A new approach was made for the cyclic deformation in terms of dislocation dynamics which is derived from modifying Johnston-Gilman's theory, and the change in the flow stress during cyclic deformation was analyzed in annealed copper. The analysis was quantitatively in fairly good agreement with test results as well as qualitatively. On the other hand, the Bauschinger effect could not be expressed well by the present analysis, and therefore, the stress-strain hysteresis loop estimated had a "fatter" shape than the actual one. This suggests that more detailed study will be needed for the evaluation of the internal stress produced by the reversed strain.

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This paper contains an asymmetric solution for the stress distributions around a hemi-spherical pit on a free surface of a thick plate under uniaxial tension. In this analysis, thirteen sets of Boussinesq's stress functions were chosen so as to satisfy the boundary conditions automatically, both on the upper surface and at infinity. On the other hand, the remaining conditions on the lower surface and on the surface of the pit are satisfied with the aid of the Hankel transform and relations between the cylindrical harmonics and spherical ones, and lastly "half-range expansion" technique. Numerical results are given for three different values of radius of the hemi-spherical pit.

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In this paper we consider a scattering problem of SH-wave by a cylindrical discontinuity in an inhomogeneous elastic medium. Its inhomogeneity is assumed as ; μ=μ₀(r/a)^λ, ρ=ρ₀(r/a)^λ-2, and then SH-wave velocity varies as a linear function of the distance from the center of the discontinuity. An exact solution is obtained in the form of "wave sum, " and is valid for all time and space. It is shown that the cylindrical discontinuity does not cause any diffraction of SH-wave, but incident and reflected waves propagate around the discontinuity just as the diffracted wave. Therefore, in the case of our inhomogeneity no "shadow zone" exists around it. Numerical examples are also plotted in the figures to show the effect of inhomogeneous parameter λ on the stress variation around the discontinuity.

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The Navier-Stokes equations are solved numerically for two-dimensional peristaltic flows by using the finite-difference technique employing Up-wind S.O.R. method. Although many analyses of the peristaltic flow based upon the perturbation method have been widely developed, they have yielded the results only for a specific flow in which the magnitudes of wave amplitude, wavelength and Reynolds number are restricted. However, the present numerical method has no restriction in principle on these three quantities and permits us to obtain the solutions for a wider range of these quantities than them. Through the numerical calculations, an investigation is made on the influences of these three quantities on the flow pattern, compared with the theoretical results obtained by the perturbation method. And this paper intends to elucidate the characteristics of a peristaltic flow at moderately large Reynolds number where peristaltic pumping has a possibility of engineering application.

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This study deals with a transient laminar flow, which is started from rest, in the entrance region of a porous pipe. This flow analysis is applied to transpiration cooling systems and research equipment for production of tidal current. In this report, the problem is analyzed by a modified momentum integral method using the integral form of the equations of continuity, momentum and energy. The following conclusions were obtained ; (1) Dynamic distributions of velocity profiles, wall frictions and pressures are obtained numerically. (2) The relation between the flow rate of injection or suction and inlet length of the entrance resion is made clear. (3) Each dynamic state in the pipe is found with changeable inlet velocities and with variable suctions or injections. (4) It is confirmed that the modified momentum integral method is valid for the slip velocity on the porous wall which makes the inlet length short.

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The characteristics of Pitot tubes in dilute polymer solutions are experimentally studied with respect to the effects of the tube diameter, the magnitude of the velocity and the concentration of the solutions. It is shown that the coefficient of Pitot tube becomes larger than unity as Reynolds number or an elastic effect increases. It represents a remarkable dependence on Reynolds number, but it is characterized by comparative stability for a large outer diameter. An empirical equation for the coefficient of Pitot tube in dilute polymer solutions is obtained by using an analytical result of the flow around a stagnation point.

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Pool boiling experiments were conducted on a 10 mm dia. heated surface facing upwards in the range of subcooling from 15 to 50K at atmospheric pressure. The heat transfer mechanism in the transitional boiling region can be estimated by a mathematical model based on the mass transfer mechanism of evaporation and condensation through a coalescent vapor bubble. The changes with time of the mass flux of condensation and the dried area on the heated surface, which are important factors governing the characteristics of transition boiling heat transfer, are estimated by a model based on this mass transfer mechanism. An explanation was obtained on the mechanism of liquid invasion onto the heated surface from the correspondence between the change with time of the dried area and local temperature fluctuations of the heated surface.

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A method is presented to analyze the forced vibration of a complex mechanical structure by using the natural modes of its components. The structure is divided into some components. All components are classified into master components and branch ones. The natural modes of each component are determined separately by the finite element method. The natural modes of all components are synthesized to form generalized system coordinates. The equation of motion under these system coordinates is solved to know the natural frequencies and the natural modes under these system coordinates. Using these natural modes, the response of the forced vibration is solved by the technique of the modal analysis. The forced vibration of three specimens is analyzed by the present method. On the other hand, the forced vibrations of these specimens are measured experimentally under the harmonic exciting force to get the compliances. The calculative results are compared with the experimental ones to check up on the accuracy of the calculation and availability of the proposed method.

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In this paper, the in-plane vibrations of a curved bar of which the cross-section varies are analyzed by using the classical theory. The equations of vibration and the boundary conditions are determined from the stationary conditions of the Lagrangian of vibration in a period of the curved bar with varying cross-section. The equations of vibration are solved exactly by a series solution. As numerical examples, the natural frequencies and the mode shapes of symmetric elliptic arc bars with both clamped ends and with both simply supported ends are obtained. And the variations of the natural frequencies and the mode shapes for the variations of the cross-section are clarified.

