In this experiment the effects of the lamellar and globular pearlites and their combinations on the wear of carbon steel were studied in the temperature range from ambient temperature to 800°C. Therefor 0.89%C carbon steel was used as a fixed spescimen and 0.64%C carbon steel as a rotating one. The wear test machine was Dr. Okoshi's Rapid Wear Testing Machine which is the same as the one used in the last report. On the other hand the oxidation property at 200°C and the hardness at each test temperature were measured, and under consideration of these results the behaviour of wear phenomena was discussed. Further the results which one of the present authors obtained in the earlier experiment were again discussed. The results in this report show that the maximum values of wear rate at ambient temperature and 800°C were greater on the lamellar pearlite than on the globular. This is caused by the difference of the pearlitic structures, which changed not only the mechanical property but also the oxidation property of the carbon steel that is the same carbon steel.

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A prediction method of low-cycle fatigue strength has been developed whereby the number of cycles to initiate a crack can be estimated for a notched specimen from the characteristics of the hysteresis loops of unnotched specimens and a few fatigue data of unnotched or notched specimens. Good predictions were obtained for annealed 0.48% carbon steel notched specimens under completely reversed load. The prediction method can be applied to various materials, specimen shapes and loading modes. The plastic strain range Δε_p at notch root was computed by the finite element method and the Bauschinger effect was also taken into consideration. The method was compared with Langer's and the one based on Neuber's rule. Although it is difficult to predict by other methods that the number of cycles to crack initiation of notched specimens can be larger than that of unnotched specimens at high load level, the present method does not contradict this phenomenon.

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The effects of properties of the matrix and the glass content on the fatigue properties of FRP were investigated under pulsating tensile stresses, using specimens which were reinforced with roving plain woven glass-fabrics. The results are summarized as follows : (1) FRP which uses a large flexible resin as matrix decreases its fatigue strength in high cycle tests. But this effect does not appear in low cycle tests. (2) The fatigue strength increases in proportion to an increase in the volumetric content of glass fiber within a certain limit, and the ratio of the fatigue strength at 10⁶ cycles to the ultimate tensile strength is nearly equal to 0.4. (3) The micro failure caused by the behavior of glass-fabrics (which was mentioned in former reports) affected the fatigue properties of FRP. Their stress-cycle curves fall in the region of the strain which caused cracks inside of the warp strands.

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The effect of metallurgical factors and the effect of residual stress, respectively, on the fatigue strength of an induction hardened machine component were investigated. The specimens, salt bath quenched in the similar heat cycle to that on the surface of an induction hardened component, were used. On the basis of the assumption that the effect of mechanical mean stress and the effect of residual stress on the fatigue strength were equivalent, the following results were obtained. The effect of increasing the hardness on the fatigue strength of the material without residual stress is not quite so great. On the other hand, when the hardness increases, the effect of mean stress on the fatigue strength of the material becomes greater. Thus, it is important to use this kind of hardened materials under compressive residual stress or mechanical compressive mean stress.

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The calculating method of the natural frequencies for the axial vibration, without coupling in the tangential and axial vibration, of the grouped turbine buckets in which the effects of the shear deformation and the rotary inertia were considered, was obtained, so that it is now possible to calculate the natural frequencies more precisely than in the past. By this method the natural frequencies of the grouped backets were calculated, and it was found that the calculated values fairly agree with the measured ones. The natural frequencies without the effect of the shear deformation of the shroud were mostly higher than those calculated the other way. In the case of the mode of vibration in which the vibratory amplitude of each bucket of the grouped ones is equal, the effect of the shear deformation of the shroud on the natural frequency is small.

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As a part of the analysis of response of pulsation from a reciprocating compressor complicated piping system, calculation method of pulsation is proposed in this paper which is an extension of natural frequency calculation reported in the preceding paper. Experiment is also conducted in measuring pulsations on the discharge-line of a Diesel engine supercharging air compressor in order to compare with the calculation results. The calculated amplitude of vibration becomes larger in the vicinity of resonant frequency due to the elimination of damping force, but the vibration mode has a perfect coincidence with experiment. Results of both experiment and calculation coincide very well in the non-resonant region. Also assumption of the discharging velocity out of compressor is proved almost correct.

