In the previous paper, we obtained the thermal stress distributions in a circular disk due to an instantaneous line heat source. The present paper is concerned with corresponding results for the action of a point heat source which appears in the welding practice. Numerical work is carried out for the case of the thermal stresses in a circular disk due to an instantaneous hot spot on the middle point of radius. In the final part, we show that the results for the line heat source in the previous paper may be obtained by integrating the solution in this paper with respect to γ or θ.

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This paper deals with the dynamic behaviour of 0.03% C steel at high temperature (up to 700°C) within the range of strain rates of 10∼10³/sec. The effects of temperature and strain rate on the compressive strength were clarified experimentally and the particular behaviour at the temperature near blue brittleness was explained using the Cottrell's theory. The dynamic stress to cause a certain amount of strain rises with the increase of strain rate at room temperature, but the stress is scarcely affected by the strain rate at 200∼600°C, and then the stress increases again with the strain rate at 700°C. The blue brittleness occurs at higher temperature with the increase of strain rate. For the static test and the dynamic tests of 10²/sec, 3×10²/sec and 10³/sec of strain rate, the blue brittleness temperature is about 200, 550, 600 and 700°C respectively.

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This paper summarizes the results of fatigue tests of round specimens of carbon-steel castings 10, 35, 50 and 100 mm in diameter. The specimens were tested under rotating bending, pulsating tension, and completely reversed tension and compression in order to investigate the effects of various defects on the fatigue strength. The various defects were all deliberately made and included artificially drilled holes, blowholes, and shrinkage cracks. The fatigue strength, the fatigue ratio, and the fatigue strength reduction factor were obtained from the fatigue test results of specimens having these various defects, and the fatigue strength of steel castings was compared with that of steel forgings. The following results were obtained. (1) The fatigue strength, the fatigue strength reduction factor, and the size effect on the fatigue strength are smaller in the case of steel castings than in the case of steel forgings. (2) The fatigue strength of specimens having artificially drilled holes is approximately equal to that of specimens having blowholes of the same size. (3) In the case of small blowholes (d/D<0.2) the size effect is extremely small. (4) There is a correlation between the defect ratio, obtained from radiographic inspection or fatigue fracture of the specimens, and the fatigue strength. (5) From these fatigue test results, we obtained the endurance limit diagram of carbonsteel castings under direct stress.

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In the previous paper, plain bending fatigue tests were carried out on tin-base white metal lining on steel plate in lubricating oil and the fatigue strength of the metal was discussed in terms of the crack propagation rate. In the present paper, the fatigue tests are made on lead-base white metal and copper-lead bearing alloy to find the effects of lining thickness, operating temperature and activity of lubricating oil on their fatigue strengths. Lining metals are different in fatigue strength from the bulk metal and the bending fatigue strength of lining metals shows the same tendency as the endurance under bearing tests which is, however, variable with test procedures. The fatigue strength of metals increases as the lining thickness decreases. The larger the ratio of the elastic modulus of backing metal to that of lining metal, the greater is the effect of lining thickness on the fatigue strength. The fatigue strength of lead-base white metal is more affected by temperature than that of tin-base white metal. The fatigue strength of the metal is decreased by the chemical adsorption of lubricants at the tip of fatigue crack. On lead-base white metal and copper-lead alloy, the fatigue strength also decreases due to the surface pre-corrosion by free fatty acid in oil.

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Calibration test for photo-rheological stress analysis in a plastically deforming body is performed by using a softened celluloid specimen heated at 55.5°C and subjected to a combined stress which consists of uniaxial tension and hydrostatic pressure under the variable stress rate and principal stress ratio. The relation between the principal stress and strain differences and the relation between the fringe order and the principal stress and strain differences established under the constant stress rate are proved to be useful also for the variable stress rate in the test. The value of principal stress difference obtained by the photo-rheological stress analysis using the above mentioned relation according to the fringe order obtained from the test agreed well with the assigned value of principal stress difference.

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This paper treats the vibration of a circular plate with its inner boundary built-in and a rigid ring around its outer boundary. The author obtains the frequencies by minimizing the Lagrangian of the circular plate with a ring. He also obtains the frequencies of a stepped circular plate by similar method and compares them with those of a circular plate with a ring.

