The vibration of a square frame work with four legs is studied here. The four bars of the square frame work are of the same dimensions and homogeneous with the four legs. The frequency equations and the modes of vibration are obtained by minimizing the Lagrangian of structure, which is represented by the unknown boundary values. There are six modes, of which the first and the second frequencies are shown in graphs. This paper is concluded with the comparison between the results of the experiments and those of the theory.

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The linear thermoelastic problem is solved by using potential of thermoelastic displacement and stress function for the insulated spherical cavity in a circular cylinder with axis parallel to the heat flow. Stress distributions are given for a range of some various sizes of cavity.

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As to a special vessel, whose cross section is elliptic or approximately elliptic, the design formulas are not decided yet. In the previous paper the authors reported the experimental results together with the theoretical analysis on the strength of the vessel of this sort. The analysis, however, is attended with very complicated calculations so that it can not be used for practical design. Therefore, in this paper, the representation of the maximum stresses of the vessel as the functions of its principal dimensional elements is considered using the results of the previous experiments ; and moreover the validity of a practical design formula, which is based on the maximum stresses, is proved by authors' analytical theory for usual design range.

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At the present time the U-shaped bellows are used widely in many fields, but hitherto few papers on their strength have been issued. In this research this problem is treated by using the shell theory which was presented by the authors in the previous paper, and the design formulas and charts for the U-shaped bellows are given. In this first report, the case of axial loading is considered, and comparatively simple design formulas are obtained by making some assumptions to simplify the solution. The accuracy of this solution is checked up by the results of a more exact solution which will be described in detail in the second report.

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The Naghdi's basic differential equations for the general axially symmetric shell, which include the effect of transverse shear deformation, have not hitherto been solved numerically for some definite shell problems. In this paper, the Naghdi's equations for the problem of the torispherical head of pressure vessels are treated by means of the numerical method, which is developed by W. K. Sepetoski and others, and the effect of transverse shear deformation for the problem mentioned above is elucidated.

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Plane bending fatigue tests are carried out on a white metal lining on a steel plate to clarify the fatigue failure of plain bearings under fluctuating loads. The fatigue strength of the metal is discussed in terms of the crack propagation rate under various test conditions. The fatigue strength is affected by lining thickness, operating temperature, and the viscosity and activity of the lubricating oil. From the analysis of each factor, the following are known quantitively. The effect of lining thickness is due to the binding of strain at the tip of fatigue cracks. The effect of the operating temperature is due to the variation of physico-chemical properties of lubricants as well as the variation of mechanical properties of the metal. The viscosity of lubricant varies the oil pressure in the wedge of the crack where the oil penetrates according to its viscosity. The fatigue strength of the metal is also decreased by the chemical adsorption of lubricants at the tip of fatigue cracks.

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Annealed copper specimens were fatigued at room temperature in push-pull, and the surface of the specimens was observed through an optical microscope. The main results are as follows : (1) The number of cycles until the appearance of slip bands in cases of low cyclic speeds was smaller than in cases of high cyclic speeds. (2) Slip bands could be observed even at a very small number of cycles, that is, 2×10² cycles at a relatively low stress level as well as higher stress levels, when stressed at low speeds. (3) Fissures develop at least in three ways, to be more precise, they mainly originate from intrusions caused by slip movements, or originate from rows of pits, or originate through co-operation of intrusions and rows of pits.

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In the previous papers, the authors have investigated the behaviour of half-value breadth of X-ray diffraction line, residual stress and micro-structure under completely reversed stress amplitude, and have discussed on the changes in half-value breadth in relation to the basic mechanism of fatigue. In the present paper, as a continuation of the previous studies, the authors carried out some investigations on the changes in half-value breadth, residual stress and micro-structure in a case of fatigue under bending stress amplitude combined with mean stress, for the purpose of studying the mechanism of fatigue failure of metallic materials under mean stress. It has been found that, in the early stage of fatigue which corresponds to the period of fatigue hardening, there is little difference between the changes caused by stress alternation with positive mean stress and those with negative mean stress. However, in the second stage of fatigue which corresponds to the period of the growth of micro-crack, the changes in half-value breadth and residual stress become rapid, while they become slow with compressive mean stress. On the other hand, from microscopic observation, it has been confirmed that tensile mean stress promotes the growth of macro-crack and compressive one suppresses it. Then, it is suggested that the mean stress affects the growth rate of micro-crack just the same as macro-crack, and consequently influences the fatigue life.

