This paper presents a comparison of the spin-test results of both unnotched and notched disks with a center hole. The unnotched disk bursted after it deformed plastically in quasi-circular shape satisfactorily under approximately steady strain rate. On the other hand, the notched disks deformed in elliptic shape and its change further became greater with an advance of rotating speed because of a severe strain concentration generated around the notch roots and the final bursting at relatively low speed would come quickly. For the unnotched disk the usual average stress theory was adopted as the criterion of burst, but it was not applicable to the notched disks. The measured results of X-ray residual stress in unnotched disk almost coincided with the plastic stress distribution calculated on the basis of the Tresca criterion with the Mises flow rule, but the measured results for the notched disk were different from them.

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The stress concentration problem of a strip with two circular holes subjected to uniaxial tension is treated, assuming that the holes have equal diameters and are arranged symmetrically with regard to the center point of the strip. A numerical method is adopted in which the general form of the stress function expressed in the polar coordinates and its transformed equation in the rectangular coordinates are alternately used; the former with the method of the Fourier analysis for satisfaction of the boundary conditions on the circular edges, and the latter with the method of the Fourier transform for the conditions on the rectilinear edges. These boundary conditions are considered at points of finite numbers on both the edges. The stress concentration factors are calculated for the cases of the angles between the line connecting the centers of the holes and the center line of the strip being 0°, 45°, and 90°, and the calculated results are summarized in some diagrams.

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This paper contains a three-dimensional solution for stresses around a hemi-prolate spheroidal pit at a free surface of a semi-infinite elastic body. At infinity, the body is subjected to all-around tension parallel to the free surface. In the analysis, the method of Boussinesq's two harmonic stress functions approach is used and the solution is expressed by three sets of the prolate spheroidal harmonics. The boundary conditions on the free surface and at infinity are satisfied automatically, while the remaining boundary conditions on the surface of the pit are satisfied with the aid of half-range expansion. Numerical calculations are carried out of four different shape ratios of the prolate spheroid.

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In this paper, an exact analysis for the dynamic stresses and deformations in a circular cylindrical shell with both ends clamped subjected to impulsive motions at the clamped end is presented on the basis of Flugge's dynamic shell theory and with use of Laplace transformation. The end motions are prescribed by three kinds of loading functions whose velocity histories in time are half sine, rectangular and exponentially decaying pulses, respectively. In the results, it is shown that the dynamic deformations and stresses are much affected mainly by the velocity histories of the end motions and by the relation between the period of the lowest natural frequency of the cylindrical shell and that of the end motions.

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The problem considered is equivalent to a mixed boundary value problem in the theory of elasticity where the displacement of the contact area is assumed to be translation of an annular rigid punch in a direction parallel to the surface of an elastic half-space. The solution is obtained by expressing the two stress components of the contact area as appropriate Fourier series and then reducing the problem to consideration of an infinite system of algebraic equations. Numerical results are presented for the distributions of displacements and stresses on the plane z=0.

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This paper contains a three-dimensional solution for the stresses in an infinite elastic solid which contains two spherical inclusions of the same size. The stress field at infinity is assumed to be uniaxial tension in the direction perpendicular to the common axis of the inclusions. The solution is based upon Papcovich-Neuber stress function approach referred to the spherical harmonics. Numerical results are given for various ratios of the elastic moduli of the inclusion and the surrounding matrix and four different radii of the inclusion. The stress distributions around the spherical inclusions are shown graphically.

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The problem of a thick plate subjected to impact torsion by a rigid circular cylinder is analyzed based on the dynamic theory of elasticity. The dynamic stress intensity factor at the periphery of the contact region of the plate and the cylinder is investigated for the cases of a given rotational angle and torque. The results obtained are as follows: (1) In the case of a given rotational angle, the static result is larger than the dynamic one, and the dynamic result is larger for a thicker plate. (2) In the case of a given torque, the dynamic result is larger than the corresponding static one, and is larger for a thinner plate.

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The mechanical properties of PMMA were assumed to be reproduced from a three-parameter solid type of mathematical model consisting a spring in parallel with a Maxwell element. The longitudinal strain variations were measured at two different locations in a bar of PMMA. The measured strain at one locations was approximately resolved into strains with ramp distributions in time. The analytical solution based on the one dimensional theory of longitudinal impact was obtained for the strain of the other location by superposing the ramp responses. The dynamical three parameters at different stages of iteration were given. convergence of iteration was satisfactory.

