The principle of heat treatment by ultrasonic heating lies in using the calorification originated from internal friction in metals caused by ultrasonic vibration with large amplitude. Therefore, this heat treatment is a selective one according to the vibration mode. When a new heating method is put practical application, its practicability and generality are extraordinarily important. In this report, arbitrary selection of the length and the heated position of materials was aimed at. With various additional masses attached to the test pieces, the relationships between the length of the test pieces, the position to which additional masses were attached, resonant frequency, the weight of additional masses, and the heated position were identified. As a result, it became clear that the selection of the length and the heated position of materials is possible. And further, the tempering by ultrasonic heating was tried successfully as a link in the chain of ultrasonic heat treatment.

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Low cycle fatigue tests were performed on a low carbon steel of 0.1 percent carbon content, which has various grain sizes of the range from 18 to l63μm in diameter. The cyclic softening is followed by a stationary state in cyclic deformation behavior in the fine grain material, while the coarse grain one exhibits a rapid cyclic hardening in the early stage, which is followed by a saturation hardening. Such a difference in cyclic deformation property can be interpreted well by considering that in the yielding behavior between the fine and the coarse grain materials. The cyclic stress-strain property is not influenced, by the grain size. The coarse grain material of 163μm in diameter has about 0.4times shorter fatigue life than that in the fine grain one of 18μm. The grain size dependent fatigue life of this kind is valid for both processes of crack initiation and propagation.

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Push-pull fatigue tests were conducted on butt-bonded three layer composite plates composed of iron and copper to study the propagation behaviors of fatigue cracks along interfaces. Observations showed that the cracks along interfaces are classified into three patterns of "interface cracks" propagating precisely along the interface between iron and copper, "subinterface cracks" propagating in copper region at a distance of 20∼30μm from the interface and "copper cracks" propagating in copper region far away from the interface. The propagation of the subinterface crack among others was fastest due to weakening of the subinterface region caused by diffusion of impurities into this region. The growth rate of the interface crack is largely affected by the amount of copper deposited on the iron side of the fractured surface, and the larger is the amount of copper deposit, the larger is the growth rate. The growth rate of the subinterface crack can be evaluated at least qualitatively by the value of K_I estimated for cracks located at interfaces of three layer composite plates, but further study is necessary for the estimation of more reliable values of K_I for such cracks.

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In an ultrasonic fatigue test of mild steel, the authors investigated the effects of strain amplitude, mean stress, and pre-strain on the changes of resonant frequency, and found a close relationship between the reduction of resonant frequency due to ultrasonic fatigue and the change of the microscopic structure. "The yield point for the stress of vibration" was defined by a strain amplitude which causes a rapid decrease of resonant frequency. Moreover, from an ultrasonic fatigue test with mean stress, a fatigue limit diagram was made for practical use.

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One type of nonconservative force is induced by an impinging air jet onto a flat plate which is fixed at the free lend of a cantilevered column and mounted normal to the axis of an elastic line. The stability problem of the column, i.e., generalized Reut's problem, is studied theoretically by using exact and approximate methods of solution, involving the generalized method of Galerkin. The effects of internal and external dampings, eccentricity of the applied force, and the mass of the attached plate are discussed. A pre-buckling analysis reveals that the presented problem is a new buckling problem which has not been known well previously. In the corresponding experiment which was conduced to demonstrate the realizability of the mathematical model discussed, only divergence-type instability occurred, while flutter-type instability did not.

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Applying the fundamental formula which has been derived by them from the consideration on a physical phenomenon of contribution of the internal stress in a definite subsurface layer of metal to the X-ray diffraction, the authors propose an exact theory of residual stress measurement for the Front Surface Method by successive thin layer removal in a sphere of a ball bearing by using the characteristic X-ray of Cr.

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Experimental results of the pressure recovery and velocity profiles in conical diffusers having a tailpipe with various inlet main flows which have an asymmetric uniform shear are presehted. Experiments were performed on four types of diffuser angle and four degrees of shear of inlet flow for each diffuser. Main results obtained are ; 1. Although the diffuser performance of the present case decreases with an increasing shear of inlet main flow as in the case of free discharge, the rate of performance reduction with shear is strongly decreased as compared with the case of free discharge. The effect of the tailpipe on the diffuser performance becomes stronger with an increasing shear of inlet main flow. 2. In the tailpipe, the velocity profile of each diffuser is uniformalized within the distance of 6 to 9 times the tailpipe diameter from the tailpipe inlet, in spite of the large asymmetry and non-uniformity of the tailpipe inlet flow.

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Measurements are performed for the unsteady forces and moments acting on the rotating circular cascading blades which vibrate harmonically in a torsional mode about the mid-chord with an arbitrary interblade phase angle. The results obtained are compared with the calculated results. It is found that the experimental results are qualitatively in good agreement with the calculated ones. When the interblade phase angle is small, it is found that the force and moment change in a periodic manner of a function given by the flow coefficient, the blade frequency and the wake length of the vortex distribution, and that the damping moment becomes negative under certain circumstance.

