Observation and analysis were made on the effect of thermally induced residual stress on propagation and opening behavior of fatigue cracks in multilayered composite plates which were composed of low carbon steel and ferritic or austenitic stainless steel. It was observed that the crack propagation behavior in the composite plates was quite different from that in the monolithic plates, when the crack growth rates were plotted against k_max·But, when those were plotted against ΔK_eff, the data points of the composite plates came close to those of the monolithic plates, although there were some scatters. This suggested that the residual stress had a large influence on the crack opening behavior in the composite plates. Therefore, by calculating the actual stress intensity factor K'_max for the composite plates based on an initial distribution of residual stresses, their crack opening behavior was estimated by using k'_max and the crack opening behavior of monolithic plates. The estimated trends showed a fairly good agreement with those of the observed results.

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The buckling problem of an annular plate subjected to in-plane shearing stresses distributed uniformly at the inner and outer edges is solved in this study by the finite difference method. The boundary conditions of all combinations of clamped, simply supported and free edges except the case of free-free edges are considered. Calculations are carried out for cases of radius rations 2.5∼12 an calculated results are indicated in two diagrams. For the case of clamped-clamped edges, it is verified that our calculated results coincide well with those by other two researchers and also coincide almost with experimental data obtained in this study.

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This paper presents an interactive structural analysis system using the Boundary Element Method. The system is applicable to solving two-dimensional thermal elastic problems, two-dimensional heat conduction problems, and three-dimensional elastic problems. In the analysis programs of this system, highly effective numerical integration schemes such as the double exponential formula and analytical integration are introduces. These enable us to integrate singular boundary integral equations with high acccuracy and efficiency. This system is applied to sample problems, and its effectiveness is discussed.

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Inhomogeneous deformation at the free surface of a copper specimen in compressive plastic deformation is studied. The inhomogeneous deformation of grains in the plane of specimen surface is observed under scanning electron microscope, while the inhomogeneous deformation perpendicular to the surface is studied by measuring the surface roughness. It was found that the standard deviation of the measured strain for various grains as well as that of the measured surface roughness increase with the applied strain. Discussion is made on the relation between the variation of strain for various grains and that of the surface roughness.

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Taylor's slip model is incorporated by a rigid-plastic finite element analysis based on the upper bound theorem. Five independent slip systems are assumed to operate in each grain and the principle of the maximum plastic work proposed by Bishop and Hill is used to selected five operating slip systems out of the twelve slip systems in fcc crystals. For the numerical calculation, a simple plane model of polycrystals is adopted which is composed of rectangular grains. Discussions are made on the characteristic feature of the plastic deformation of polycrystals.

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The regular oscillation of an attached jet occurs when the jet squirts into a suddenly enlarged flow passage from the rectangular nozzle which is set lower than the passage, depending on the shapes of the nozzle, flow passage and jet velocity. This paper presents the condition which causes the oscillation and the relations between the oscillatory frequency and the various conditions such as passage dimensions or jet speed. The mechanism of oscillation is qualitatively explained from an observation of the oscillatory flow pattern and a measurement of the pressure.

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The Ka^^'ma^^'m vortex shedding from a circular cylinder with a yaw angle in a uniform flow was investigated using a wind tunnel. The yaw angle made the vortex shedding irregular and its frequency low. In addition, an intense secondary flow along the cylinder generatrix in the wake just behind the cylinder was induce by the yawing. When a pair of parallel plates were placed parallel to the free flow behind the cylinder in order to cut off the secondary flow, the vortex shedding in the area between the plates became regular and the frequency returned to the value for a normal one. The vortex shedding was more regular when the distance between the plates was made smaller, whereas the highest frequency was attained when the distance was 1∼1.6 times the cylinder diameter. It is concluded that the depression of the vortex shedding frequency by the yawing is attributed to the secondary flow behind the cylinder.

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The steady flow characteristics around a valve plate installed at the exit of a rectangular duct and the fluid force acting on the valve plate are studied experimentally, in order to determine the flow characteristics around flap valves. which are usually used to prevent reverse flow at the stop of pumping in large-size low-head pumps. It is shown that the outlet flow has strong three-dimensionality with large lateral leakage from both sides of the valve plate, which results in that the outlet flow has the characteristics of a discontinuous separated flow rather than that of a jet flow. Empirical equations for pressure drop coefficient and moment coefficient around the plate axis are obtained, as well as a simple approximate method for estimating fluid force acting on the plate. The influence of an obstructing wall near the valve exit upon valve performances is also determined.