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The propagation of the harmonic viscoelastic waves in the laminated media in the direction normal to the layers is analyzed, and the frequency equations for the dilatational waves and the shear waves are formulated. The frequency-complex were number spectra are obtained for the laminated composites which consist of elastic reinforcing layers and viscoelastic matrix layers. And the phase velocity spectra and the attenuation spectra are investigated in the range of low frequencies. It is found that the phase velocity spectra for the viscoelastic dilatational waves show different features from those for the elastic waves. It is also found that even when the volume fraction of elastic layers is increased, the attenuation constant does not necessarily decrease, but that it has the largest value at a certain volume fraction.

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The propagation of harmonic viscoelastic waves in laminated media is analyzed. The frequency equations are formulated for various wave modes propagating in the direction parallel to the layers of viscoelastic laminated media. The frequency-complex wave number spectra are obtained for the waves in an alternate laminated composite which consists of elastic reinforcing layers and viscoelastic matrix layers. And the phase velocity and the attenuation on the lowest branch are investigated in the range of low frequencies. It is found that the phase velocity of a viscoelastic wave propagating parallel to the layers is influenced by the shear wave velocity in the reinforcing material, by the longitudinal wave velocity in the plate made of the reinforcing material, or by the shear wave velocity in the matrix material. The wave attenuation also related with the above influences.

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In practical design of columns, the estimation of the plastic buckling strength is important in view of reducing the structural weight or the cost of material. In this paper, the problem of maximizing the plastic buckling load of a column of given volume, length, and material is studied. The finite element method based on the incremental theory is used to determine the ultimate strength of eccentrically loaded columns. the shape of columns, i.e. arbitrary distribution of the cross sectional areas of columns along their length, is postulated to be an exponential function with three parameters. These parameters are the design variables in our problem, and optimum solutions for them are determined by Rosenbrock's method. Numerical results are obtained for clamped-free and simply supported columns. It is found that the optimum-designed columns have the shape in which the plastic region appears simultaneously on the whole surface of column along thee length. They have a significantly larger strength than uniform columns having the same weight and length.

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The present paper deals with a new function which transforms conformally a row of flat-plates into a row of circular cylinders. This new function if the basic function which can be used to obtain the two-dimensional potential flow about blades with arbitrary profiles in cascade. The distortion between the physical plane and the mapped plane, as the result of applying this new transformation, is exceeding small. Therefore, the flow about blades with arbitrary profiles in cascade can be obtained more easily and accurately by this method than by the other methods; i.e., the conformal transformations of the blades in cascade into a single circular cylinder or into two concentric circular cylinders. Furthermore, the flow through a cascade whose angle of stagger and solidity are larger can be obtained easily by this method. In addition, the flow near the leading edge can be obtained accurately.

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In this paper, a two-phase flow with randomly distributed particles is considered. The Navier-Stokes equation is integrated over the control volume fixed to the absolute co-ordinates, and then an exact volume-averaged momentum equation is derived. We remove the difficulty of mathematical treatment due to the random particle distribution by using a smooth weight-function. By the above volume-averaged equation, we can explain some phenomena of two-phase flow. As an example, the apparent viscosity of the two-phase parallel flow, where the particle concentration is distributed arbitrarily in the plane perpendicular to the flow direction, is obtained theoretically and compared with the summarized experimental data.

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This paper deals with an experimental and a theoretical analysis of growth and decay of a spherical air bubble rising in a stationary oil closed in a chamber subject to such a rapid rate of pressure variation as one bar during two or several milliseconds. The oils used were two kinds of base oils for hydraulic fluids with low and high viscosities, and base oils including a small quantity of silicon-type deforming agent were also used. The following are discussed from the comparison of the measured bubble motion with the numerical analysis: (1) mass transfer effect on expansion or compression of the bubble boundary. (2) effect of deforming agents added to the oil on the mass transfer through the bubble boundary, and (3) effect of surface dilational viscosity on violent bubble oscillation in a low viscosity oil.

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The experimental results of pressure distribution and velocity profile of diverging and converging flows are obtained. The results of dilute polymer solutions are compared with those of Newtonian fluids. In a converging flow, a remarkable drag reduction such as a pipe flow is not recognized. In a diverging flow, when α=5° and the concentration becomes 60 ppm, pressure recovery represents a value about 30% larger than Newtonian fluids. The logarithmic velocity distribution are shifted upwards from the law of the wall due to the influence of both the pressure gradient and polymer additives.

