Fretting fatigue tests are carried out with various materials combinations, and the reduction rates of fatigue strength by fretting are obtained with an observation on the behaviors of frictional force. Stress analyses on the contacting surfaces are conducted elastically by using the maximum stress due to friction together with repeated stress applied on specimens, and the results are compared with the experimental results. The fatigue strength is reduced more remarkably by fretting under bending than under twisting and the damage is greater to materials combination with higher tangential stress. These results agree fairly well with the consideration where the fatigue cracks are initiated under the maximum repeated shearing stress calculated from the combination of bending or twisting stress and frictional stress. The strength reduction rate is, however, greater than the analytical one for specimens of aluminum alloy and for lower cycle frequencies. Although further studies should be made on the behaviors in fretting fatigue which are similar to those in corrosion fatigue, it may be concluded that the initiation of fretting fatigue cracks is due to the maximum repeated shearing stress.

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Tensile fatigue tests were carried out on plain specimens of annealed S20C steel with two stress conditions of constant minimum and constant mean stresses, and observations were made on the variations of stress-strain hysteresis and permanent fatigue strain with special attention to the occurrence of delayed fatigue yielding. Marked delayed yieldings were observed when the maximum stress σ_max was in the range between the upper and lower yield points of the material, with delayed period ranging from 10³ to about 5×10⁶. This yielding was characterized by a sudden increase of permanent strain ε_f and simultaneous initiation of hysteresis loop. After yieldings, ε_f and Δε_p, the half width of hysteresis loop, showed characteristic variations according to the magnitude of σ_max. Discussions were made on these points in some detail, and also on the relation between the total hysteresis energy and the fatigue life.

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Fatigue tests on plain and notched specimens, specimens with mill scale and welded joint of 40∼100 kg/mm² various structural steels under different stress conditions were carried out. Relations between fatigue limits and tensile properties of the base metal were investigated. Slope of S/N diagrams and number of cycles at knee point, in relation to tensile strength and stress concentration factor of notch, were discussed. The influence of oxidation of weldable steels on the fatigue limit, and the fatigue strength of welded joint in various steels were also examined.

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This paper is concerned with the transient creep problems of shells of revolution under an axisymmetric load. The mathematical theory of creep as it applies to shells of revolution is developed for two hardening laws-the time and the strain hardening laws, and the basic differential equations derived are numerically solved by finite difference method. As a numerical example the torispherical head of a pressure vessel which is composed of a spherical, a toroidal and a cylindrical shell is analyzed with the computer program developed for two hardening laws.

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This note deals with the thermal stresses in a plate containing two insulated circular holes of different sizes under uniform heat flow in an arbitrary direction. Bipolar coordinates are used, and the temperature distribution and the stress functions which are adjusted so as to satisfy the boundary conditions at the edge of one hole, are expanded into Fourier's series at the edge of another hole. The parametric coefficients involved in them are determined from the given boundary conditions at the edge of the hole and at infinity. Expression of the thermal stress along the edge of the hole is derived and the values of it are calculated. Some limiting cases are also discussed.

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When an axial step load is applied experimentally at one end of a semi-infinite bar, the stress wave front is not an exact step but is accompanied with some finite rising time. In this paper, the effect of the viscous property of the material on the shape of the wave front is considered.To express the viscoelastic property of the material, a Voigt model is used for the analysis. The approximate solutions for the strain wave and the stress wave are obtained and it is clarified that the rising time is proportional to √(τt), where t is the elapsed time after the impact and τ is the relaxation time.The relaxation times for steel and stainless steel are also measured experimentally and it is revealed that the values of the relaxation time of steels are less than 10^-8 sec.

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In the present paper, the meaning of an isoclinic parameter appearing in the elasto-visco-plastic state of a transparent material is investigated experimentally.Celluloid softened by heating is selected as the elasto-visco-plastic material. A complex loading having a trajectory which consists of two branches intersecting normally is realized on a thin-walled cylindrical shell of celluloid heated at 65°C with the sequences of axial tension and torsion.The relation between isoclinic parameter and the directions of principal stress and principal strain is investigated on the trajectory after its corner in relating the amount of pre-strain.As the result of experiment, the following trends may be concluded. After the rotation of principal axis of stress with a large difference between the principal stress and strain differences, though the isoclinic parameter shows the direction of principal stress for the pre-strain less than a certain value, it tends to the direction of principal strain from that of principal stress with an increase of strain after the corner for a pre-strain larger than that value.