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An experimental study has been made of reattachment of a radial turbulent jet flow discharged from a cylindrical nozzle onto an adjacent offset disc plate. The effects of a step height (distance of nozzle center plane from the offset plate) and control flow rate (ratio of control flow to main jet flow, suction and blowing) on a flow pattern near the nozzle outlet section were investigated. Mean velocity and turbulent velocity distributions were measured with the aid of a hotwire anemometer. The velocity profile, shape and length of a jet potential core, and deflection of a jet center axis depend mainly on the combinations of the step height and control flow rate. An oil film flow visualizing technique was applied to determination of the flow pattern.

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The turbulent diffusion process has been examined experimentally in the case of a continuous point source in turbulent water flows with three different uniform mean shear rates. Shear-flow generators used were non-uniformly spaced rods, and the diffusing matter was a dye solution. The present study mainly deals with the characteristics of the mean concentration field. It is revealed that the horizontal and vertical profiles of the mean concentration are nearly similar, and vertical profiles in particular are skewed to the side with a smaller flow velocity by the shear effect. A diffusion model for a continuous point source by Okubo & Karweit (1969) is investigated and compared with the experimental results. The effect of shear rate on the spread of matter is discussed on the basis of this model.

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The turbulent diffusion process of dye solution has been examined experimentally in the case of a continuous point source in turbulent water flows with three different uniform mean shear rates. In this report, the experimental results about concentration fluctuation intensity are presented. The characteristics of the mean concentration field have been reported earlier⁽¹⁾. The data show that the horizontal and vertical profiles of the r. m. s. values of the concentration fluctuation appear nearly similar, and vertical profiles in particular are skewed to the side with the smaller flow velocity. The above characteristics are the same as the results of the mean concentration field. By using a random rectangular wave model for the concentration fluctuating signal, an analysis for the concentration fluctuation intensity is made. The calculated profiles agree quite well with the experimental results.

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Coherent structures in a fully developed turbulent pipe flow are studied experimentally. The space-time correlations between wall pressure fluctuations and two components of velocity fluctuations, and behavior of those fluctuations conditionally sampled with respect to bursts are measured. According to the results, a factor of the averaged convection velocity of the burst to the center velocity is about 0.68, the bursts contribute to the production of higher frequency components of the wall pressure fluctuations, and further, there exist large scale coherent structures which extend from near the wall to the center region of the flow. Moreover, these results are compared with those of the fully developed turbulent plane boundary layer flow.

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In the turbulent wake of the upstream cylinder in a uniform flow, the downstream cylinder is set in the form of a cross with the upstream cylinder and the point of mutual contact comes at the center of the test section. It is found that the acoustic radiation from the two circular cylinders forming a cross is far smaller than that from one cylinder. In the contents of the noise reduced by adding the downstream cylinder, the broadband noise as well as the dominant frequency tone is reduced. The variation of the acoustic radiation is measured as affected by the diametral ratio of the two cylinders, distance between them and velocity of the air.

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The governing equations for magnetic fluids with good conductivity of heat and electricity have not been sufficiently discussed thermodynamically. In this paper a new strict simplified method of deriving the basic equations for such conducting magnetic fluids is presented using the thermodynamically method in which free energy and dissipation function are used on the assumption of the nonrelativistic and nonpolar theory. As the result, a physically desirable expression of the pressure part and Maxwellian stress in the constitutive equation of stress is derived in a general theory that polarized and magnetized media exist. Then the following results are obtained from this theory: the surface forces acting on the material control surface include not only stress but also electromagnetic momentum flux density and the pointing vectors in the material volume are obtained in the relativistic electromagnetic fields which move against the fixed system.

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In order to clarify the starting and running characteristics of a Wells turbine in an oscillating flow, an experimental investigation has been performed. The results have been compared with the analytical results. In the analysis, both starting and running characteristics were calculated on the basis of the experimental results obtained under steady unidirectional flow conditions. Comparison between experiment and analysis has shown that the effect of hysteresis and Reynolds number on torque coefficient should be considered in the analysis. Furthermore, running characteristics have been investigated from a view point of the method of load control.

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In relation to vapor explosions, splash phenomenon observed when a droplet of water hits the surface of molten tin is studied experimentally over a wide range of parameter conditions. Especially, the tin temperature for the onset of splashing is measured in detail by changing widely droplet size, droplet velocity and subcooling of water droplet. Then the temperature condition for splashing is compared with the criterion of Ochiai-Bankoff as well as the condition for the onset of explosive boiling in an ethanol-silicone oil system. It is concluded that the splashing is caused by rapid increase of the vapor pressure when the vapor film between molten tin an water condenses due to the action of subcooled water.

