The temperature and particle size dependence of work hardening of metallic materials with second phase particles at elevated temperatures, where the dynamic recovery by volume diffusion of atoms is dominant, has been calculated on the basis of a continuum mechanics model without any ambiguous parameters. It was confirmed that there was a good agreement between the result of calculation based on this model and the one of tensile test in an austenitic heat-resisting steel with M₂₃C₆ carbides. Further, the model in this work was also applied to the interpretation of the internal stress during steady-state creep in this steel.

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A solution is presented to a doubly mixed boundary-value problem of an elastic layer which is resting on a rigid base with an annular hole and is indented by an annular rigid punch. The problem is reduced to a solution of infinite systems of simultaneous equations by assuming that both the normal displacement in the place of the hole and the contact stress under the punch may be expressed as appropriate series.The effect of the hole and the thickness of a layer on the stress field is discussed, and the disturbances due to a hole are presented in curves calculated numerically.

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This paper presents an analysis of the dynamic stresses in a solid rotating disc subjected to an arbitrarily varying angular speed. The Laplce transforms are used to find a solution. The inversions are performed by using Cauchy's integral and convolution theorems. The following problem is solved as a numerical example; the rotation of the solid disc increases with a constant acceleration untill it reaches 10, 000 rpm, thereafter keeping that speed. Expressing T_c the time in which the disc attains 10, 000 rpm, the dynamic stresses are computed for various values of T_c. Comparing the results with the quasi-static stresses, the maximum ratio of the dynamic and quasi-static stresses at the center of the disc is 1.03 for T_c=1.0×10^-3 s, 1.27 for T_c=1.0×10<-4> s and 2.01 for T_c=1.0×10<-5> s.

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An experimental study of plastic behavior considering temperature change and plasticity-creep interaction effects is reported in this paper. Combined stress tests are performed on thin wall tubular specimens of austenite stainless steel SUS 304 at from room temperature to high temperature (600°C). The subsequent plastic behavior after temperature change, the inelastic deformation during temperature rise and the plastic behavior subsequent to plastic and creep pre-strain are experimentally investigated. Stress strain relations in these experiments are obtained and discussed with the conception of a equi-plastic strain surface.

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This paper describes theoretically and experimentally obtained pressure distributions around an airfoil placed in a periodically fluctuating air flow. The following facts are found out: (1) When the amplitude of fluctuating velocity is small, the time averaged pressure distributions are nearly equal to those in steady flows. (2) The amplitude of fluctuating pressures increases approximately in proportion to that of air velocity. Furthermore, the values are fairly well predicted by the flat plate airfoil theory. (3) The angle of lead of the pressure fluctuation to the velocity becomes smaller in the decelerating regions and larger in the accelerating regions. The above is not well predictable by the theory. (4) It is clear that it is necessary to consider the distribution of the airfoil thicknesses in order to calculate the time averaged values and phase angles with high accuracy.

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A new numerical method for obtaining the forces on a body immersed in viscous fluids is derived for a uniformly accelerated elliptic cylinder from rest. In an analytical study, Fourier series expansion and boundary layer variable expansion are used because of good convergence and accuracy at high Reynolds numbers. An application of discrete Fourier transform to a block tridiagonal matrix leads to a high speed calculation over ten times as fast as the SOR method. From this analysis, the coefficients of drag, lift and moment exerted on a unit spanlength are obtained, and they consist of two components due to pressure and viscous force. Distribution of vorticities on the surface, which is important for the characteristics of heat conduction, is reveal ed in detail. Furthermore, the authors confirm that the separation time shown by Blasius at the trailing edge has a larger error when the eccentricity of the elliptic cylinder goes to unity.

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A two-dimensional nonsteady detonation having two triple-shock structures is numerically produced in a diluted stoichiometric oxyhydrogen mixture at P₀=1.013x10⁴ Pa. The interaction between the detonation and a blockage placed in a channel is observed in terms of the attenuation of the detonation. In particular, the behavior of the detonation near the rear side of the blockage is strongly influenced by the Prandtl-Meyer expansion, i.e., the effect of retarding exothermic chemical reactions. As a result, the detonation changes to a decoupled shock wave causing a chemical reaction, when a strong interaction between a triple shock wave and the blockage occurs, viz. in particular, when one of the triple shocks is either eliminated by its collision with the front part of the blockage or weakened by its passage through the Prandtl-Meyer region. When the blockage weakly interacts with triple shocks, however, the detonation remains coupled although a slowdown occurs and a complete re-establishment is observed at about 3 channel widths behind the blockage: There happens no change in the number of triple shocks throughout the interaction process.

