinders with a rotating inner cylinder is more stable to the disturbance of Taylor vortex type than the flow between concentric cylinders. However there is no investigation of axial resistance connected with the development of Taylor vortices in the flow between eccentric rotating cylinders with axial flow. We measured the pressure drop in the eccentric annulus with a rotating inner cylinder under fully developed conditions, using water and glycerine-water solutions. And in this paper the relation between pressure drop and a few parameters, such as rotating Reynolds number, axial-flow Reynolds number, eccentricity ratio and clearance ratio, is investigated experimentally in connection with the development of Taylor vortices.

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The flow characteristics of water through right-angled pipe fittings were studied by theoretical and experimental method. By means of the theory of two-dimensional potential flow, streamlines and pressure distributions along the walls of right-angled branching canals, in which the flow separated at the branch corner, were evaluated and compared with the experimental results. Both results coincided very well. From the calculated and experimental results, the mechanisms of the pressure loss of right-angled pipe fittings were analyzed. The pressure loss in the main flow was equivalent to the pressure loss of a sudden enlargement and that in the branch flow to the sum of the pressure loss of a sudden contraction and a sudden enlargement.

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The authors made flow experiments on the three kinds of right-angled pipe fittings which had correctly geometrical shapes and were set in the horizontal plane. Their diameter ratios were 53.2/53.2, 53.2/42.1 and 53.2 mm/28.0 mm. Flyash and sand slurries were run through them in the "hold up flow" and in the various upstream velocities of the main flow and the flow conditions. Then the authors obtained the following conclusions : (1) The densities of slurries in the downstream of the main flow and the branch flow are equivalent. At the same concentration in weight the coefficients of the pressure loss in the main flow and the branch flow are equivalent in the case of flyash and sand slurries respectively. Both coefficients of the pressure loss in the main flow and the branch flow increase with the increasing concentration in weight, but the incremental rate of the former is less than that of the latter. (2) The pressure loss in the main flow is equivalent to that of a sudden enlargement and the pressure loss in the branch flow is the sum of a sudden contraction and a sudden enlargement as in the case of water flow. As the pressure loss in the branch flow, especially in slurry, is greatly influenced by the contraction, roundness at the branch corner may be very useful in order to reduce its pressure loss. (3) The experimental results were expressed as the empirical formulae including also the previous experimental results with the water flow.

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Instead of using the nozzle in the previous report, rough tubes are used as a water jet source. Jet core-length is measured against tube wall roughness, tube diameter and temperature of water. The jet core-length saturates after it increases with the jet velocity. Saturated value of jet corelength of each rough tube is constant if the frictional coefficient of the tube is less than a critical value, but it decreases if the frictional coefficient is larger than this. The critical coefficient depends upon the stability number (=W_e/R_e), ratio of kinematic viscosity of water to air as well as upon Nikradse's equivalent sand roughness of the tube. It is confirmed that the relation between the frictional coefficient and Reynolds number of the jet just at which its core-length saturates is identified from the boundary of complete rough regime in Moody's diagram. The limit of roughness which has any effect on the jet core-length is found on this boudary, and the allowable finishing order of jet nozzle wall for hydraulic process can be estimated by applying this limit.

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The attainments of the performance of turboblowers or compressors for any gas are generally checked by air tests conducted in the manufacturer's shops. Unfortunately, the method of translating the performance from air test condition to the gas operating condition has not been established completely. With a view to establishment of the translating method, the authors proposed some appropriate methods predicting equivalent performance making reference to some literatures which were published. There are two principal methods of the air test in the manufacturer's shop. (1) Selection of the equivalent test speed for air tests at which the air test condition and the gas operating condition are identical respecting to the density ratio or the Mach number. (2) Modification of the air test data conducted at the same speed as the operating condition. However, the correlations between shop and field testing have not been obtained theoretically. But within certain ranges, satisfactory correlations could be obtained. Such ranges should be confirmed experimentally. Some convenient charts were proposed in this paper. In order to establish the available methods of the translating compressor performance from one gas to another, it is necessary to confirm the methods by the experimental results with shop and field testing.

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In order to obtain wider and better performances of an axial-flow pump, the suction performances must be improved. Three impellers having different solidities and blade sections were tested to study the overall-and suction-performances and to observe the cavitation conditions inside the impellers. The additional head loss due to cavitation and the head rise ratio have been shown as the function of the product of cavitation parameter by solidity. The cavitation zone parameter has been illustrated as the pressure distribution on the blade surface. The suction performance may be estimated from it.