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An experimental investigation of natural convection heat transfer has been performed under the condition of uniform heat flux in an open thermosyphon. Water, ethyl alcohol and ethylene glycol were used as working liquids. The length-to-radius ratio, expressing the thermosyphon tube geometry, was changed in the range from 14.3 to 92.8 by using seven tubes with different dimensions. Expressions correlating the experimental data on heat transfer coefficients were derived for both laminar and turbulent flow regimes. Axial temperature distributions of the heated wall and working liquid were measured and discussed in relation to the flow regimes.

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The disadvantage of rotary type compressors for automotive air-conditioners is that the refrigerating capacity increases linearly in proportion to the increase linearly in proportion to the increase in engine speed, and so in the present research, attention was focussed upon the phenomenon of the refrigerating flow in the suction stroke, and the conditions for construction of capacity self-controllable type compressors by selecting suitable parameters were established, In this report, the basic equations which represent all stages of the vane's position in suction passage during the suction stroke have been introduced. By theoretical analysis of the equations, it was found that the capacity self-control characteristics by choosing the area of the suction port and suction groove could be calculated. These results were confirmed by the experiments.

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The higher efficiency in steam turbine has become an important requirement after the oil crisis with increased energy price. To meet this requirement an advanced aerodynamic technology has been incorporated in the design of reaction blading. Correlations of blading loss characteristics are built into a three dimensional flow field calculation computer program, and utilizing this program flow pattern optimization is achieved. A new reaction blading has been developed by applying this achieved. A new reaction blading has been developed by applying this advanced technology. Experimental verification for the new reaction blading in both cascade and turbine tests has brought about overall turbine performance improvements and the excellent corrsepondence of internal aerodynamic parameter to the predicted values.

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Thin film thermocouples have been successfully produced, using ceramics as the body material, through the application of the technique used to make thin film thermocouples previously developed by the authors. The measurements of instantaneous temperature and instantaneous heat flux on the surface of the ceramic plate fixed on top of the piston were made, using the thin film thermocouples thus developed. As a result, conditions of the heat transfer to the ceramic wall of high temperature have been established.

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A finite difference method was applied to simulate the transient flows in the combustion chamber in a deep-bowl direct-injection diesel engine. The flow field was treated as an axisymmetric one in which turbulence and its dissipation were taken into account by using an ordinary k-εmodel. Description of the flows was satisfactory and the computed results were used to draw the characteristics of the flow and to assess the effect of some controlling parameters. The obtained results show that the wall friction reduces angular momentum of the swirl considerably. It is also shown that the swirl intensity largely affects secondary flows induced in the vertical plane in the piston cavity; the flow pattern changes from a simple toroidal vortex to a double-vortex flow as the swirl intensity is increased. A discussion is made on the intensity of turbulence and its effect on the flow field at the end of compression.

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The effectiveness of a correction method using static response as an approximate solution for response values of higher modes has been presented by O. E. Hansteen. In this paper, a method is presented in the form of generalized coordinates, for the purpose of extension to component mode syntheses or a free-free (incompletely supported) system. The basic concept of the generalized coordinates and calculation algorithms are shown. External term error estimation is then considered, when generalized coordinates are employed. Two models are used to verify that the error norm of external load vectors is close to zero (less than 10^-4).

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The effect of venturi diameter on phase lag of the fuel control rack response has been investigated using 5 kinds of simulated venturis, which are different in size but similar in shape of flow passage to the actual subventuri, installed in an apparatus simulating the intake air flow at hunting or in a hunting engine intake system. The results show that the phase difference between subventuri pressure and suction pressure depends on the difference of ascribed to the phase lag of the reduced pressure at subventuri. Furthermore, this study provides a preventive measure against hunting.

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The basic equations for the beam-type vibration of rotating cylindrical shell are derived by the Timoshenko beam theory. The frequency analysis is presented for three kinds of boundary conditions and the validity of this model is examined by comparing the results with those based on the cylindrical shell theory. It is found that as for the natural frequencies of non-rotation, and rotation cylindrical shells and for the critical speeds reasonable results can be obtained by solving the problem on the basis of the Timoshenko beam theory.

