The problem of the statical deflection of a rhomboidal plate with clamped edges subjected to uniformly distributed pressure, is studied in this paper on the basis of the energy method, which was once used by one of the authors in the eigenvalue problems. As numerical examples, the deflection and the bending moments at the center of the plate, and the maximum bending moments along the edges are calculated for three oblique angles-75°, 60° and 45°.

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The results of cantilever type rotating beam fatigue tests on low carbon steel and Cr-Mo-V steel at room temperature, 300°C and 500°C in a wide frequency range from 775 to 15000 rpm were summarized and examined in detail. From S-N diagrams it was found that the highest fatigue strength cccurred at 7500 rpm for both steels at elevated temperatures, whereas from S-t diagrams in which abscissa was time to failure instead of number of stress cycles, it was found that the life time gradually decreased with an increase of frequency. Some irregularities were observed in the strength of low carbon steel at 300°C. It should be noted that the fatigue strength for the frequency higher than 10000 rpm decreases rather rapidly at elevated temperatures.

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It has been reported by the authors that the estimation of fatigue life of the materials under constant stress amplitude can be made using the liner relation of b/B-logn/N (where B and b are the initial and the current half-value breadth of diffraction line in fatigue and n/N is the cycle ratio). In the present paper, the following experiments were performed ; the first, the experiments were made on the case of varying stress amplitude of two stress levels above fatigue limit and investigated the change of half-value breadth due to varying stress amplitude. The second, the half-value breadth was measured by using satisfactory method in physical meaning and compared with the conventional method which has been adopted in these series of investigations. Finally, discussed on a change of half-value breadth under varying stress amplitude and postulated a certain method for nondestructive estimation of fatigue life.

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Relaxation, step down and creep tests were carried out on a Cr-Mo steel at a temperature of 500°C and the characteristics of the material obtained by these tests are discussed in order to correlate them to each other. It was found that the log-log plot of stress versus strain rate in relaxation lies on a broken straight line. It may be considered that the relaxation in the higher stress range corresponds to transient creep and that in the lower stress range to steady creep. This simple correspondence dose not always hold, because the stress decrease during relaxation is accompanied by creep recovery. The predictions of relaxation using the informations obtained from other sorts of tests, which have been proposed up to this time, are not always satisfactory due to the lack of consideration of relaxation characteristics. Using the method presented by the authors, which is based on the fundamental relation between stress and plastic strain rate, the residual stress can be satisfactorily predicted. It is also found that a step down test is effective for determining the relaxation properties of materials.

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The authors named the rotor having two unequal principal moments of inertia except the polar moment of inertia, "asymmetrical rotor", and studied the vibratory characteristics of the motions of the shaft carrying an asymmetrical rotor analytically and experimentally. The results are as follows : (1) The rotating shaft is statically unstable near its major critical speeds, and the unstable regions become wider as the asymmetry gets larger and the damping forces smaller. (2) The unstable region of the lower major critical speed vanishes as the mounting point of an asymmetrical rotor on the shaft comes to the center of the shaft. (3) There are 8 natural frequencies p_i, p^^-_i (i=1, 2, 3 and 4) in the free vibrations of a four degrees of freedom system treated in this paper, and the relation p^^-_i=2w-p_i always exists. (4) As the asymmetry disappears gradually, the natural frequency p_i approaches that of a symmetrical rotor, and the amplitudes E^^- and F^^- of free vibrations peculiar to p^^-_i disappear. (5) The vibratory characteristics mentioned above (1), (3) and (4) except (2) of the shaft carrying an asymmetrical rotor are the same as those of the flat shaft carrying a symmetrical rotor.

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Use of a vibratory feeder is commonly seen in mass prcduction fields for conveyance of machine parts or particles such as raw materials. However, the principle how these particles are conveyed by vibratory motions, has not been thoroughly investigated. In this paper the motion of the particle fed by a sinusoidally oscillating plate of feeder is studied from a dynamical view point. The particle or the part is assumed to be a mass point for simplicity of analysis. When the amplitude of oscillation is small, the particle is conveyed by gliding motion on the surface of the vibrating plate. When the amplitude exceeds a certain value, the particle jumps up from the surface of the plate, so that in this case the procedure of feeding differs from that of a jumpless case. Analysis covering both cases is carried out and the validity is demonstrated experimentally.

