Supersaturated solid-solution alloys of the Al-Si system up to 15at%Si were prepared by means of high pressure and high temperature techniques. A cylindrical specimen with a size of φ 6×6 mm for the solid-solutioning treatment was held under the pressure of 5.4 GPa and the temperature of 600°C for 10 hours, and then quenched to room temperature. The elastic constants of thus obtained specimens were measured by a three-dimensional resonance method. Young's modulus E and shear modulus G of the solid solutions were quite smaller than those of the two phase alloys, and they had lower values depending on Si-contents. For example, E=77.1 GPa of the two phase Al-10at%Si alloy dropped to E=62.0 GPa of the solid solution. Density variations of the specimens were also discussed.

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The high speed rail testing machine was originally developed in the world to simulate the Shinkansen traffic condition in Japan, especially the contact rolling problems between rail and wheel in a laboratory. Its main features are as follows. This machine is of a unique type and principally consists of a circular rail and two wheels, which contact each other. Test piece : actual bent rail (for example, 12 m×2 pieces), parent metal and welds. Wheel : two actual wheels, easily changeable and hydraulically-operated, running in one direction. Radial load: applied by a simple mechanism with large loading capacity using centrifugal force and oil pressure, and easily variable. Thrust load: generated by vertical oscillation of rotor by oil pressure actuator. Driving system: a wheel driven by oil pressure motor. Brake: DC motor brake and oil pressure brake. Pitch of rail sleeper arrangement; 580 mm. Medium: air, fresh water and sea water, Conditions : the same as those of the Shinkansen.

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This is a report on the result obtained by using a high speed rail testing machine, which is described in the first report. The contact rolling defects of the actual rail were observed in the laboratory. Especially, the running surface layer of the rail was investigated in detail and the possibility of surface crack propagation was analyzed by fracture mechanics. The main results obtained are as follows: (1)Defects on the running surface; cracks are initiated at the surface and propagate much in the wheel running direction and a little in the opposite direction. In this test, however, white phase is observed in the running surface layer and cracks run out through the phase is observed in the running surface layer and cracks run out through the white phase. (2) Head checks at the gauge corner; many cracks occur at the gauge corner with the same pitch and with the same inclination to the wheel direction. (3) The above tendency is very similar to that the Shinkansen. (4) The possibility of crack propagation was calculated by fracture mechanics and would be very small for shorter cracks of 0.5 mm in depth due to the friction effect of cracked surfaces themselves.

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In order to investigate the J-integral resistance curve (J-R curve) and the instability fracture criterion of sheet specimens under Mode II loading condition, Mode II tests have been carried out on center cracked specimens of 2024-T3 aluminum ally. The dependence of the J_u-R curve (J-R curve for Mode II loading) on the specimen geometry is examined experimentally. Furthermore, the influence of the compliance of the loading system on the unstable fracture condition is studied experimentally, and the applicability of the tearing instability criterion proposed by Paris et al. to Mode II loading condition is investigated. It is shown that the influence of the specimen geometry on the J_u-R curve is relatively small. The unstable fracture point estimated by the tearing instability criterion is in good agreement with the experimental result, and it is shown that the tearing instability criterion is applicable to the Mode II loading condition.

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The problems of elastic buckling and flexural vibration of variable thickness annular plates have been analyzed by the Galerkin method. Eigenfunctions of natural vibration of a constant thickness annular plate without in-plane force have been adopted as admissible functions. Numerical calculations were carried out for the annular plates of linearly varying thickness under uniform in-plane force along the inner and/or outer edges. Both symmetric and symmetric deformations were taken into consideration in this procedure. It has become clear that whether the taper ratio has influence on the buckling mode depends on the specific boundary conditions at the inner and outer edges. The proposed method could be easily applied to the case where the thickness variation is more complicated.

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Elastic boundary value problems can be formulated in the form of boundary integral equations, whose numerical solutions are obtained by boundary element methods. This paper deals with error estimation of boundary element solutions. Especially, approximate solutions obtained by constant or linear elements are investigated for cases of two-dimensional elastic bodies with smooth boundaries, which may contain cracks. In the analysis, the boundary element solutions of an infinite plane with a Griffith crack or a circular hole are derived in analytic forms. Examinations of them lead to estimation of residuals and errors.

