Sheet test specimen of commercial pure copper was used and tests on three types of stress waves were performed under atmospheric and hydrostatic pressures of 1000kg/cm² at 270°C. From the present experiments the following were concluded. At the same stress wave, time to rupture of the material under hydrostatic pressure was remarkably longer than that in atmosphere. In this connection, slower crack initiation and propagation rate were observed under hydrostatic pressure as compared to atmospheric pressure. From the calculation of both fatigue damage φ_f of the material and creep damage φ_c in the tests of fatigue with hold-time, the value of commulative damage, φ_c+φ_f, is larger than unity under both hydrostatic and atmospheric pressures. The fatigue damage of the material is predominant under hydrostatic pressure but the creep damage of the material is influential under atmospheric pressure.

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This paper is concerned with the study of the dynamic behavior of a cylindrical shell subjected to a concentrated periodical force acting at a certain point on cylinder surface. The interesting phenomena observed in the free vibration analysis of the cylindrical shell are confirmed from the standpoint of the forced vibration due to a concentrated force with wide applications and it is also pointed out that there may occur some peculiar phenomena in the forced vibration. In this paper the fundamental equations of vibration of a cylindrical shell including the in-plane inertia are described for the three theories based on Mizoguchi, Flugge and Donnell, and the displacement response is compared by those theories, in addition to the theory neglecting the in-plane inertia.

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Although the stress analysis of a body containing cracks has been widely investigated concerning the stress intensity factor well used in fracture mechanics, few papers are reported on slab problems in spite of their availability. In the present paper, a slab with a pressurized annular crack on the middle plane is treated on the basis of three-dimensional theory of elasticity. The displacement normal to the crack faces is supposed to be expressed by the Fourier series. Thus the triple integral equation is replaced by a set of the infinite simultaneous equations and its solution is much simplified. Additionally, displacements, stresses and stress intensity factors are also shown by those coefficients of Fourier series and their numerical results are easily obtained. It is concluded that displacements and stress intensity factors become large as the slab thickness is small under the same conditions.

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A certain type of oscillation, which may be termed the super-division harmonic oscillation, can occur in a nonlinear multidegree-of-freedom vibratory system subjected to periodic excitation of frequency ω, when the quantity (1/N)Σ^^k_i=1m_ip_i (N=2, 3, ...; m_i=±1, ±2, ...) constructed from some of the natural frequencies p_i (p_i>0) of the system, is close to ω. Theoretical investigation on the occurrence of this type of oscillation is carried out for a case of a two-degree-of-freedom system with nonlinear spring characteristic of fourth order polynomials of the displacements. The analysis shows that the above type of oscillation occurs in the system when either (1/3)(p₁+P₂) or (1/2)(2p₁+P₂) is close to ω. Numerical calculation is performed and the characteristics of the oscillation are discussed. The theoretical analysis is checked by an analog computer.

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When a rotating shaft is supported by single-row deep groove ball bearings with "angular clearances", there appear rotating anisotropies both of shaft stiffness and of nonlinearity which are induced by imperfections in rotating parts. We have already reported about the particular vibration phenomena at the major critical speed in the case where unsymmetrical nonlinear characteristics appeares more strongly than symmetrical ones. In this paper, we try to clarify the effects of symmetrical nonlinear characteristics on the resonance curves in such case. Furthermore, we deal with the case experimentally and analytically where symmetrical nonlinear characteristics appear more strongly than unsymmetrical ones. In this case, a particular shape of resonance curve appears at the major critical speed, and this resonance curve changes its shape depending on the angular position of the unbalance.