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Recently auto design techniques have been developed in many fields, but still there seem to be many difficulties in developing a human-like a ability of computer, for example, graphic prcessing, pattern recognition and evaluation of result. The authors tried to make clear the problems by preparing auto design systems on piping systems. The authors designed and programed several auto design systems, and compared them with each other from the view point of their flexibilities and others. And they obtained the conclusion that there was no difficulty to build up auto design systems for such sorts of problems in principle, if we could introduce several new techniques. As the authors' new techniques, PROFIL function and formulated pattern processing were developed. And the learning ability of the system was examined, when the design examples by a skilled designer were taken as examples of teacher side.

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Three view type drawing has been used widely for a long time, and it plays an important role in the field of design engineering. Recently, computer graphics has been developed and applied to practical use, but there are many serious problems remaining unsolved, for example, problems concerning the method to feed the three dimensional information accumulated as a three view type drawing into a computer and so on.In this paper, the author presents a formulation of the process to generate a solid figure from a three view type drawing automatically by machine. According to this formulation, a practical system was built up for the case of polyhedra. Executing several experiments the auther confirmed the effectiveness of this formulation. He points out a "Ghost Figure Problem" of a wired figure obtained during the procedure of this system and presents a method to solve it. Furthermore, he proposes a method to solve a "Hidden Line Problem".

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In this paper, considering the lateral vibration of circular plates, the flexural vibrations of a bar with circular plates are studied. By minimizing the Lagrangian of the system, frequency equations are obtained for those vibrations : (1) the vibrations of bars attached with uniform circular plates, and (2) the vibration of a bar attached with a circular plate, of which the thickness along the radius varies exponentially and which is loaded uniformly around the outer periphery. Some numerical and experimental results are shown in graphs.

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A flow field survey and aerodynamic force measurements were carried out on a rotating circular cylinder, which was placed perpendicular to the flow near the transition Reynolds number. Remarkable changes in the unsteady wake flow pattern were observed to occur at a particular rotational Reynolds number, which is based on the peripheral speed of the cylinder, with a corresponding abrupt reduction in the steady lift force. The characteristics of the wake vortices also showed substantial difference below and above the same rotational Reynolds number. And it is also made clear that the upper limit of the periodic vortex formation was observed to be governed by a non-dimensional peripheral speed, which is the ratio of the rotational Reynolds number to the ordinary Reynolds number.

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An experimental study of the characteristics of turbulence in closed vessels, which may be available, for example, to the analysis of turbulent combustion in an engine cylinder, is presented.The decaying process of the characteristics of turbulence in a closed vessel is better considered to be divided into two periods. In the first period (pre-relaxation period) they are mainly influenced by the way that the turbulence has been generated and in the second period (relaxed period), that is nearly a homogeneous one, they are scarcely influenced by the way of generation, but inevitably by the wall of vessel.As to the relaxed period, an empirical relation for the change of the turbulence intensity is formulated in this paper.

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Two-dimensional cascade date at inlet angles higher than 65° have been presented which are required often for the designs of axial blowers. Cascade tests of NACA 65-series compressor blades were performed by the testing technique which had been established by the authors in the foregoing paper. Reliable data have been obtained in the ranges of inlet angle β₁ =65∼80°, solidity σ=0.5∼1.33 and camber C_l0 =0.0∼2.0. In the result, characteristics of cascade performance at high inlet angles are found. In the case of high inlet angles, it is necessary to take care in selecting a design angle of attack, because the range of angles of attack for effective operating region is very narrow. Limited blade loadings at high inlet angles are smaller than those at low inlet angles. Investigating various blade loading factors, defined by some researchers, Lieblein's equivalent diffusion ratio has been modified to apply also to cascades at high inlet angles. Some available data about the minimum loss coefficients and the blade efficiencies have been presented.

