In order to utilize a slip-initiation phenomenon in metal by fatigue for stress measurement, the phenomenon in pure iron is examined. It is found that at high temperature the slip-initiation phenomenon is not affected by interrupting the test, unlike the growth of crystal grains in the electro-plating method of stress analysis. By applying chromium evaporation on the surface of a notched specimen to protect oxidation of the material and using the present technique, the concentrated stress at the bottom of the notch can be measured accurately in the high temperature range below 300°C.

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Push-pull fatigue tests were conducted on the butt-bonded composite plates composed of iron and copper, to study the effects of the residual thermal stress and the difference of the elastic moduli on the propagation behavior of a crack across the interface. The composite plate specimens used in this investigation were fabricated by means of a diffusion bonding method. The experimental results indicated as a general trend that, when a fatigue crack propagated from a material of lower elastic modulus to one of higher modulus, the propagation was decelerated when the crack approached the interface, but after crossing the interface it was accelerated as the crack tip moved away from the interface, and the reverse was true for a crack propagating from a material of higher elastic modulus to one of lower modulus. The effect of the residual stress is clearly observed particularly in the former case where the crack propagation was markedly accelerated in the vicinity of the interface due to the tensile residual stress.

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Recently, the circumferential velocity of a grinding wheel is increasingly rapid, and it is necessary to study the rupture strength of a brittle rotating disk by using the probability theory. In this report, first, Weibull's multiaxial distribution function is applied to considering both inner and surface cracks at the same time. Then, using a new distribution function, the expected value of the rupture strength of a rotating disk is analysed. Comparing with the experimental results of the graphite rotating disks, the newly introduced distribution function is found more precise than the old Weibull's one.

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An isothermal thin water film, flowing concurrently with an air stream in a horizontal duct was investigated. In this paper the flow patterns are classified visually into six regimes according to the wave properties. Then, a detailed area plot for these flow patterns with the air and the water flow rates as the axes is obtained especially in the region of low water flow rate including the zone where the dry patches occurred on the bottom surface of the duct. On the other hand, the time varying film thickness was measured. Then four maps for the isoplathes of wave characteristics such as the averaged, the maximum and the minimum film thicknesses and the amplitude of the waves were drawn on the flow map. The relation of these two maps is strong ; i.e., comparison of these maps shows that the flow patterns can be classified more roughly into three zones ; the first zone for flow with dry surface, the second zone where statistically similar waves to each other with small amplitudes are observed on the interface, and the last zone where large amplitude waves travell on these small waves with higher sped than the small ones.

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The present work analyzed the high Reynolds number flow of a two-dimensional liquid jet which ejects downwards from a channel of a constant width experiencing small gravitational force. The flow is assumed to be laminar, and the effect of surface tension and that of interference between the jet and the neighbouring gas are not taken into account. The solution of the flow field is composed of the upstream solution which is valid in the neighbourhood of channel exit and the downstream solution valid in the region far from the channel exit. The flow is compared to the inlet flow of two-dimensional channel.

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The present work analyzed the high Reynolds number flow of a two-dimensional liquid jet which ejects downwards from a channel of a constant width experiencing small gravitational force. The flow is assumed to be laminar, and the effect of surface tension and that of interference between the jet and the neighbouring gas are not taken into account. The solution of the flow field is composed of the upstream solution which is valid in the neighbourhood of channel exit and the downstream solution valid in the region far from the channel exit. The flow is compared to the inlet flow of two-dimensional channel.

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A new method is presented which gives complete plots of transient waves in hydraulic pipes with non-linear boundaries. The numerical procedure of the Laplace inversion plays an effective role there. The availability of the method is confirmed in the experiment to observe dispersions of pressure pulses by an air bubble placed in an oil pipe. This method also makes it possible to experimentally investigate transient flows in a pipe with a circular orifice. The results show that the characteristics of an orifice placed in a transient wave transmission line are approximated by the steady-state ones, if there is no reserve flow at the orifice. Moreover transient variations of flow-rate are measured by a modified "impedance tube" method which is realized by virtue of the present analytical technique. The measurement reveals the hysteresis in the relation between the instantaneous pressure drop across, and flow-rate through, the orifice.

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An experimental investigation has been carried out to study the effect of sound waves with a particular frequency on forced convective heat-transfer from a heated circular cylinder over the Reynolds number range from 5000 to 20000. The results indicate that the convective heat-transfer coefficient can be influenced by a given sound wave, and in this case it causes the Nusselt number to increase appreciably on the back half of the cylinder On the other hand, the approach of the vortex region formed in the wake to the cylinder surface plays an important role in the mechanism of an increase in the Nusselt number in separated region.

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The results are presented of an experimental study on the flow and heat transfer in a two-dimensional parallel duct in the presence of a recirculating zone. The formation process of recirculating flow changes at about a/L⁰.6 (a =L-s, L: a half width of duct, s: nozzle width), depending on whether Karman vortex is shed or not. An experimental correlation has been obtained which makes it possible to calculate the local heat transfer variation in all the flow regions downstream of the maximum heat transfer position for various a/L. Some consideration on the maximum heat transfer mechanism is made in connection with the behavior of recirculating flow.

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As an initial step of the study for optimal control or transient behaviour analysis of the automobile engines, a simulation model of engine-load system with power-output was proposed. The result showed good agreement between engine test and simulation. The simulating technique is based upon a digital type state-space method. So it is very easy not only to catch the dynamic behaviour of several parameters within the system but also to change the elements which construct the system.

