Rotating bending fatigue tests were made on specimen which were polished longitudinally or circumferentially with two kinds of silicon carbide papers and then elecro-polished. The fatigue processes were observed successively by the two stage plastic replica method, with special attention given to the starting points of a final fracture . The materials used are a normalized S45C steel, and a quenched and tempered S45C steel. The main results obtained are as follows : (1) Non-propagating micro-cracks are observed on the surfaces of the specimens after 10⁷ cycles of the fatigue limit. (2) The characteristics of a change in surface states due to stress repetitions can be explained in terms of the notch sensitivity of the material and the roughness of the specimen surface.

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The crack energy density was proposed by the author as one of the most important crack parameters, of which the physical meaning is clear throughout the life of a crack. In this paper, this crack energy density is applied to the problem of fatigue crack growth and it is tried to establish it as the parameter which is available from the first to the last of the life of fatigue crack. The results are as follows ; (1) The role of crack energy density as a crack parameter is made clear. (2) The relationship between the range of crack energy density, Δε and the load-displacement curves of specimens is obtained and it is shown that Δε is useful as a fatigue crack parameter throught the life. (3) It is shown that the growth rate of fatigue crack is determined by the increment of crack energy density per one cycle, Δε^t_<cycle> and the gradient of the distribution of crack energy density.

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This paper deals with a contact stress distribution in bolted joints when a full-face metallic gasket is used between a cover and a base of pressure vessel. Replacing the cover, the gasket and the base with a finite cylinder and two finite follow cylinders respectively, the contact stress distribution is analyzed using three-dimensional theory of elasticity. Effects of the thickness and the stiffness of gaskets on the contact stress distribution are shown by numerical computations. Next, the force ratio of bolted joints with gaskets, which is a ration of an increment of bolt axial force to an inner pressure, and the sealing performance are analyzed. A bending moment is produced in bolts by the inner pressure. The maximum stress produced in bolts is also analyzed taking the bending moment into consideration. For verification of the analytical method, experiments are performed. Analytical results are in a fairly good agreement with experimental ones.

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An axially-loaded stteped cylindrical rod is studied. This rod is composed of two semi-infinite rods connected at each end. The problem is reduced to the solution of a set of simultaneous equations under the continuity conditions of the displacement and the stress at the contact plane. By these equations, the order of the stress singularity at the corner can be obtained. The numerical solutions of stresses at the contact plane are obtained for various rations of the shear moduli and the radii.

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This paper deals with the theory of obtaining the solutions of elastostatics from the solutions of elastodynamics, namely, wave modes. A harmonic wave in an elastic strip consists of P and S waves. These two waves fall into linear dependence at zero frequency. But, as the frequency of the wave tends to zero, the limits of the P or S wave and of a linear combination of the P and S waves become independent solutions of the static equation. There are innumerable pairs of such solutions. The general solution for a rectangular plate may be constructed in the form of a series of these solutions with unknown coefficients. Some problem are calculated numerically as application examples.

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The problem of torsion of a conical-form rigid cylinder embedded in an elastic half space has been investigated in a previous paper. The problem may be regarded as an analytical model of stress analysis in drilling. The principal object of this paper is an application of the problem of a half space to one of an infinite thick plate. The method of solution used here is to distribute torsional body forces in a thick plate so as to satisfy the boundary conditions of a conical hole of an infinite elastic thick plate. For this purpose, we apply Green's functions for torsional body force problems of an infinite elastic thick plate. Stresses and displacements of the thick plate with a conical hole and torques necessary to twist the conical-form rigid cylinder are shown graphically and compared with the results about an elastic half space.

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Torsion problems for two rods bonded to each other by an adhesive layer are investigated. It is assumed in analyses that the mechanical behavior of the adhesive layer is approximated by that of shear springs, and hence the shear stress in the adhesive layer can be proportional to the difference of the shear displacements between the upper and the lower surface of the adhesive layer. Making use of the series expansion techniques, we reduce the problems to infinite system of linear equations which can be solved numerically. Consequently the stress distributions are obtained for various values of mechanical properties of the rods and the adhesive layer. We also investigate a special case of these problems i.e. the torsion of a half space by an adhered rigid rod.