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It is well known that the experimental, two-dimensional cascade date are far more available than the theoretical calculations to work out a reliable design of blade rows of the axial flow compressor. In this paper, three kinds of design diagrams for the NACA 65 series compressor blade section have been presented, based on the available exprerimental cascade data. First, the improved carpet plotting diagrams have been prepared corresponding to the optimum design angle of attack which is obtained semi-theoretically. Next, introducing the "angle-of-attack selecting factor", another type of design diagrams has been prepared, by which one may select the suitable angle of attack in the effective operating range. The effects of the factor on the fan characteristics have been investigated experimentally. Lastly, defining the "inlet angle selecting factor", the other convenient diagrams have been composed, with which it is possible to estimate a performance of the cascade as well as to select the blade row elements.

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In this paper, a theory on blades of axial, mixed, and radial turbomachines is presented, in which the shapes of blades are obtained with the prescribed velocity distribution along the blade surfaces. The singularity method is used in this theory; vortices, sources and sinks are arranged along the camber line of blade sections on the mean stream surface of revolution. The effect of three-dimensional flow due to the arbitrary shapes of the mean stream surfaces through blades is also taken into account.

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This paper presents analytical and experimental studies of a magnetohydrodynamic flow in the entrance region of a channel. The flow state in the entrance region is analyzed by the momentumintegral method; and the velocity profile, entrance length, wall shear stress and pressure drop are obtained for various Hartmann numbers. The present results are in good agreement with the results of Hwang et al. using a finite difference method. Experiments are described in which measurements of pressure gradient and flow-rate were taken during the flow of mercury in the rectangular channels of 5 : 1 and 10 : 1 aspect ratio respectively, in the presence of a transverse magnetic field. The agreement between experimental results and analytical ones is relatively good.

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Under certain conditions of turbulent pipe flow, dilute polymer solutions display a significant reduction of frictional resistance. A similar effect on a rotating disk is reported by J.W. Hoyt and A.G. Fabula.In this report, the problem of the flow around a rotating disk in a dilute polymer solution of infinite extension is treated. In the analysis, the Denn model is taken as the rheological model for polymeric fluids, and the equations of motion are solved approximately with the perturbation method when the flow is laminar, while the momentum integral equations are utilized in the case of turbulent flow. The results show that the frictional resistance in a laminar flow case becomes a little greater than that in a solvent, but in the case of turbulent flow it decreases compared with that of a solvent.

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While the basic analysis of the intermittent lubrication system was theoretically treated in the 1st report, in this report the design theory of its system, including a hydrostatic thrust bearing, is examined with some experiments.By observing the experiments and simulating the dynamic behavior of the system by analog computer, the results are obtained as follows.(1) Oil film thickness, power loss, and temperature rise are systematically defined by dimensionless quantities such as hydrostatic thrust parameter, power loss parameter, linear size factor.(2) Oil film thickness is automatically regulated by the intermittent lubrication system with variable impedance, causing an improved performance of the oil distributing surfaces.(3) Remarkable temperature rise is observed in high speed operation at low temperature.(4) The influence of the speed and the resistance coefficient on the oil film thickness and dynamic pressure are simulated by analog computer with pretty good accuracy.

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The operating mechanism of an axial flow molecular pump has already been reported in the first and second reports of this study. On the basis of the results of these reports, a method for determining the blade row arrangement is proposed. Then, an axial flow molecular pump is designed and manufactured for trial. Lastly, the performance of the manufactured pump is tested by experiments. The ultimate pressure of 5.2×10^-9 mmHg and the pumping speed of 670 l/sec for room temperature nitrogen are obtained. These measured values agrees with the predicted values.

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In the hydraulic system with pressure source cylinders are in many cases operated by opening an electro-magnetic valve.In this case, when switching time of the valve is short, a surge wave is generated and it damages the equipment.The author investigated the method of surge absorption by means of acumulators.In a hydraulic system, mixing of air into oil happens easily, and surge pressure is influenced considerably by it.By theoretical and experimental study, the author clarified that surge increase resulted from the fact that the oil column, stiffened by the mixture of air into oil, took on the characteristic of a hard spring.Supposing that the inertia of the cylinder is large enough, the hydraulic system is restricted to the fixed end condition.

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Author studied mechanism of unsteady heat conduction based upon 1st and 2nd law of irreversible thermodynamics, and arrived at "minimum principle of integrated entropy in the continious single component system. In order to compute by this principle, we must use calculus of variation" as its technique.In this paper, we can show the solution of boundary value problem of non-linear unsteady heat conduction in the heating process when thermal constants are leanear function of temperature by example of heating of plate, and obtain physical meaning of non-linear problem in heating.

