An experiment was performed by applying combined loadings of a constant axial stress and a torsional stress cycle to a thin-walled tube of softened celluloid. The results obtained are summarized as follows: (1) When the torsional stress is applied after the axial stress, the deformation resistance of the material decreases due to an abrupt change in the deformation state, and the ratchet strain and the range of cyclic torsional strains increase markedly in the first few cycles. Such an effect of pre-stress declines thereafter as a hardening trend appears with an increase in the number of cycles N. (2) The hardening trend of both strains may be expressed by an exponential function of N. (3) Fluctuations showing an alternate softening and hardening every few cycles appear in both strains. (4) The softening and hardening characteristics and fluctuations in both strains may be interpreted as indicating variations in the micro-structure of the material which may be assumed the cause of the residual strain.

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To investigate the plasticity-creep interaction effects, the combined stress tests for plastic behavior subsequent to creep pre-strain and creep behavior subsequent to pre-strain were performed at room temperature. In the experiments, the thin wall tubular specimens of SUS 304 stainless steel were used. The stress-strain relations were obtained in these experiments and the plasticity-creep interaction effects were discussed on the basis of the experimental results. An attempt to predict subsequent behaviors to plastic and creep pre-strain was made using an equi-plastic strain surface and an imaginary hardening value of creep strain.

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An analytical method of three-dimensional vibrations on a cylindrical specimen was developed, in order to determine the elastic constants by the resonance method. As trial functions on the Rayleigh-Ritz method of eigenvalue approximation, trigonometrical functions on circumference and Legendre polynomials along a column were used. A finite element method was applied to concentric cylinders divided in the radial direction. Many resonant frequencies in a small cylindrical specimen (φ6×6 mm) were easily measured over 20th of the higher mode by the newly devised techniques. The elastic constants G=26.2 GPa, ν=0.345, E=70.4 GPa of pure aluminum and G=30.2 GPa, ν=0.33, E=80.3 GPa of Al-12%Si eutectic alloy were obtained.

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A master camera. scanning-moire method is a moire method in which the grating is replaced by the scanning lines of a television In the present paper, the principle of moire pattern appearance. the effects of thinning out of scanning lines and the relation between moire fringes and strain are studied by the sampling theorem. If deformed model gratings are sampled by a television camera and they are thinned out properly by using an image processing system, the strain distribution in a wide strain range can be analyzed from one picture.

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In order to evaluate the stress intensity factor of Mode I crack, the grain growth in an electrodeposited copper foil and the slip-initiation phenomena in a recrystallized foil are applied. Taking note of the fact that these phenomena are controlled by shearing stress amplitude, the crack opening displacement and the stress concentration near the crack tip region in a center cracked plate made of carbon steel are measured by applying these foils bonded to it. The stress intensity factor calculated with use of measured values is in rather good agreement with numerical solution. It is concluded that these methods can be applied for evaluating the stress intensity factors of Mode I cracks.

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Vickers and Knoop indentation tests were performed on alumina ceramic specimens by measuring acoustic emissions. In Vickers indentation test, the Weibull plots of the threshold load Pth, at which total AE energy begins to burst, seem to obey a 2-parameter Weibull distribution function, while those in Knoop indentation test seem to obey a combined Weibull distribution function. The ratios of the numbers of the specimens, in which Pth was observed, versus total numbers of the specimens were 62% in Vickers indentation, and 41% in knoop indentation. Some additional differences were observed between Vickers and Knoop indentation tests.

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CT specimens are analyzed elastic-plastically by the three dimensional finite element method and the distribution of the three dimensional J integrals along the crack front is obtained. For 1CT specimens without side groove. the J value at the center of the specimen is the maximum and is the minimum near the surface. It is shown that the change in both values becomes smaller when introducing the curved crack front assuming the fatigue precrack. For the side grooved specimen. the experimental J value using the net thickness is better than that using the effective thickness. It is shown that the J value is nearly equal along the crack front for the 25 side grooved specimen. In every case, the J value obtained by the load versus displacement curve coincides well with the average J value over the specimen thickness.