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Turbulent integral and differential scales have been measured in a turbulent boundary layer with injection and the effects of injection on these scales are investigated. In the inner layer, the longitudinal integral scale decreases with increasing the injection rate, but the transverse integral scale remains unchanged. On the other hand, both of these scales decrease in the outer layer. The ratio of transverse to longitudinal integral scales increases with increasing the injection rate and approaches a value of 0.5. This result suggests that turbulence tends to be isotropic with injection. The ratio of differential to integral scales becomes greater near the wall with increasing the injection rate, mainly due to the reduction in the turbulent Reynolds number.

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Relations between frictional losses and dimensionless frequency in an incompressible pulsating laminar pipe flow are investigated in terms of three kinds of friction factors. Furthermore, the frictional losses calculated from previously reported various approximate representations for wall shear stress are compared with those calculated from an analytical one in order to examine the validity of approximations. It becomes evident that the behaviours of instantaneous and time average friction factors in the quasi-steady, the intermediate, and the inertia dominant regions are qualitatively similar to those in a pulsating turbulent pipe flow and that the time average friction factor and the root mean square friction factor proposed here can be correlated to time-averaged cross-sectional mean viscous dissipation, while the instantaneous friction factor cannot represent the instantaneous cross-sectional mean viscous dissipation except for the quasi-steady region.

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Flow patterns in a pulsating turbulent pipe flow are classified into three types, i.e., the quasi-steady, the intermediate, and the inertia dominant regions with respect to dimensionless frequency ω' and time-averaged Reynolds number R_eta. Although the behaviour of frictional losses in the quasi-steady and the intermediate regions is being made clear experimentally, very little is known about them in the inertia dominant region. Assuming that if ω' is large enough, wall shear stress τ_ω becomes similar to that in a pulsating laminar pipe flow, two approximate representations for τ_ω are proposed. The characteristic parameters describing the flow pattern and the frictional losses estimated from these representations are compared with experimental results and the applicability of these representations is examined.

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A free surface of an incompressible ideal fluid of finite depth is covered with a thin elastic plate subject to an in-plane force due to the transverse displacement. It is found from the relation between the wave number and the frequency for linear waves that the rigidity and the tensile in-plane force of the plate make the wave profile capillary-like, and the compressive in-plane force makes the wave profile gravity-like. An approximate solution using the method of multiple time scales is sought for a wave with small but finite amplitude. In case of rubber plates the phase speed of non-linear waves increases with an increasing amplitude. It is known from the third order expansion that there are two different waves and three different resonance states.

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A few fundamental steady flows of polar fluid, i.e., flow in a circular tube, flow between two parallel plates and flow between two ooaxial cylinders are analysed with the help of the theory of Eringen. Couple stress and spin angular momentum are considered in this approach. The exact solutions for velocity, micro-rotation, vortioity and shearing stress are obtained mathematically. These solutions are characterized by two parameters, i.e., the ratio of viscosities ε and the size effect parameter λ which do not appear in a Newtonian fluid. ε is the ratio of vortex visoosity to shear viscosity. λ means the size relation between the corpuscle and the characteristic length. The solutions are compared with those of Newtonian fluid and it is investigated how they vary with ε and λ. Apparent viscosity is determined for each flow. Material constants of polar fluid can be decided from these apparent viscosities.

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The steady, nonlinear motion of a viscous, incompressible fluid between two concentric rotating spheres is numerically studied at some great Reynolds numbers. Several numerical methods are compared on the same boundary condition in which the outer sphere rotates and the inner one is stationary. The variation of the velocity profiles in the θ-direction in the clearance between the spheres and the effects of Reynolds number increase on the velocity profiles are considered. Although the velocity distributions near the pole in the clearance between the spheres are similar to those of the enclosed rotating disks, those at the equator are found to be markedly different from those of the concentric cylinders, one of which rotates, because the secondary flow in the clearance still has a great effect at the equator. In the case where both the inner and outer spheres rotate, contour lines of stream function, velocity profiles and the coefficient of viscous frictional moment are considered numerically in relation to some rotating angular velocity ratios α and the value of |1-α|.

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As an augmentative means of forced convective heat transfer, a cylinder was inserted in a parallel plate duct and the resultant local heat transfer coeffidient on the duct wall at R/L=0.4∼0.8(R : radius of cylinder, L : a half width of duct) was measured. It was clarified how heat transfer corresponded to the fluid flow behind the cylinder and near the wall and some consideration on the mechanism of augmentation in heat transfer was made. Experimental correlation has been obtained which makes it possible to calculate the local heat transfer variation in all the flow regions both upstfeam and downstream of the maximum heat transfer position for various R/L.

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The authors obtained more accurate solutions of the boundary layer momentum and energy equations for a wedge-type flow by the electronic computer using the Runge-Kutta method and deduced an approximate equation of the temperature gradient at the wall with a high accuracy. When a two-dimensional water jet with finite nozzle width strikes normally on a flat surface, it forms a flow field which can be divided into two flow regions ; the first one is an impingement zone and the other is a uniform parallel flow zone. It is the purpose of this paper to estimate local heat transfer coefficients in such a flow field, where the velocity gradient just outside the boundary layer changes along a flat surface and to study theoretically the effect of the nozzle height above the flat plate on the local heat transfer coefficient Furthermore the calculated results were compared with experimental ones of local heat transfer coefficients along a flat surface with constant heat flux.

