An expression for the evaluation of fatigue life is proposed on the basis of the fatigue crack growth low, confirming the fact that tensile mean stress and tensile residual stress do not influence the fatigue crack initiation life but accelerate fatigue crack growth. By using this expression, bending S-N curves for base metals and laminated inhomogeneous plates (clad plates) are discussed. As a result, for the surface microcracks of base metal subjected to bending fatigue, the constant m of the fatigue crack growth law in which the growth rate is proportional to the mth power of stress level has been evaluated. The ratios of crack initiation to fatigue lives have also been estimated. In addition, especially in the laminated inhomogeneous plates, tensile mean stress has remarkably decreased fatigue lives, because fatigue crack growth constitutes a significant portion of fatigue lifetime.

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This paper is concerned with the periodic cracks in the neighborhood of the interface of two anisotropic bodies under longitudinal shear. The analysis is based on the singular point method. Replacing the cracks with continuous distributions of screw dislocations, we obtain a singular integral equation with Cauchy kernel. Numerical results for he stress intensity factors are plotted in termes of the geometrical parameters of crack arrangement and physical properties of the anisotropic bodies.

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In the linear couple-stress theory, three-dimensional elastic stress analysis of a plate is carried out in order to evaluate the thin-plate theory. The problem treated here is the axisymmetric bending of a clamped circular plate subjected to an annularly distributed load. For this analysis, use in made of the indirect fictitious-boundary integral method. From the results, the applicability of the thin-plate theory is investigated, and the effects of various parameters, such as the characteristic length and the ration of bending-twisting module, on the behaviour of a plate are made clear.

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In this paper, the deformations and stresses in a horizontal reservior supported along two generators and partially filled with a liquid are discussed, utilizing the fundamental differential equation of a thin cylindrical shell introduced by one of the authors. In order to give an accurate distribution of the stresses near the supports, the analysis is performed without assumptions of the distribution of the support reactions along generators. By investigating the relationship between the position of the supports along generators and the maximum stress caused in the reservoir, the optimum position of the supports is studied. Numerical results show that both deformations and stresses in the horizontal reservoir supported along two generators are smaller than whose no supports when the tank is long.

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Combine stress tests were performed on thin wall tubular specimens of SUS 304 stainless steel by varying the testing temperature in the range from room temperature to 600°C. Plastic stress-strain relations subsequent to prestrain at various temperatures were investigated experimentally under combined stress states. The experimental results were compared with the stress-strain relations at constant temperature. The influence of temperature variation on the stress-strain relations was examined. The stress-strain relations in combined stress states were evaluated by using the equi-plastic strain surfaces.

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Effects of grain and grain boundary strengths on the creep crack propagation at 700°C were investigated using an austenitic heat resisting steel, JIS SUH38. It is found that all creep cracks propagate through grain boundaries due to intergranular cracks and cavities formed by creep deformation, and that the empirical formula for creep crack propagation rate, d(2l)/dt=V^^·/θ (V^^·: notch opening displacement rate, θ: crack opening rate), which was previously proposed by the authors, is valid even for specimens having various levels of grain-and grain boundary strengths. From the results obtained, it is concluded that in order to increase the resistance to creep crack propagation the strength of grains should be increased in harmony with the strength of grain boundaries and that it is rather harmful to increase the resistance to creep crack propagation to strengthen excessively the grains alone, especially when the grain boundaries are weaker.

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A fracture toughness testing method for sheet specimens under Mode II loading is proposed and its validity is investigated. The method makes it possible to conduct Mode II testing in a tensile testing machine on the center cracked specimen and the side edge cracked specimen with the same geometry as that for Mode I testing. In order to evaluate fracture toughness, and expression of the Mode II stress intensity factor K_II under nonuniform shear stress is derived by the finite element analyses. The proposed method is applied to PMMA. The result shows that the angle of crack extension and the fracture toughness as obtained by the proposed method are in good agreement with those by Jones' testing method (compact shear specimen method).

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A new stability-instability criterion (named T_ε(T^*_ε) criterion) for crack growth which is applicable to small scale yielding cracks and also to large scale yielding cracks is proposed based on crack energy density concept. T_ε criterion is a criterion in which attention is paid to the rate of variation of crack energy density at a crack tip point of every moment, and T^*_ε criterion is another version of T_ε criterion and is a criterion in which attention is paid to the rate of variation of crack energy density at a fixed point which will be a new crack tip point after extension. The relations between T_ε(T^*_ε) criterion and other known criteria (criterion based on g-R-a curves; T_j, T_δ and T_W criteria) are also discussed and it is shown that the physical meanings of other criteria can be made clear and all criteria can be systematized based on the new criterion.