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It is well known that a curved beam with a thin wall subjected to bending moment, has its bending stiffness reduced due to a flattening of its cross section, until local buckling occurs at last. Restricted cases, for example, circular tubes had been treated by the analytical method. Present paper gives a convenient representation for the stiffness matrix of finite element in order to analyze the finite bending of a thin walled curved beam with arbitrary cross section. Here the buckling of a circular tube is examined and compared with the proposed simplified solutions, and several representative cases are computed.

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Plasticity-creep interaction effect was experimentally investigated at various temperatures. Combined stress tests were performed on thin-wall tubular specimens of austenite stainless steel SUS 304 at various temperatures in the range of 27 600°C.Plastic behavior at 600°C subsequent to creep prestrain produced at room temperature and those at room temperature subsequent to creep prestrain produced at 600°C was experimentally determined under various loading conditions. The stress-strain relations obtained by these experiments were compared with the results calculated by the equi-plastic strain surfaces. The influence of creep prestrain at room temperature on subsequent plastic behavior at higher temperature was nearly equal to that of plastic behavior at room temperature was weaker than that of plastic prestrain.

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A quantitative measurement of contact pressure by means of ultrasonic waves using angle proves has been proposed to measure contact pressure distributions between two elastic beams. At first, in a proposed calibration method, the relation between mean contact pressure and sound pressure of reflected waves is obtained using calibration blocks with various surface roughnesses made of the same material as beams. Both sides of laminated beams are compressed under a locally uniform pressure, and the sound pressure of reflected waves is measured. The experimental results agree fairly well with the theoretical ones and the experimental ones obtained by a normal probe. It is confirmed that the proposed ultrasonic method is practically useful.

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G.Maier has investigated problems in which normality conditions with regard to plastic strain increments pertaining to the yield surface in stress space are not satisfied and work-softening effects are considered by the aid of quadratic programming concepts. Authors applied this method for solving the elastic-plastic plane stress problem as a quadratic optimization in terms of displacement rates and plastic multiplier rates. The matrices are formulated in explicit forms for the problem of a perforated strip under tension. A comparison is made between the results obtained by the present method and by the ordinary matrix method. It is shown that the elastic-plastic problem is fairly tractable to the present method.

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The starting time of a transonic Ludwieg tube is dependent on the timing of opening the main tunnel valve and the plenum exhaust valve, as well as the plenum chamber volume, the exhaust rate, the opening times of the main and the exhaust valves, and so on. In the previous paper, the starting process of the transonic Ludwieg tube with a main valve downstream of the transonic test section was studied in the case that the main and the exhaust valves started to open simultaneously. In the present paper, starting to open the plenum exhaust valve was delayed or advanced from the opening of the main valve, and the effect of plenum exhaust delays on the staring time of the transonic test section was discussed. Further, the effect of the orifice position in the plenum exhaust system on the starting time was experimentally investigated. The starting time becomes a little smaller by locating the orifice at the downstream section of the exhaust valve.

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Static blade boundary layers, outlet flow angles and total pressure drop through annular cascades have been measured removing the boundary layers on annulus walls, in order to make clear the effects of an inward radial movement of fluid in the blade boundary layers. The numerical solutions of velocity profiles in laminar and turbulent boundary layers on the blades agreed with experimental data.

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The time-mean and fluctuating forces acting on a circular cylinder placed in and near a turbulent plane mixing layer and its vortex-shedding properties were experimentally investigated. Reynolds numbers based on the cylinder diameter d and the main-slow velocity outside the mixing layer were 3.4 ×10⁴ and 4.3 ×10⁴ for the force measurements and in a range 5.5 ×10³ 4.4 ×10⁴ for the measurement of the vortex-shedding properties. When the parameter d/δ, δ being a width of the mixing layer, was of the order of 2.0, the time-mean force showed a sharp maximum near the center of the mixing layer; the r.m.s. force was larger by about 40 percent near the edge of the mixing layer than in the main flow. Strouhal number of vortex shedding was found to be smaller when the cylinder was immersed in the mixing layer than when it was in a uniform main flow. The extent of the reduction and lateral positions where the reduction began were dependent on the parameter d/δ.