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Considering the pronounced reduction of energy dissipation in turbulent flows of viscoelastic fluids, it is predicted that the elasticity of the fluids may affect the stability of laminar flows. In this report, the problem of the stability of the laminar boundary-layer flow along a flat plate with no pressure gradient is treated. In the analysis, the Denn model is used as the rheological model for viscoelastic fluids, and the stability equation is formed with the aid of the method of small disturbances. The analytical results show that the elasticity of the fluid destabilizes the flow and that the non-Newtonian viscosity of the fluid stabilizes the flow.

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Rotary motor with four vanes carried by rotor sliding in its four slots perpendicular to each other is here studied theoretically. The centrifugal effect of the vane tips sliding on the pseudo-elliptic working cylinder is neutralized by making use of a rhombic link. Two pairs of opposite links are connected by separate diametral links at their middles. These two diametral links are hinged independently on the main shaft of the rotor to secure relative position of the rhombic link as a whole to the rotor axis, allowing the configuration of the rhombic link itself as it goes. The roots of the four vanes are connected independently to the pins through the apexes of the rhombic link. These pins carry rollers to run in contact with the control cam of pseudo-ellips in shape. Some considerations are made to apply such a vane-motor to compressors, expanders and also internal combustion motors.

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In order to establish the limits of applicability and to define the accuracy of float-area-type flow meters, studies on instabilities of the float were performed. From the behaviour of the float, types of instabilities were classified into three when the float with stabilizer was employed and into four when the without stabilizer was employed. In this report, studies were made on the causes for one of the instabilities, classified above for the float without stabilizer, which was the rotational vibration of the float. It was shown that there existed three kinds of causes, the first of which was the resonance between the natural frequency of the rotational vibration of the float and the frequency of periodic hydraulic forces acting on the float, the second was the transition from laminar to turbulent of the flow in the clearance between the float and the tapered tube adn the third was the correlation between the position of the centre of gravity of the float and the hydraulic forces acting on the float.

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Heat transfer to plane turbulent jet reattached on an offset parallel flat plate for the nozzle has been studied by the law of analogy to mass transfer. For the experiment the technique of sublimation of naphthalene is used. The flow development on an offset plate depends on shapes of bubbles induced due to separation and reattachment. The change of bubble shape occurs generally when the ratio of offset distance to nozzle height is 6.5. Considering such flow field, empirical formulae have been introduced for the following items. (1) Maximum Sherwood number in reattached region. (2) Mean Sherwood number in separated bubble region. (3) Local Sherwood number over the region of reattached wall jet. (4) The effect of reattachment by the curved jet on distribution of the local Sherwood numbers.

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An experiment on boiling heat transfer in a vertical open thermosyphon is performed. Tubes and annuli are used as the open thermosyphon. The latter consists of an unheated core and an externally heated tube. Data are taken using pure water by changing the diameter and the length of the heated tube, the diameter of the unheated core and the entrance temprature of the liquid. The heat transfer coefficient α is correlated with q⁰.4(Δt_s/Δt)⁰.9, where q is heat flux, Δt_s is excess wall temperature above saturation of the liquid, Δt is wall temperature minus entrance temperature of the liquid. It is also shown that the heat transfer coefficient is hardly affected by the length and the diameter of the heated tube. For the extremely small gap of the annulus, however, the heat transfer coefficient increases with a decreasing gap. The heat transfer coefficient in the thermosyphon is larger than that of pool boiling, but the critical heat flux is considerably smaller. Flow patterns in the open thermosyphon are observed and their relation with the heat transfer coefficient is discussed.

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Experiments on a heat transfer coefficient and a critical heat flux in a vertical open thermosyphon are performed. Tubes and annuli are used as the channel of the open thermosyphon. The latter consists of an unheated core and an externally heated tube. Pure water, ethyl-alcohol, normal-hexane, carbon-tetrachloride and sodium oleate aqueous solution are used as test liquids. Data are obtained with different lengths and diameters of the tube, diameters of the core and entrance fluid temperature of the thermosyphon. The experimental results are correlated on the basis of dimensional analysis and experimental expressioins are presented.