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This paper presents a solution of transient stress in the interior of an elastic half space under a uniform normal or tangential impulsive load acting on a semi-infinite strip and a rectangular region of its surface. First, the response of a half space loaded over a semi-infinite strip, finite in width is obtained by superimposing the solution which has been derived to the problem of one quarter. Subsequently, the solution to a half space loaded on a rectangular region is obtained by the superposition of response of the semi-infinite strip. The response of one quarter pressure may be derived by using double Fourier transforms on space, Laplace transform on time and Cagniard's method. The solution has singularities on the real axis of Fourier transform plane. We must take notice of the problem of Whether the singularities are inside the closed curve of Cagniard's path in the super position or not.

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In designing bolted joints, it is important to examine the tightening effect and to estimate the force ratio, that is the ratio of an increment of bolt axial force to a load. Up to now, in order to improve the tightening effect, raised faces of interface have been used. But the use of these interfaces depends on experience and the theoretical grounds are not made clear. In this paper, in the case of circular flanges having raised faces the tightening effect is analyzed using a three-dimensional theory of elasticity and point matching method. Then the force ratio 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. The bending moment is also analyzed. For verification experiments are carried out. Analytical results are in a fairly good agreement with experimental ones.

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An entirely new theoretical solution based on Wu's approach to prediction of compressible three-dimensional flows in turbomachines is described. This solution, due to its exactness in theories, makes it easy to consider secondary flow effects on a mean flow and can be applied to more complicated flows such as three-dimensional flows in twisted passages with inlet distortion. Form a practical point view a mass-averaged, pitch-averaged meridional through-flow is assumed. Basic relations for the flows on two different kinds of relative stream surfaces are reduced to nonlinear integral equations. For the uniqueness and nonlinearity of their solutions use is made of successive iteration which fully depends on pseudo-analytical theories and conformal mappings to transform twisted blade-to blade surfaces caused by secondary flow effects onto surfaces of revolution. Numerical methods adopted are easy to accomplish in the whole flow regions.

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This paper theoretically and experimentally investigates pressure distributions around and airfoil places in a periodically fluctuating airflow. The calculated results agree fairly well with experimental results, because of the airfoil thickness being taken into account under the assumption of a thin airfoil. The following facts are, furthermore, found out: (1) The time averaged pressure disctributions consist of quasi-steady components, independent of the reduced frequency, and nearly equal to those for steady flow conditions in the range of small fluctuating amplitudes. (2) The amplitude of the first harmonic component of the unsteady pressures is in proportion to that of the velocity fluctuation and comes under the influence of the virtual mass with the growth of the reduced frequency. (3) The phase of pressure fluctuation leads to that of velocity wave and is independent of fluctuating amplitudes. The phase difference becomes larger in the accelerating region and smaller in the decelerating region in the chordwise direction.

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The effects of time-averaged Reynolds number, pulsation frequency and velocity amplitude ratio on the structure of turbulence in a pulsatile turbulent pipe flow were experimentally investigated. A turbulence model including a lag in response-time was presented and its applicability was examined from comparison with experimental results. The radial distribution of time-averaged component of the root mean square value of turbulence agrees well with that of steady pipe flow. The amplitude ratio and phase difference of oscillatory component were defined by choosing the cross-sectional mean velocity as a reference velocity. They are independent of velocity amplitude ration but affected by pulsation frequency and time-averaged Reynolds number. The present turbulence model is applicable to the whole cross-section of a pie except for the region very close to the wall.

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The flows behind the runner exit of a high specific speed Francis turbine were studied by using a probe for unsteady water flow. A 5-hole pitot probe was used along with pressure transducers, set near the holes, to measure the flows. The mean velocity and total head distributions behind the runner exit between one pitch of the runner vanes from the crown to the band, were examined under five operating conditions. Especially, flows near the vane wake and flows when a reverse flow occurred on the suction surface were examined. And, some comparisons were made with flow pattern obtained by the oil film method.

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The flow past a circular cylinder undergoing transverse oscillation in a uniform flow is investigated by means of flow visualization technique. The experimental conditions. are R_e=1100, A/D=0.2, and S/c=fcD/U=0.2, where R_e is the Reynolds number based on the diameter D of the cylinder, A and f_c the maximum amplitude and frequency of the oscillation of the cylinder, respectively, and U the speed of the uniform flow. Oscillations of the separation points and the stagnation point, and the rate of vorticity fluxes through the section near the separation points were examined during cycle. The phenomenon that the vortex sheds periodically in the same frequency as the cylinder was found to be caused by a significant change in the vorticity distribution in the vortex region, which was induced by vorticity feeding from the third separation point found behind two ordinary separation points.