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The purpose of this study is to obtain a better understanding of the heat transfer mechanism in the evaporator of a heat pipe. In the previous report, sintered powder was tested as a wick and it was concluded that the heat transfer mechanism involted thermal resistance of conduction through the wick-liquid matrix and evaporation resistance at the liquid-vapor interface. In this report, various kinds of screen meshes are used as the wick and pure water as the working fluid, to evaluate the effect of working pressure and the number of screen layers on the heat transfer. Experimental results indicate that the heat transfer mechanism for screen mesh is equivalent to that for sintered powder. The authors intend to expand the analytical method discussed earlier and to establish an experimental correlation which can be used for practical design of heat pipe evaporator with screen mesh.

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Taking account of damping effects, the nonstationary vibration during angular acceleration of a shaft through two critical speeds situated close together is analyzed theoretically, and both an exact solution and approximate expressions for it are derived. The results obtained from calculations of the exact solution show that the rotational speed at which the highest maximum amplitude will occur varies in a sawtooth manner above a certain acceleration rate, and that the highest maximum amplitude does not always decrease as the acceleration increases. A method for evaluating both the maximum amplitude and its rotational speed is proposed on the basis of the analytical results, and the evaluated values are compared with those from the exact solution.

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The asymmetric vibrations of cylindrical shells with variable thickness are studied by the improved shell theory and the classical one, The equations of vibration and the boundary conditions are obtained from stationary conditions of the Lagrangian of vibrations of cylindrical shells. The solutions are obtained in such a case that the thickness of cylindrical shells, built in at one end, varies exponentially along its axis. After numerical calculations, all boundary conditions at the other end are discussed, the effects of parameters on vibrations are investigated and the results by the improved theory are compared with those by the classical one.

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In the case when a single-degree-of-freedom system, which has the symmetrical nonlinearity with a linear term and a cubic nonlinear term, is subjected to the periodic force containing a constant force, the possibility that a subharmonic vibration of order 1/2 appears has been suggested and its characteristic has been investigated. The necessary condition for the subharmonic vibration of order 1/2 is expressed by the parameters of damping, coefficient of cubic nonlinear term and constant force. Further the relationship between the constant force and the waveform of the subharmonic vibration is determined. The validity of the analysis has been shown by means of the experiment.

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When a vertical rotating shaft is supported by single-row deep groove ball bearings, there appear symmetrical nonlinear spring characteristics in the elastic restoring force of the shaft due to the "angular clearance" of the bearings, provided that both bearing center lines at the upper and the lower bearings are aligned well. In such a system, two exciting forces with ω₁ (ω₁ : angular velocity of the precessional revolution of the balls) and 2ω₁ appear due to the coexistence of irregularities of balls and angular clearances of bearings. As the result of this, sub-combination tones of the angular velocity (3/2)ω₁ occur. In this paper, this kind of nonlinear forced oscillations is treated experimentally and theoretically.

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This paper is the first report on a series of works on stability evaluation of a multi rotor system supported by oil film bearings. Vibrational energy of each element of the system is calculated and relation between the energy behaviuor and the stability is investigated with a rotor supported by two bearings. Investigation of energy level of each bearing gives us information on an instabilizing bearing and it is known that the concept of the energy level of the bearings is very useful for design and diagnosis of the rotor system.

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This paper describes an experiment of the part 1 and also a sensitivity analysis of a rotor system. In the expeririment, energy levels of two bearings in the rotor system are measured and the values obtained are compared with the theoretical results in the part 1. Next the concept of the sensitivity is introduced and a method to improve the rotor/bearing system is studied from the sensitivity analysis and the energy levels.

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In order to study the effect of material anisotropy on the cutting mechanism, orthogonal cutting test was carried out using test pieces of aluninum single crystal of various orientations. The results are as follows : i) There is good agreement between the angle of slip 1ines observed on the side surface of the machined test piece and the one theoretically calculated from the active slip system. ii) It i s made clear that the shear angle in cutting of single crystal can be estimated reasonably from the active slip system of crystal. iii) The expectation of shear angle in polycrystal which has a distinctive preferred orientation can be also theoretically calculated on the basis of that in single crystal. iv) Process of shearing deformation is examined in detai 1 by observing slip line in shear zone.

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Although the performance of cutting tools has been evaluated by the tool-life values in the conventional turning tests, it is difficult to apply such data for the estimation of tool wear characteristics in different types of cutting tests. The purpose of this study is to clarify the relationships between various test results on flank wear. Three types of cutting tests, i.e., conventional turning, step turning and facing tests are performed on mild steel withsintered carbide tools. The tool wear growth curves of all tests are respectively formulated based on a few assumptions. The wear rate, which is defined by the wear land width per unit cutting length excepting the initial wear, is mainly used for analyzing the results. Thus, some relations are revealed between the results of above three tests ; a significant difference is recognized in the wear rate between facing test and the other two tests.

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