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Adhesive tensile strengths, o f scarf joints with various scar f angles and butt joints with various adhesive layer thicknesses have been measured to establish fracture criterion for joints of steel plates bonded by brittle epoxy adhesive. A three-dimensional elastic stress analysis of these joints was performed by FEM. Fractures of both joints were explained quantitatively by introducing a boundary layer depth of 0.035 mm at free surfaces of adhesive layers and obeying maximum principal stress criterion. In adhesive layers of scarf joints with 0.1 mm layer thickness, the boundary layer depth of 0.035 mm included most of stress concentrated area at free surfaces. Locations of fracture initiation and fracture modes of adhesive layers observed with an optical microscope and a scanning electron microscope agreed with those expected from stress distributions and boundary layer conception.

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In the previous paper, three flow patterns were found at small spacing between two cylinders arranged in tandem as follows: the first is a flow without reattachment of the shear layer separated from the upstream cylinder, the second is an unstable flow and the third is an unique flow like that the frequency of the vortex shedding is nearly constant regardless of the free stream velocity. The purpose of this paper is to investigate the conditions of the occurrence of the above flow patterns and their flow characteristics in more detailed. It becomes clear that the unstable flow is caused by the intermittent reattachment of the shear layer onto the downstream cylinder, the unique phenomenon on the Strouhal numner occurs in the range of 2.5×10⁴≤Re≤6.5×10⁴ and is a transition phenomenon due to interference between the two cylinders. Beyond Re=6.5×10⁴, the Strouhal number becomes again constant.

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Experimental and theoretical studies were conducted on the acoustic characteristics of orifice holes exposed to a grazing flow. The impedance tube method was applied and the grazing flow was given by an open jet to avoid standing wave effects in the radiation field. The radiation resistance was found to become negative at specific conditions determined by flow Mach number, frequency and hole diameter. The open area ratio of orifice holes was pointed out to have a stronger influence on the impedance than considered. The concept of ' constant volume flow through orifice hole' is not necessarily valid. A potential flow theory was presented on the radiation impedance of a tube opening exposed to a grazing flow. In the theory the flow region and the tube region were connected to satisfy the coincidence conditions of displacement and pressure at the opening. This theory was found to predict fairly well the various aspects of impedance obtained in the experiments.

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A detailed experimental investigation was carried out on the characteristics of the flow around three circular cylinders arranged in line. There are three cases concerned with the behavior of the shear layers separated from the first cylinder on the downstream ones: the first is a case without reattachment (W), the second is one with reattachment (R) and the third is one rolling up in the front region of the downstream cylinders (J). The flow patterns were classified according to W, R and J as follows: patterns A(W, W), B'(W, W⇌W, , R), B(R, R), C(R, J), E(R, J⇌J, J) and D(J, J). The characteristics of these flow patterns were clarified. The results were compared with conventional results on two and four circular cylinders arranged in line.

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A steady flow of liquid metals in curved circular channels under a transversely applied magnetic field is investigated theoretically and experimentally. A laminar flow in low Dean number region is analyzed numerically. The internal mechanisms. i.e. velocity profile. distributions of current densities and others. are made clear. Based on the result. the resistance coefficients for the laminar flow in high Dean number region are calculated by means of boundary layer approximate method. An experimental study is carried out on a mercury flow. Pressure loss is measured and the resistance coefficient obtained by this experiment is shown to be in good agreement with that of the the theoretical analysis. And the effects of the electrical conductivity of channel wall on the behavior of flow are examined.

