In the present paper, a new method of the experimental studies on the plane stresses in an orthotropic plate is explained and some results are shown. The plane stresses in an orthotropic plate are well known to be dependent on two aeolotropic constants inherent of the material and the experimental determination of the form factor as a function of these seems to be technically diffcult. According to the new method, however, the stresses in any kind of the orthotropic plates can be determined experimentally from a few standard plates easily, and the accuracy of the results has been found good enough.

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In plastic deformation, it is generally assumed that the shear strains γ₁, γ₂, and γ₃. are proportional to the shearing stresses τ₁, τ₂ and τ₃. But the experiments by Lode and also the experiments by Taylor and Quinney show that this assumption is not correct. The way of deformation such as shown by experiments, however, is not yet accounted for. A new theory on plasticity has been advanced by the authors, and it was already explained that, not only the relation between plastic stresses under various states of stress, but also the forms of hysteresis curves, anisotropy due to plastic deformation, and the relation between the yielding of mild steel and the deformation beyond that could be well accounted for by this theory. As for strain ratio relationship this theory also conforms very closely with the experiments.

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On unnotched specimens, fatigue failure criterion was proposed under a combination of alternating and static stresses. The fatigue test data were then examined to obtain a general fatigue failure criterion, especially on notched specimen with stress concentrations. It is pointed out that after the stresses have been found for the critical regions, a criterion which uses the applied static stresses and alternating stress must be used to predict whether they are safe.

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Plate specimens of a medium carbon steel (0.48%C) with sharp V notches on both edges were stretched so that the nominal tensile stress at the minimum cross section would have the values of 0.8σ₈ and σ₈, respectively. As the result of this plastic tension, residual compressive stresses were introduced around the notch root. These residual stresses were measured by the X-ray diffraction method, and their changes due to alternating stressing in reversed bending were investigated. In the fatigue tests, the specimens with residual stresses were found to have higher fatigue limits and also prolonged fatigue lives over those without residual stresses, and these improvements were larger in proportion to the values of residual stresses. The growth of fatigue cracks was also investigated, and it was clarified that residual compressive stresses have an effect of suppressing the propagation of fatigue cracks. Applying the theory of threshold stress to spread the fatigue cracks proposed by T. Isibasi, and based on the change in residual stresses and on the crack growth curves, the contribution of residual stresses to the fatigue strength was calculated.

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Dynamic creep and fatigue tests were carried out with a 13 chromium steel at 450°C. The results were discussed from the standpoint of the analysis, which had been presented by the authors previously, to predict the dynamic creep and fatigue strength from static creep or rupture data together with fatigue data under reversed stress. Satisfactory agreements were observed between the predicted and the experimental strength values in both cases of dynamic creep and fatigue. Under repeated stress, the strength was found to be determined by the creep characteristics and can be predicted from static creep or rupture data. In the case of alternating stress testing, where tensile and compressive stresses were applied alternately, the strength was determined by fatigue characteristics and prediction was made by using the fatigue data under reversed stress.

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In the ultrasonic fatigue machine previously reported, it was necessary to adopt the test pieces contracted in the mid portion in order to induce the higher stress there, and a graphical method was required for the estimation of the value of the stress induced. In this paper, the analysis of vibration of the contracted test piece at resonance conditon is developed and the result is confirmed with experiments. By this, the stress estimation can be done without the graphical complexity, if an oscillatory amplitude at the top of the test piece is measured. As an application of this analysis, S-N characteristics for bearing steel and copper are obtained.

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Flat bar specimens of Epoxy Resin with a double notch on one edge were subjected to pure bending. The double notch consisted of a primary circular or 60°-V notch and a secondary U notch formed at the base of the primary notch. The effects of the root radius and the depth of the primary notch and also that of the depth of the secondary notch on the stress concentration factor were investigated. The stress concentration factor showed a nearly similar change to that of a single notch when the depth of the secondary notch was varied. This was also true in the case of the variation in the depth of the primary notch. As to the effect of the root radius of the primary notch, the stress concentration factor made a reverse change to that of a single notch. In all cases examined, the stress concentration factors of a double notch showed smaller values than the product of the independent stress concentration factors of a primary and a secondary notch.

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The problem of natural vibrations of an isosceles-triangular plate with all edges clamped or with two equal edges clamped and the base edge supported is treated in this paper by means of the energy method, which was applied by one of the authors to the eigenvalue problems of a rhomboidal plate with all edges clamped. Numerical values of the fundamental frequencies are calculated for plates with several contained angles, and they are checked by experiments.