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The present paper deals with experimental results and the theoretical approach to a pressure drop in an air-water two-phase upflow across horizontal tube bundles. The tube bundles are staggered in equilateral arrangement of three different pitch/tube diameter ratios (1.4, 1.28, and 1.08) and they consist of six different tube rows (7, 9, 11, 13, 15, and 20) for each ratio. The experimental data indicate that pressure drop depends on superficial air velocity and pitch/tube diameter ratio, but not on superficial water velocity. The experimental results are compared with predicted values of pressure drop. Vast majority of predictions are shown to lie within ±3% of the experimental values.

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Waves on the free surface of a viscous liquid layer in horizontally infinite extent under a vertically imposed oscillation are investigated theoretically by a linear theory. They are governed by a kind of ordinary differential equation with periodic coefficients. In the case of the subharmonic response, the stability boundary, which separates the unstable region from the stable one, is obtained numerically for a given wave number of the disturbance. The curves, which envelope these stability boundaries for various wave numbers, i.e. the neutral stability curves, are obtained in the frequency-amplitude space. It is found from these neutral stability curves that there is a minimum value in the critical amplitude, above which a disturbance begins to occur. Meanwhile, the neutral stability curves are obtained experimentally by using glycerine as a viscous liquid. The experimental critical amplitudes are shown to be in good agreement with the theoretical ones.

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A two-dimensional Couette-Poiseuille flow under a constant pressure gradient in a channel bounded by a wavy wall at rest and a plane wall with a constant velocity is studied theoretically without imposing restrictions on the profile of the wavy wall, except that the width of the channel is small in comparison with the wavelength of the wavy wall. A solution considering the inertia is obtained by a method of successive approximations. The solution is applied to a channel flow bounded by a simple-harmonic wavy wall and a plane wall. It is found that the presence of inertia can play an important role in the effect of the profile of the wavy wall on the flow. The critical condition under which the discharge or the viscous force acting on the wall is equal to zero is determined with the moving velocity of the plane wall. The minimal values of the discharge and the viscous force acting on the wall are obtained as a function of the amplitude of the simple-harmonic wavy wall. Finally, the approximate solutions are shown to be in good agreement with the numerical solution of this problem.

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The characteristics of the flow around a normal flat plate and a triangular cylinder near a plane surface has been investigated experimentally in the Reynolds number range of 10²to 3×10⁴. Frequency analysis of hot wire signal of the wake flow in a wind tunnel revealed that regular vortex shedding from the normal flat plate and the triangular cylinder was suppressed for spaces less than about 0.6 and 0.37 times the body width respectively. Investigation of the time-mean distance between two shear layers in the vortex formation region demonstrated that the suppression of vortex shedding for both configurations occurred for any space between the inner shear layer and the plane surface less than about 0.3 times the shear Iayer distance. Flow visualization experiments in a water tank revealed the structural differences of the wakes with and without vortex shedding.

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The effect of the aspect ratio of the duct cross-section on a liquid film flowing concurrently with an air stream was investigated using three horizontal ducts. The dimensions of the duct are 10 mm×40 mm (height×width), 40 mm×40 mm and 10 mm×80 mm. The results are summarized as follows: The boundary of flow patterns between the pebble wave flow and the disturbance wave flow strongly depends on the duct height. On the other hand, the boundary between a smooth surface flow and a two-dimensional wave flow as well as the nonwetting regime depends mainly on the duct width. The reason is that the volumetric flux of the liquid flow in the vicinity of the side walls of the duct is considerably larger than that in the central part of the duct width due to the formation of meniscus. Therefore, only the experimental values for the film parameters obtained at the central part of duct width are useful for comparison with the theoretical results obtained by the assumption that the flow is two-dimensional, even if the aspect ratio of duct seems to be sufficiently small.

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Hydraulic torques of centrifugal pumps driven in two-phase flow are estimated using gas and liquid velocities at the impeller exit which are obtained from momentum conservation equations of both phases in the impeller, in the equations friction loss coefficients between the impeller wall and the phases as well as on the gas-liquid interface are chosen so as to fit a calculated value to a test datum in an appropriate condition. The estimated values show pretty good agreement with test data for pressures of 3.3 and 6.9 MPa and void fractions of 30 - 70% in several operation modes of normal directional flow and rotation. Although the agreement is not good in operation modes of reverse directional flow and rotation, the variation of the estimated torque with void fraction shows a tendency similar to that of the test data.

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Velocity distributions dose to wall of a turbulent swirling flow in a circular pipe have been measured. Unlike the ordinary parallel flow the streamline of swirling flow twists helically downstream, which may change the structure of flow in wall region as is expected from the study of streamline curvature effects of a two-dimensional curved flow. Effect of streamline curvature is characterized by a parameter Ω, nondimensionalized angular momentum flux, by which the flow is classified as (1) not influenced, (2) partially influenced and (3) completely influenced according to the magnitude of Ω. The flow is found to be three-dimensional when Ω surpasses 0.186.