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Effects of a free-stream turbulence on a series of two-dimensional separation-reattaching flows (separation bubbles) were investigated experimentally in a low-speed wind tunnel. Models tested were two-dimensional triangular cylinders with a tail plate. Some important properties of the separation bubbles were measured with a split-film sensor driven by constant -temperature hot-wire anemometers. The effect of the turbulence on the reattachment length X_R was found not to be uniform with respect to the separation angle. Large-scale vortices were formed by coalescence in the reattaching zone of the shear layer and were shed downstream with a non-dimensional frequency 0.65 ×(free-stream velocity) /X_R, which was the same for all the combinations of the separation angle and the free-stream turbulence employed in this study. Geometry of the separated shear layer suggested that the large-scale vortices in the reattaching zone became flatter as X_R increased.

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The combined effects of a transverse velocity component, a growth of a boundary layer and a transverse curvature cause a self-induced favorable pressure gradient for the flow on a rotating circular cylinder in an axial flow. When an external pressure gradient is adverse, the effect of this favorable pressure gradient influences the boundary layer separation and the flow development downstream of the separation point. The types of post-separation behavior can be classified into several flow patterns varying with the ratio of the transverse surface velocity to the typical axial velocity. In this study, by perturbing the solution at some surface velocity, the solution for a slightly different surface velocity is obtained, and the influence of the change in the surface velocity to typical axial velocity ratio is investigated. The first- and second-order perturbations are calculated, and it is shown that the change in flow pattern can be predicted by the present perturbation method.

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Numerical solutions are presented of an oscillatory laminar flow in curved pipes of square cross-section over a wide range of parameters, i.e., Dean number D and dimensionless frequency α. Velocity profiles, stream lines of a secondary flow and distributions of wall shearing stresses are calculated and the effects of D and α on the flow pattern are made clear. Depending on D and α, one to three pairs of vortices which vary periodically are induced in the cross section. The relation between the kinetic energy of the secondary flow and the influence of the curvature on the flow is discussed.

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Pressure distributions and vortex shedding were measured in a cryogenic wind tunnel from subcritical up to transcritical Reynolds numbers (10⁵ ≤ R_e ≤ 10⁷) and Mach numbers up to 0.3 without changing experimental arrangement. Drag coefficients were calculated using pressure distributions. Pressure distributions and drag coefficients show characteristic changes for subcritical, lower transition, critical, upper transition and transcritical Reynolds numbers respectively. Strouhal number is constant in the range of Reynolds numbers 10⁵ ≤ R_e ≤ 3.2 ×10⁵. Narrow band vortex shedding could not be found in the critical Reynolds numbers range (3.2×10⁵ ≤ R_e ≤6.9×10⁵), but it was found again in the upper transition and transcritical Reynolds number ranges. The pressure distributions and spectra of velocity fluctuations are presented for several characteristic values of Reynolds numbers. Results are also compared with those of other authors.

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A theoretical and experimental study is presented for the dynamic behavior of two liquid layers with a free surface in a container subject to vertical vibration. This study is concerned with two fluids sloshing phenomena. The stabilities of the plane free surface and interface of two superposed fluids with different densities are analyzed theoretically. In the analysis, the two liquids are ideal fluids, the interfacial surface tension is considered, and wall contact effects are neglected. An experiment was made on vertical vibration of a rectangular container holding kerosene and water. The agreement between theory and experiment was satisfactory on the occurrence of 1/2-subharmonic wave motions. The response amplitudes of the free surface and interface wave motions were measured. Many drops formed by the interfacial disintegration were observed in the lower fluid.

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Eccentricity of swirl center in a swirling flow through a pipe is analyzed by using momentum theory which affords a balance equation between moment of axi-asymmetric pressure force caused by an eccentric flow and a change of moment of momentum. By solving this equation, one can obtain a solution of helically twisted swirl center. The calculated results show good agreement with the experimental ones.

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Numerical solutions to the Navier-Stokes equation are obtained by using a successive-over-relaxation method for a steady incompressible flow past a sphere at the Reynolds numbers below 1.0, where the Reynolds number is related to the sphere diameter. The numerically-obtained streamlines and the numerically-determined sphere drag agree well with the recent experimental streamlines around a sphere and the recent measurements of the sphere drag respectively at the Reynolds numbers below 0.4. The analytical solutions, the present numerical solutions and the recent experimental results lead to the conclusion that the first-order solution to Oseen's equation represents the most simple and suitable flow-model among the analytical solutions for the steady incompressible flow past a sphere at the Reynolds numbers below 0.4.