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The vibration caused by the passing balls in a ball bearing appears in both the radial and the axial directions. The cause and the phenomena of the axial vibration are more complicated than those of the radial one. In the previous paper the authors dealt with the subharmonic vibration of the order one-half caused by the passing balls as one of the axial vibrations and showed that the axial motion became unstable at a certain range of the rotational speed. In this paper, firstly it is shown that the axial harmonic vibration caused by the passing balls becomes unstable only when the number of balls is small and in the ball bearing having many balls such motion does not appear. Secondly in the case where the outer race is slightly inclined to the shaft it is shown that the axial harmonic vibration caused by the passing balls becomes a forced vibration and shows resonant phenomena.

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This paper presents a theory of on-off control systems operating on sampled data. First, limit cycles which occur in these systems are analized, and then the transient response for step input is discussed. As the method of analysis, a rigorous method, an approximate method and a phase plane method are used for the limit cycles, and a phase plane method and a numerical method for the transient response. Controlled systems treated here are a process, a servomechanism and a second order underdamped system, while on-off elements treated here are a two position relay, with and without hysteresis, and a three position relay without hysteresis. Finally, the method of improving the control is discussed and the application of differentiater or delay element is suggested.

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This paper gives an exact solution in the form of a perfect Fourier series for the harmonic response to a sinusoidal input of a feedback control system including an element with a dead zone. The process of analysis used is quite the same as that introduced by the author for calculating forced vibrations in an unsymmetrical piecewise-linear system and utilized for the solution of a feedback control system including an element with saturation characteristics.

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Using 5 types of rounded nozzles, 24 types of cylindrical nozzles (l/d=0.799∼16.520, l : length, d : diameter) and 5 types of knife-edged orifices of 0.3mm to 1.2mm diameter, the discharge characteristics were investigated for Reynolds number from 550 to 10000, using distilled water and low-pressure air. The results are summarized : 1. Discharge coefficients, which were calculated on the basis of experiments using distilled water and low-pressure air, fall on the same curves, if arranged by Reynolds number and l/d. 2. Discharge coefficients for each type of nozzle or orifice were collected and one experimental formula was worked out. 3. Downstream pressure of nozzle or orifice is reduced to a minimum at a position of about 1.2 times the pipe diameter and is recovered at about 5 times the pipe diameter. 4. Recovery rate of pressure is about 1.7 m (m : area ratio) for rounded nozzles and 1.2 m for others.

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The discharge characteristics of nozzle or orifice for high-pressure type air-micrometer were investigated for pressure difference from 0.2 kg/cm² to 3.0 kg/cm² over a range of pressure ratio from 0.25 to 0.95. The experiment has revealed the following : 1. By plotting (c : discharge coefficient of incompressible fluid, ε : expansion factor) against the pressure ratio, using parameter l/d, a nearly linear relation is obtained. For rounded nozzle, cylindrical nozzle and knife-edged orifice, a change of flow regime occurs respectively at the pressure ratio of 0.53, 0.55, and 0.63. 2. The values of cε at a position where the pressure ratio is equal to 1 agree with discharge coefficients of incompressible fluid over the so-called "limit of constancy"of Reynolds number. 3. Discharge coefficients of each type of nozzle and orifice were collected and one experimental formula is worked out for each. 4. Downstream pressure and temperature are recovered at a position respectively 5 times and 4 times the pipe diameter. 5. Recovery rate of pressure was nearly same as in 1 st Report.

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Die Verteilung der geforderten Teilchen in einer waagerechten pneumatischen Forderleitung wurde mit Hilfe einer stereoskopischen Versuchseinrichtung ermittelt. Die Teilchen befinden sich dabei in der unteren Halfte der Forderleitung in etwas dichterer Verteilung, die um so mehr zunimmt, je naher die Materialbeladung sich ihrer oberen Grenze bzw. die Luftgeschwindigkeit ihrer unteren Grenze nahern. Diese Verteilung wird auf die Turbulenz der Forderluft bezogen. Es folgt aus dem Gedankengang, daB die Fallgeschwindigkeit der Teilchen kleiner ist als die Geschwindigkeitsschwankungen der Luftstromung. Die Geschwindigkeitsverteilung der Forderluft bei Materialbeladung wurde mit derjenigen der gewohnlichen Luftstromung im Kreisrohr verglichen. Es ergab sich, daB Mischungsverhaltnis und Schubspannungsgeschwindigkeit von EinfluB auf die Geschwindigkeitsverteilung der Luftstromung sind.

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Die Verfasser haben Versuche uber die Druckverluste im Krummer einer pneumatischen Forderleitung durchgefuhrt. Um den zusatzlichen Druckverlust zu bestimmen, wurde die Annahme gemacht, daB der gesamte Druckverlust im Krummer einer pneumatischen Forderleitung aus dem Druckverlust bei reiner Luftstromung, der durch die bisher erhaltene Beziehung angegeben wird und dem durch die geforderten Teilchen verursachten Druckverlust bestehe. Fur den zusatzlichen Druckverlust ist die Beziehung ζ₈=aμ aus den Versuchsergebnissen neu abgeleitet worden. Dieser Druckverlust nimmt mit wachsendem Mischungsverhaltnis linear zu. Ferner sind die Stromungserscheinungen der Teilchen im Glaskrummer beobachtet worden. Zur Betrachtung des Einflusses der Teilchen auf den zusatzlichen Druckverlust ist diese Beobachtung von groBem Vorteil gewesen.