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In a previous report, the author discussed the stability of a conical hydraulic poppet valve with an elastic support. There he considered chiefly a valve having only inlet piping. In this paper, the results of further investigations are reported on the same type of valve, considering both inlet and outlet piping. Some theoretical considerations are first developed using the characteristic equation of this system which has already been derived in the previous report. Some experiments were conducted varying the length of the inlet and outlet piping. The experimental results agree fairly well with the theory. The following conclusions are obtained ; (1) the outlet piping increases the frequency range in which instability occurs, (2) very short inlet piping may increase the instability range.

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Analysis and experiments were performed to study the static characteristics of the thrust of poppet valves. Valves with cone angles between 40 degrees and 90 degrees were tested under different conditions. Experimental result reveals the momentum theory is valid for the estimation of the thrust. For poppet valves having lappings with valve seats, pressure integrals on the seats are required for the estimation of the thrusts. The boundary layer theory was applied to the flow in the clearances between valves and valve-seats, thence pressure integrals were calculated. Developed formulae were different whether the flow was laminar or turbulent. Thrust coefficient in the transition region lay between two calculated values, hence only rough estimation was thought possible. In the regions considered laminar or turbulent, analytical results coincided fairly well with experimental results.

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The author investigated the vibration damping of the hydraulic system by the bladder type accumulator composed of rubber. First, observation concerning the deformation of the bladder was made. When the main pipe pressure is not so large compared with feed gas pressure of the Acc (abbreviation of accumulator), the rubber film moves axially like a solid piston. Secondly, the frequency response of the Acc itself was measured. When the inside profile of Acc neck is simple, measured natural frequency agrees well with calculated value. The damping of the Acc system is composed of oil flow and rubber bladder itself. Furthermore, the author investigated the 1st mode vibration damping method of the existing hydraulic elevator system of the cylinder-plunger type using the Acc and made clear the optimum design of Acc. Also, when the wave phenomenon is dominant, the author shows by the numerical calculation, the optimum insert position of Acc is the position of maximum pressure of the vibrational mode.

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The effect of system pressure upon the growth characteristics of an isolated vapor bubble was investigated experimentally using water, ethanol and carbon-tetrachloride. The Jakob number was varied between 0.34 and 1040. It was found that with an increasing pressure the growth rate tends to be smaller, while in low pressure region the growth exponent happens to exceed 0.5. The model of evaporation of a thin liquid layer beneath the bubble was examined, which turned out to be successful for the explanation of the experimental facts.

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An analysis is made for the effects of buoyancy forces in laminar forced-convection on a vertical flat plate. In general, since it is difficult to obtain an exact solution, an approximate similarity solution is given by introducing the assumption that a role of G_r/R_e² in stream function, [numerical formula] is negligibly small as compared with η. The validity of this assumption is examined by comparing with the experimental data of Kliegel. Numerical calculations are performed for both the constant fluid properties and the variable fluid properties, and the results are compared with Szewczyk's solution previously obtained by perturbation analysis. The velocity and temperature distribution, the friction factor and heat transfer coefficient are given for various values of the parameter G_r/R_e².

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The spectroscopic analyses of the radiation from the luminous flame of the liquid fuel and the gaseous fuel were carried out in the wavelength range from 1.5μ to 5.4μ, and the monochromatic infrared spectra of the radiation from the soot particle cloud were measured. The results obtained are as follows. The radiation from the soot particle cloud in the luminous flame is a continuous spectrum like the one from solid surface and not a band spectrum. The radiation from the luminous flame is composed of band spectra of the gas and a continuous spectrum of the soot particles. The high emissivity of the soot particle cloud is caused by the high continuous spectrum. The monochromatic absorption coefficients of the soot particle clouds obtained in this experiment differ from the theoretical values but the effects of the size distributions upon the monochromatic absorption coefficients agree well with each other. The relation between the effective emission thickness and the total emissivity of the soot particle cloud which is calculated from the present monochromatic emissivity agrees very well with the author's previous result obtained using radiation pyrometer.

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A gas turbine which has a variable geometry free turbine can be expected to be improved not only in part load performance and acceleration capability but also in engine braking. Therefore it is suitable as the vehicular power plant from the above three view points. The control unit of such a gas turbine, however, becomes more complex than that of a conventional one. In the present paper, the steady and dynamic performances of such a gas turbine are investigated by the nomogram method and analog simulation respectively. The relations between part load performance, acceleration capability and nozzle angles are obtained, as well as the transient performance for a wide range of nozzle angles from the design value to engine braking. The results can be used as the basic data for the selection of turbine cycle, estimation of required component characteristics and design of controller at design phase.

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Although exhaust gas ejectors have been little utilized in engines, their application is worthy of consideration because of their basic simplicity. An application for engine cooling has been investigated using a four-stroke cycle Diesel engine and an air model. Following results are obtained : (1) The cooling air for an engine may be supplied only from the ejector which is well designed. Fuel consumption can be decreased by using the ejector together with a fan for engine cooling. (2) Flow rate of air induced into the ejector becomes larger with an increase in engine load. However, flow rate per unit horse power becomes smaller. (3) Flow rate of secondary fluid for the ejector, whose driving fluid is intermittently supplied, is much larger than that for the ejector of steady state, because the inertia effect of fluid in the ejector is a useful factor to draw the secondary fluid.