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Measurements of temporal- and spatial-variations of axial and radial velocity components and pressure have been made together with their fluctuating components in a pulse jet intermittently discharged through an electro-magnetic valve into the still air. and the characteristics of the pulse jet have been examined by comparing the results with those of a steady jet. It was found that half width of the jet and its flow rate per cycle are increased by pulsing and that an increase of flow rate is caused by the large-scale fluctuating components which are generated at the initial period of pulsation.

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Casing treatment is known to improve the stall margin of axial compressors. However, it is known as well that casing treatment lowers the efficiency of compressors. An experiment was planned in order to test a series of configurations of casing treatment which are supposed to have favourable effects and to obtain the optimum ones, if any, judged from above-mentioned two standpoints: larger stall margin improvement and smaller lowering of efficiency. The result shows that the relation between the stall margin imp improvement and the compressor efficiency for all of the tested configurations falls on some smooth curved-line, and thus, there exists no particularly superior treatment configuration to others. It rather shows that a certain amount of loss in efficiency is inevitable in order to obtain the required amount of stall margin improvement. Influence of rotor tip clearance on the effect of casing treatment was also examined. The result can be used as a guide for the selection of configurations in designing the casing treatment.

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The drag reduction in a hydraulic transport of solids in a horizontal pipe has been studied experimentally by a spiral tube with three-shaped groove tube walls. The reductions of the pressure loss and critical velocity are obtained, and the experimental formula for the pressure losses has been given by referring to Durand's formula. The difference between the flow behavior of the solid-liquid mixture in the spiral and that in the straight pipe, is shown by the results of flow visualization and measurement of the solid particle concentration.

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With an aid of Helmholtz function in combination with new mixing rules based on our PVTx measurements, the thermodynamic state-surface for a refrigerant mixture of the R 12+R 22 system was described in the range of 240≤T≤420 K, P≤9 MPa and ρ≤900 kg/m³. Using T-s diagrams for several compositions illustrated, the coefficient of performance for the standard refrigeration cycle using the present binary mixture system as refrigerant was calculated. Analysis of the coefficient of performance was explained by the composition dependence of cycle performance was explained by the composition dependence of the thermodynamic state-surface of the present system.

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For representing PVTx state-surface of a binary refrigerant R 12+R 22 system, B-W-R equations of state for both pure components in combination with mixing rules for the coefficients were applied. Proposed B-W-R equations of state with new mixing rules for the system of interest were developed based on the PVTx measurements for seven different compositions obtained by a constant-volume method coupled with several isothermal expansion procedures. The dew- and bubble-point curves of the present system were determined by analyzing these PVTx measurements graphically. The B-W-R equations of state with the mixing rules proposed here represent the PVTx measurements with an average pressure-deviation of 0.67% over a wide range of temperatures 300 to 420 K, of pressures up to 9 MPa and of densities up to 900 kg/m³. The composition dependence of the thermodynamic properties of density, isobaric specific heat capacity, enthalpy and entropy is discussed in detail.

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Experiments of the convective heat transfer in an inclined air filled rectangular cavity were carried out under the conditions of angle of inclination from 0° to 180° and a wide range of aspect-ratios (H/W = 5 ∼ 83). Depending on the angle of inclination, three flow pattern modes of a three-dimensional Benard cellular flow, a screw type flow with the axis parallel to the direction of inclination and a two-dimensional boundary layer flow were identified by visual observations of two directions. In addition, useful correlations of non-dimensional heat transfer coefficients were derived in the relations between Nusselt number Nu_W and modified Rayleigh number Ra_W cosθ or Nu_W and Ra_W sineθ.

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The breakup length of a high speed jet was studied by measuring the electrical resistance between a nozzle and a fine wire detector located in a spray jet. The maximum injection velocity was 190 m/s and the maximum Reynolds number was 6.4×10⁴. In the spray flow region, the breakup length of a liquid jet which was injected at high injection pressure into a chamber has a finite value. As the injection velocity increased, the breakup length progressively decreased and reached a constant value. As the ambient pressure increased, the breakup length decreased. The effect of L/D (the ratio of nozzle length to the diameter) upon the breakup length was great at atmospheric ambient pressure, but not so great at a high ambient pressure.

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In this study, a finite element complex modal analysis method modified with a dummy gyroscopic matrix is presented which is applicable to various types of dynamic response problems of rotor systems. Numerical examples taken here show the validity and effectiveness of the proposed method, for instance, it is seen that the method enable us to solve the dynamic response of a rotor system passing through its critical speeds whose base is subjected to a ground motion.