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In this paper it is analyzed what influence the symmetrical nonlinearity of restoring force and the mean square value of a random loading have upon the mean square value and aspectrum of displacement in a vibration system having a single degree of freedom. In this analysis an iteration method is applied to solve the equation of motion, assuming that the nonlinearity and loading have small values, and the first approximate mean square value and spectrum of displacement are derived. In the case of a hard spring, the mean square value of deflection is smaller than that in the case of linear spring, while in the case of a soft spring it is larger than that in the case of a linear spring. These phenomena are remarkable when the system is under heavy loading. The spectrum of displacement has a peak value at the higher frequency in the case of a hard spring and at the lower frequency in the case of a soft spring.

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In this paper the author analyzes the effects of the unsymmetrical nonlinearity of restoring force and the mean square value of a random loading on the mean square value and spectrum of displacement in a vibration system which has a single degree of freedom. In this analysis an iteration method is applied to solve the equation of motion, assuming that the nonlinearity and loading have small values, and the approximate mean square value and spectrum of displacement are obtained from an equivalent loading spectrum. The random loading is expressed by Fouries series, and in the case of white spectrum an experiment is made using an analog computer.

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1. When a heat source travels along the surface of a semi-infinite solid with a constant velocity ν, the temperature θ in the semi-infinite solid is given by [numerical formula] where w=x-vt, β=ν/α, and the temperature distribution of the heat source can be expressed as θ(w). 2. Though the eigen-values of this partial differential equation are complex numbers, the solution can be obtained in the form of a real Fourier's integral. Thus the temperature distribution in a semi-infinite solid and heat transmission through the surface are calculated. 3. This Fourier's integral was numerically calculable by a digital computer. 4. It was much easier to solve the above partial differential equation by the accelerated Liebmann's method using a digital computer than to solve it by the Fourier's integral method, and the result obtained by one method coincided with the result obtained by the other.

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This paper deals with the unstable combustion of liquid fuel in a combustor. Owing to the increase of air-fuel ratio in the range larger than stoichiometric one, combustion becomes unstable, the noise increases and also the pressure and the temperature in the combustor oscillate at a frequency of 20 to 50 cps. Moreover, blow-off phenomenon results from this unstable combustion. The results obtained are as follows : (1) The frequency of combustion oscillation changes with air-fuel ratio, fuel flow rate and mean drop size of fuel. (2) The amplitudes of pressure and temperature change become larger with the increase of air-fuel ratio and fuel flow rate. (3) The flow rates of fuel and atomizing air oscillate in the case of combustion oscillation. (4) The mechanism of combustion oscillation is made clear by high speed photography.

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Since the pressure sensitive diaphragm of a low pressure indicator is usually made large to increase the gain per unit pressure, it is difficult to arrange the diaphragm to be flush with the inner surface of the wall, to which the indicator is fixed. The error, resulting from the passage leading from the inner surface to the diaphragm, increases with the decrease in the resonant frequency of connecting passage. The authors have theoretically and experimentally investigated the effect of the connecting passage on the accuracy of the pressure measured. They found out that the resonant oscillation in the connecting passage, which occurs due to the cross-sectional area of passage being made large to raise the resoant frequency, can be successfully avoided by fitting the passage with a damper such as a throttle. The delay of the measured pressure-change due to the damper is permissibly small.

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This paper presents the features of a 13000kg/hr supercritical test boiler which was erected at the third factory of the Ishikawajima-Harima Heavy Industries Company and also describes the experimental results of its steady and dynamic test. Especially the analysis of dynamic test is made in comparison with the simulation by the analogue computer. Test results can be applied to development of the central supercritical pressure steam generator.

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In view of the current tendencies in power requirements, it will become a necessity in the very near future to construct in Japan large-capacity supercritical pressure thermal power plants. In this paper, we outline the supercritical pressure test plant recently built by Hitachi Ltd., at the Hitachi Laboratory, and discuss some of its experimental results. These plant facilities include a boiler with steam conditions of 350kg/cm²g and 650°C and a steam flow rate of 2 t/hr, a 200kW turbo-generator, as well as a complete set of plant equipment and a large variety of testing apparatus. Here a wide range of research activities are being conducted on heat transfer and flow characteristics of supercritical steam and water, control methods and operating methods of entire plants using once-through boilers, the water treatment of supercritical pressure plants, and heat-resisting materials for supercritical pressure plants. In this paper, we report on some of the results of this research.