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This paper presents an exact solution for the stress wave propagation in an elastic sphere under two equal and opposite concentrated loads varying with time as the Heaviside unit step function at the end points of a diameter. The solution is based on the stress function approach and the Laplace transform method for axisymmetric problems. The Laplace transformed solution is given by a meridional Legendre function and a radial spherical Bessel function which are derived from the method of separation of variables. Inverse transform to which is applicable the residue theorem, gives and exact solution of the transient response up to the arrival time of stress waves. The results of numerical evaluation are shown graphically for the displacement and the stress variations versus time in the elastic sphere.

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The J integral evaluation is carried out for the surface cracks of a pressure vessel under thermal transient loadings. First a semi-elliptical surface crack existing on the inner surface of the vessel shell is treated and the effect of the aspect ratio of the crack on the J integral distribution along the crack front is studied. It is shown that the J integral value becomes nearly equal for a shallow crack when considering the thermal loading. Then the effect of cladding is studied by analyzing the surface crack existing on the nozzle surface through the phase boundary between the base metal and the cladding. The result show that the J value becomes smaller if the existence of the cladding is assumed rather than neglected.

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In designing bolted joints, it is important to examine the sealing performance and to estimate the force ratio, that is the ration of an increment of bolt axial force to a load. Up to now, in order to improve the sealing performance, raised faces of interface have been used. But the uses of these interfaces depend on experience and the theoreticial grounds are not made clear. In this paper, in the case of pipe flanges having raised faces, the sealing performances are analyzed by using a three-dimensional theory of elasticity and the point matching method. Then, the force ration is analyzed. Moreover, with an application of the load a bending moment is produced in bolts and a stress is caused by the bending moment. This bending moment is also analyzed. In order to verify these analyses experiments are performed. Analytical results are in a fairly good agreement with experimental ones.

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For the investigation of fracture criteria, adhesive tensile strengths of scarf and butt joints bonded by a brittle and two ductile epoxy adhesives have been measure, and three-dimensional finite element analyses have been performed. Deformation of the Joints was influenced considerably by mechanical properties of adhesives. Fracture of the joints bonded by the brittle adhesive satisfied maximum principal stress criterion. At the scarf angles of 15° to 60°, fracture of the joints bonded by the ductile adhesives satisfied the von Mises criterion and at the scarf angles of more than 60°, a brittle (cleavage) fracture occurred in those joints by plastic constraint due to an increase of stress triaxiality in adhesive layer. Locations of fracture initiation and fracture modes of adhesive layers observed with an optical microscope and scanning electron microscope agreed with those expected from experimental results of deformation and adhesive tensile strength, and result of stress analyses.

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In the present paper the elastic-plastic stress at the impact end of a cylindrical specimen subjected to longitudinal compression impact with a stress bar which remains elastic during the test is investigated experimentally and theoretically. The measured elastic response of the stress bar showed explicitly an elevation of dynamic stress and its relaxation at the impact end of the specimen. The impact end stress of the specimen was analyzed by using the strain-rate dependent theory for plastic wave propagation, taking into account a rise time of impact and impact conditions. An extreme elevation of the dynamic stress was predicted in the case of a step impact, but it went down rapidly with an increase in the rise time of an impact velocity. Taking the stress as an incident stress to the stress bar, the elastic response of the stress bar based on the Love theory for elastic waves almost agreed quantitatively with the experimental results as well as qualitatively.

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The purpose of present investigation is to analyze the stress waves propagating due to suddenly applied normal loads at the end points of diameter of a spherical cavity embedded in an infinite, linear, homogeneous, isotropic, elastic medium. The solution for Laplace transformed wave equation is give by meridional Legendre function and radial spherical Hankel function. The unknown functions included in such solutions are determined by the boundary conditions for loads represented in the form of a series of Legendre functions. Formal solution obtained by the evaluation of residue, gives a dynamic response to the arrival of stress waves.