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It is well known that the Rockwell hardness testers are suited to measure quickly the hardness of metals. But, because the Rockwell hardness test is static, the load is better to be applied until every indentation deforms completely. And the speed of the load application must be so slow that the inertia force of the moving parts may not affect the hardness numbers measured. The object of this research is to investigate the influence of the loading conditions of the major load on the Rockwell hardness numbers (H_RC) measured by the Rockwell hardness testers commonly used in our country. As the result, the law of similarity for selecting the loading conditions was found. And, for its application, the author proposes the method of selecting the applying time and the keeping time of the major load in the H_RC measurement.

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Der Zweck vorliegender Untersuchung ist, die Erscheinung der Abrasion bei Warmeverformung zu untersuchen. Fur diesen Versuch wurde eine geeignete Abriebprufmaschine hergestellt, bei welcher eine erwarmte stillstehende Probe gegen eine rotierende Probe gedruckt wurde. Als Werkstoff der erwarmten Probe wurden gegluhte Kohlenstoffstahle mit 0, 35, 0, 8 und 1, 0% C gewahlt. Die rotierende Probe bestand aus gegluhtem Kohlenstoffstahl mit 0, 76%C. Die Versuche wurden zunachst bei Raumtemperatur durchgefuhrt. Dann wurde die stillstehende Probe auf 500°C bzw. 700°C erhitzt. Nach Vorversuchen wurden eine Belastung von 11, 5kg/cm² und eine Abriebgeschwindigkeit von 1, 16 m/s gewahlt. Nach der Prufung wurden der Zustand und das Profil der Abriebflache bzw. die Form und die Bestandtiele des Abriebstaubes beobachtet.

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The ideal quality of the locomotive is that it produces a great tractive effort with less adhesive weight and with little vibrating stress in driving axle system, so that it has a superior adhesive characteristics and mechanical strength. In order to attain the ideal, the adhesive characteristics must be improved, and self-excited vibration of the driving axle system during slipping must be suppressed. Research has been performed in these directions. The fundamental equation for slip motion of AC locomotives was derived, and the conditions for suppressing self-excited vibration were sought. These data were studied by means of analog computers and truck testing equipment, and actual tests on service lines were conducted. As a result, success was attained in suppressing self-excited vibration. Studies were subsequently conducted of methods of improving the adhesive characteristics while simultaneously suppressing self-excited vibration. As a result, it was established that this objective could be attained.

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We have carried out a series of experiments to find out the capillary end effect in viscoelastic fluid flow. The main results of this investigation are : (1) The capillary end effect can be explained even by normal stress effect. (2) End correction factor does not always increase with increasing of the shear rate. (3) Linearity of the applied pressure-(l/d) plots indicates that the relaxation phenomena would not appear in this experiments.

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In the investigations of both the steady and unsteady flow in turbomachines, it has been found to be highly successful to visualize the flow in ducts and around the bodies. Recently W. Clutter and O. Smith have presented a suitable technique for flow visualization using small hydrogen-bubbles produced by electrolysis of the working water itself. According to their experiments, unfortunately the method was not applied to the flow with higher velocity than about 0.6m/sec. In order to observe the stream lines flowing at about 5∼8m/sec in an axial-flow type testing water compressor, the authors improved the electric source and the working liquid in the hydrogen-bubble method, and developed several new probes which are inserted into the stream as cathodes for the electrolysis process and which consist of a straight or kinked platinum wire and fork-type brass stem. In a small water tunnel having a test section 60×200 mm and two observation windows on each side, direct current of high tension (2000volts) was charged between the probe and the tunnel duct and thereby the lines of hydrogen-bubbles generated from the probe wire were visible fairly well even in the higher velocity stream of about 7m/sec. Further, using the above mentioned method, some photographs of the rotating stalls occurring in the testing water compressor were taken successfuly as was expected.