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Fully developed incompressible turbulent flow in a two-dimensional channel with turbulence promoters has been simulated numerically. A k-ε model, which consists of two model transport equations for turbulence energy and energy dissipation rate besides the mean velocity equation, is applied. The Reynolds number is set at 1.1×10⁴ and only 4000 grid points are distributed. A detailed comparison between the calculated results by k-ε model and large eddy simulation is made. The distributions of mean velocities, turbulence energies and turbulence shear stresses by both methods are in good agreement near the upper wall without turbulence promoter, but quite different behind the turbulence promoters. The calculated results are also compared with the experimental results. The large eddy simulation method can describe these flow fields well. Calculations were carried out on the HITAC M 200/280H system computer of University of Tokyo.

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Fully developed incompressible turbulent flow in two-dimensional channel with turbulence promoters has been predicted numerically by large eddy simulation. Parameter C in Smagorinsky model can be assumed constant generally in the range of high Reynolds numbers. In this paper, C is varied with SGS Reynolds number in low Reynolds number region and SGS eddy diffusivity near the solid boundary is considered as a function of the distance from the boundary, the velocity gradient and the molecular viscosity. These improvements of SGS eddy viscosity model and the boundary condition of SGS eddy diffusivity have little effect on the mean velocity distribution, but have a significant effect on the distributions of turbulences and turbulent shear stresses. Computed streaklines and Strouhal number of vortex shedding behind the turbulence promoter are compared with visual experiments. The Reynolds number in computation is set at 1.1×10⁴ and 9000 grid points are distributed.

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In order to express the particle behaviour in a pipe flow, the vertical-and longitudinal-probability density functions of particles should be adopted. The method using those functions to express the particle behaviour in a pipe flow was already adopted by Binnie, Barnard and Sharp. They supposed that the particle movements were Markov's process and that suspension and dispersion of particles were caused by turbulent diffusion of a pipe flow. The authors have analysed and tested the particle movements on the basis of assumption that suspension and dispersion of particles have been caused mainly by lift of shear-flow and particle saltation at the pipe wall, especially with coarse particles, rather than by a turbulent diffusion of the pipe flow. The test apparatus has a 22 m closed conduit pipe of 52 mm diameter with a transparent test section. The particles used are 6 mm diameter nylon spheres.

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Although negentropy had been defined as an entropy with an inverse sign, it was not appropriate for some purposed. and so the author previously proposed a definition by the difference between entropies. This definition is based on an isolated system, and in order to apply the concept of negentropy to a system under the general situation, the definition must be changed again. The present report proposes a definition by Kullback-Leibler information, and shows that an extended negentropy according to the new definition is positive and represents the nonequilibrium and the potential of work, as was shown with the case of negentropy before extension. Further, it is shown that exergy is derived form the above definition by Kullback-Leibler information making use of the statistical mechanics. The extended negentropy contains as a part of itself the concept before extension, which is based on an isolated system.

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Measurements of the vapor-liquid coexistence curve in the critical region for Refrigerant 114 (C₄Cl₂F₄) were made by visual observation of the disappearance of a meniscus at the vapor-liquid interface within an optical cell. Twenty-three saturated densities between 410 K and the critical temperature were obtained in the density range 290 to 894 kg/m³. The experimental uncertainties of temperature and density were estimated within ±15 mK and ±0.5%, respectively. On the basis of these results, the critical temperature T_C and the critical density p_C for R 114 were determined to be 418.78 K and 576 kg/m³, respectively, in consideration of the disappearing meniscus level as well as the intensity of the critical opalescence. The critical pressure P_C for R 114 was calculated to be 3.252 MPa by the available vapor-pressure correlation with the present value of T_C. In addition, the critical exponent β and the law of the rectilinear diameter near the critical point were discussed.

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A new method of experimental identification is proposed in which a stable solution is always obtained for the real numerical calculation. Identification means the construction of a mathematical model which explains the dynamic characteristics of a machine or a mechanical structure. There are two ways in identification, namely theoretical and experimental ones. And there are two types of the techniques for the experimental identification. One is the type called 'Curve fit' which can identify the model prameter. It has been studied by many reseachers. The other is the type which identifies 'Characteristic matrices'. But, there are not many published reports about these techniques which will be useful. In this report, a method of experimental identification of the characteristic matrices is explained, and an example of numerical simulation is given.