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A detailed visualization experiment was made on unsteady flows in the vortex-region behind a circular cylinder which was started impulsively from rest at the Reynolds number of 1, 200 referred to the diameter of the cylinder. An improved hydrogen bubble technique was employed in order to visualize streaklines from the unsteady boundary layer on the surface of the cylinder. Also a new method to estimate accurately the vorticity distribution in unsteady vortex region was developed. By use of these methods, the mechanism of vorticity produced on the surface of the cylinder and fed to the vortex region and the mechanism of onset of turbulence in the vortex region were made clear in relation to the vorticity distribution and the flow patterns.

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The velocity field of the flow around a circular cylinder started impulsively from rest was studied by the aluminium dust method. The experiments were carried out at R_e=1, 200 and when τ=U₀t/d was from 0 to 5, where R_e is the Reynolds number based on the diameter d of the cylinder, U₀ the cylinder speed, and t the time after the start of the cylinder. Circulations taken along several closed contours around a vortex-center, and the positions of vortex-center were measured during the motion of the cylinder. On the basis of these measured values, the velocity fields in the vortex region were calculated by using a simple model which approximates the vortex flow by a single viscous point-vortex. The analytical results were in a fairly good agreement with the experimental results.

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Turbulence structure in the intermediate wake of a circular cylinder was studied by a conditional-sampling technique. The measurements were made at a section 8 diameters downstream of the centre of the cylinder. Lateral velocity fluctuations at each position of measurement were found to a proper reference signal to make the conditional sampling if they were combined with longitudinal velocity fluctuations along the wake axis. Velocity fluctuations were decomposed into those produced by large-scale coherent structures and those associated with small-scale structures. Maps of streamlines, vorticity, velocity vectors and correlation of velocity fluctuations were presented in the large-scale structures. Intensity, correlation and intermittency of the small-scale fluctuations were also presented and discussed in relation to the flow field in and around the large-scale structures. A mechanism of entrainment by the large-scale structures and diffusion of their vorticity was suggested on the basis of the above results.

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Gas-solid two phase flow in sudden expansion of upward flow is experimentally examined by using different expansion rations and different solid particles. The result shows that the additional expansion loss coefficient takes a negative value when the flux Richardson number exceeds 0.0015 as in horizontal and vertical downward pipes and that a degree of decrease of the additional expansion loss coefficient is the largest in a vertical upward pipe.

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A new two-parameter integral method is presented which is applicable to unsteady two-dimensional laminar boundary layers whether they are separated or not. The governing equations consist of three moments of boundary layer equation and the assumed velocity profiles are those of unsteady trailing edge flow and Falkner-Skan flow with slip(non-zero wall velocity). The governing equation system being hyperbolic, the spontaneous generation of singularity associated with unsteady separation is confirmed as the focusing of characteristics. The obtained results of the boundary layer quantities as well as the generation of separation singularity are in good agreement with those of exact methods (e.g. van Dommelen and Shen) for starting flows of cylinders.

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Experiments of the flow of dilute aqueous solutions of polyethylene oxide through curved pipes with circular cross-section are carried out over the Reynolds number range of 500 to 1×10⁴. Concentration of the polymer solution is varied from 0.5ppm to 100ppm. The ratio of the curvature radius to the pipe radius, R/a, of curved pipes is set at 16.3, 28.8 and 46.0. These fluid are found to cause frictional drag reduction under the turbulent flow condition in a curved pipe as well as in a straight pipe. Experimental values of a frictional loss are correlated with the Weissenberg number, the Reynolds number and the radius ratio R/a. The empirical formulas for the frictional loss estimation are proposed separately for both the laminar and the turbulent flow regime. It is also shown that the transition to turbulent flow depends on the Weissenberg number as well as the Reynolds number.

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An axial velocity of a laminar, fully-developed oscillatory flow in a curved pipe was investigated experimentally and numerically. A laser doppler velocimeter was used to measure the axial velocity. The measured result was in good agreement with the numerical analysis, and the effect of oscillatory Dean number D and Womersley number α on velocity near the inside wall became larger than that near the outside wall under the condition of comparatively large Dean number and moderate Womersley number.