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In this paper, by using rough surfaces consisting of various grains or wire-netting, axial clearance taking minimum value of resistance was found out in the same way as the cases of smooth surface when the roughness of disc is equal to that of vessel and when not equal. And the experiments of partially roughened surface in which lathed only outside parts of disc having large effect on friction were carried out. The main results are summarized as follows : (1) When axial clearance is measured from the mean half value of protuberance height, moment coefficient C_f is not affected by roughness in laminar flow region. (2) C_f takes minimum value at S/d≒0.008 8 for rough vessel and S/d≒0.006 6 for disc only roughened, where S is clearance and d is disc diameter. (3) C_f of rough disc in smooth vessel and that of vice versa are identical at S/d ⪈ 0.006 6. (4) When the surface is partially roughened within a certain radius, C_f is nearly constant. (5) For netted surfaces equivalent roughness is considerably varied by pitch of netting and clearances.

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Temperature distributions for the flow of air flowing through the entrance region of a heated pipe have been investigated. The local temperatures of the flow were measured by a resistance thermometer. In the region of laminar boundary layer, thermal boundary layer was calculated by solving approximately the energy integral equation, and the analytically produced results were found to agree closely with the experimental ones. At the turbulent boundary layer, there are some disagreements between the experimental results and the theoretical values calculated by Latzko's and Deissler's analytical solutions. From the t⁺, y⁺ relationship a slight correlation can be found between the temperature profiles in the turbulent boundary layer and those in the long pipe. The buoyancy effects in the entrance region were investigated experimentally.

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By using the theoretical formula and the empirical one which one of the authors has published, the pressure drop and the clogging limit in a horizontal pneumatic conveyance pipe were calculated for several conditions and the results were compared with many experimental results. For six other kinds of formulas on pressure drop and clogging limit which have been published by the other authors, similar calculations were accomplished. Consequently, it has been concluded that S. Sugwara and S. Kikkawa's formula is the most excellent from every point of view followed by E. Muschelknautz's formula.

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Effects of the impeller vane roughness and thickness on the flow conditions and hydraulic losses as well as on the overall performances of the mixed-flow propeller pump are presented. The vane roughness has a most harmful influence upon the optimum performances, and also has a marked effect on the peripheral component of the discharge velocity near the impeller tip. The change in hydraulic losses in the impeller due to the variation of vane roughness is equivalent to that of the flat plate. The effects of roughness at various parts on the vane surface are also discussed. The head-capacity curves with varying vane thickness may be calculated actually on assumption that the capacity varies proportionally to the space area between vanes while the head remains constant.

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The baffle plate is the most important factor in the shell-side pressure drop of the multibaffled shell-and-tube heat exchangers. An experimental equipment which consisted of a shell with baffles but had no tube was constructed, and the pressure drop in it was measured and analyzed. The result was compaped with the pressure drop in an experimental heat exchanger which contained both baffles and tubes. Thus a method of estimating the pressure drop in heat exchangers was derived. This method is a simplification of Bell's method and is believed to be more accurate.

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The phenomenon of "Singing Flame" or "Gauze Tone" is the vibration of an air-column in a tube excited by heat supply. As the temperature of the airflow changes at the hot heater in adverse phase to the air velocity variation, there occurs some phase lag in the airflow when passing through the heater. Then, according as the phase of the velocity variation at the heater is by a quarter period before or after the phase of the pressure variation, the vibration is encouraged or discouraged. The characteristic that according to its position the heater can be an exciting source or a damping source to the vibration, is thus explained.