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The nonlinear response of a clamped beam to a mass which strikes it has been studied theoretically and experimentally. In the theoretical analysis the nonlinearity due to large deflection of the beam with immovable edges is take into consideration. The governing equation is solved approximately by using both Galerkin's method and the harmonic balance method. Numerical results are compared with those of the experiment in which a steel sphere is used. For large mass and large impact velocity, a close agreement between both results is obtained.

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Nonlinear dynamic response of a string excitation will differ qualitatively from the usual harmonic response, because the natural frequencies of a string are in the rations of integers. As a continuation to the previous paper which treated the dynamic response near the second primary resonance point, the present paper treats the dynamic responses near the first, third and forth primary resonance points. It is shown theoretically that near each of these primary resonance points, various types of multimode responses accompanied with super-harmonic or subharmonic oscillations can occur in addition the usual harmonic response. Numerical examples are given and the characters of the responses are examined. Experimental analysis is also performed with use of a thin steel strip, and the validity of the theoretical analysis is confirmed.

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In this paper the authors presented a computational method to de termine the original waveforms at source points where acoustic emission (AE) is generated. Using a fast electrical pulse as a standard input signal, it has become possible to obtain the reproducible transfer function of AE measuring system from the generation of AE to the detection of received signals. By introducing the numerical operations to minimize noise and distortion which are often contained in analyzed waveforms, Fourier synthesis has been made applicable to an inverse problem such as source wave analysis. Consequently the authors have been able to obtain reproducible source waves with higher accuracy in considerably short time of calculation. A few experiments to determine source waves were carried out and the results showed the validity of the method.

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Dynamic characteristics and control method of a flexible robotic arm of first degrees of freedom system are shown modelling a flexible arm as an elastic beam. Vibrations of the arm in positioning can be suppressed by the dynamic compensation with consideration of the arm flexibility, of which current robotic arms have more or less in manipulating payloads. Subsequently, a control method of a SCARA type of a second degree of freedom system is shown based on the local feedback with variable adaptive gains to suppress vibrations in positioning control. In case of arm collisions against other objects, a control method to recover the state before collision is also shown as an application. The control methods proposed here are not limited to this type of robotic arms, but also applicable in more general cases.

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In recent years the advanced micro-electronics techniques are contributing to the progress of industrial robotic manipulators. Direct digital control of manipulators is one of the most promising applications of a new generation of computers. Improved control techniques are required for the digital control to attain a fine performance of manipulators. This paper proposes a software servo control system for linear quadratic optimal control with I-action (LQI control) for a good performance over a wide range of motions and payloads. The effectiveness of this control system is demonstrated in several simulations and experimental results.

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The pressure-viscosity relation of lubricants, which is important in elastohydrodynamic lubrication, was examined with a diamond-anvil high-pressure generationg apparatus which can produce a pressure of up to 100 GPa. Owing to the optically transparent property of diamonds, the crystallization of lubricants could be observed and their pressure was measured by the ruby fluorescence method, in which the linewidth broadening over the viscosity of 10¹² Pa·s was used in determining glass transition pressure. The results were compared with the existing values, and the correlation between the glass transition pressure this method to the study of tribology.

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This paper presents a study on the root stress analysis of internal spur gears by 2-dimensional elasticity theory and mapping function. A calculating method of tooth profile of internal spur gear generated with a pinion cutter was indicated and a mapping function for the profile approximated to the tooth profile of an internal spur gear was obtained. The root stress of internal spur gears calculated by 2-dimensional finite element method (FEM) and measured ones, and the validity of root stress analysis of internal spur gears by the theory of elasticity was confirmed. Furthermore the effects of addendum modification and loading position on clarified to a considerable extent.

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To make clear the relation between the tooth bearing of bevel gear and assembly errors quantitatively and theoretically, a theoretical calculation of tooth bearing was carried out for Gleason and Reinecker type straight bevel gears and for Reinecker type skew bevel gear considering the geometric tooth profile of these gears. And the tooth bearing of each bevel gear was also measured using a tooth bearing tester which was produced for this study. Comparison of the calculation method, and revealed the characteristic of tooth bearing of each gear.

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The tooth bearing test of bevel gear is performed frequently, because it is necessary in this test to judge synthetically the precisions taking account of various gear errors. In the previous paper, the authors demonstrated a calculation method for the tooth bearing of bevel gear. In the present present paper, the tooth bearing was measured with changing the assembly condition, using a tooth bearing tester specially produced for this study. It was found that the characteristic of tooth bearing of bevel gear can be made clearer by expressing the sizes and the positions of tooth bearing in the tooth bearing in the tooth trace and tooth profile directions by numerical values. Furthermore, the influence of the shaft angle error on the tooth bearing of bevel gear was also made clear.