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The temperature history of a fuel air mixture prior to the start of combustion at the end of compression stroke in an engine is to be studied with the use of an infrared radiation pyrometer.In this report, the functions of the pyrometer were studied analytically to improve the overall accuracy of the pyrometer, and the results of improvements were shown. It is found that the overall accuracy of ±1% will be attained when the signal from the infrared radiation detector is measured within the accuracy of ±5%. Several improvements were made following the conclusions of the analysis, and an overall accuracy of ±3°C was achieved over the range of 200∼500°C of the gas temperature. The influence of the initial states of the gas and that of an optical window were analyzed, and the diagrams to correct them were shown.

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In the previous report, the theoretical basic intercooling cycle was analyzed both when neglecting the pressure loss in the intercooler, and when considering it.Furthermore, using an approximate calculation method, the authors analyzed the change in the thermodynamic performance when intercoolers are used in a simple gas turbine.Here the authors, using the same approximate calculation method and considering the pressure loss in each component, analyze the change in the thermodynamic performance when an intercooler is used in the regeneration-reheat gas turbine.Then performance characteristics of the simple gas turbine with an intercooler are calculated using a more precise method.The results there of are compared to those obtained with the approximate method.

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It is clear that the pile-up phenomena on both sides of the grooves produced by means of abrasive grains have some effects on the roughness of finished surface. In this paper for the purpose of making the effect of the pile-up on the surface roughness clear the ratio of an actual generated asperity height to a geometrical asperity one, η_S for a conical cutting edge and η_Sγ for a conical cutting edge with a spherical top could be estimated theoretically using the theory of plasticity. The theoretical values of η_S and η_Sγ showed a good agreement with experimental ones. It is evident from the experimental results that the values of η_S are independent of the depth of cut and increase with the apical angle of conical cutting edge. It is also clear that the values of η_Sγ decrease with an increasing apical angle of edge, depth of cut and coefficient of friction. And η_Sγ decreases with a decreasing radius of top of conical edge but is scarcely influenced by the cutting speed and the cutting fluid.

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In order to clarify the dynamic characteristics of non-uniform motion mechanisms with ball bushings as prismatic or cylindric pairs, the frictional characteristics of ball bushings have been investigated, and the behavior of a mechanism at low speeds has been analysed in relation to the frictional characteristics. Moreover the vibration caused by inertia forces at high speeds has been investigated.The frictional characteristics have been revealed to deteriorate remarkably under light or eccentric loads. It has been clarified that stick-slip-vibrations occur in mechanisms with ball bushings owing to the difference between the coefficients of static and kinetic frictions.Dynamic behavior of a spatial four-bar mechanism with a ball bushing at low speeds is governed by the frictions of the bushing. An approximate analysis has been made of the vibration caused by inertia forces of links at high speeds.

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The influences of the bearing clearance and the eccentricity of loads upon the frictional characteristics of the ball bushing and upon the dynamic characteristics of non-uniform motion mechanisms have been analysed.It has been clarified that the friction decreases when the bearing clearance is taken zero or negative, and that the amplitude and critical velocity for occurrence of stick-slip vibration may be reduced by making the clearance and the eccentricity of loads small. As well as the translational vibration, the angular vibration of the bushing and the bending vibration of the shaft have been analysed in relation to the circulation of the balls.

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This paper contains an approximate solution by numerical calculation for the deflections and moments due to a transverse concentrated load acting at the midpoint of a wide plate, which has varying thickness.In calculation, the flexural rigidity of the plate with varying thickness is approximated to that of a gear tooth and differential equations of the plate are substituted for finite difference equations. In these operations, the mumerically calculated results for the plate are compared to the results hitherto obtained for a uniform thickness plate and also to experimental results.Deflections obtained from the numerical calculation and the experiment show good coincidence. But moment distribution along clamped edge is different from results of a uniform thickness plate. Therefore conventional substitution of deflection and moment of the plate for gear tooth should be reconsidered.