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Instability wave motion of the liquid film jet in a high speed co-current uniform gas stream was investigated experimentally an theoretically. The following results were obtained. The instability waves arose in both the flow direction and a perpendicular direction to it, and these waves have approximately the same wave number. Examination of the linear Kelvin-Helmholtz instability and the liquid film energy made it clear that the wave numbers of the instability waves agreed well with experimental results. It was found that the wave number of the liquid film jet could be estimated by a theoretical analysis. A close relation of the wave frequency to the liquid film breakdown was confirmed experimentally.

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measurements of the vapor-liquid coexistence curve in the critical region for Refrigerant 13B1 (CBrF₃) were made by visual observation of the disappearance of the meniscus at the vapor-liquid interface within an optical cell. Twenty-two saturated densities for temperatures between 332 and 340 K were obtained in the range of densities 376 to 1108 kg/m³. The experimental uncertainties in temperature and density measurements were estimated within ±10 mK and ±0.5%, respectively. Based upon the results along the coexistence curve, the critical temperature T_c, the critical density p_c and the critical pressure P_c for R 13B1 were determined to be 340.08 K. 764 kg/m³ and 3.956 MPa, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence. In addition, the critical exponent β was determined to be 0.340 and the correlation of the vapor-liquid coexistence curve for R 13B1 was established.

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When a homogeneous, isotropic particle of soda glass, hexadecane or others is immersed in the incident light of the laser beam, the scattering efficiency, the intensity of the scattered light and the polarization ratio of the light of these matters change according to temperature. In principle, this optical measuring method is a new-technique compared with the direct measurement method such as the thermocouple, the resistance thermometer and the spectroscopic CARS method. The analytical results using Mie's scattered light phenomenon show that the temperature measurement by this method is practically available.

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This paper deals with transient heat transfer for a water drop impinging on a heated surface in the surface temperature range from the maximum boiling rate point to the non-wetting region. The boiling curves were obtained by analyzing the transient temperature variation inside the heated surface taking account of the time variation of the area covered by the drop. Comparing the boiling curves obtained in this way with that for pool boiling, the heat flux in both cases increases with an increasing subcooling, while the heat flux in the present case is several times higher than that for pool boiling. It was proved that the maximum heat flux point of the boiling curve was located on an extension of the nucleate pool boiling curve and that the boiling heat transfer for a drop on the heated surface was classified into four types according to the degree of subcooling and the heated surface temperature.

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The effect of addition of high volatile fuel droplets to a lean mixture on a burning velocity, using an inverted cone burner, has been investigated. The used droplets are methanol-water, ethanol-water and soapbubbles enclosed propane-air or hydrogen-air mixtures. With these fuels, it is possible 1) to change the heat of combustion and the latent heat of fuel droplet without a significant change of droplet diameter, 2) to change the fuel vapour quantity around the droplet, and 3) to produce any concentration of gas cloud when the soapbubbles are used. The results obtained are follows : 1) The effect of addition of high volatile fuel droplets on the increase of burning velocity becomes large with an the increase of heat of combustion or a decrease of latent heat of the droplet ; 2) burning velocity increase when the soapbubble encloses a high burning velocity gas even if the latent heat of the soapsuds is greater than the heat of combustion ; and 3) the addition of droplets will increase the area of reacting zone of flame.

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For the purpose of analyzing the combustion process in a spark ignition engine, it is necessary to know the combustion temperature in the combustion chamber. The author has developed a new technique of measuring the combustion temperature using the sodium line reversal method. By this new technique, it is possible to scale temperature for the output of flame radiation from the combustion chamber. The distribution of flame temperatures in the cylinder could be measured by this method even near the cylinder wall. For the purpose of measuring the flame temperature in the commercial engine, a compact sensor with prisms and optical fibers was developed. The measure values obtained form these techniques are discussed for various operating engine conditions.