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An experimental investigation of the mean velocity profiles is presented for the jet issuing into a quiescent ambient air from rectangular exits. Exits having small aspect ratios and differing in shape are utilized. The experimental results of mean properties such as axial velocity decay, half-width, static pressure, etc. are reported. It is found that some of the mean properties show remarkable changes according to the exit shape. Attaching a short length of uniform cross section above the exit plane, the gross appearance of the jet issuing from a smoothly contracted nozzle becomes similar to that issuing from a long channel. An empirical formula, taking the characteristic length as the square root value of the exit area, is presented for axial velocity decay and jet spread in an axisymmetric decay region.

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A new complete set of the basic equations for magnetic fluids with internal rotation are determined by the thermodynamical method in which free energy and dissipation function are used on basis of the coservation laws. Then a simple way to find a form of the dissipation function is given. As a result, the quasi-conservative part in the constitutive equation of stress and the constitutive equation of couple stress are derived in a physically suitable form in comparison with the other theories which have been proposed by many researchers. For instance, exact representation for the pressure part of stress is obtained, and Maxwellian stress tensor is introduced into the constitutive equation of stress in physically the most desirable form in the general case where a substance exists. Furthermore, an equation of energy for magnetic fluids possessing an internal angular momentum which has never been presented is formulated in this paper.

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On the returned flow type of the normal cyclone which has one tangential inlet pipe, the vortex core is deviated from the center line and vibrates violently. Then in order to compare the collection characteristics of the ultra-fine solid particles (fly-ash) and the flow patterns of the tangential and axial velocities, the eccentric cyclone in which the exit pipe deviates merely δ = 10 mm from the center line of cyclone and the normal cyclone were made by the acrylic resin. From the experimental results of the both types of the cyclones, the pressure drop of the normal cyclone was larger than the eccentric cyclone, the collection efficiency of the normal cyclone was promoted in comparison with the eccentric cyclone, the maximum tangential velocity of the normal cyclone was faster than the eccentric cyclone, therefore the centrifugal effect of the normal cyclone was larger than that of the eccentric cyclone and also from the results of the axial velocity distributions in the eccentric cyclone the existenses of the double and triple large circulations which hindered the separation characteristics of the fine solid particles were suggested.

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The most suitable form of a rectifying device which can stop a swirl and produce a fully developed pipe flow on outlet side of it is investigated analytically. In this analysis, the flow is assumed to be an inviscid axisymmetric swirling flow and treated as a rigid rotating uniform flow with perturbation. Euler's equation is then linearized and solved. The perforated plates, of which the rectifying device is composed, are treated as the actuator disk on the basis of their aerodynamic properties.

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Performance of a centrifugal pump was examined experimentally when the trailing edges of the impeller blades were designed in various shapes, and the change in the pump performance was discussed in relation to the velocity variation due to the shape changes. Sharpening of the blade on its pressure or suction side caused a change in the exit flow angle as well as a decrease in the meridian component of velocity, and an increase in the pump head was brought about. The increase was more pronounced in the pump with impeller blades sharpened on the suction side edge due to a larger increase in C_u2. A relationship between the increase in the pump head and the blade edge sharpening was investigated experimentally and a simple theory to predict it is presented.

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This work is description of a fundamental study to evaluate and characterize a helical screw expander, which is a rotary positive displacement type machine, for small energy conversion machines. Ideal helical screw expander, in which the working fluid is supposed to expand adiabatically without losses, is investigated and compared with experimental results. Using the indicator diagram technique, the characteristics of internal leakage has been investigated.

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The relative flow patterns of a centrifugal blower impeller were visualized on the hub, intermediate and shroud by the spark tracing method simultaneously visualizing stream lines, which indicate the flow direction. The stationary image of flow patterns in the impeller was observed using the rotating image stopping processor in which a traiangular prism rotated at half the angular velocity of impeller, and quasi three-dimensional relative flow velocity distributions were obtained. Experiments were carried out in the regions of small, design and large flow rates and the flow patterns of each region became clear. The surging phenomena were observed clearly at the small flow rate.