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The purpose of this study is to make clear the distribution of oil film pressure due to the squeeze film effect in comparison with one due to the wedge film effect. In the experiment, by making use of strain gauges, we measure at first the pressure distribution of oil film in a journal bearing when the journal rotates at a constant angular velocity under constant load. Next, we investigate the relation between the motion of the journal center and the distribution of oil film pressure which is caused by the whirling motion of the journal. In the analysis, we get the solution of oil film pressure for an infinitely long bearing under the boundary condition which is clarified experimentally. Based on this solution we analyse the variation in the pressure of oil film caused by small circular motion of journal center. The analytical results are found in good agreement with the experimental ones.

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The author proposes a synthetic criterion J of the form J=J_m+kJ_e to evaluate a control system, where J_m is the evaluation function for the operation, J_e is that for the initial investment and k is a constant. It is shown that the maximum M of the manipulated variable can be included in J in the case of the optimization of a system under a constraining condition |u|&gne;M, where u is the manipulated variable. As the result, it is shown that the choice of M can have a considerable influence on the value of the evaluation function, and that a better solution will be obtained if M is considered as one of the design parameters, when the optimum control is intended. A control of a pure inertia model is considered as an example, for various types of J_m.

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For the laminar entrance-flow problem, the present author developed previously a new momentum-integral method of solution in which the independent parameter [numerical formula], where h is the half gap width and U=[u]_y=h, was introduced together with the usual Pohlhausen's parameter [numerical formula]. The method was applied to solve the problem of the radially outward entrance-flow between two parallel discs, and it was confirmed that the theory might describe satisfactorily the complicated characteristics of the fluid flow which involved separation and reattachment phenomena. In the present paper, the author's method is further applied to analyze the most fundamental case, the two-dimensional flow between flat plates, and is compared with prior methods of solution. The result of the author's analysis agrees very well throughout the whole flow field with the exact solution given by a difference method : faults inherent in many other momentum-integral methods proposed to date are eliminated from the present method. It can be emphasized from the present research that, in order to describe satisfactorily the laminar entrance-flow phenomenon in terms of a momentum-integral method, it is most indispensable to introduce Γ as an unknown variable to be solved.

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The direct problem on the cascade flow in mixed- and radial-flow pumps and turbines has been solved by various methods. Among these the method of using the finite difference calculus and the relaxation method is sufficiently applicable to cascades with arbitrary blade shapes and with varying passage-heights and passage-angles. In this paper, such a numerical method is improved in the way of division of the stream function and on three relaxation procedures to save the labour for calculation and to increase the accuracy of the solution. Then three numerical examples are presented to examine the accuracy, to compare with the experimental data and to show the applicability of the method.

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The elastodynamic extruder or pump was developed in 1959 by Maxwell and Scalora. This plastic extruder is based on the phenomenon called Weissenberg effect. In this paper pressure distributions for no discharge flow and discharge flow are investigated using the experimental apparatus similar to the above mentioned elastodynamic pump. Moreover pressure distributions are approximatly analyzed by using the combination model of Rivlin's large deformation theory with the power law for the non-Newtonian viscosity, and the 3-constants Oldroyd model respectively. Those analytical results are compared with experimental data, and it is found that the former model may be more convenient than the latter model for practical purpose.

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In the 1st report, the pressure distributions due to the normal stress effect were treated. In this paper, the results of theoretical and experimental analysis on the performance, i.e. the power, discharge quantity and thrust of the elastodynamic pump are reported.

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This paper presents a detailed study of the heat transfer between concentric cylinders with an inner heated cylinder rotating and an outer cooled cylinder stationary. The heat transfer in the case of zero axial flow of fluid in the annuli was carefully measured for air, water, iso-buthyl alcohol and spindle oil with varying rotational speeds and annular gap widths. The heat transfer in the laminar plus Taylor vortices type of flow is analyzed with the assumption of constant physical properties. The heat transfer data confirm the existence of the critical Taylor number obtained theoretically for isothermal flow. The Nusselt number increases suddenly at the modified critical Taylor number and the theoretical results show a comparatively good agreement with the experimental ones. The simple empirical equation to fit well the heat transfer data over a wide range of Taylor numbers has been presented.

