Yield criterion of anisotropic materials is developed under the maximum shearing stress hypothesis when the elements of materials are acted upon by three normal stresses in the direction of principal axes of anisotropy and a shearing stress around one of them. It is found for isotropic materials that the yield surface can be represented by two elliptical cone surfaces and a cylindroid one in the stress co-ordinate which is composed of the π-plane and its normal as a shearing stress. Under the assumption that these surfaces are independently distorted, translated and rotated, the numarical yield surface of anisotropic materials is found to be in good agreement with the experimental results of plates in any direction other than the direction of the degrees of angle, 60° to 70° form initial path of tensile prestrain.

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Corrosion fatigue tests of various materials have been carried out in 1% saline and in 0.3N hydrochloric acid, accompanied with the measurements of corrosion current and notch sensitivity. In corrosion fatigue the critical depth of pits from which fatigue cracks initiate is determined by the stress concentration of pits depending on the corrosion resistance of materials and by the notch sensitivity. Corrosion effects κ (the ratio of fatigue strength in air σ to that in corrosive media σ_c) are referred to the static and the dynamic corrosion resistance, which are indicated by the corrosion current density i_c0 at the beginning of the tests and by the inclination s of the corrosion current-testing time curve respectively, and to the notch sensitivity which is obtained by fatigue tests in air with notched specimens. Finally Eq. (14), (κ-1)/η=K₃K₄√((e<SUP)<K₁K₂>-1)/K₁>√(i<SUB)c0τ_T> is obtained. (κ-1)/η is proportional to K₃K₄√(i<SUB)c0τ_T> for the same corrosive media irrespective of materials and of testing conditions. Test results show a linear relation between (κ-1)/η and √(i<SUB)c0τ_T> for the variety of materials, K₃ and K₄ being constant for the materials used in the present experiment. Thus, the meaning of the corrosion effect κ proposed by one of the authors is made clear. Besides sτ_T=K₁ is obtained between the corrosion fatigue life τ_T and the dynamic corrosion resistance s, where the value of K₁ is 4 in 1% saline and 2 in 0.3N hydrochroric acid.

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Many reports on vibrations of cylindrical shells have already been published. But it seems that the vibrations of a system connecting two cylindrical shells of different thicknesses have not been studied yet. In this paper, the authors investigate the vibrations of combined cylindrical shells free at one end and clamped at the other or clamped at both ends. The Lagrangian of the combined system is expressed by unknown boundary values alone, and the frequency equations and modal patterns of vibration are obtained by minimizing the Lagrangian as to the unknown boundary values. From the results of the numarical calculations, it is recognized that there is little difference between the non-dimensional frequencies of the combined system and those of a cylindrical shell of uniform thickness with the same boundary conditions.

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While floating-bush bearings have been used in high-speed turbomachinery in recent years, there have been few investigations of the dynamic performances of such bearings. Experiments on the stability of a rotor with floating-bush journal bearings were carried out in this study. It was found that although the floating-bush would hardly rotate until the shaft speed reached the point where the oil-whirl occurred, the floating-bush stabilized the rotor system in a higher speed range. The stabilizing effect of the floating-bush bearing was conspicuous when the ratio between inner and outer clearance and the absolute clearance were large. It was also seen that the bush speed depended on its dimensions, particularly on the inner clearance and approached a nearly constant value as the shaft speed increased.

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A method is presented for calculating the unbalance vibration of a rotating shaft system consisting of variable cross sections, disks, journal bearings and unbalances. Property of oil film bearing is assumed to be that of the springs and dampers including those which give resistance to the change of inclination angles and velocities of inclination angles. These latter springs or dampers will be called "rotational" springs or dampers. These coefficients of cylindrical journal bearings are derived from the short bearing approximation. It is concluded that the property of rotational springs and dampers of oil film in the bearing cannot be neglected, and that the calculated results obtained by means of this method agree very well with most of the experimental results for the case of rotating shaft systems with two or three cylindrical journal bearings, that of an overhung shaft system, and that of a shaft system with distortion.

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A rigid rotor which is supported in externally pressurized gas jouranl bearings has resonant speeds. When the width of the bearing is small and the bearing clearance is large, the damping force of the bearing is very small at resonance. Then the rotor can not be run up ober the resonant speeds, unless an unbalance of the rotor is substantially removed. This paper, therefore, investigates the resonant characteristics of the gas bearing and the allowable unbalance of the rotor theoretically and experimentally in relation to the dimensional and operational conditions of the bearing. Theoretical results are found in good agreement with experimental ones for the radial clearances over 0.03mm. An available design chart with which the allowable unbalance of rotor could be known is presented.

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Moving particles on vibratory feeders take various modes of movement influenced by their own nature and also the surface of vibrating plate and the intensity of vibration. Meanwhile, the performance of the feeder is not effectively used, for the movements of the particle are not yet fully analyzed. The conveying velocity of the particle was studied in the previous report. In this report the authors analyze the characteristics of the modes of movement and energy which are needed to convey the particles. It will be very usuful for designing an effective feeder to refer to a chart which has been obtained through this analysis.