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The bottom of the boiling bubble is optically observed by the experiment using the electroconductive glass as the heating surface in water. It is discovered that in the contact part of the boiling bubble with the heating surface there exists a thin liquid layer and that the layer has sometimes a small drying part. The ratio of the area of the contact part of the boiling bubbles to the total heating surface is not 100% but about 50% even near the burn out heat flux.

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The behaviors of boiling bubble and boiling heat transfer are much connected with each other, and usually it is said that the turbulence in liquid as caused by boiling bubbling is very effective for heat transfer. But we found in this experiment that this effect is not so great, and that the effect of a bubble contacting with the heating surface is very great. We acertained this fact by the experiment in which the boiling bubble or the air bubble was contacted with the fine heating wire and in which the measurement of the temperature of the wire and photography of bubbles by a high speed camera were conducted at the same time.

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In this paper, the effectiveness and the coefficient of heat transfer with the transpiration of distilled water and air across the porous plate are discussed. The conditions selected for the experiments were as follows : Velocity of bulk flow is 5∼35 m/sec Temperature of bulk flow is 100∼600°C Mass flow ratio is 0.05∼10% From this investigation the following conclusions have been obtained : 1) Water is more excellent than air as coolant and the difference in cooling effect between air and water is considerable in the range of little mass flow ratio, 2) Nusselt number with transpiration of water is larger than that for solid plate and Nusselt number increases with the mass flow ratio in our experimental investigation, 3) Nusselt number with transpiration of water is nearly in proportion to R₆^4/5 for the constant mass flow ratio.

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A theoretical calculation on the collapse rate of a single spherical bubble was developed. A vapor bubble, small enough to be treated as a sphere, was taken as a model and a numerical analysis was made assuming that the pressure impact equivalent to the given subcooling was inflicted upon the bubble. The results show that there are two different stages of collapse and also that the later stage dies out when the system parameters or subcooling exceed the critical conditions. It also became clear that there is a possibility of bubble volume oscillations. This partially explains the experimental facts reported in some papers. Some experiments were made using water, the final level of which was the atmospheric pressure, and fairly good agreement was observed with the calculated values.

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A new type heat-flow meter was devised. Its detecting element is a metal disc both surfaces of which are covered with thin plates of another sort of metal. The both metals compose a thermocouple and from the e. m. f. of the couple the heat-flow rate of the disc is obtained. Some meters for practical use based on this principle were produced. After the calibration using an electric furnace, the flux of heat at the furnace-walls of a pulverizedfuel-fired furnace is measured with them. Using this type of heat-flow meter, heat-flow rate over 10000kcal/m²hr can be measured successfully. The accuracy of the meter is within 1000 kcal/m²hr and the time constant of the delay of indication is under 10 sec.

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Super-high speed turning of medium carbon steel S45C was studied using tungsten carbide, titanium carbide and ceramic tools. Tool force, tool wear, tool life and surface finish were investigated at the cutting speed from 150 to 3000 m/min. It was found that a certain grade of ceramic tool has great possibility of being employed for super-high speed machining from the viewpoint of tool force and tool life. Super-high speed machining operation produced an excellent surface finish, increasing the productivity of finish operation. But the tool life at super-high speeds was short at the present stage. Application of cutting fluids in super-high speed machining improved surface finish a little, but decreased tool life.

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Diese Arbeit stellt das Ergebnis der Untersuchungen dar, die zur Erhohung der Fertigungsgenauigkeit von Walzfrasmaschinen durchgefuhrt wurden, wobei der Drehfehler des Teilschneckentriebes mit einer von einem Lochstreifen gesteuerten Kompensationsvorrichtung, die aus einem Umlaufgetriebe, einem hydraulischen Servo-System, einem Amplitudenmodulator und einem Addierwerk besteht und der Schneckenwelle die zusatzlichen Drehungen fur den Ausgleich des Drehfehlers liefert, kompensiert wurde. Durch diese Kompensationsvorrichtung wurde der Summenteilungsfehler des Werkrades bis auf 23% vom ursprunglichen Wert herabgesetzt, und der zyklische Fehler der Teilschnecke bis auf 37%.

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