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The present work theorizes the phenomenon of rapid combustion in a diesel engine by introducing a concept that the ignition delay of the injected fuel element varies from time to time according to the changes in temperature and pressure of the charge. In this process the rate of heat release is multiplied by the rate of shortening of the ignition delay, thus causing an explosive combustion. In this paper, a theoretical analysis was conducted to establish the course of the changing delay and thereby the physical and chemical features of the process were described by simultaneous differential equations. Discussions were made on the influences of the following factors on the maximum rate of heat release ; namely, ignition delay, injection rate, pilot injection and vaporization velocity of fuel. The results show that the present theory can successfully describe the qualitative nature of the combustion knock in a diesel engine.

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Experiments of discharging water into water were performed using two disc valves i'and h', with broader valve seat face in comparison with earlier experiments of discharging water into air. The characteristic curves of valve i'change continuously unlike those of the valve for discharging water into air. The same curves of valve h'change a little discontinuously at a larger lift than one for discharging water into air. Excepting the vicinity of discontinous change, the discharge coefficients of valve i'and h'do not differ between discharging water into water and discharging water into air but the nondimensional lifting force in the case of discharging water into air is larger than that in the case of discharging water into water. These phenomena were illustrated by the measurement of pressure head at the center of the valve seat and the observation of the movement of fine silk threads attached to the periphery of the valve and the valve seat, and so on. By these experiments, the difference of the valve characteristics between discharging water into air and water into water was made clear.

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Die Reibungskraft an Zahnflanken hat Einflub auf den Wirkungsgrad von Zahnradgetrieben, auberdem erzeugt sie den Verschleib an Zahnflanken und Schwingungen des Zahnrades. Die Verfasser massen die Reibungskraft an Zahnflanken mit dem Reibungskraft-Mebapparat, der von ihnen entwickelt wurde. Aus diesen Untersuchungen konnen folgende Schlubfolgerungen gezogen werden. (1) Wahrend des Einzeleingriffs nimmt die Reibungszahl mit dem Abstand vom Walzpunkt ab. (2) Eine Reibungszahl, die sich aus der Maximalreibungskraft in der Nahe des Walzpunkt errechnet, nimmt mit der Zunahme der Umfangsgeschwindigkeit am Walzkreis oder der Olviskositat ab. (3) Je grober die Rauheit der Prufrader ist, z.B. wie bei gefrasten Zahnradpaarungen, desto wirksamer ist der Einsatz von EP Olen. (4) In Gebiet dieser Versuches-bedingungen gibt es keine bedeutenden Unterschied in der Reibungszahl zwischen der V-Null Verzahnung und der Normal Verzahnung. (5) Aus diesen Versuchsergebnissen ist die empirische Gleichung fur die Reibungszahl μ entwickelt worden.

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The formation of a built-up-edge has been differentiated into two mechanisms, that is, adhesion or nucleation of built-up-edge and growth of adhered metal. As to adhesion, the affinity between tool and work material has been investigated experimentally. The findings are that the position of a metal in the periodic table and the solubilities of the mating metals are substantially associated with the strength of adhesion. Although the temperature at the interface is primarily significant to accelerate the adhesion, the effect of relative velocity has been revealed to be negligible.

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The temperature distribution inside the carbide tool of a face-milling fly cutter was calculated from the previously obtained data of the tool chip interface temperature during the cutting period in machining a medium carbon steel. Effects of the cutting speed, tool material grade, use of water-miscible cutting oil, work width and cutter diameter on the surface and internal tool temperature are discussed in the present study. The ratio of the cutting time to the period of a cycle (referred to as the cutting time ratio) is a decisive factor for the internal temperature pattern, and it also determines the cooling rate of the tool surface during the non-cutting time. A modified non-cutting time is proposed as a unique parameter which determines the tool-chip interface temperature during the non-cutting time when different work widths or cutter diameters are used.

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