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In order to improve the performance of a Wells turbine the effects of guide vanes with circular-arc profile have been investigated experimentally by model testing under steady operating condition. The experimental results have been compared with those of the case without guide vanes. It is found that the running characteristics as well as the starting characteristics are considerably improved by the guide vanes. The improvement is mainly due to diffuser effect of the outlet guide vanes.

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Three-dimensional flow and heat transfer in a rectangular miter-bend, with a 90°C turn, were studied for the purpose of examining the effect of centrifugal force due to bending, in connection with a corrugated wall channel as a means of augmenting the forced-convection heat transfer with a single-phase flow in a heat exchanger. Analysis of the results is made on the heat transfer in a laminar region for aspect ratio α=1, Reynolds number R_e=300 and Prandtl number P_r=0.71. Heat transfer characteristics under the constant wall heat flux condition in terms of distributions of temperatures, local Nusselt numbers and cross-sectional mean Nusselt numbers are shown with detailed examination of heat transfer mechanism.

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Three-dimensional flow and heat transfer in a rectangular miter-vend, with a 90^° turn, were studied for the purpose of examining the effect of centrifugal force due to bending, in connection with a corrugated wall channel as a means of augmenting a forced-convection heat transfer with a single-phase flow in a heat exchanger. Analysis of the results is made for Reynolds number R_e=10 to 600 and aspect ratio α=0, 0.5 and 1. Aspects of the flow and heat transfer characteristics are shown in terms of velocity vectors, path lines, intensities of secondary flow, wall pressure, wall shear stresses, local Nusselt numbers and cross-sectional mean Nusselt numbers.

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A vertical cylinder embedded in a horizontal plate-like solid initially at its fusion temperature is subjected to a step change in temperature. The resulting melting process with natural convection in the time-dependent melt region was analyzed by means of a finite difference method. The shapes of melting front and the temperatures along the one-half height of the phase change material (PCM) were measured in the experiments using n-octadecane as a PCM. The analytical results agreed well with the experimental results. The variations of the dimensionless volume of melt region with Rayleigh number and a dimensionless time are clarified. A relationship between Nusselt number on the heated cylinder and Rayleigh number is obtained.

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Experiments have been made to clarify the effects of the thickness, aspect ratio and height of honeycomb structures on the performance of honeycomb solar collectors, and a new model, in which the honeycomb heat capacity and the absorption of the solar irradiation by the honeycomb wall are taken into account, has been proposed to predict the performance. Calculated values by this model agree better with the experimental results than those by a previous model, and the suitable honeycomb thickness, aspect ratio and height are determined by using this model. Furthermore, the performance of the honeycomb collector is compared with those of other types of collectors and the effectiveness of the honeycomb collector is indicated.

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The purpose of this study is to reveal the mechanism of the low speed hunting peculiar to the pneumatically governed engine, and to work out its preventive measure. In the present report, it is first shown that the conventional linear theory on the engine-governor system does not explain the actual phenomena. Further, on the basis of the experimental investigation it is found that the key factor is the phase lag of the governing pressure taken at a narrow passage called subventuri beside a throttle valve, because the hunting disappears when the phase lag is minimized by displacing the pressure source to the common inlet duct just down the throttle valve and the subventuri.

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Formaldehyde was experimentally confirmed to be formed in a diluted exhaust gas from a methanol-fueled spark ignition engine by ultraviolet irradiation. For exhaust gases released into the air from an ethanol-fueled engine, formations of acetaldehyde and formaldehyde took place due to the phtochemical reaction. The amount of aldehydes formation as well as alkylnitrite, methyl-product from an ethanol engine emission is C₁-nitrate, under the condition of ultraviolet exposure and high dilution with air.

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The effect of the fuel supply time on the transport delay of fuel in carbureted engines was analyzed. The following points were made clear; (1) If fuel was supplied from the carburetor under the condition that fuel was not present in the intake pipe initially, fuel supply to the cylinders could be delayed due to the volumetric delay in the intake pipe. This occurred even if fuel was transported together with air without any vaporization delay. The volumetric delay was affected by the supply time. (2) The fuel supply to the cylinders within 2 rotations from the fuel supply start was affected by the supply time when part of the fuel was vaporized.