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Although single-blade centrifugal pumps are frequently used to handle waste water with solids, they have poor durability because they show severe vibration caused by a fluctuating radial thrust. Very few reports on the fluctuating radial thrust of turbo-machines have been published to date. Hence, details of the behavior and mechanism of the fluctuating radial thrust remain unclear, and a method for reducing the fluctuation is not established. In this report, instantaneous blade surface pressure distributions affected by volute pressure distributions are measured on the suction cover surface of a pump with an open-type centrifugal impeller having one blade. The fluctuating radial thrust mechanism is then clarified on the basis of these measurements, and a difference between actual radial thrust and the integrated value of static pressure along the impeller outlet is discussed. Furthermore, the radial thrust is separated into dynamic and static radial thrust vectors and a method for reducing the dynamic components, which are the cause of pump vibration, is demonstrated.

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A mathematical model capable of predicting a pressure rise associated with cavity collapse and cavitation duration following a column separation with accuracy enough for practical usage, on the downstream side of a valve instantaneously closed in a fluid power pipeline, was investigated. Particular attention has been paid to assessing the effect of gas released from liquid during the growing phase of the cavity. For that purpose, mechanism of commencement, growth and collapse of gas bubbles and volume of gas released were observed by using a valve made of transparent acrylic resin and a high speed camera. So far as the timing and pressure peak upon collapse of the first cavity are concerned, the predicted results from the present "gas-nonbubbly flow" model, in which the effects of gas released at the separated cavity and of an unsteady shear resistance in pipe flow were considered, agreed with the measured results within 5 per cent at worst.

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Local mass transfer and pressure coefficients on the side wall and the end surface of a finite circular cylinder have been measured. The experiments have been conducted under the condition of subcritical flow regime (Re∼10⁴), 1/d=1∼6 and δ/d=0.1/1.0. The main results are summarized as follows. Slenderness parameter (1/d) and boundary layer thickness (δ/d) have a remarkable influence on the flow behavior and the local mass transfer distribution, especially on the end surface of the cylinder. Heat transfer coefficient on the end surface is higher than that of a two-dimensional cylinder, without distinction of the reattachment of a shear layer. Furthermore, Nusselt number of the side wall is smaller than that of a two-dimensional cylinder. And overall Nu on the finite circular cylinder is given in a simple correlation between parameter 1/d, δ/d and Re.

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Investigations pertaining to the effect of water density inversion on steady natural convection in an inclined rectangular cavity whose two opposing walls are kept at different temperatures have been carried out experimentally and analytically. Surface temperature of the cold wall is maintained at 0°C, while that of the hot wall is varied from 2°C to 20°C. Photographs and analytical descriptions of the flow patterns, temperature distributions and average Nusselt number are presented. From the present results, it can be understood that the density inversion of water has an important effect on the convection in the fluid layer, and the average Nusselt number is a peculiar function of surface temperature of the hot wall and' inclination angle, unlike previous results about common fluid without density inversion.

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A hot wire should be put in the interfacial space between a couple of solid materials. The clearance at the interface becomes the third phase which is not considered in the theory of hot wire method, and would cause some errors in the measurement of thermal conductivity. This paper gives solutions to a heat conduction problem of solids with a thin interfacial clearance, with the aid of heat source theory, and with the aid of numerical calculation. It is found and experimentally proved that the temperature increase rate develops slowly on account of the existence of the clearance but it reaches finally the rate which indicates the right thermal conductivity of solid material. Some means to make the temperature development fast are discussed.

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As thermal insulation powder usually contains numerous voids in each particle of the powder, the previous theoretical equations on its effective thermal conductivity do not agree with experiments if the equations are employed without modification. In the present study, the thermal conductivity of a particle is firstly estimated by a simple cell model, then the effective thermal conductivity of the powder is calculated on the assumption that the powder consists of particles with the above estimated thermal conductivity. On the other hand, the effective thermal conductivities of the powder of perlite and hollow glass microsphere are measured at low temperatures, and are compared with the calculated values. The result shows that at a given temperature and gas pressure the experimental values agree well with the calculated values.