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Distributions and frequency characteristics of sound pressures, which are emitted from the surface of a cylinder block of an internal combustion engine, in the space around the cylinder block are analyzed. At first, vibratory transfer functions of the cylinder block are analyzed by the component mode synthesis method. Using modal dampings obtained in experiment of the cylinder block by the harmonic exciting test, a vibration analysis of the cylinder block is tried in consideration of damping. Next, distributions and frequency characteristics of sound pressures are analyzed using the vibratory transfer functions calculated by the component mode synthesis method. Besides, noise analysis is tried using vibratory transfer functions obtained in experiment, too. The calculated results agree nearly with the experimental ones.

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This paper deals theoretically and experimentally with a nonlinear forced oscillation at a major critical speed in a rotating shaft which is initially bent. When an unsymmetrical shaft carrying a disc or a round shaft (a shaft with circular cross section) carrying an unsymmetrical rotor has an initial bend, and when it is supported by singlerow deep groove ball bearings having angular clearances, its nonlinear spring characteristic fluctuates with rotation of the shaft due to the initial bend. In such a rotating shaft system, there appears a nonlinear restoring force rotating with the shaft. The resonance curves at the major critical speed in this system are more complicated in shape than those in a straight shaft system and their shapes vary with the angular position of the rotor unbalance.

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An actuator made of a Ti-Ni spring and a plastic wire, to which the Shape Memory Effect (SME) is applied has been developed. The recovery process is controlled by a electrical pulse heating. The movement of the actuator is controlled sequentially by changing the pulse width. Instead of the conventional potentiometer, the actuator is positioned by feed back control utilizing the relation between the recovery strain and electric resistance change of Ti-Ni alloy during the process of SME. The actuator has been structurally simplified and miniaturized since it consists of materials and electric device. It has been found that it operates within ±2% positioning error without any overshoot by this feed back control.

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In order to elucidate the effect of an energy saving type lubricant on surface durability, steel rollers are tested under four kinds of EP gear oils with additives of V.I. improver and molybdenum disulfide using a sliding rolling contact fatigue tester. The effect of V.I. improver and the usefulness of molybdenum disulfide under ordinary Hertzian stress range could be basically understood. The fatigue life depended on coefficient of friction and surface temperature of the roller. The fatigue life and surface failure could be explained by an amplitude of ratio of stress to hardness considering the coefficient of friction, hardness distribution change due to temperature change of the roller surface and work-hardening.

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An interactive geocentric modeling system based on a new CAD/CAM through processing, combining computer aided drawing and geometric modeling, was developed. In this system, three dimentional data can be produced from the internal data of practical engineering drawings. For an example, its application to FEM analysis is shown.

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This paper presents a study on the effects of rim thickness on root stress and bending fatigue strength of internal gear tooth. A root stress analysis by the 2-dimensional finite element method (FEM), a static loading test and a bending fatigue test for internal gears of different rim thicknesses were carried out. The root stresses increase with a decrease in rim thickness on both the tensile and compressive sides. The bending fatigue-limit-load of the thin-rimmed internal gears decreases with a decrease in rim thickness for l_w<3m and remains almost constant for l_w≥3m. The validity of the calculating formula of tooth bending strength of internal gear proposed by ISO was examined on the basis of the results of the static loading and the bending fatigue tests.

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The root stresses and tooth deflections of welded structure gears (thin rim) are computed by the 3-dimensional finite element method (FEM). The effects of shapes of tooth, the partitions and constraint conditions of gear models on the root stresses and tooth deflections of a thin-rimmed gear with ribs and a web are discussed. A suitable gear model and constraint condition for the analyses of the root stresses and tooth deflections of welded gears by FEM are indicated. The root stresses and tooth deflections computed by FEM for the rack-shaped tooth model adopted in this report agree well with those measured. The root stresses and tooth deflections of a symmetric type of single web gear are clarified to a considerable extent.

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The root stresses and tooth deflections due to a concentrated load in welded gears with different web arrangements were computed by the 3-dimensional finite element method (FEM) and measured. The computed results agree well with the measured ones. Further applications were developed to the analysis of the root stress distributions in longitudinal direction for the normal- and maldistributions of loads along face width. A symmetric type of single web gear is more advantageous for the maldistribution of loads because of its relaxing effect, while a double web gear is disadvantageous for the maldistribution of loads.

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In this report, the load distribution on toothed belt drives under a state of initial tension is theoretically and experimentally discussed. From this study the following conclusions have been obtained; the load distribution is affected significantly by the pitch difference between belt teeth and pulley teeth and the mechanical characteristics of belt materials; it is confirmed that the tendencies of the load distribution acting on the belt teeth and the belt tension distribution are completely different at a certain initial tension.

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An interactive geocentric modeling system based on a new CAD/CAM through processing, combining computer aided drawing and geometric modeling, was developed. In this system, three dimentional data can be produced from the internal data of practical engineering drawings. For an example, its application to FEM analysis is shown

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