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As the 1st report on the dynamic characteristics of fluid temperature between inlet and outlet of a room, a two-dimensional room with various relative positions of inlet and outlet is treated. First, a mathematical model describing the characteristics of fluid flow in the room is determined experimentally in as simple a form as possible. Next, when the heat transfer into the wall is theoretically added to the above flow model, a mathematical model describing the dynamic characteristics of fluid temperature is obtained. The mathematical model is examined and discussed by experiments. The main results are as follows. The flow model explains well the phenomenon of fluid flow in the room, and parameters in the flow model agree almost with the values estimated by observations of flow patterns. Moreover, the theoretical results of fluid temperature agree well with the experimental ones.

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A linearized theory based on the pressure dipole method is developed for evaluating the blade thickness effects on the cascade of blades in subsonic shear flow. One of the most significant conclusions obtained from the analysis is that the blade thickness effect on the zero lift angle is strongly influenced by the spanwise gradient of the oncoming fluid velocity. The velocity gradient causes a decrease in the zero lift angle at the span stations of higher velocity and an increase at the span stations of lower velocity.

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Onedimensional pressure waves (shock waves) were generated in a liquid (water) column contained in a vertical pipe by the impingement of a piston accelerated by compressed air. The waveforms obtained were sawtooth waves with peak pressures of 100-500kg/cm² and widths of 1 to 2 msec. While waves in this pressure range were found to behave essentially as sound waves, the steepening of the wave front with originally a rise time of tens of micro-seconds to a discontinuity over a propagation distance of around 2 meters was observed, which was explainable in terms of the compressibility of the liquid. The density change across the wave front measured with the integrated schlieren technique was found to be proportional to the pressure change in accordance with the relation of adiabatic change of he medium. The motion of the piston following the impingement was observed by means of instantaneous photography, and a fine correspondence of the deceleration process with the generated waveform was evidenced. The displacement velocity of the liquid behind the wave front was also measured with a simple technique.

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Concentration and velocity measurements are carried out in a turbulent region of axisymmetric jets of H₂, He, Ar, CO₂ and air with quiescent air. The spreading angles of concentrations and velocities are larger for the lighter issuing gases. Though the decreases of concentrations with the axial distance are associated with the differences of the densities between issuing and surrounding gases, the decreases of velocities are proportional to the ratio of these densities. The differences of these behaviors for each gas are displayed by the contour maps of concentration and velocity. For lighter issuing gases, the velocities decay fast, but the concentrations remain at rather high values. On the other hand, for heavier gases, both oh the decays have considerably small values. And the results of experiments show that the turbulent exchange coefficients are proportional to a half power of those density ratios.

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This paper describes the results of an experimental study on the flow around two-dimensional sharp-edged plates attached to a plane wall at different inclinations to the flow. Experimental data were collected to investigate the effects of (1) inclination of the plate to the flow, (2) the charactristics of the smooth wall boundary layer in which they are immersed, on the pressure forces of the inclined plates. Further, the flow patterns around the inclined plate are examined in some detail. For flows with zero-pressure gradient, correlations are obtained between the variation of pressure forces and inclined plate height h, which is analogous in form to the law of the wall of a boundary layer velocity profile. This law of the wall is applicable up to h/δ = 1.21.5 in the range of inclination angles between 30°and 150° tested in this investigation. A method of calculating the pressure distributions on the front surface of the inclined plate is proposed based upon a flow model that can be analysed by a hodograph technique. The method, however, involves four parameters which must be determined on the basis of experimental informations.

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In this paper, the pressure losses that occur in the cylinder port of an axial piston pump are analyzed and the critical condition for a suction operation is obtained. And using a simulated model of a rotating cylinder block, the values of loss coefficients that appear in the analysis are examined experimentally. As the result of this investigation, it becomes clear that, for the purpose of improvement of suction performance, the radius of pitch circle of cylinder ports should be small and the crosssectional area of cylinder ports should be large.