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In this paper, the free vibrations of toroidal shells with circular cross section are analyzed by using a thin shell theory. The equations of motion and the boundary conditions are derived from the stationary conditions of the Lagrangian of the toroidal shell. The equations of motion are solved exactly by a power series expansion and then natural frequencies and mode shapes are obtained. Effects of various parameters upon natural frequencies are clarified in a discussion of numerical results. The frequencies obtained by this analytical method are compared with those by other approximate methods and the validities of the present exact solution are confirmed.

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The method of claculating the natural frequencies of coupled vibrations between the radial vibration of a part of the ring and the tangential vibration of the teeth with the stator core of the induction motor is discussed. The difference between the claculated values of natural frequencies and the measured ones with three models of the stator core is within a few per cent. Therefore, it is possible to predict natural frequencies of the stator core in the design of an induction motor. The effect of the shear deformation of the teeth on the natural frequencies, and the nature of the natural frequencies with omission of the terms for kinetic energy on the rotary motion of the teeth are also discussed.

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Regions of instability of vibrations of columns subjected to periodic axial force are determined by approximation of characteristic equations with infinite determinant. Approximation by a determinant of order three or four gives sufficiently accurate regions of instability which cannot be determined by the Hsu formula. More accurate numerical method also is shown.

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This paper describes the numerical and the experimental results about the optimum problems analytically formulated in the previous paper for a rotating machine with an overhung weight and a shaft. The main results obtained are as follows: (1) Much less CPU time and also much less necessary memory space in computer are required in computation by a matrix method presented in the previous paper than by the transfer matrix method. (2) The analysis is especially effective for solving the optimum problems of maximizing the first critical speed of the rotating machine and the optimum shape of the shaft can be directly supplied to the machine design. (3) The improvement of optimum results is simply accomplished by making the resultant shaft system discrete and by correcting only the critical speeds.

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This paper describes a sound visualization method using three color-light-emitting diodes; the distribution of sound pressure levels around each sound source obtained actually by this method; and the comparison of this method with one using a plotter for recording the measured results. In this sound visualization method, the distribution of sound pressure levels is measured with a sound visualization device built as a trial. This device consists of an auto-scanning device of a microphone with three color-light-emitting diodes; an indicator of sound pressure level which switches on or off those diodes at each instance when the sound pressure level changes by 5 dB; and a photographing set for recording the color-lights emitted from those diodes on a film. The results show that properties of sound field, such as the distribution of sound pressure levels of sound diffraction can be precisely obtained by this method.

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The control of the shaking force and the shaking moment in a link mechanism consists in obtaining the specified shaking force and the specified shaking moment without changing the motion of mechanism for the required mass parameters of each link. In this paper, a new approach to this problem is presented. The equations for the control of the shaking force and the shaking moment are set for an individual or a combined control system, and two methods of the control and the mass synthesis for a controlled mechanism are presented. As an example, a crank lever mechanism is controlled using the methods. The waveforms of the shaking force and the shaking moment can be controlled and their magnitudes can be decreased as the specified ones.

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A computational method is presented for obtaining the steady-state temperature responses of bayonet-type heat exchangers subject to sinusoidal flow rate changes of large amplitude. The frequency- and amplitude-dependent describing functions between the input sinusoidal flow rate changes and the fundamental component of the steady-state response of the outlet temperature of tube-side of shell-side fluid are also derived. Numerical examples are given and the effects of the amplitude of the flow rate changes on the frequency responses are shown: (1) The vector loci of the describing functions are illustrated. (2) The dc-components of the periodic responses are plotted for various values of the amplitude. Finally the responses calculated by the present method are confirmed by means of the Runge-Kutta-Gill method, and it is shown that the present method can reduce the computation time remarkably.

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The effects of fluid inertia forces on the pressure distributions of sector-shaped step thrust bearings operating in laminar and turbulent regimes are examined theoretically. Assuming negligibly small pressure differences at a leading edge of pad and evaluating the pressure differences at a step by considering the conservation of mechanical energy and the continuity of lubricant flows there, pressure distributions and load carrying capacities considering the effects of inertia forces are calculated for a wide range of film thickness ratios. The results obtained show that fluid inertial forces have significant effects on the pressure distributions of sector-shaped step thrust bearings.

