Both specimens fatigue-stressed at room temperature to introduce a surface crack in the range of length 50 μm to 1.5 mm and ones annealed to remove the prestress history were fatigued in rotatory bending at elevated temperatures. Precracked specimens fatigue-stressed at elevated temperatures were fatigued at room temperature also. The threshold values for fatigue crack propagation were examined. The following results were obtained. (1) The valleys and the peaks in the threshold-temperature relations for both the prestressed and annealed specimens appear at about 200°C and 375°C, respectively. These peaks are due to a rapid strain aging. (2) While the threshold values at the peaking temperature is increased by the room temperature stress history, those at room temperature are decreased by the same stress history. (3) The threshold values at room temperature are increased by the peaking temperature stress history.

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In this paper, the problem of a thin walled cantilever pipe with a slit of arbitrary width and position, is studied by an exact method using a differential equation for a thin cyildrical shell introduced by one of the authors, K.Mizoguchi. The behaviour of the stresses and deflections in a cantilever pipe in the case of variation of the width and the position of a slit is investigated, and the results are compared with those obtained by the simple beam theory or a modified beam theory. The variation of the position of shear center with length of a cantilever pipe is also discussed.

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The initiation of inhomogeneous deformation which occurs in a rectangular elastic-plastic thin plate under biaxial tension with arbitrary stress ratio is studied as a bifurcation problem. A simple solution for the approximate bifurcation stress is obtained on basis of Hill's theorem of the uniqueness of solution. Influences of the stress on inhomogeneous bifurcation mode and the bifurcation strain are considered by some numerical results. Validity of the solution is confirmed by a simulation using a finite element method.

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This paper contains an analysis of the state of stress in a semiinfinite elastic body containing a prolate spheroidal cavity whose surface is subjected to an axisymmetric pressure. The solution is based upon the Boussinesq stress function approach and is obtained by making use of the cylindrical and prolate spheroidal harmonics. The boundary conditions on the surfaces of the semi-infinite body and of the cavity are well satisfied with the aid of the relations between the cylindrical and prolate spheroidal harmonics. Numerical results are given for some different major semiaxes and shape ratios, and the stress distributions around the cavity are shown graphically.

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The vibratory cavitation device with a vibratory probe oscillating in close proximity to a specimen surface was improved ; by recirculation of the testing liquid through a bore in the horn and the gap between the stationary specimen and the vibrating probe the temperature distribution on the stationary specimen came within ±0.5°C, and the errors in the experimental results were able to be kept below ±3%. It was confirmed that the stationary specimen is damaged by cavitation with a more ductile mode than the vibrating specimen. This is attributed to absence of stress of longitudinal vibrations.

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Approximate methods based on the experimental assumptions are often carried out to predict a turbulent flow on account of difficulties obtaining a general solution of the Navier-Stokes equation of motion. In this report, after deciding the distribution of integral scale of turbulence and assuming a one parameter turbulent model, calculations were done according to Spalding's finite differential-difference methed based on the equation of turbulent energy transfer to obtain an asymptotic distribution of velocities and turbulent energy in the downstream of a two-dimensional body placed normal to a uniform flow. Comparing the results with experiment, it became clear that Spalding's numerical method is also applicable to predict a two-dimensional wake, and that a similar solution is obtainable assuming the integral scale of turbulence to be proportional to the width of wake.

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The internal flow and the performance of an annular diffuser composed of a cylindrical casing and a conical hub were examined experimentally. When the flow has no whirl component at the inlet, the optimum convergent angle of the hub, giving the best pressure recovery, is about 24 degrees. But with an increment of the whirl component, the component roughly changes to the free vortex pattern at the downstream passage independent of the initial flow pattern and the axial velocity is faster near the hub side than near the casing side. Accordingly, it is possible to prevent the separation by giving an adequate whirl component at the inlet, even if it occurs at the hub wall with a large convergent angle in the case without the whirl component. When the whirl component becomes stronger, a reverse flow occurs along the hub wall at the definite area ratio irrespective of the convergent angle.

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An experimental study has been made to investigate heat transfer and flow around tubes of in-line tube banks. Measurements were conducted for seven cylinder spacings in the Reynolds number range from 10⁴ to 6x10⁴. It is found that the mean heat transfer coefficient shows no essential variation with the cylinder spacing for the second and farther downstream cylinders. The flow through the tube bank deflects in the case of a very narrow cylinder spacing and the heat transfer behaviors under such situations are clarified.