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Effects of liquid viscosity and surface tension on a mean droplet diameter were investigated by using glycerine-water and ethyl alcohol-water solutions. And it is found that when the rotating speed is low, an increase in viscosity causes a decrease in the mean diameter ; but in the state of spray dispersion the effect of viscosity becomes negligibly small. It is also found that the decreased surface tension reduces the diameter regardless of a disintegration mode of jet. The size distribution of droplets was also examined. Two peaks are formed in a frequency curve when the rotating speed is relatively low, but with the increase of the speed they approach nearer and finally, i.e. in the region of spray, come to embrace each other. Empirical formulas for the S.M.D. and for a frequency curve are derived in the region of spray.

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When a train enters into a tunnel, at first the pressure of the air immediately before the train head rises and the portion of the air with raised pressure spreads forward with a velocity nearly equal to that of sound. In other words the wave front, the boundary surface between the undisturbed air and the compressed air, moves forward. And it is reflected at the exit of the tunnel and comes back to the train head. In the present paper the aerodynamic phenomena during the time interval from the instant of the train head entering into the tunnel to the instant of either its tail end coming into the tunnel or the wave front being reflected back to its head, whichever occurs earlier, are treated theoretically. The air is assumed to be compressible and inviscid. The velocities and pressures of air in each portion of the tunnel are calculated. The pressure drag of the train is also obtained. It is interesting to note that the effect of compressibility of air is remarkable in spite of a comparatively low speed of train.

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We have been studying experimentally the heat transmission characteristics of our tubes of a new type in the cases of the air flowing across the bundles of tubes, and have already reported a portion of the results two times. Putting together all the results of our researches, we obtained the design data for a heat exchanger which consists of our new heat transmitting tubes. The main design formulas are as follows : 1) The heat transfer coefficient of 1 st tubes in staggered arrangement for ratios p₁/d₀=p₂/d₀=2.11 is given by the equation N_u=0.602 R_e^0.527 in which p₁ is the longitudinal pitch of tubes and p₂ is the transverse pitch of tubes, d₀ is the outer diameter of tube, and R₆ is the Reynold's number calculated with the maximum velocity between the tubes. 2) The pressure loss Δp of the air flow through the bundle is given by the equation [numerical formula] in which n is the number of tube rows in the flow direction, γ is the specific weight of the air, and U_max is the maximum velocity between the tubes. The coefficient of resistance ψ may be determined from the equation ψ=2.81R₆^-0.224

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By measuring the weight of a carbon globule hung in a hot gas stream from a precise balance, the burning rate of a carbon globule was determined and the temperature of the carbon globule was measured with an optical pyrometer. The conditions selected for the experiments were as follows : Concentration of oxygen in the gas stream Co₂=5.7, 15.6 and 21.0% Initial diameter of he carbon globule 2r_i=6.2, 8.9, 12.3 and 16.0 mm Velocity of the gas stream U_g=5, 10, 15 and 20 m/sec Temperature of the gas stream t_g=800 and 900°C By comparing the results of these investigations with those of the published theoretical analysis, it has been concluded that 1) the experimental results qualitatively agree with the theoretical ones in every respect, 2) the burning rate of a carbon globule changes proportionally to U_g^0.45 and (r_i/r)^0.46 in an air stream, 3) the combustion rate of a carbon globule changes nearly in proportion to Co₂/1.2, 4) decreasing of the oxygen contained in a gas stream decreases the effects of the velocity of gas stream and radius of a carbon globule on the burning rate of the carbon globule decrease.

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The performance of a two-cycle engine is fairly well improved by the effects of the inlet and exhaust systems. The flow areas of the inlet and exhaust systems of the usual engine are not always suitable to make full use of the effects of these systems. The present authors have experimentally investigated the inlet system of a crankcase-scavenged two-cycle engine, which brings a most remarkable improvement to the delivery ratio. It has been confirmed that the delivery ratio increased by the effect of the induction pipe reaches a maximum at the period of inlet port opening, which is longer than the usual. Further they have examined the flow resistance of the carburetter and the air cleaner by replacing them with an orifice, and found out that the effect of the induction pipe is entirely nullified at the area ratio of the orifice to the induction pipe below 0.3∼0.4.