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A three dimensional numerical analysis method is used to clarify the air-lubrication phenomena of spherical foil bearings in rotary head recording devices. This method is extended for calculating large bearing penetrations encountered under actual operating conditions. Two procedures are proposed for improving poor convergence in numerical calculation. One uses linear extra-polation from solutions for smaller penetrations to obtain initial values close to the solution for larger penetrations. The other stabilizes the calculation by optimizing the relaxation factor between 0.02 and 0.05. This procedure is used to solve problems involving spherical bearing scans with large penetrations on plane and cylindrical foils. The effects of bearing penetration and foil stiffness on the air-lubrication characteristics are presented and discussed.

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In plane spherical foil bearings, the effects of bearing penetration on the spacing distribution and the minimum spacing are experimentally investigated to clarify the air-lubrication phenomenon in rotary head recording devices. A technique has been developed to measure the spacing distribution with an accuracy 0.013 μm by converting monochromatic interference light intensity to spacing. The minimum spacings and spacing patterns measured by this technique are compared with the results obtained by numerical analysis. Good agreement is obtained when bearing penetration is less than 140 μm.

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This paper refers to a theoretical study on the lubrication of a crosshead-pin bearing specially equipped with an eccentric journal in a 2-stroke cycle diesel engine. From the analyses of the journal center locus and the oil-film pressure distribution it is clarified that the main and the eccentric bearing surfaces bear the load alternately and facilitate the oil-feed from the circumferential oil-groove to each surface in unloaded period, and that the load carrying capacity is greatly improved. The following optimums for design become evident. (i) The offset ratio is preferably large without exceeding the limit determined by the load carrying capacity. (ii)The ratio of the radial clearance to the radius is as small as possible. (iii) The width of the main segment is preferably large in the range 65 75% of the whole bearing. (iv) The effective circumferential angel and the ratio of the width to the diameter are as large as possible.

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The authors made a high performance disk machine to clarify traction characteristics of lubricating oils, and succeeded in obtaining the traction coefficient curves of the typical lubricating oils at appreciably higher pressures than in earlier experiments. By analyzing the traction coefficients obtained in experiments, the authors made empirical equations for calculating traction coefficients. Unknown factors in the equations could be accurately decided by experiments conducted under low/medium pressure conditions where performance of experiments was comparatively easy. Using the equations, it is possible to estimate the traction coefficient curves at high pressure (p_mean =2.0 - 2.7 GPa) where performance of experiments is very difficult due to metallic contacts between surface even when test rollers with very smooth surfaces are used.

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This paper shows a new method for calculating the load distribution ratios and stress in spur gears by using the finite element models with many gear teeth. The results about the ratios of load taken by meshing gear tooth to the full load and the stress distribution show a noticeable difference between the analysis assuming that the load is shared between 2 pairs of teeth and the one assuming that it is carried by a single pair of teeth. This method makes it possible to clarify the effects of the ratio of contact and the addendum modification coefficience upon the load distribution ratio, stress distribution in gears and the stress concentration in the fillet at the base of the tooth.

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In the present paper, the root fillet and rim stresses and the tooth deflections of thin-rimmed spur gears with different rim thicknesses and web arrangements were analysed by the three-dimensional finite element method. The method of changing the rim thickness of a thin-rimmed gear model in the FEM-analysis was examined and on the basis of the obtained results the effects of rim thickness on the root stress distribution were investigated. Furthermore the root and rim stresses of thin-rimmed gears with different web arrangements were computed and measured. The effects of web arrangement on the root fillet and rim stress distributions were clarified to a considerable extent.

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In this study a power transmission spur gear is recommended as a profile corrected spur gear. Supposing it is allowable that the given value deviates about ten-odd percent from actual acceleration, it is synthesized how a tooth profile error with waved form influences the rotational vibration of a profile corrected spur gear, using a simulator developed by authors. The influence degrees are revealed in an influence chart in which they are determined in relation to a rotational speed and a contact ratio. According to the result, the performance of spur gears having a waved form error is closely related to the speed but not associated with contact ratio. Especially at high speed a gear having this error is not recommendable, because this type of error influences adversely the rotational vibration of the gear at high speed.

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