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The purpose of this work is how to design the variable oil damper whose damping is adjustable by varying the area of orifice in the piston. In this report, we deal with an oil camper having a few cylindrical orifices in order to study the fundamental characteristics of the variable oil damper. Two new method for analyze the damper are proposed. The first method of analysis is based on the assumption that the diameter of the piston is equal to the inner diameter of the cylinder but no friction occurs between the contact surfaces. However the assumption is far from being satisfactory in the actual oil damper. The second can be applied to the oil damper whose piston is smaller than the cylinder (in other words, the oil flows through the annular clearance and the cylindrical orifices). In these analyses, the flow through the channels is assumed to be incompressible, unsteady and laminar. Consequently, it is made clear that the magnitude of the damping in the latter type of oil damper is heavily subject to variation of the frequency of the oscillating piston.

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A two-dimensional horizontal seismic experiment with single axis and simultaneous two-axes excitations was performed to obtain the core seismic design data on the block-type high temperature gas-cooled reactor. Effects of excitation directions and core side support stiffness on characteristics of core displacements and reaction forces of support were revealed. The values of the side reaction forces are the largest in the excitation of flat-to flat of hexagonal block. Preload from the core periphery to the core center are effective to decrease core displacements and side reaction forces.

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A self-excited oscillation of a hollow rotating shaft partially filled with a liquid is investigated both theoretically and experimentally. In this report, the theoretical explanation about the mechanism of a self-excited oscillation is give, the validity of which is confirmed by experiments using a model with one degree of freedom. The results show that the fluid force acting on the wall of a hollow rotating shaft consists of two components, one of which is out of phase by 90 degrees with the displacement of the shaft and that this component makes the field of rotating resistance with resonant characteristics which causes the self-excited oscillation.

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The torsional vibration analysis by the Foreier series method has been carried out of rotors coupled by a gear coupling to determine the steady-state response considering the backlash of gear, the damping by the lubricant, the shaft camping and the forcing torque magnitude. And then the diagrams of the steady-state response curves and the maximum response factors have been presented. It is clear through the study that the response factor of torque is larger than that of angular displacement when the teeth separation takes place and the larger the backlash of gear is, the smaller the maximum response factor is when the contact of teeth arises tat the back side of teeth.

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In the case of a common rolling contact fatigue testing machine, the roller is rotated at uniform velocity. In this research the roller was rotated at non-uniform velocity by applying an eccentric gear mechanism to the machine in order to bring about a contact condition of rollers close to that of gears. Specific sliding of the roller was so adjusted as to change continuously from 0 % to -125 % during one rotation. Under this condition the rolling contact fatigue tests were performed using thermally refined and induction-hardened steel rollers. The roughness change of the roller and the surface failure were discussed in relation to the specific sliding.

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In this study a power transmission spur gear is recommended as a profile corrected spur gear. Supposing it is allowable that the given value deviates about ten-odd percent from actual acceleration, it is synthesized how an accumulative pitch error influences the rotational vibration of a profile corrected spur gear, using the simulator developed by authors. The influence degrees are revealed in an influence chart in which they are determined in relation to the rotational speed and the contact ratio. The permitted amounts of errors for each kind of error are shown in a table when the permissive vibration of a pair is decided. The classification of errors in the dynamic performance has been made clear.

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This paper presents a study on the root fillet, web and rib stresses and tooth deflections of thin-rimmed spur gears with different web thicknesses and arrangements by the three-dimensional finite element method (FEM). The effects of web thickness and rib on web and rib stresses of single web gears with ribs were investigated by carrying out web and rib stress analyses by FEM and a static bending test. The effects of web thickness, rib and maldistribution of loads along face width on root stress distributions and tooth deflections were clarifies. Furthermore the effects of web distance and maldistribution of loads along face width on root stress distributions of double web gears were investigated.

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It is well known that flows of Newtonian fluids in porous matrices are governed by Darcy's low. However the law for non-Newtonian fluids has not been established. In this paper, a modified Darcy's law for non-Newtonian fluids such as pseudo-plastic fluids and a Bingham solid is derived by applying the dimensional analysis to mathematical models of the fluids assuming a flow in the porous matrices as one in both thin films and capillaries.

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Today, we have quite a few theories about the optimal design of a distributed control system organized by several small computers. The aim of this paper is to discuss a general theory of distributed control system, and is also to provide some criteria to computer system designers. Firstly, the author treats a cost model having a hierarchical structure. The model, which depends on both cost of components and size of the total system space, is optimized and its structure is identified. Secondly, after the system structure is determined, a problem of quantitative optimization is discussed. Optimal numbers of computers needed in the system are calculated from two parameters that is, size of the total system space and a cost of the smallest computer available each time. the second parameter is thought to be strongly dependent upon the current level of technology. Finally, the results or knowledge of this paper have been applied to an actual control system. Although the model used in this paper were the most simple one, the rules led from these models proved to be sufficiently applicable to actual, much complicated systems.

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