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In this paper, the author analysed the hunting of a truck when spring and friction are connected in series against truck turning. A describing function method is applied to the analysis of the truck hunting having a non-linearity, and the Frank-Koenig's method is used to search for a criterion of stability for polynomials with complex coefficients. And it is made clear that the turning stiffness of truck, the friction of side bearers, the supporting stiffness of axles, the slope of wheel treads and the creep coefficients between wheel and rail, have effects on the truck hunting. The results will be helpful for designing of cars. According to these results, the optimum value of the longitudinal supporting stiffness of axle and that of the lateral one to give the maximum speed of hunting are conerned with the magnitude of the turning amplitude of the bogie on the hunting. Besides, it is clear that to supplement both the turning stiffness and the irictional force has an effect to raise the hunting speed at large amplitude.

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The optimal control problems are extended to the case which includes plant parameters not only in the dynamics of plant and performance functional but also in the constraints of control input. The plant parameters are, for example, heat transfer surface area, horse power of motors, size of control valves, etc. The authors show that a wide variety of these problems can be treated more generally by applying non-classical calculus of variations than by using L. S. Pontryagin's Maximum Principle directly. The result is shown by several numerical examples.

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This paper presents the experimental results and the theoretical analysis of the optimalizing control of boiler efficiency, which is attained by the minimization of the total heat loss consisting of a sensible heat loss of exhaust gas and a heat loss due to CO. The experiment is carried out using a gas-fired boiler. The control method and the experimental apparatus are explained in brief. The experiment shows the optimalizing control is satisfactroy. On the basis of the above results, a mathematical model of the controlled system is constructed, where the input is the excess air ratio and the output the total heat loss. The analysis of the optimalizing control system is performed on the steady-state deviation from the optimum and the stability near the value, taking account of dynamic lags and unsymmetrical characteristics of the system. The contributions of each parameter of the system to these problems are clarified. Moreover, the effect of noise on the steady-state deviation is analysed by use of the probability density function obtained from the Fokker-Planck equation. The theoretical values are found to be in good agreement with the results obtained from the simulation on a digital computer.

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The laboratory equipment used in association with the pumping plant of the cooling-water supply for steam electric stations was made in order to give validity to the analysis of the previous paper. In this experiment, water column separations were caused by the negative pressure surge at two positions, just after the valve and at the middle of the conduit. In this paper are shown the effects of : the time of gate closure : normal head of the pump : and normal velocity on the first or the second pressure rise due to the rejoining, and the relationship between the time of the maximum pressure rise and the normal velocity. The theoretical results on the assumption that the boundary between the vapor void and the water column is a free surface agreed well with the test results over the range in which the second pressure rise is caused.

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Pipe flows of dilute aqueous polymer solution are studied experimentally. Measurement is made for two different pipe-sizes using 0.5 to 70 wppm solutions of polyethylene oxide of approximate molecular weight of 6×10⁶. The results show : 1) the friction coefficient is dependent, under a certain condition, on a heading tank water level and this phenomenon is not due to pressure : 2) the Toms effect is promoted at relatively small Reynolds number by decreasing the pipe diameter, increasing the concentration and /or the heading tank level : 3) an unusual pressure drop occurs upstream immediately before the orifice plate : and 4) interesting behavior of dye filaments in pipe flow is observed in the transition and turbulent flow regions.

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A correlation of the frictional characteristics of dilute polymer solutions is established from the measurements of the velocity profile. The difference of profile from Newtonian fluids is found in the buffer layer. Analysis is made with much attention paid to the difference of the buffer layer. It is assumed that the Toms effect occurs only in the region, in which the shear rate is larger than the critical shear rate γ^*. This critical shear rate γ^* is dependent on the concentration and the heading tank level under certain condition. Comparisons of the analytical results with the experimental results are made for two different pipe-sizes using solutions of 3.5 to 35 wppm. The results show : 1) Such parameters as the concentration, pipe diameter or heading tank water level have influence on the Toms effect only in unsaturated regions of the Toms effect ; and 2) the pipe size which will be used for the model test to predict the characteristics in a large pipe is limited by γ^*.

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An experimental study is presented of the flow and heat transfer of non-Newtonian fluids (CMC-, PVA-solution in water) past a flat plate, in order to obtain fundamental information about the behavior of non-Newtonian fluids in motion, especially in turbulent flow, and their characteristics of heat transfer. Velocity and temperature distributions of the fluids past a plate are measured in the range of the main velocities of 10∼70cm/sec and of the heat fluxes of 0.9∼1.8×10⁴kcal/hr·m². As the main velocity of the fluid is increased the velocity and temperature distributions and the heat transfer characteristics approach those of Newtonian fluids. The behavior of momentum and heat transfer of non-Newtonian fluids becomes the same as that of Newtonian fluids at the main velocity larger than the value at which the shape factor of velocity boundary layer is nearly equal to that of the fully turbulent flow of Newtonian fluids (&ap;1.3). These characteristics of flow and heat transfer can not be accounted for by the Reynolds number based on the power-law model.

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The second burnout, which was controlled by the liquid microlayer and dry area on the heating surface, was analyzed theoretically on the basis of bubble characteristics upon the electro-conducting glass submerged in stagnant water under the atmospheric pressure, and it was found that by suppressing the hydrodynamic instability the burnout heat flux could be increased considerably, but it encountered second limitation which could not be overcome by any ordinary method. The numerical value of the second burnout for water heated on horizontal surface under the atmospheric pressure was estimated to be about 10⁷kcal/m²hr which was almost ten times as large as the usual value. Discussion was also made on the transition boiling, and it was concluded that the so-called transition boiling with considerable superheat was really a film boiling because of no liquid film upon the heating surface.

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