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In this paper, the free vibrations of a cylindrical shell which is symmetric about the cross-section at the center and whose thickness varies quadratically are analyzed by both the classical theory and an improved one. The equations of vibration, like in the previous paper, are solved exactly by a series solution and three boundary conditions are considered, that is, both ends are clamped, simply-supported and free. The effects of the variations of thickness, etc.upon the natural frequencies and the mode shapes are clarified. And at the same time, the improved shell theories are compared with the classical ones.

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The response of a single-degree-of-freedom nonlinear spring-mass system, with the third order displacement term retained, has been considered when an impulsive force acts on a vibrating system in steadystate condition. By replacing the impulsive effect with the velocity increment and using the phase plane diagram, the response for the impulse is analyzed. The velocity increment frequently leads to a jump phenomenon in systems with multiple steady states. A method for determining an equivalent velocity increment is developed. The results obtained by the method illustrate the jump phenomenon from the small amplitude state to the large amplitude state and vice versa.

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We made an apparatus consisting of a steel rod and a thin disk and compared an actual wheel squeal with the experimental one. Train squeal noise is generated in particular kinds of nodal diameter modes of axial vibration of the wheel and at these frequencies the damping coefficient has a small value. These characteristics have the same tendency as those of squeal noise generated in the fundamental experiment. We solved an autonomous nonlinear differential equation for the frictional vibration of the disk by the averaging method and investigated the effects of the damping coefficients and contact load on the stability of the solutions.

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The authors investigate the generating mechanism of a damping force in an oil damper. Its damping is caused by the oil flow in the annular cross-section clearance between cylinder and piston. A theoretical research on damping mechanism was done, assuming for mathematical simplification that the oil stream is a steady, laminar flow. Besides above assumption, various assumptions are set up for the analysis. Therefore the resulting calculus of damping is an approximation, but it has better accuracy than the previous one being used up to the present day. The practical oil damper is generally used in oscillating state, so the oil stream is unsteady. Theoretical results, however, agree well with the experimental values, as far as λ=h√(ω/2υ) is less than 2, where h, ω and υ are radial clearance, circular frequency and kinematic viscosity, respectively. Consequently, it is found that the present analysis is valuable for this type of the oil damper.

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To examine the effect of mechanical properties, in particular, the compressive yield strength of a contacting ball on the surface temperature at the conjunctional area, the surface temperature is measured on a fourball tester of Soda Type by means of the dynamic-thermocouples method in which the ball is electrically insulated from the tester. From the experimental results it would appear that when the Hertzian stress on the conjunctional area is smaller than the compressive yield strength of the contacting ball, variation of the surface temperature is remarkable due to the effect of the compressive yield strength, and the surface temperature is transiently minimum in the vicinity of the compressive yield strength of the ball.

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In order to clarify the mechanism how the surface durability of steel roller is improved by surface-hardening, using tufftrided and industrial chromium plated steel rollers whose hardened layers are comparatively thin but whose mechanical characteristics of hardened layer and core are extremly different from each other, sliding-rolling contact fatigue tests were conducted. As the result, it was elucidated that by tufftriding, the surface durability is elevated over that of core steel, but industrial chromium plating is not expected to improve the surface durability, fatigue failure modes on both rollers are spalling, and [A(τyz/HV)] max can be employed as the index of the surface durability.

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In this paper, the effects of specific sliding and sliding velocity on the seizure behavior of non-EP gear oil under rolling-sliding contact condition were revealed. And the relation between seizure and temperature was examined considering the lubrication state of frictional surfaces before seizure. As the result, the following conclusions are deduced : (1) Specific film thickness (ξ₀)_DS just before destructive seizure which makes further operation impossible is significantly affected by specific sliding and sliding velocity. (2) When (ξ₀)_DS≤0.3 where a destructive seizure occurs after lasting boundary lubrication, seizure occurrence is more related to maximum contact surface temperature. Maximum contact surface temperature (T_cmax)_DS just before destructive seizure decreases as specific sliding increases. (T_cmax)_DS in sliding contact is in the range of 456 to 477 K, which gives the reference value of the thermal stability of the boundary lubrication film. (3) On the other hand, when (ξ₀)_DS>0.3, seizure occurrence has intimate relation with bulk temperature of outer surface of cylinder T_b. (T_b)_DS just before destructive seizure decreases as specific sliding increases.

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Experiments on the load carrying characteristics of hypoid gears with various oil viscosities and concentrations of anti-wear agent were carried out. As the result, it was found that there are some general tendencies about the limiting load for scoring and friction loss of the hypoid gears. The limiting load for scoring is quite dependent upon the viscosity of base oil and the concentration of anti-wear agent but the frictional loss mainly dependent upon only the oil viscosity but independent upon the concentration of anti-wear agent. Furthermore the friction loss of the hypoid gears was compared with that of the spur gears.

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The characteristics of tooth profile of straight bevel gears of Gleason type were examined and the root stresses were investigated experimentally by making use of a static loading apparatus, which was developed by the authors. It was found that the tooth profile of straight bevel gears of Gleason type deviates from spherical involute curve in both the tip and the root of the tooth and that the root stresses at the middle of tooth trace are larger than those at the toe and the heel. Furthermore various calculating methods for contact ratio of straight bevel gears were compared on the basis of the measured contact ratio.

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This is a study on the scheduling of a multi-project system under restrictions of limited resources (manpower, equipment etc.). In this scheduling the job durations are controllable by the number of units of resources. A new approach tries to produce a strict optimizing method in which the computation is easier than that of my previous strict optimizing method. Here "a theory of a supplement schedule" is developed, which is not dealt with in any previous studies. Then this theory presents an algorithm which can be put to practical use.

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