Rotating bending fatigue tests were conducted on 18% Ni maraging steel with in 10⁸ cycles to failure. Solution treated specimens and five kinds of aged ones having the same hardness level were tested to investigate their effects on fatigue lives. SEM observations were made on the fractured surfaces, and the distribution of fatigue lives was theoretically analyzed. The major conclusions are as follows: (1) The fatigue strength of aged 18% Ni maraging steel was higher than that of solution treated one by at least 14kg/mm². (2) A large scatter of the fatigue lives was observed for the aged specimens, but the effect of different aging treatments was not recognized. (3) It was confirmed that the fatigue cracks were almost initiated from the inclusions near the surface, and that the scatter of fatigue lives was mainly caused by the distribution of inclusions. (4) Based on several assumptions concerning the distribution of inclusions and stress concentrations around them, the distribution of fatigue lives was theoretically derived, which showed a good agreement with the experimental distribution of lives.

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In this paper, the dynamic displacements and stresses in circular cylindrical shells having finite lengths with both ends free and both ends clamped, which are suddenly subjected to equal and opposite radial concentrated loads, are analytically investigated on the basis of Donnell's shell equations including the effect of radial inertia force. The values of the dynamic factors at the loaded point, defined by the ratio of the dynamic maximum radial displacement to the static one, decrease as the cylindrical shells become long, but do not coincide with the result in the case of an infinite cylindrical shell unless the lengths are sufficiently great. Applying the method of solution proposed in this paper, the dynamic responses of finite circular cylindrical shells may be analyzed under arbitrary loading and boundary conditions.

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The in-plane vibrations of curved bars are researched, of which the center line is arc of an ellipse or of a sinus curve. Two method to solve the problems are used, one using a function representing the arc curvature by arc length and the other using a variable, of which the relation to arc length represents the curvature. These methods are useful to investigate the in-plane vibrations of curved bars, of which center lines are some plane curves other than ellipse and sinus curve.

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This paper deals with a method to detect the so-called abnormal phenomena during nuclear operations. The new method consists of the following ideas; an index defined as the sum of ratios of the square of a factor score to the contribution weight of the factor, which is evaluated by applying the multi-factor analysis technique to the data of the state of nuclear reactor systems like neutron flux, temperature, flow rate and so on. The excess of the index over some given threshold shows the reactor system would be in an abnormal state. Then a theory of optimal filtering by Kalman with aid of the stochastic approximation is applied to estimate the neutron flux distribution at its abnormal state and subsequently the squared sum of difference between desirable and estimated flux distributions shows the spot at which the abnormal phenomena would have occurred in terms of the peak of its distribution.

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The purpose of this paper is to investigate the effects of the vortex rate gyro configurations on the performance characteristics. The experiments were conducted using a V. R. gyro of which the vortex chamber diameter, and the chamber thickness and the sink tube configuration could be varied. The important factors --detecting factors of three kinds of pick off, optimum set position of the pick off hole etc. -- were measured through the alteration of various gyro configuration, and the angular momentum loss at the sink tube entrance was investigated by comparing the theoretical static characteristics with the experimental. In the experiments on the dynamic response, we obtained an empirical formula of the correction factor which modified the theoretical equation of the time constant in the V. R. gyro response.

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One of the major obstacles to raising the work efficiency of the machining process using a machine tool in the past was the phenomenon of chattering. Several factors are conceivable as the causes of chattering. It is generated, first of all, by extremely unfavorable dynamic stiffness in the structure of a machine tool. Numerous active dampers have been announced for improving the dynamic stiffness of the structure of machine tool. A Quasi-Moment Damper differs from previous methods in that attention is paid to the bending moment as a control quantity. This paper includes the experimental results and theoretical analysis of a ram provided with a quasi-moment damper.

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For the purpose of increasing the dynamic stiffness of mechanical structures, this paper proposes a servodamper method. Without the necessity to tune the damper characteristics to the requirements of the structure, the servodamper can be applied even to structures whose dynamic characteristics vary in a very large frequency range. From a viewpoint of state feed back control, a design procedure of the servodamper system is shown. Then proposing a new concept of a minimum performance index, this paper presents a criterion to determine a control law for the servodamper control system. Using the criterion defined in this paper, a damping effect on structures is discussed quantitatively. Finally, the result of the experiment of the servodamper system is reported.

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Several periodic and transient flows through cascades were analized by applying the conformal mapping method to acceleration potential. It is shown that the method is simple and practical even for the flows of complicated boundary conditions, by using the potential function of multi-poles at the origin of the mapping plane. Also, several transient flows through cascades are treated in the same way giving the cascade effects on the transient lift response, and the generality of the method is shown.