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Critical flow is studied for a completely separated two-phase flow which is a compressible gas flow coexisting with an incompressible liquid flow without mutual mixing within a constant-area duct. It is predicted from a theoretical analysis that the critical state appears at the exit of the duct with the condition : M_q=1+KM³_g; where K=(1-x)/x(p_g/p_i)²(a/u_i)³, M_g : mach number of gas flow, x : quality, p_g : density of gas, p_i : density of liquid, a : sonic velocity of gas, and u_i : velocity of liquid flow. The two quantities M_g and K included in the afore-mentioned equation have a possible range of 1≤M_g<√(3) and 0≤K<2/√(27) respectively. For the experimental verification of the analytical prediction, the condition of a completely separated two-phase flow is successfully realized in a specially designed apparatus with use of air and water. The state of flow at the exit of the duct is determined quantitatively by making use of the characteristics of the present two-phase flow, and the data thus obtained reveal that the analytical prediction afore-mentioned is satisfied in the experiment.

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By investigation of the chemical reacting behaviour of the pre-mixture, it has been made clear that radical precursors and intermediates produced by the decomposition of the pre-mixture are responsible for the combustion of main fuel. In this paper, the influences of different organic ompounds as an auxiliary fuel are investigated on the ignition lag, the pressure diagram, the flame luminosity, the smoke density etc. W come to the following conclusions : (1) The organic compound which contains some hydrogens of weak bond-strength may be favorable for lean pre-mixture. (2) Using such a fuel as alcohol or n-paraffin, which is prone to free radical, as the auxiliary fuel, the flame of main combustion has a poor luminosity. (3) There is little difference in the effects of lean pre-mixture on the exhaust smoke among the fuels investigated. In the case of pre-mixing with a constant quantity of main fuel, the soot formation will be suppressed as much as the amount corresponding to the lean pre-mixture or more.

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Automatic assembling machines require a regular cycle of motion and standstills. Therefore, various mechanisms for imparting intermittent motion have been devised. Of these mechanisms, the Geneva mechanism is one of the most commonly used, because of its simplicity. However, in designing this mechanism, consideration has never been given to design sensitivity. In other words, the analysis of the difference between an ideal model and one which incorporates manufacturing tolerances and clearances has not been made. In this paper, the effects of these tolerances and clearances are discussed. The results obtained are summarized as follows : (1) The influence of manufacturing tolerances of both driving and fixed linkage on the generated function is clarified. (2) The effect of the backlash of the locking cam, and the effect of the locking cam's radius on the indexing precision are also clarified. (3) A new Geneva wheel is proposed.

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The frictional behavior under unlubricated condition was investigated, which is affected by the surface conditions such as surface films, adhesion and wear. When the surface films on the contact asperities were ruptured during sliding, the real area of metallic contact generally grew as sliding proceeded. There was a simultaneous growth in the friction force resisting sliding. Two frictional experiments have been carried out to examine the mechanism of the friction. One consisted of measuring the friction force at a single point of contact for sliding of a soft slider on a hard flat surface. This assured understanding of the behaviors of the breakdown of films and the junction growth. The other comprised the measurements of friction force at the multiple points of contact between a soft rough and a hard smooth surface. The friction force was also deduced theoretically in both cases of the single and multiple points of contact.

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Theoretical analysis of stress at the root fillet of the shrinkage-fitted gears correspond with that of the force-fitted gears in the two-dimensional theory of elasticity. But practical stresses induced at the root fillet of gear tooth are not equal in both cases. To explain the reason for this, the residual stresses induced and their change at the loaded side and the opposite side of the root fillet, roughness and hardness at the root fillet of tooth, and bending fatigue strength of the shrinkage-fitted gears were investigated. Results obtained are as follows. (1) Bending fatigue strength of the shrinkage-fitted gears show lower values in comparison with that of the force-fitted gears. (2) This decrease of bending fatigue strength is caused by the stress at the root fillet of tooth induced by air-cooling, which occurs in taking out the gear rim from electric furnace to shrinkage-fit. (3) Practical formulas for the residual stress along the fillet curve of the shrinkage-fitted gears are introduced by modifying formulas for the force-fitted gears.

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As are evident from experimental results of the 2nd report, bending fatigue limits of the force-fitted gears show lower values in comparison with those of the solid gears. In this paper, as an attempt to increase the bending fatigue strength of the force-fitted gears, surface rolling on the root fillet of gear tooth was adopted success fully. The following are the conclusions obtained : (1) By fillet surface rolling the bending fatigue limits are increased by 37% at the most suitable rolling conditions. (2) Whichever process, surface rolling or force-fitting, may be taken previously, the order of process has no influences on the bending fatigue strength, the bending static strength etc.

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