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In the first report the published papers on the fatigue strength of rolled screw threads were reviewed, and it was reported that the fatigue strength of rolled screw threads might be affected by the rolling condition. Then the process of thread rolling was analysed theoretically. In the second report the results of the rotating bending fatigue tests on the specimens with a rolled V groove were presented. In this experiment the rolling conditions of V groove were changed by varying the number of revolutions of a specimen during the rolling process. The type of rolling pressure curve was held constant. In this third report the results of the fatigue tests similar to those in the second report are presented. In this experiment the type of rolling pressure curve as well as the number of revolutions of a specimen is varied. When the rolling is performed by the usual method using the rolling attachment reported in the second report, the rolling pressure curve becomes an increasing pressure type. Using the same attachment the constant pressure type can be obtained by a simple additional operation. In these two types of rolling pressure curves the V groove is rolled at the three levels of the number of revolutions of a specimen. The fatigue tests are carried out on these specimens. The fatigue strength of the specimen with a rolled V groove increases with the decrease of the number of revolutions of a specimen, and is higher in the constant pressure type than in the increasing pressure type.

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In this paper, the analysis of complex motion in cam mechanism is carried out by new graphical methods which illustrate easily the "actual"displacement, velocity and acceleration of the follower, and the errors in Thomson's method which was solved erroneously by means of vectors are pointed out. For the critical and allowable pressure angles of a cam, moreover, the authors present convenient methods for graphical solution.

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Three grades of nodular cast iron (60, 80, and 100) were tested to determine the cutting and feed forces required to machine the materials, to determine the performance of several grades of carbide and ceramic cutting tools, and to investigate the flank adhesion phenomenon. Cutting characteristics for grade 80 and grade 100 were found to be the same as for high-strength gray cast irons with similar Bhn values. Flank adhesion, with accompanying sharp increases in cutting force values, was encountered only when grade 60 was machined with carbide tools. An attempt was made to correlate tool composition and flank adhesion. In order to determine the effects of cutting conditions on flank adhesion in detail, nodular cast iron grade 60 was machined dry and wet with cast iron cutting grade and steel cutting grade carbides. Decreasing the feed rate raised the critical cutting speed at which flank build-up occurred and lowered the resultant tool force. For tools with positive rake angle, the critical cutting speed was generally higher and tool forces were lower than for tools with negative rake angle. Large clearance angle eliminated flank adhesion. The use of cutting fluids prevented flank adhesion, and tool force patterns were smooth and smaller than those for dry cutting. Flank build-up was analyzed chemically and metallurgically. Methods to prevent flank adhesion are recommended.

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It is well known that the rate of wear is usually very high at the beginning, but later decreases to a lower constant value. The mechanism of these transient phenomena of wear has never been made clear. This paper deals with the relation between initial wear and stationary wear. The adhesive wear is the most important of wear types because it can not be avoided when two bodies are set in contact and rubbed against each other, and it will occur the easiest in vacuum. A special wear machine was constructed for the wear test in vacuum. The experiment was done on the specimens of carbon steel in vacuum of 5×10^-5 mm Hg. The tests revealed that the harden patch was very important.

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In order to investigate the pitting phenomena, the heat treated gears of 0.35% carbon steel and the induction hardened pinions of 0.40% carbon steel were tested with the gear endurance testing machine under various loads, lubricant temperatures and pitch-line velocities. It was observed that, if the loads were beyond a certain value (endurance limit), the pitting grew rapidly with the cycles of load repetition, then it results in progressive pitting, and the involute errors and dynamic loads of gear teeth increased along with the growth of pitting, and if the loads were less than the endurance limit, then it resulted in non-progressive pitting, and the pitting appeared to grow only to a certain extent but not any further, and in this case the involute errors and dynamic loads changed little. It is noteworthy that the viscosity of lubricant and the pitch-line velocity of the gear remarkably affect the endurance limit.

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