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An oscillatory motion of natural convection in a rectangular cavity has been studied both experimentally and analytically. Experiments were conducted mainly in the case that the hot and cold surfaces were set up as the upper and lower half walls of a side plate, and the other walls were insulated. A periodic oscillation of the hot and cold cells was found to occur by the flow visualization in a certain range of the Rayleigh numbers. The influences of the Prandtl number and the aspect ratios of the cavity on the oscillation frequency were also examined. Unsteady two-dimensional equations, which govern a laminar natural convection, were solved numerically to simulate the oscillation. The calculated flow patterns and oscillation frequencies were in fairly good agreement with the experiments. From these facts, the applicability of above numerical schemes to the other systems of the oscillations was discussed.

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Temperature measurement techniques for a practical combustion chamber liner wall were investigated. Fourteen methods fo sheathed thermocouple installations on thin stainless steel plates simulating a combustor liner wall were tested by flowing a hot gas along one side and a cold air along the other side. It was found that the Reynolds numbers of the hot and the cold streams have no significant influence on the errors but every installation method has its particular characteristics for the accuracy of the measurement. It was also found that the radiative measurement of a black coated wall may cause a significant error because there occurs a steep temperature gradient across the coating layer.

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Experiments have been performed to investigate the effect of cooled-plate characteristic on frost formation under the condition of forced convection. Two kinds of plates having the different contact angles to water, were utilized. Special attention was focused on the incipient phenomena of the effect of the plate contact angle to water on the frost forming on the cooled plate. It was found that when the temperature difference between the cooled plate and the dew point of air stream, was less than about 1.50c the frost thickness might never build up greater than 0.5mm.

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In a self-exciting system of Van der Pol type with the restoring force expressed as the product of a non-linear function of deflection and a periodic function of time. parametric resonances and moreover subharmonic vibrations can occur. Steady state solutions in the regions of parametric resonance of first order and of subharmonic resonance of order l/2 and the stability are determined by a transformation to the rotating coordinate system and the averaging method. In the neighborhood of these resonances a beat phenomenon occurs and its amplitude is estimated by an approximate limit cycle. By numerical calculations it is ascertained that approximate solutions have high accuracy.

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In this paper, the asymmetric vibrations of barrel-like shells of revolution are analyzed by using an improved thick shell theory. The equations of motion and the boundary conditions are determined from the stationary conditions of the Lagrangian of the shells of revolution. The equations of motion are solved analytically by a series solution and then natural frequencies and mode shapes are obtained. Effects of various parameters upon natural frequencies are clarified through analysis of numerical results. The results by the present improved thick shell theory are compared with those 'by the classical thin shell theory and the effects of the rotatory inertia and the shear deformation upon natural frequencies are clarified.

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The natural frequencies of raidal vibrations in models of the stator core of three induction motors were measured. It is found that two natural frequencies have the same deformation wave numbers and the relation between the deformation wave numbers and natural frequencies is represented by two curves. These curves have two asymptotes, one of which shows the characteristics of the natural frequencies of the ring, and the other shows the characteristics of those of teeth only. The lower of the two natural frequencies can be calculated precisely by Dunkerley's formula. The experimental results are in good agreement with the theoretical results calculated on the assumption that the vibration system is of two degrees of freedom.

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Vibration experiments on a rotor-bearing system were systematically executed in four different types of excitation and the results were discussed with respect to non-linear effects of the bearing oil film. Not the obvious non-linearity of the unbalance response, but linearity to a large amplitude was shown by the corresponding alternative force and the static force acting on the rotor itself, and the non-linear solution and the static deflection were compared.

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For wheel-type earthmoving vehicles, many of the dynamic characteristics are not clarified in a theoretical manner. Theoretical analysis of the characteristics is carried out in order to establish standards for design, inspection and operation. This paper deals with the behavior of a motor grader, and establishment of a simulation working model is tried. A dynamic analysis based on this model has been carried out, the results being in good agreement with the experimental values. The dynamic load and deformation of the frame are determined.