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Gear train system sometimes consists of more than 2 shafts. But dynamic characteristics of such system have not been analyzed in detail. Especially, on a counter shaft on which there are 2 pairs of gears in mesh, their power transmitting direction does not coincide each other. As a result, vibrations of power transmitting direction and tooth sliding direction couple together even if gyro effect is ignored. We discuss the dynamic characteristics of a counter shaft from this point of view. The results obtained from this investigation are : (1) Affected by the angle between 2 power transmitting directions on a counter shaft, the natural frequencies and mode shapes change. (2) Usually, when the shafts are rotated inversely, its natural frequencies and mode shapes change. (3) The flexural mode shape is not confined in a plane.

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Nonlinear dynamic response of a string subjected to periodic excitation will differ qualitatively from the usual harmonic response, because the natural frequencies of a string are in the ratio of integers. To demonstrate that the string in fact responds unusually, a typical case is taken up and a theoretical analysis is conducted. The case taken up here is the response near the second primary resonance point. The theoretical analysis shows that, in addition to the usual harmonic oscillation, two other types of oscillations can occur. One is an oscillation that contains, as its principal components, the subharmonic oscillations of orders 1/2 and 3/2, and the other the so-called summed ant differential harmonic oscillation. The conditions under which these types of oscillations occur are obtained, and the characters of the oscillations are discussed. Experimental analysis is also conducted with use of a thin steel strip. The occurrence of the above two types of oscillations is ascertained experimentally, and the validity of the theoretical analysis is confirmed.

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Large plusations cause engineering problems such as piping vibrations etc., which may impede plant operation. Therefore a pulsation study should by carried out during the design stage and the results should be incorporated into the piping design in order to minimize pulsations. In this paper, a method of digital simulation which is equivalent to analog simulation specified in the API standard is proposed . The digital simulation method which takes dynamic interaction is composed of interactive two models which are Compressor Simulation Model for calculating the pressure and temperature in the cylinder etc., and Piping Model for calculating pulsations using the application of model analysis method. Experiments were carried out to verify the adequacy of the digital simulation method. Comparisons between the calculations and experimental data showed that the results agreed and that accurate predictions could be made using the digital simulation.

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This paper deals with the torsional vibration control problems of a rotor shaft during start-up and shut-down. Two control methods are proposed in this paper. One is an optimal regulator method, and the other is an optimal tracking regulator method. These two control methods consist of constant feedback coefficients and compensation inputs. The authors investigated in detail the two control methods concerning the above mentioned rotor shaft problems. From both the simulations and experiments, it was found that the optimal tracking method was superior to the optimal regulator method.

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When the tooth of a nylon gear of visco-elastic body was applied with a force the tooth deflected largely and a rotational lag occurred at the mating steel gear. This caused an abnormal abrasion at nylon gear tooth flanks and the tooth profile changed conspicuously. In order to prevent these things, the nylon gear was developed. The gear included a stiffener of steel in the core of tooth and the tooth was made hard to deflect. In this report, the manufacture of this gear was outlined and the characteristic of abrasion and the tooth profile change in the course of operation were made clear.

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To improve the nosing limit of thin walled aluminum tubes by conical dies, the effects are examined of the circular curved part at die inlet, the outer guide of cylindrical part, and the local annealing in the nose forming zone. The circular curved part at the die inlet is effective in nosing with large die semi-cone angle. The local annealing method prevents not only buckling at cylindrical zone but also wrinkling in nose forming zone, and is a useful means to improve the nosing limit. Furthermore, a guide line for die design is made on the raidus of curvature of circular curved part at die inlet and the optimum length of local annealing at which nosing limit reaches its maximum.

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This noise control device, which produces a greater noise reduction effect than a barrier is capable of refacting the sound waves and reducing a noise by destructive interference, and it consists of many pipes which make a structural delay circuit. It is very important to design the pipes of the noise control device such that the device may produce a great noise reduction effect when it is applied to noise pollution problems. This paper describes the fundamental design method of the pipes and refers to the experimental data in an anechoic room and some sound theories. As a result of this study, the fundamental design method of this noise control device has been established.