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Velocity profiles of a turbulent diverging flow are formulated by using a wake function. the frictional coefficient, the stress distributions and the mixing length are calculated by an empirical equation, which includes the result of Newtonian fluids. In a Newtonian flow, the frictional coefficient decreases when the fluid flows in downstream direction because of the inverse pressure gradient. Then, the position of the maximum stress shifts to the center from the wall, and the polymer additives promote this tendency. when the pressure gradient is small, the mixing length of a diverging flow is decreased by the addition of polymers, but it is increased when the pressure gradient is large.

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Frequency characteristics of a spool-valve-controlled servomotor with a non-symmetrical cylinder under an inertial load are investigated. Basic equations for the cylinder motion are presented and approximate solutions for them are derived. Experiments are carried out and the results are shown to be in reasonably good agreement with the calculated ones in the frequency range lower than 10 Hz. It is concluded that, as far as the gain is concerned, the effect of area ratio can not be neglected no matter how small the input may be, and that the approximate equations derived in this report for calculating the frequency characteristics are available with a high accuracy below 10 Hz.

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An experimental study was conducted to investigate the heat transfer and fluid flow around the second cylinder of three cylinders for in-line arrangement in cross flow of air. The fluid flow around the first cylinder and its wake were controlled by setting tripping-wires to the first cylinder in the neighborhood of the separation point. Their in-line pitch ratio was in the range 1.3&lE;c/d&lE;5.0, where c is the center to center distance and d the cylinder diameter, and the Reynolds number range 12000</ Re_d<5200. Heat transfer characteristics of the second cylinder are found to exhibit a strong dependency upon the wake width downstream of the first cylinder.

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Effects of probe temperature and probe material on electrostatic probe measurements in a partially-ionized high-density plasma were investigated. Probe measurements were performed in an atmospheric-pressure argon arc plasma and also in an argon arc plasma in which a small amount of hydrogen was added. Cylindrical probes of tungsten, rhenium and molybdenum were used at various temperatures. The work functions of these probes in atmospheric-pressure gases were estimated by the thermionic emission method. Further, ion saturation current to a cylindrical probe was calculated taking account of the local properties of the plasma. The ion current increases as the probe temperature rises but its increment is not large. The floating potential shifts in the negative direction at higher probe temperatures. This potential depends also on the material of the probe. These results are explained by the thermo-hydrodynamic effect and the variation in the work function of the probe.

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An infrared radiation pyrometer which was used for the measurement of the end gas temperature in an engine has been studied to measure the burnt gas temperature in engines. The theoretical temperature of the pyrometer reading, taking account of the temperature gradients in a measured gas, effects of atmosphere along the pyrometer axis and the spectrum of H₂O used as the medium, coincides fairly well with the measured values in the range of 15502050 K. The scatter of the measured values fell with ±29 K RMS. The effect of CO₂ which has an absorption band in the 2.7μm H₂O band has been examined by both theoretical and experimental means. But the influence was found to be negligibly small. The free carbon particles in the burnt gas were assumed as grey body, and the effect was calculated to be negligible under the conditions investigated.

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A compression ignition of hydrogen fuel has been investigated using a conventional swirl chamber type diesel engine. It has been suggested that the hydrogen-fueled diesel combution is attainable in spite of the expected difficulty due to a high resistance to autoignition. Smooth running can be obtained if a proper amount of the fuel leakage vitiates the charge in the swirl chamber prior to the injection, otherwise ignition fails to ignite leading to an abnormal combustion with a strong knocking and to misfiring. The conditions required for a smooth burning have been studied by varying the amount and the timing of preinjections and the quantity of the fuel leakage. The test results have shown that the fuel leakage at an adequate rate keeps the hot core in the midst of the swirl chamber from being destroyed and promotes ignition of the main fuel, thus resulting in smooth running.

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A new method of determining regions of instability of free vibrations of a rotor supported by an asymmetric massless flexible shaft in asymmetric massless bearings with external damping is presented. A general solution to equations of motion can be described in an exponential form or a sinusoidal one. According to the diagrams between pure imaginary or real roots and the rotating angular velocity, it is easy to determine the regions of instability. If the value of damping coefficient is large, the regions of instability do not exist, and if that is sufficiently small, the diagrams between the roots and the angular velocity almost coincide with those of a system without damping.

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The free out-of-plane vibration of an arc bar of variable cross-section is analyzed by use of the transfer matrix approach. for this purpose, the equations of out-of-plane vibration of an arc bar are written as a coupled set of first-order differential equations by using the transfer matrix of the bar. Once the matrix has been determined by the numerical integration of the equations, the natural frequencies and the mode shapes of the vibration can be calculated numerically in terms of the elements of the matrix for a given set of boundary conditions at the ends of the bar. This method is applied to bars of linearly, parabolically and exponentially varying rectangular cross-sections, and the effects of the varying cross-section and slenderness ratio are studied.