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The scoring resistance of the tip-chamfered gears was examined from a standpoint of the flash temperature rise. Further, using a power-circulating gear machine the scoring resistance and the surface durability of the gears were clarified. The scoring resistance of the gears significantly increased with the amount of the tip-chamfer that is desirable for scoring. In contrast, the surface durability of the gears decreased with an increasing amount of the tip-chamfer.

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This paper deals with a general theory for calculating stress distributions in spur gears which are obtained by considering the ratio of contact, the stiffness of mating teeth and the friction forces at contact points. The method proposed in this paper makes it possible to analyze easily the actual behaviour of two meshing gears such as the load sharing ratio, the stress concentration near root of the teeth in contact. Furthermore, with the help of the finite element method, this study makes it possible to clarify the complicated stress distributions of both the driving and the driven gears whose characteristics have never been analyzed.

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Plastic gears have various merits such as silent running, self-lubrication, and so on, but they also have some demerits such as less load-carrying capacity and unsteady life time. In our sixty-two experiments, most of the failures of plastic gears were fractures of teeth from near pitch points. On basis of these results, a new design equation for bending strength, described by the bending stress at the pitch point, is proposed. In the equation, some coefficients: tooth thickness coefficient, load increasing factor, stress correction factor, etc., are introduced to realize higher load capacity economically by making the best use of the characteristics of plastic materials.

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A design of bolted joints with gaskets almost depends on experience and a sealing performance is not made clear by theoretical analyses. In the present paper, discussion is made on the distribution of contact stresses when a clamped part with a gasket or a filler plate is fastened with two tap bolts to a base which is large enough comparing with the clamped part. The distribution of contact stresses is analyzed as a three body contact problem using the two-dimensional theory of elasticity. Moreover, the contact stress is measured by means of ultrasonic waves. Next, the force ratio (a ratio of an increment of bolt axial force to a load) and the maximum stress caused in bolts taking a bending moment into account are analyzed. For verification, experiments are carried out. The analytical results are in fairly good agreement with the experimental ones.

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A surface roughening phenomenon was investigated using commercially pure aluminium sheets deformed plastically along various proportional strain paths. Surface profiles were measured in three directions of a major principal strainε₁, a minor principal strain ε₂ and 45 degrees toε₁ direction. The mean value of R_a in the three directions could be expressed by the equation: R^^-_a = 3.14ε_d, where ε_d is an absolute value of principal strain vector in-plane, independently of the strain path. Both R_a and the wavelength λ_m at spectrum maximum showed a relatively large difference between ε₁ and ε₂ direction in the case of balanced bi-axial tensile path. The anisotropic geometry of surface topography corresponded with the direction of the maximum shear stress plane in the bulk metal.

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In this paper, the chucking characteristics were investigated experimentally. The chucking force during cutting, which had not been studied, was measured with a load washer. Many advantageous characteristics were ascertained in detail with this measuring system. The results obtained from this study are as follows: (1) Fluctuation obtained force is generated periodically with the rotation of main spindle due to the combined effects of directional orientation of the chucking stiffness and the cutting force. (2) This chucking force of a three-jaw scroll chuck decreases with an increase in the fluctuation of chucking force. Especially, the fluctuation appears remarkably in the presence of chatter vibration.

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To establish a computing method for the chucking pressure distribution in the main spindle chuck workpiece system, a mathematical model is firstly proposed, wherein two types of joints are mainly considered : one is a bolted joint between the main spindle and the chuck body and the other is the guideway between the chuck body and the jaw (jaw guideway). Using this mathematical model, then. an FEM analysis on the shucking pressure distribution is carried out, simultaneously comparing the computed result with the measured value. From this comparison, it can be found that both the values show good agreement with each other. Consequently, the validity of the proposed mathematical model can be proved to a great extent.

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The purpose of this work is to develop systematic methodology to improve the safety of robot systems both at present and in future, ranging from their design stage to practical use. In this paper, the Action-Changes and Action-Chains Models, which can be applied to any type of man-machine systems, are proposed to clarify the concept of "hazards" and the production process. In the models, actions between system elements are divided into six types according to the characteristics, and the action chains produced among system elements are divided into five types according to the relations of two selected elements and the others in the chain. The hazards of a robot to a human are, then, effectively identified by enumerating the actions between the elements and changes, the action chains among the elements, and the injuries to a human by utilizing the models.

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