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This paper presents a new method for noise source identification in a multiple noise sources environment where the noise sources may be coherent to each other. IT is found that the major characteristics proportion of the noise source is generated in vibration of forge machine by using multi-dimensional spectral analysis. This analysis is modelled as a multiple input/single output system when the noise generating system of forge machine is very complicates. In this analysis the concept of residual spectral analysis and the partial coherence function are applied. For their contributions, relationships between noise sources and radiated sound pressure are computed by micro-computer system. Finally, overall levels for radiated sound pressure obtained by multi-dimensional spectral analysis are compared with those measured.

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Applying the lubrication equation and a modified form of Darcy's low for a Bingham solid to porous step thrust bearings, pressure distributions, core formations, load capacities and friction torques in lubricant film are analyzed, and pressure distributions, flows and stationary regions in porous bearings are evaluated. Interesting result are that the flow region becomes small with a decrease of permeability and an increase of yield stress of a Bingham solid. Experimental result are compared with the analytical ones.

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When a pair of conical involute gears transmit a rotational motion between two shafts whose axes intersect, the deviation of a shaft angle, a small offset between two shafts, and errors of mounting distances of the gears do not affect accuracy and uniformity of the transmitted motion. For easy understanding of this ability of the conical gears, this paper first describes results of running tests on a tooth bearing and an angular velocity ration, which verify this ability of the conical gears experimentally. Second it studies a theory of a gear tooth action which proves this ability theoretically. Furthermore, a contact ration and a relative curvature at a point of contact between tooth surfaces are described, and the tooth bearing is analyzed. Finally hertzian contact ellipse and the maximum contact stress are obtained.

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It is confirmed that crystalline grains of various metal materials are refined through a solidification process with a horizontal circular vibration which consists of only a revolutional component and does not include a rotational component. By the experiments about 99.7%A1, it became clear that; (1) higher vibration frequency, larger vibration amplitude, or lower casting temperature makes crystalline grains more refined, (2) vibration during and just after pouring refines crystalline grains, while the subsequent vibration does not cause a remarkable difference in the refinement, (3) the grain refinement is significantly influenced by the condition of mold wall, and (4) the above effect of vibration remains until after successive working.

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In this paper, the parametric instability in chuck work process is investigated. And an analytical criterion of stability is given, and experimental confirmation is carried out. The vibration of this type is considered to have a significant influence on machinability. However, the applicable isolation of this vibration has not been done. The results obtained are as follows: (1) The parametric vibration is generated by the directional orientation in the stiffness of chucked workpiece. (2) The theoretical analysis for predicting the conditions of parametric instability could be verified by good agreement with the result of cutting test. (3) In the chuck work process, the parametric vibration is amplified with mingling regenerative chatter by the condition of low and fluctuating stiffness.

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Although the carbon-fiber-reinforced plastics (CFRP) is very similar in forming process to the glass-fiber-reinforced plastics (GFRP), both materials differ in the cutting behavior since their physical and mechanical properties are different. In this study, a turning (facing) test on the CFRP pipes was performed with several kinds of tool materials, and the wear patterns and wear land growth ship between the physical and mechanical properties of tool material and the wear were compared with the data in a previous report for GFRP and discussed.

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The temperature rise caused by the moving heat sources of which the distributions of heat intensities are parabolic and uniform over the area of a rectangle was calculated in consideration of heat radiation from the surface under the assumption of a three-dimensional heat flow. Further, the flash temperature rise generated on the meshing faces of the gears was examined by estimating convective heat transfer coefficient between the tooth surface and a lubricating oil. From the calculated results it is seen that the difference between the maximum values of the temperature rise caused by the above-cited distributed heat sources decreases with an increasing heat transfer coefficient, and the effect of heat radiation on the flash temperature rise of the tooth surface is considered negligible.

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This paper presents a theoretical analysis and a model experiment of sinking behavior of a very long pipe with a water-inflow. With application of a water-inflow, the effects of intake and exhaust port diameters at the pipe ends and pipe length and diameter upon the sinking behavior are examined by numerical analysis using the Runge-Kutta method and by a model experiment. As the result, it is known that the water inflowing method to set up a riser is preferable because a violent landing on the sea floor does not occur. And it is clarified that the maximum bending moment increases as the pipe length and the inner area of cross section increase. Further a way to suppress the maximum bending moment is proposed.

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