In order to gather information relating to the low-cycle fatigue behavior of anisotropic materials, the low-cycle fatigue prorerties of thick rolled steel plates were investigated in several directions under the condition of uniaxial tension-compression. The steel plates used showed considerable anisotropy in fracture ductility in the thickness direction, while anisotropy in the yield and ultimate tensile strengths was observed to be very slight in any direction. The low-cycle fatigue behavior was also the most anisotropic in the thickness direction. The fracture life in a given direction, however, was found to follow the Manson-Coffin type relation, which is usually applied to isotropic materials, if the fracture ductility determined from the tensile test in that direction was used. The crack initiation life also exhibited a similar trend, although in a more exaggerated manner. Differences were found in fracture mode depending on the directions relative to the rolling direction.

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This paper discusses a method for evaluation of contact stresses between two or more elastic bodies with frictional forces on the contact surfaces, by means of a finite element method. The matrix equation is solved by some nodal points being prepared on the contact surfaces. These nodal points are classified into "adhere to" or "slide over" one another categories, depending upon whether frictional forces are greater than the shearing forces or not, and contact conditions are applied for each case. For example, numerical results for two rectangular plates and two cylindrical columns having different sizes and Young's moduli which are compressed into one another are obtained. Contact pressure along the contact surface of rectangular plates without friction is in good agreement with the exact solution for semi-infinite plate, except near the end of the contact surface. Also the influences of friction on the contact stresses are discussed.

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This paper treats a flow past a circular cylinder whose one end is set on a flat plate and the other free end is immersed in a uniform stream. The surface pressure distributions were measured to obtain the local drag coefficient and the mean drag coefficient, by varying the length-diameter ratio l/d from unity to 12.5. It is found that the separation point of the circular cylinder removes forward with a decreasing ratio l/d except in the neighborhood of the free end of the cylinder and the local drag coefficient changes greatly when l/d varies from 6 to 7 because a vortex street does not exist at l/d≤6. The vortices shedding frequency decreases as the free end of the cylinder is approached and it depends on both l/d and Reynolds number.

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A peculiar wavy flow occurring in a rotating channel through which fluids flow radially is studied experimentally and theoretically. This wavy flow is created by a Coriolis force which arises from uneven distributions of flow velocities due to the inlet bend of the channel. The wavy nature of the flow is analyzed by using the momentum theory, and the result is verified by experiments. The following results are obtained : (1) The pitch of the wavy flow is reversely proportional to Ω, the reciprocal of which is a Rossby number. (2) The wavy motion damps downstream due to the wall friction. (3) The pitch of the wavy flow is almost independent of the inlet curvature.

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A Pressure Compensated Deceleration Valve (abbreviated as the PCD-valve) is a new type hydraulic valve which combines an ordinary pressure compensated flow control valve (abbreviated as the FC-valve) with a hydraulic deceleration one. Our object is to produce a constant pressure difference between the inlet and outlet of the throttle for the varying input pressure and area of the throttle of this valve, and to obtain, with high response and stability, the flow rate which is proportional to the spool displacement. In this report, the influential factors on the pressure difference between the inlet and outlet of the throttle of this valve, and the methods of improving its static characteristics are discussed. Further, the influential factors on the response and stability are also discussed, and through a frequency response test, the improvements of the dynamic characteristics are presented. With the data obtained from these pre-experiments a PCD-valve was made for trial. Its deceleration characteristics when used in a metering-out circuit are discussed. According to the result, the natural frequency of this PCD-valve increases remarkably and its 0-dB gain range becomes wider than an ordinary FC-valve in the frequency response test.

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In order to obtain a knowledge about the fundamental characteristics of opposing jet flames, two dimensional opposing jets in air stream are treated experimentally in the state without flames. Results obtained are mainly summarized as follows. (1) By the value of velocity ratio λ, opposing jets are divided into two types as follows ; the nozzle attached type flow (N-type flow) for λ<1 and the recirculation type flow (R-type flow) for λ>1.65. And for 1<λ<1.65, the transition type flow can be recognized. Each type of flow is decided by the fact whether the stable recirculation eddy is formed or not in the region a little behind the outlet of nozzle. (2) The flow field is examined by drawing up the isobaric line diagram, the flow pattern and the diagram of constant concentration. And in R-type flow, it can be divided into the negative pressure region near the outlet of nozzle and the positive pressure region near the stagnation point. In each region, the concentration is made uniform and it is considered that such a type flow is useful for combustion. (3) Considering penetration distances, their experimental equations are obtained.

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The flames in swirling jets are very stable when the swirl strength is adequate. Experiments were made of premixed swirling jet flames and the combustion characteristics were obtained in relation to swirl strength. Furthermore the stabilization mechanism of the flames was also explained qualitatively, using the experimental results of air jets. With an increase in swirl strength, a recirculation region develops and a flame rising near the nozzle exit forms a stable inverted cone surrounding this region. However, if the swirl is too strong, the excessive development of the region will result in so-called "high speed flash-back".

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This paper makes the discussion on the accuracy of measuring gear loss by Oil Immersion Formula, in which the temperature of the oil steeping test gear is measured. The conclusions are as follows : (1) There are some suitable time intervals for measuring oil temperature. At 17.75 rps, for instance, it was considered appropriate to begin the interval counting began one minute after starting. (2) In the test stand, bearings were set up in the wall of the oil tank, in which gears were to run. The bearing heat generated by gear load had no influence on oil temperature. (3) The measured gear loss values were not affected by the oil viscosity that varied in accordance with the temperature rise during operation. (4) Oil Immersion Formula is superior in accuracy to the conventional method using a power circulating gear testing machine.

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This paper describes gear loss in relation to speed and torque. Loss of gears finished in various manners was obtained by measuring the temperature of the oil steeping test gears, and the variance in the data thus obtained was analyzed. Torque, speed and type of gears were considered as influential factors in this analysis. The analytical results show that speed is the most important factor to gear loss rate while torque has little influence compared with speed. Furthermore, it became clear that the relation between speed and loss rate is complex depending on the type of gear and torque while said relationship may be simplified if considered as the relation between speed and gear loss.

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Due to the greater power loss caused by higher operating powers and speeds the-operating temperatures of gear systems in use nowadays are higher causing the strength of tooth surfaces to decrease. Usually, the power loss consists of (1) the tooth friction, (2) the lubricant churning loss and (3) the bearing loss. In this paper, the churning loss is discussed. Essentially, lubricants are used for decreasing tooth friction and for dissipating the heat generated, and in order to know the best method of lubrication the amount of churning loss and its cause should be determined. In the present experiment, the churning loss of a spur gear system with jet lubrication is measured, and several analyses are proposed. From the results thereof, it becomes clear that the churning loss consists of the power required to trap the oil between the mating gears and to accelerate the oil in the tooth space. And it is considered that at high speeds the churning loss does not become so large regardless of the viscosity of the lubricating oil.

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