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As a vibrating system (principal mass) attached on a non-damped magnetic dynamic absorber, containing two fixed side magnets and an absorber magnet (floating magnet), is subjected to the action of an external periodic force, the absorber mass (floating magnet) of the magnetic dynamic absorber comes to collide with one side magnet or both side magnets when the system is excited. If the collision occurs periodically, the amplitude of the principal mass will be decreased. In this paper the steady-state vibration of the system accompanied with collision is analized and experimented. The reducing effect in the principal mass developed for the magnetic dynamic absorber is discussed, especially the optimum reducing effect is treated, and the maximum amplitude of the principal mass and others can be obtained in this optimum state.

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In this paper are analyzed the static stability of a truck crane carrier and the reaction force of outriggers against the ground, taking into account the elastic deformation of the frame and outriggers. From this analysis, simple practical formulas of a load acting on the outrigger float are obtained, and are compared with the conventional formulas. Here are also studied the effects of dimensions and specifications, rigidity of the frame and the outriggers, rotation angle of the upper machine, angle of inclination of the carrier, unbalanced height of the outriggers and the ground contact conditions on the static stability and the reaction force of the outriggers.

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Potential flow theory based on the complex variables familiar to the two-dimensional analysis of inviscid flow has been applied to the flow of grooved journal bearings. The idea of a densely distributed surface source has been successfully introduced to deal with the continuously varying film thickness. Thus, the method reported in the authors' previous papers has been extended to make it possible to deal with a more complicated problem. The calculations are carried out assuming an incompressible fluid and small eccentricity of the axis. Load capacity, damping factor, stiffness and the film force in the case of whirl have been evaluated and compared with narrow groove theory. Also calculated two-dimensionally is the pressure distribution in the film.

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This paper presents a study on the bending fatigue characteristic of normalized S45C spur gears in vacuum under two-step loading conditions as well as uniform cyclic loading. for this experiment was used a gear bending fatigue testing machine of hydraulic type with a vacuum chamber of stainless steel, which was developed by the authors, and is available for the tests in various atmospheres. The difference between bending fatigue limits in air and in vacuum is hardly noticeable. The cyclic life, however, shows the tendency to be extended with a decreasing pressure in vacuum atmosphere (p&lE;10^-3 torr). Both the maximum cumulative cyclic ratios S for normalized S45C gears in air and in vacuum are nearly equal to 1.5, which is intermediate between those for shotpeened S45C gears and for annealed S15C gears.

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In the previous report, the load distribution was analyzed assuming that the load-carrying belt teeth which are wound on the pulley mesh completely with pulley teeth. But in practice, the toothed belt drives have some incomplete meshing teeth at the beginning and the end of meshing. In this paper, the load distribution under consideration of incomplete meshing teeth is discussed, and the analytical result on load distribution is found to almost exactly agree with the experimental one.

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The pitch difference between toothed belt and pulley exerts great influence on the fatigue strength of toothed belt. We reseached experimentally the relationship between pitch difference and fatigue strength for L-belt section of polychloroprene rubber and polyurethane toothed belts. From this study, the following results have been obtained. There are several features of fracture which relate to pitch difference and belt tension. A high fatigue strength can be expected if the pitch difference is selected to equalize the load distribution.

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The maximum stress in the flange used at the joint of a pipe line is a meridional one at the outer surface of the hub end, but it cannot be calculated by the formulas in the Standards. In this paper, the stresses of several flanges are determined by the finite element method, and a formula is introduced, by which the maximum meridional stress can be easily estimated by applying the correction factor α^^- to the axial stress σ_z according to the ASME Standard. Then α^^- is given as follows: α^^-=-0.0284×[(S₁-S)/r]²+0.3815×(S₁-S)/r+0.644 where, S₁: thickness of hub at large end S: thickness of pipe r: fillet radius at hub end

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In this paper, the influence of heat generated in profile milling on the thermal behavior of a workpiece (a disk) is analyzed theoretically. Applying Duhamel's theorem to the results of an instantaneous heat source problem, the theoretical equations of the thermal behavior for a moving heat source problem are easily derived. This method is confirmed using thermoelastic displacement potential. Comparing the temperature variations observed in an experiment with the theoretical values, the amount of heat input to a disk is estimated. Then, thermal stresses and deformations are computed numerically using actual values of physical constants of the workpiece. The numerical results on deformation are in good agreement with the experimental results, and it is concluded that the theoretical equations obtained are useful for predicting the thermal behavior of a workpiece.

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