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An experimental study was conducted to investigate the heat transfer and flow around tubes in staggered tube banks in a cross flow of air. The cylinder spacings examined C_y/d x C_x/d are 1.6 x 1.6 and 1.2 x 1.2 where C_x and C_y denote the cylinder spacings along and normal to the upstream uniform flow direction, and d the cylinder diameter, respectively. Main results obtained are as follows. In case of 1.2 x 1.2, the mean Nusselt numbers for the second and subsequent cylinders are almost equal to each other and much higher than that for the first cylinder. In case of 1.6 x 1.6, the third cylinder exhibits the maximum heat transfer rate. This may be due to the high velocity of an oncoming flow to that along with its high turbulence intensity.

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The transient characteristics of heat transfer in a vertical porous layer were examined analytically. The natural convection depending on the geometric aspect-ratio H/W (height to width of the porous layer), the porosity and the physical properties of porous media played an important role in the evaluation of the transient characteristics of heat transfer in the porous layer. That is, the natural convection had the effects of shortening the time period until a steady state of the porous layer was reached and the porous layer was homogenized thermally. By managing the intensity of natural convection with a proper combination of porous media and the dimension of porous layer, it would be possible to obtain the desired time period for a steady state of the porous layer to be reached and to control the amount of the heat stored in the porous layer.

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The present paper deals numerically with natural convective heat transfer in a confined rectangular cavity of a relatively low geometric aspect-ratio H/W (H, W : height and width of cavity) with different vertical wall temperatures. The numerical calculations using the Up-Wind finite difference method are carried out for a confined rectangular cavity having H/W=0.03∼1, Prandtl number Pr=1∼10³ and Rayleigh number Ra=10²∼10⁶. The results obtained indicate that the geometrical aspect-ratio H/W significantly affects the rate of heat transfer through the fluid layer. Moreover, useful and convenient correlations of the heat transfer through the fluid layer are derived from the results.

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A new method of measuring the PVTx properties of fluid mixtures was proposed and a new apparatus was designed and constructed. The apparatus constructed here was examined for its performance by the measurements of the PVT properties of R22. Then the PVTx properties of a mixture of 80 wt% R12+20 wt% R22 were measured in the range of temperatures 293 to 418K, of pressures 0.7 to 9.6 MPa and of densities 141 to 1049kg/m³. Twohundred PVTx measurements were made along the 13 isochores. Based on the obtained data, dew- and bubble-point curves were determined and the available estimation methods were discussed.

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This is a theoretical and experimental study of natural frequencies of bending vibrations of a beam with non-uniform cross section. General solution of the differential equation of the eigenvalue problem has been obtained by making use of power series solutions. This solution is applied to a uni-tapered cantilever with I-type cross section, and the nondimensional frequency equation is introduced, yielding a good coincidence of the numerical computations with experimental values concerning the natural frequencies. Secondly, a uni-tapered beam with rectangular cross section supported at two intermediate points is taken up, giving a nondimensional frequency equation. Numerical results are compared with those obtained by the Frobenius method, demonstrating the superiority of the series solution to the Frobenius method.

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Various types of nonlinear forced oscillations are expected to occur in a beam subjected to harmonic excitation. Among them the present paper concerns the super summed and differential harmonic oscillations. The theoretical analysis shows that only the summed type can occur in the beam. It also reveals that the transition to the state in which the super summed and differential harmonic oscillation occurs from the state in which only the harmonic oscillation occurs, is made continuously by increasing the excitation frequency. The experimental analysis confirms the results of the theoretical analysis.

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A practical conventional technique whereby earthquake response of the mechanical appendage system-pipings, tanks, electrical and mechanical equipment-supported by the primary supporting system installed on nuclear power plants and other industrial facilities can be approximately estimated is proposed and discussed Basic response properties for the appendage system can be represented by the proposed floor response amplification factor (FRAF) in this technique. This factor depicts the ratio of the maximum response of the appendage system to the response spectrum for the supporting system and can be conventionally drawn upon tripartite diagram for engineering use and its statistical characteristics are investigated. This technique can be applied to a nonelastic case where the restoring force-deformation relation for the appendage system can be simplified as a perfectly-elastoplastic model and its applicable range is investigared.