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In the previous paper, the exhaust-pulsation of a UD-3 engine having a simple straight pipe exhaust system was experimented. The apparatus was identical with the one described in the 1st Report. In the present paper, the influences of the exhaust pipe system having diffusers, nozzles, bends or elbows on the performance characteristic are dealt with. Results are as follows. a) In the case of an exhaust pipe with diffusers, the pulsation coefficient for a straight pipe is available with the equivalent length derived from the impedance theory. Only a few percent increase in power was observed in comparison with a straight pipe system in a favorable condition. b) For the nozzle, the pulsation effect can not be expected below an area ratio of 0.3, particularily in the case of a super-charged engine. From the standpoint of an effective exhaust energy, a shorter pipe length is preferable. c) The bend effect has little influence on the performance, judging from the pressure wave observations and the propagation velocity.

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By two new electronic methods……(a) a digital method and (b) a gray wedge scope method……the propagation of the flame in the spark ignition engines was studied. Making use of the ionization gaps, the arrival of the flame front was detected, and how the flame travels in the combustion room could be made clear. These methods have the advantage that statistically enough data can be easily obtained. From the obtained shape of the time frequency distribution curve for the arrival time t_a, the progress of the propagation of the flame was interpreted. In practical engines, a study on the irregularities in combustion caused by changing the setting direction of the ignition plug was carried out, and some interesting effects have been observed.

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A new gas sampling valve working at high speed was prepared for the study of the scavenging in a two-stroke engine, and its own performance was examined to obtain the basic data for the future design. This new valve is a kind of an electromagnetic solenoid valve, and it is actuated by passing an instantaneous heavy current into a coil that generates an inverse magnetic field against the fixed magnetic field. The experiments were done to determine the working region of the valve, the time lag of the opening, the duration of valve opening, the volume of the sampled gas, etc. As a result, the time lag for the opening, t_d, was about 0.5∼1.0 milliseconds, the duration of valve opening, t_f, could be obtained for 1∼10 milliseconds and the gas could be sampled at a rate of about 10 cc/m sec under the pressure difference of 1 kg/cm².

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The construction of a free-running-type equilibrium ultracentrifuge is reported in this paper. A centrifuge rotor, made of steel, weighing about 12 kg, is suspended magnetically in the vacuum chamber, the pressure of which is less than 10^-5 mmHg, and its position is controlled automatically. Acceleration of the rotor to operating speed and braking of the running rotor are done by the driving motor whose shaft is connected to the rotor by a stainless steel rod. During the sedimentation experiment, the rod is disconnected from the rotor and then the rotor is kept running freely by its own moment of inertia. The sedimentation is observed with either a Rayleigh interferometer or a Schlieren optical system. Experiments on molecular weight determinations of digitonin gave good results.

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The rotary straighteners for straightening round bars and tubes are discussed. The author found that the residual stress distribution in the bar straightened by the rotary straightener represents an alternate vortex of tensile and compressive stress zones around the center of the bar, which is not affected by the repeated rotary bending. To obtain better straightness, therefore, the bar has to be bent more severely at the point under the rolls, and receive more multiple rotary bending near the outlet in the straightener. For the rotary plastic bending of the bar, the direction of the bending moment does not coincide with that of the bending of the bar, and there is some angle between both directions, and therefore power is consumed for the rotary plastic bending of the bar. From this point of view, the author derived a formula to calculate the power required for straightening of the bar.

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Die beim Frasen oft entstehenden Biegeschwingungen des Gegenhalterarms oder Frasdorns wurden durch ein Mikroskop vergroBert und gleichzeitig auf einen umlaufenden Film aufgenommen. Uber die Entstehung und den Charakter dieser Schwingungen wurden experimentelle Untersuchungen durchgefuhrt. Zuerst wurden die durch die Unbalance des Motorrotationsteils und den Eingriff des Frasmessers erzeugten Fremdschwingungen untersucht. Danach wurde versucht, uber den Charakter des in der Praxis zumeist auftretenden Ratterns, das von der Biegung des Gegenhalterarms oder Frasdorns herruhrt, eine Aussage zu machen. Diese Untersuchungen wurden so durchgefuhrt, daB der Fraser nacheinander an vier verschiedenen Stellen eingespannt wurde. Bei jeder Einspannung wurde der Entstehungsbereich des Ratterns durch Anderung des Vorschubs und der Werkstuckbreite verglichen. Mit dieser Untersuchung wollen die Verfasser einen Beitrag zur Verhutung der Schwingungen beim Frasen liefern.

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Burning characteristics of an extremely high ash coal, of which the calorific value is about 2000 kcal/kg, was tested by pulverized fuel combustion with a dry system. A special test furnace was designed which would be most adequate for the combustion of such a high ash coal. From the test, results obtained are as follows : 1) High combustion rate can be expected even from shales of 65∼75% ash, with high combustion efficiency. 2) To get stable combustion of low grade coal in a dry system, the furnace wall temperature must be kept in an adequate range, 750∼1100°C.

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