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The method of characteristics based on Benson's technique has been widely used for the analysis of unsteady flow in the exhaust system of internal combustion engines. But, being a one-dimensional analysis method, this method cannot be applied to a junction directly, and some assumptions or experimental data are used for the analysis of this part. The authors have been requested to increase the accuracy of this analysis for a long time, and one of them has recently developed a numerical technique that can be applied to two-dimensional compressible flow of any boundary shape, which is named " Modified FLIC Method". This paper presents the applicability of the Modified FLIC Method to unsteady flow analysis at a junction of the exhaust system by comparison with experimental results.

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For reliable prediction of flow stability in sodium-heated steam generators, a dynamic model was proposed for boiling flow oscillation in parallel channel systems, and an analysis code was developed. The model contains a description of a sodium flow exchanging heat with a water flow in counter-current fashion. the code was applied to three representative flow systems whose heating conditions differed from each other, whereby their flow stabilities were compared with a focus on the effects of heating condition. Eigenvalues and flow impedances of the oscillation determined for each system reveal that: (1) Two fundamental system for the steam generator, parallel tube system in an evaporator and steam generator modules arranged in parallel, have different stabilities under low frequency oscillation. (2) Existing analysis model conditioned on constant heat flux gives different results on stability from those of either steam generator model under low frequency oscillation.

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Measuring the spread of tracer bubbles from a point source located at the center of an 80 mm. dia. pipe, we obtained the information of the diffusion of bubbles in a fully developed turbulent air-water two-phase flow. The features of the measuring technique in this apparatus are as follows: First, the local void fraction is measured with a fiber glass probe based on the principle of light refraction. Second, we used a sampling probe based on the principle of the hot-wire anemometer probe, by which we were able to discriminate bubbles between helium(tracer) and air. As a result, we conclude that the diffusivity of the bubble is smaller than the eddy diffusivity of momentum and it increases with an increasing value of void fraction.

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The author estimates the optimum design position of an intercooler from a thermodynamical point of view, on single shaft intercooling type gas turbines for driving generators. First a general equation is derived in order to calculate the position of an intercooler for maximizing thermal efficiency. Next the effect of the position of an intercooler on the design point and the off-design point performance is clarified, considering the changes in the specific heat of the working fluid with temperature and excess air ratio, as well as pressure loss at each cycle component. Based on such analysis and in order to estimate the optimum condition of the design position of an intercooler, the following are judged to be the most influential factors for deciding this condition: thermal efficiency and specific output for the design point, the performance under part-load operations and various atmospheric temperatures and the characteristics under no-load operations.

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Some experimental results on the relation between transmission errors and dynamic loads of spur gears are presented. Using a power circulating type gear tester, the dynamic loads on two pairs of gears, i.e. an accurate one and a rough one, were measured and their dependence on gear speed and tooth load was investigated. The dynamic loads on the accurate gear pair showed recurrent time variations over a wide range of gear speeds. On the other hand, significant randomness of dynamic load was observed with an increasing speed in the rough gear set. An analogue computer simulation was also performed under the experimental condition. Good agreement was achieved between the experimental results and the simulation qualitatively; and it seems to show the propriety of the statistical theory on the estimation of dynamic loads which has already been developed in the previous paper.

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The dynamic characteristic of the resultant vibrational system consisting of the workpiece and its supporting members has much influence on an occurrence of self-excited chatter vibration. This characteristic is analysed in relation of the workpiece shape with the dynamic performance of the machine used, and correlated to the grinding process dynamics to introduce a new stability equation for chatter. It is experimentally verified that this equation can be used for every workpiece shape in order to predict stable grinding conditions without chatter quantitatively.

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Recently, it is increasingly required to produce mechanical components by a simple blanking so accurately that the components blanked off can be fitted without any further finishing process. So, an observation of the phenomenon of material parting has become of prime importance in order to know about the result of surface formation in the shearing operation. However, in a shearing process the metal undergoes an unsteady deformation in a very limited zone. Experimental difficulty in practice arises, and an analysis consistent with both deformation and stress does not seem to have been reported. In this research, for the sake of simplicity of its geometry, the deformation in the "scissors type shear" is observed and investigated in detail. It has been clarified that the advancement of the tool can be made by causing the rigid body rotation of the material as a whole, the relative shift and the indentation. This paper refers to the possibility of a new interpretation of the shearing performance in general according to percentage of these component displacements. In a blanking of sheet metals, the material behaves under a more constrained state than in the "scissors type" shear and it is considered that a change in the proportion of these component displacements depends on the severity of constraints encountered in the process.

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In theoretical researches on the shearing process so far a rigorous plasticity theory could not be applied unless one made some assumptions which are not plausible. Because of its simplicity and easiness to realize the essential qualities of the process, the present research deals with the scissors type shear in which the kinematically and statically consistent slip-line solutions could be proposed. The slip-line analysis is carried out on the four stages in a process. Four kinds of the fields thus obtained can be joined each other without any abruptness. On the basis of the proposed fields the significance of the characteristic value in the deformation stated in the prior report was elucidated. Thus it has become possible to estimate the process of punch load as well as the width of contact zone.

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