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This paper presents a seismic response analysis method for a cylindrical liquid storage tank subjected to a horizontal earthquake, which is based on an energy method with the coupling effect between sloshing and bulging taken into consideration. The kinetic energy and the strain energy of an empty tank shell are estimated by the axisymmetric shell finite element method. On the other hand, the kinetic energy and the potential energy of the liquid in the tank are estimated analytically by superposition of two type of velocity potentials, that is, one obtained by assuming the tank wall as rigid and the other obtained by considering the liquid to be coupled with the tank shell neglecting the oscillation of liquid free surface. The numerical results obtained by this method are compared with those obtained by the method described in the former report, which treats Bernoulli's equation as the boundary condition of liquid free surface, and it is shown that there are little differences between them.

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Damping is an elementary factor to be considered in designing vibration isolators. So measurement of damping coefficient or damping ratio is of great importance. Usually, these values are calculated by logarithmic decrement or resonance method. These are convenient methods, if a system possesses light damping. The accuracy of these methods, however, is not satisfactory in a large damping system. In this paper, two new methods to calculate large damping with high accuracies are proposed. One is a method utilizing a phase angle between input and output, called "phase method", and the other is one utilizing the gravitational acceleration, called "gravity method". Damping coefficients of the oil damper were measured by the methods mentioned above. As the results, it is made clear that the measured values obtained by the phase method and the gravity method show higher degree of accuracy than the ones obtained by the resonance method.

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An investigation was undertaken with a view to establishing a procedure for diagnosing rolling bearings for defects from their vibration and sound. In the present investigation the vibration and sound of a rolling bearing with one dent on the race surface of the inner or outer ring or on the ball surface were studied. When the inner ring was caused to rotate at a constant speed under a given thrust load applied to the outer ring, the outer ring radial vibration velocity was determined by a moving coil type converter. Using the data so obtained, vibration waveforms were observed, peak vibration pulses measured, and real time frequencies of the vibration analyzed by Fast Fourier Transform analyzer. As a result, the fundamental characteristics of ball bearings having one defect were clarified, and a method by which to locate the defect and determine its size was established.

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Hydrodynamic film in a face seal is analyzed by a new numerical technique, in which mass continuity is preserved in a ruptured film and thus the cavitation boundary is automatically settled. In the experiment the pressure in the cavities is manually controlled and the film thickness is measured. It is shown that the load capacity increases with a rise of negative pressure by cavitation, while on the other hand, the seal operates under starved condition with the development of cavitation, since the suction of liquid decreases as the cavity pressure approaches ambient pressure.

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The sealing mechanism of a radial face seal is theoretically investigated and the leakage flow rate of the face seal with manually controlled cavitation is measured experimentally with fixed minimum film thickness or fixed axial load. It is shown that inward pumping is induced by the composite effect of cavitation and radial film thickness variation, and the radial resistance to leakage is independent of cavitation unless any radial forces are applied to the cavities.

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A comparison of wear between reciprocating fricton and uni-directional friction was made on annealed low, medium and high carbon steels. Wear tests of the two sliding modes were carried out with a specially designed testing machine under similar sliding conditions in white spindle oil. The experiment indicated that a heavier wear always resulted from reciprocating friction under the sliding conditions used, and the wear differences between the two sliding modes increased with increasing normal forces and with decreasing sliding speeds. The wear differences can be explained in terms of the differences i.e., difficulty or easiness of plastic flow of sub-surfaces and the amount of abrasion by the wear debris trapped between sliding surfaces.

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This paper introduces an Automatic Mesh Generator (AMG) for finite element method (FEM) to analyze tooth fillet stresses of gears with a thin rim. The AMG incorporates 'Basic Mesh', i.e., a set of regular meshes : Nodes and elements for the FEM calculation are efficiently decided on the basic mesh. Coordinates of nodes of the model are calculated by an imaginary elastic deformation of the basic mesh. By the selection of a proper form of the mesh and by changing the imaginary elastic characteristics of the basic mesh, a proper distribution of nodes on the model for FEM-analysis is obtained. The amount of input data to AMG is determined only by the complexity of the model shape. The input data for another similar model can be easily made by a little correction of the input data. The values of the gear tooth fillet stresses calculated by FEM using this AMG showed satisfactory results.

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