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For the purpose of clarifying the relationship between the vibration modes of amplitudes and the atomisation, first of all, the amplitudes were precisely measured on the vibrating circular disc of a large area, and the mode of vibration was experimentally and theoretically examined. In this paper, further investigated were the methods of efficient atomisation, the mean droplet diameter, the droplet size distribution etc. . And by inclining the vibrating surface at an angle of 20° 40°, and utilizing the mode of vibration, and efficient method of uniform atomisation at a high charge rate was evolved.

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In this paper, we express the Lagrangian of in-plane vibrations of a uniform curved bar of which the center line is a plane curve by unknown boundary values, that is, displacements and slopes at boundary. And by using the Lagrangian, we show a method for analyzing rigorously in-plane vibrations of a system connecting uniform curved bars. As examples, we analyze the vibrations of a symmetric U-bar with built-in ends composed of an elliptic arc bar and straight bars and those of a catenary curved bar and straight bars and we obtain the natural frequencies and the mode shapes.

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In this paper, we express the Lagrangian of out-of-plane vibrations of a uniform curved bar of which the center line is a plane curve by unknown boundary values, that is, displacements and slopes at boundary. And by using the Lagrangian, we show a method for analyzing rigorously out-of-plane vibrations of a system connecting uniform curved bars. As examples, we analyze the vibrations of a symmetric U-bar with built-in ends composed of an elliptic arc bar and straight bars and those of a catenary curved bar and straight bars and we obtain the natural frequencies and the mode shapes.

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This paper studies free vibration of an orthotropic elliptical plate with a similar hole at the center by means of the Ritz method using a spline function as an admissible function. For this purpose, the plate is transformed into an annular plate of unit outer radius, the transverse deflection of the plate is written in a series of the products of deflection function of a sectorial beam and trigonometric function of angular co-ordinate, and the frequency equation is derived by the Ritz method. The deflection of the sectorial beam is expressed approximately as a quintic spline polynomial, which satisfies the equation governing the flexural vibration of the beam at all the knots dividing it into small elements and also satisfies the boundary conditions at both ends. The present method is applied to orthotropic annular plates and elliptical plates with a similar hole at the center, the natural frequencies and the mode shapes being calculated numerically with high accuracies.

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Unbalanced vibration and balancing of a flexible rotor/bearing system have been studied analytically in the preceding paper by the same authors for the case of elastic support with viscous damping. Based on the theoretical results obtained, some experiments are carried out and the analysis is verified experimentally with the following conclusions: (1) The vibration of the system due to unbalances is no longer a linear combination of undamped eigen-modes of an elastically supported rotor but that of forced modes of a damped system. (2) The bearing- and shaft-vibrations are minimized within the whole speed range up to the operating speed, if the rotor is balanced by means of dynamic- and modal-balancing for a simply supported rotor. (3) The rotor can be successfully balanced if bearing- and shaft-vibration is measured at high speed, even though the dynamic characteristics of the supports are not known.

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It is well known that stick-slip motion often occurs while operating a hydraulic drive system with plane slide-ways at low speed and there are a number of researches reported on the analysis of such a motion. The authors made similar experiments with a hydraulic system with comparatively small friction and found that vibrations without sticking could occur as well as the stick-slip motion. A detailed analysis of such a motion was made and the result was compared with the experiment. The time dependency of the maximum static friction and also the variation of a part of the friction characteristic were taken into consideration. The comparison shows a striking agreement between the analysis and the experiment, justifying to a considerable extent the assumptions made in the analysis, and clarifying the fundamental mechanism of such a motion in the drive system of similar structure.

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The instantaneous rotational speed of the workpiece and the instantaneous frequency of the self-excited machine tool vibration are measured by an apparatus developed by the authors based on the demodulation of frequency modulated signals. It is experimentally shown that the rotational speed fluctuates periodically because of the slippage of a belt in the driving train and the frequency fluctuates with similar time-history to that of the rotational speed to maintain a constant cycle per rotation of the workpiece. It is concluded that the similarity of the time-history is brought about by the fact that the frequency follows the fluctuation of the rotational speed. It is finally pointed out that making clear the cause that makes the frequency follow the rotational speed is necessary to get full understanding of the self-excited machine tool vibration.

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The characteristics of spherical spiral groove bearings, having ungrooved regions at their bottoms, are investigated. The radial bearing forces and the load capacity are found approximately valid for small radial eccentricities, and then the effects of the ungrooved region on the load capacity and the stability are examined. The existence of the ungrooved region alters the characteristics of the bearing. With an increase in the central angle 2θ₁ of the ungrooved region, the load capacity diminishes to zero when θ₁=90°, while the radial stiffness increases to a maximum value when θ₁≒60° and then diminishes to zero when θ₁=90°. When a grooved member is rotating and the proper magnitude of the angle θ₁ is selected, the bearing has a very high degree of stability without much loss of the load capacity.

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Recently, a precise estimation of the lubricant film characteristics of journal bearings has become necessary in designing bearings. In almost all the calculations previously performed, however, the effects of the thermal characteristics of a lubricant's viscosity and the effects of operating conditions (for example, journal eccentricity ratio, circumferential velocity and inlet temperature of a lubricant) on journal bearing performances were not taken into account because viscosity variation due to the viscosity dissipation of the lubricant film was not considered. In this paper, as the result of theoretical analysis in which the viscosity variation mentioned above was taken into account, it is shown that both the thermal characteristics of a lubricant's viscosity and the journal velocity have a great effect on the temperature and pressure distributions of the lubricant film and on the bearing load carrying capacity.

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A biped locomotion has been developed for the purpose of its application to transport machines. A leg-mechanism has been designed to realize a horizontal walking at a constant speed. A new control system has been also composed of a linear-motion balancer in order to avoid the vertical fluctuations of the gravitational center of the body and to decrease the space occupied by the balancer. The conditions of dynamic stability and the determination of parameters of the system have been discussed both theoretically and experimentally.

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