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A round jet of water impinging vertically on a horizontal plane forms a thin film flowing radially which later turns into an ordinary flow after passing through a hydraulic jump region. Hydrodynamic and heat transfer characteristics of two domains of the flow are investigated experimentally. The one domain is the jump region and the other is the interfering films of two equal jets. These two domains have several properties similar to each other because they are both interference zones of two flow regions. The radial location of the interference is found to be an important factor in the hydraulic and thermal properties of the interference region. The film of the jet flow is measured and analysed. It is found that different behavior of the interference zone are characterized by the film Froude number and the Reynolds number taking the radius from the center of the jet as the representative length.

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It was conjectured in the first report that most of the droplets within the flame do not burn individually, but fuel vapor evaporated from them collects and burns like a gas diffusion flame. The main object of this study is to confirm this conjecture. First, various measurements were made on a spray combustion flame and a gas diffusion flame under the same conditions. Comparing the two sets of data, it was found that the flames are similar in structure. Experiments on five spray combustion flames having different sizes, produced by changing the flow rate of combustion air, were secondly conducted. From the results, the conjecture of the first report was confirmed and it was found that the turbulent diffusion process has much greater influence upon the shape of the flames used in this study than the evaporation process of droplets. Finally, assuming that the droplets simply evaporate within the flame, their behavior was analyzed by making use of the knowledge which has been obtained for a single droplet. The calculated results showed fairly close agreement with the measured results.

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It is pointed out that, in making automatic the processes of machine design by means of man-machine interaction, the machine lacks the capability of generating the shape of machine parts. To overcome this difficulty in principle, the paper presents a topological method of generating convex polyhedra. As an instruction from man the edge-vertex table (k, λ_k|k=3, 4, ..., r, where k: number of edges gathering into a vertex, λ_k : number of k-edged vertex) is proposed. When the machine receives the edge-vertex table, it generates all of the mutually different linear dual graphs on convex polyhedra, where the graphs have Hamiltonian cycles. The fundamental theory for the above process is contained.

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It is useful and interesting to clarify the behavior of grease lubrication which is available on rolling bearings. To discuss such a problem, a nonlinear integral equation coupling the hydrodynamic equation of a Bingham solid and the elasticity equation of gearing materials is derived in this paper. Solving the equation numerically, the effect of core formation in a Bingham flow on the elastohydrodynamic lubrication between two cylinders becomes clear, and the process of core formation constitute an important part of the elastohydrodynamic problem. The measurements of film profiles also are carried out to compare with the analytical results.

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This paper presents a study into the effect of addendum modification on bending fatigue strength of spur gears made of normalized steel. Theoretical analysis is made regarding the effect of addendum modification on the true stresses at the root fillet of gear tooth in the case of tip loading. Bending fatigue tests are performed on gears with various amounts of addendum modification, using a pulsator of hydraulic type. The value of root stress factor for calculating true stresses at root fillet increases with an increasing value of addendum modification coefficient and the bending fatigue strength of normalized steel gears can be improved significantly by selecting the proper amount of addendum modification. Furthermore, addendum modification factor B_x for bending strength is derived on the basis of the analytical and experimental results.

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Load carrying capacity of gears for tooth breakage often poses a critical problem especially in casehardened gears. The present paper describes a study into the effect of addendum modification on bending fatigue strength of casehardened spur gears. Analysis is made regarding the effects of addendum modification on the true stresses at the root fillet in connection with the worst loading point and also on the bending fatigue strength of gear tooth. Bending fatigue strength of casehardened gears can be improved considerably by selecting the proper amount of addendum modification. Addendum modification factor B_x for bending strength is derived from the analytical and experimental results and the bending fatigue strength of profile shifted gears can be estimated with fairly high accuracy, by introducing this factor into the strength design of gears.

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Experiments of properties of soils (dry quartz sand and plastic loam) related to cutting are made. General properties of soils (stress-strain relations, dependence of failure condition on hydraulic pressure, volumetric change by hydraulic pressure or axial stress and other plastic properties), dynamic properties (stress-strain rate relation) of soils and friction between soil and plates are investigated. The results of these experiments are compared with the data of soil cutting and metal cutting.

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