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The temperature changes of the mixture gas in the induction process are given using the following notation : ΔT₁ : Vaporization of fuel, ΔT₂ : Ram effect, ΔT₃ : Preheating for intake mixture, ΔT₄ : Heat transfer from high temperature parts, ΔT₅ : Mixing with residual gas. The change ΔT₅ has almost no effect on air capacity, but ΔT₂, ΔT₃ and ΔT₄ change with engine types, operation and atmospheric conditions. Report No. 1 has expressed the sum of ΔT₂, ΔT₃, and ΔT₄ (called ΔT_{2, 3, 4}) as a function of the directly measurable intake mixture gas weight and the cylinder pressures. The suction end temperature T₁ is a function of ΔT_{2, 3, 4} and pressures needed for thermodynamical analysis. It has become possible to determine each of the changes ΔT₁ to ΔT₅ analytically. Finally the relationship between the air capacity and various temperature rises of the mixture gas is expressed theoretically.

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Report No. 1 has shown a way of determining various temperature changes in the mixture gas in the induction process, and in the suction end temperature. The directly measurable intake mixture gas weight and the cylinder pressures were substituted into the thermodynamical equations obtained by a theoretical analysis of the engine cycle. The relationship between the air capacity and various temperatures of mixture was expressed theoretically. Here the results of experimental measurements are reported. The effect of various temperature rises upon the air capacity was studied while varying the engine type, intake manifold pressure, spark advance, mixture ratio, cooling-water temperature, compression ratio, intake temperature and exhaust pressure.

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This paper contains numerical solutions for the deflections due to a concentrated load of a finite length cantilever thick plate. New boundary conditions for the cantilever thick plate are : (a) the deflection along the elastically built-in edge is balanced by shearing forces along the edge, (w)_edge=k₂Q_v, and (b) the rotation of the elastically built-in edge is in direct proportion to the moment, (∂w/∂y)_edge=k₁M_v. Instead of the boundary conditions of built-in edge, new boundary conditions are applied to the method of finite differences, an approximate solution of the problem of a finite length of a cantilever thick plate. The numerical solutions of this method coincide with the experimental deflections of the cantilever thick plate like gear tooth.

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The accuracy of straight line motion of machine tool tables is influenced by not only the geometry of guideways, but also the thickness of lubricant films. In this paper, the behaviors of surface grinding machine tables and model sliders due to lubricant films are investigated experimentally. The theoretical consideration for such behaviors is made on the basis of hydrodynamic lubrication theory. Further, the influence of the table behavior on the accuracy of finished workpieces is shown. It is shown that the film thickness increases at the leading edge of a table and decreases at the trailing edge as the table advances and that the finished workpiece becomes concave.

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This investigation aims to clarify the optimum processing conditions of a commercially pure aluminium sheet for press-formability, in correlation with the tensile properties and the crystallographic orientation. The process variables dealt with are the cold reduction and the annealing temperature after hot working. In the first report, the effects of the cold reduction are examined in as-rolled conditions. Plastic strain ratio γ of the tensile specimens taken at 45° and 90° to rolling direction shows the maximum in the 80% cold-reduced sheet. But, the γ-value at 0° to rolling direction decreases monotonously with an increasing cold reduction and is the least among those three directions at any amounts of cold reduction. From observation of the location where a fracture initiates during drawing, it is confirmed that the drawability is governed by the minimum γ-value in planar directions. As the cold reduction increases, the stretch-formability always lowers, but the drawability does not always lower. The former is well correlated with the variation of the n-value obtained from a bulge test and the latter is correlated with that of the minimum γ-value.

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The optimum processing conditions of commercially pure aluminium sheet for the pressformability are clarified in correlation with the tensile properties, crystallographic orientation and microscopic structure, by testing sheets differently cold-reduced and annealed at various temperatures. It is concluded that the drawability is governed by the minimum value of r in the sheet plane, similarly to the case of the as-rolled sheets in the previous report. Therefore, the processing conditions which increase the minimum value of r are effective in improving the drawability. The r-value of the tensile specimen taken at 0° to the rolling direction is minimum in the asrolled sheets, but the r-value at 45° becomes minimum in the fully annealed sheets. The numerical order of the r-values in the three directions is in most cases reversed by annealing. The minimum value of r becomes largest at the transition point of this reversal, where recrystallized grains are partially observed. In addition, at this point, the earless condition is satisfied. The heavier the cold reduction prior to annealing the higher becomes the minimum value of r.

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