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A new type of power-circulating, four square gear-load-testing machine in which the test gears can be loaded while they are rotating is introduced. This machine, having a capacity of 200 horse power at 1800 rpm, was designed by the authors and made in their laboratory. The results obtained were as follows : (1) The testing machine was simple in mechanism and gave no trouble during lengthy running tests of over 2×10⁷ rotations because it was designed such that the gear load could be applied mechanically using a pair of circular-arc-tooth-trace cylindrical gears (having advantageous properties such as self-centering action, due to which the load applying mechanism became very simple), oil lubricated helical and spur splines, etc.(2) Test gears could be operated beyond 5×10⁶ rotations producing only a very small number of pits (pitting area ratio less than 0.1%) at a Hertzian stress of 0.42 H_B which was greater than the Hertzian stress 0.4 H_B corresponding to the tangential load which produced the maximum reversed shear stress at the subsurface nearly equal to the endurance limit in reversed twisting (where, H_B is Brinell hardness before running).(3) It seems that past discussions made on the mechanism of pitting occurring on gear tooth surfaces must be re-examined fully using the data obtained by the authors.(4) It was clarified that the equations given by D.W. Dudley for calculating the allowable tangential load on spur gears with tooth-end contact were very insufficient in practice and that new equations based on the authors' experiments gave good results because the effects of running-in were taken into account.

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An approximate formula is given for the distribution of bending-moment of gear tooth with finite width under the condition that a concentrated load acts on any location of its surface. This approximate formula includes the effect of the pressure angle of gear.This formula coincides with the numerical solutions obtained by applying the calculus of finite differences to the basic differential equation and with the results from strain-gages on the gear tooth.The effect of the number of teeth on the bending-moment distribution is not found in the results from straingage investigation.

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Many papers on Novikov gear cutting have been published, but they have dealt with onle cylindrical gears. This paper describes the cutting method of Novikov-type spiral bevel gears. The results obtained are as follows : (1) By using a rotary cutter with elliptical cutting edges, they can be cut on Gleason's spiral bevel gear generator of ordinary type.(2) Composite test on them indicates smooth running, so they can be expected to be put into practical service.

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The qualitative analyses for the core formation inherent in a Bingham solid have already been given by the previous investigations for hydrodynamic lubrication of a Bingham solid. However, they don't make clear the behavior of the solid exactly, because the analyses for finite bearings are not sufficient.In this paper, a method of the vector analysis based on the flow characteristics of a Bingham solid, is presented for a finite bearing and shear stress and velocity distribution in the film are obtained.Using this method, we deduced the equivalent Reynolds equation of a Bingham solid and also established the general theory on the core formation. Consequently it became clear that the core formation is determined by the shear stress distribution which depends on the pressure gradient, the film thickness and the velocity of the slider surface.

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There are few papers in which the effects of the core formation on bearing performances were investigated experimentally and compared with the theoretical results. The process of the core formation has not been observed precisely.We have investigated the behavior of a Bingham solid in hydrodynamic lubrication. The general theory on a Bingham solid was already presented in the first paper.In this paper, we applied this theory to the step bearing and clarified theoretically how the existence of a yield value in shear stress affects the core formation and the bearing performances.After confirming that grease had the behavior of a Bingham solid, we observed the core distribution in the step bearing using grease as a lubricant. And comparing the experimental results with the theory, we found that both agreed and the film pressure and the range of the core formation increased as the dimensionless yield stress increased.

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A study was carried out on the oil flow in a short-bearing with a circumferential oil groove, in consideration of oil film disintegration and restoration on the unloaded side.(1) The ratio between dimensionless oil flow coefficient of the circumferentially grooved bearing (q_T) and the hydrodynamic flow coefficient obtained by the short-bearing approximation (q_H=2n) was found to be a function of the oil feed capacity number (C_npf) only so far as the present experiment is concerned (C_n=2×10^-3∼10^-1, C_npf=5×10^-2∼2). Results of the experiment coincided well with the theoretical values.(2) q_T/2n value of the circumferentially grooved bearing converged to zero as C_npf increased to a large value, while, in bearings with an axial groove or an oil hole, q_T/2n converged to finite values.(3) In the case of a circumferentially grooved bearing, unlike the other types of bearings, the oil flow could not be divided into two components resulting from the oil-feed pressure and the hydrodynamic film pressure, because the hydrodynamic component itself was affected by the oil-feed pressure.

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