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A simple and efficient infinite element has been developed for the finite element analysis of three dimensional field problems whose domain extends to infinity. The formulation is based on the assumed displacement hybrid finite element model. The present element has the following features: (1) Since it requires no interpolation nodes in the exterior region, both the number of total degrees of freedom and the bandwidth of the global stiffness matrix remain exactly the same as those of interior elements. (2) The generation of the element stiffness matrix requires neither the matrix inversion nor the integration for the direction extending to infinity. (3) The computational effort needed for the entire process is almost the same as that for a corresponding bounded problem. (4) It can be used in conjunction with conventional interior elements. Numerical results for several three dimensional infinite domain problems are presented.

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The authors experimentally examined dust deposits on a hot wire when employed as an air flowmeter. The following points were considered: surface temperature, hot wire diameter, air flow velocity, inertial separation effect, and collision ratio of dust particles onto the hot wire in a dust-proof type flowmeter. The last two points were evaluated using simulations based on experiments and theoretical calculations. As a result, it was found that the output change due to dust deposits on the hot wire could be prevented using a bypass flow type flowmeter, in which the inertial separation effect was taken into consideration.

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This paper presents a study on bending fatigue strength of spur gears in low-cycle range. The calculating methods for adjacent-tooth gaps and the circumferential load, under which adjacent-tooth contacts occur due to the deflections of meshing teeth, are introduced. The validity of these calculating methods is confirmed by carrying out a static loading test. The characteristics of the bending fatigue strength of spur gears in low-cycle range are clarified to a considerable extent by carrying out a bending fatigue test.

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The effects of tooth form error on the stresses of helical gears are less clarified than those with spur gears. In this study, the tooth fillet stress of helical gears with convex or concave tooth profile is measured, and the effects of tooth form error on the stress are investigated by comparing with an analysis of power transmitting characteristics of cylindrical gears, which has been developed before. As a result, it is confirmed that the theoretical analysis is valid, and it makes the theoretical calculation of tooth contact stress and flash temperature more reliable. From these considerations, it is verified that the concave tooth profile is undesirable for tooth fillet stress, contact stress and flash temperature.

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In toothed belt drives under a state of initial tension in the static region. the generating mechanisms of a transmission error when both of pulleys are revolved reversely from a stable meshing state between belt and when both of pulleys are in normal revolution are theoretically and experimentally discussed. The magnitude of an initial tension, a difference of the pitch difference between both pulleys and a backlash between belt tooth and pulley tooth have great effect on the transmission error. and some methods to reduce the transmission error are discussed.

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For the testing, a spring is fixed to one end of the plate for fixing a test cylinder, and the test cylinder is allowed to move up and down. If the test cylinder incorporates an eccentricity and a waviness, then the oil film pressure fluctuates and the test cylinder vibrates. We showed first the oil film pressure fluctuation and the cylinder's vibration by the numerical calculation, supposing that the waviness conforms to a sine curve. Then the experiment was done. The experimental values of the oil film pressure and the cylinder's vibration were compared with the values calculated considering the eccentricity and the waviness of the test cylinder.

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Based on the Navier-Stokes equations in which the pressure is assumed to be constant across the film thickness, various approximate solutions for the static and dynamic performances of an infinitely wide, plane inclined slider pad in a laminar flow regime are presented under the assumption of a small harmonic vibration. From comparison of the approximate solutions with the numerical one, it is concluded that one kind of averaging approach in which some of the time dependent terms are treated exactly while the convective inertia terms are averaged out across the film thickness gives close approximations in a wide range of desigining conditions, and that an other kind of averaging approach in which all the inertia terms including the time dependent terms are averaged out across the film thickness is a fairly good approximation.

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In order to study the effect of rolling texture on the cutting mechanism, cold-rolled aluminum alloy and brass plates which have distinctive preferred orientations were used as materials to be cut. Orthogonal cutting was performed by changing the angle e between the rolling direction and the cutting direction, and change in cutting phenomenon with θ was examined. Moreover, the obtained experimental results were analyzed by r-value and the anisotropic parameters which were determined from tensile tests of the same plates. The results showed that the effects of plastic anisotropy of the material appeared clearly at the cutting force, that is, cutting shear stress τ_s was affected by the harmonic mean value r in shearing direction.

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