The influences of specimen thickness, cyclic frequency and cathodic protection on the corrosion fatigue crack growth of a high-tension steel HT80 have been discussed in terms of ΔK_eff, and the accelerating mechanism of crack growth rate was made clear. In the relation between crack growth rate and ΔK, environmental and cathodic protection effects were not clearly observed, because the reduction of growth rates due to the wedge effect cancelled the acceleration due to hydrogen embrittlement. When the wedge effect was eliminated by using ΔK_eff, environmental effect, frequency effect and cathodic protection effect were clearly observed. Though there were observed no frequency effects at a low ΔK_eff, the acceleration of growth rates continued to a higher ΔK_eff at a lower frequency. The dominating factor below (ΔK_eff)th in corrosion fatigue crack growth in HT80 was stress-assisted dissolution and the one above (ΔK_eff)th was hydrogen embrittlement, and cathodic protection became effective below (ΔK_eff)th.

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Fatigue crack growth behaviors were investigated under a simple impact stress pattern by using center-notched 0.1%C aluminum killed carbon steel plate specimens, and results obtained were discussed in comparison with those obtained under non impact fatigue. At first, the fact that the crack growth rate in impact fatigue was higher than that in non impact fatigue and that there was a stress range dependence of impact fatigue crack growth rate demonstrated in the previous study done under somewhat complex impact stress pattern confirmed also in this study. Furthermore, the stress range dependence as mentioned above for impact fatigue was explained reasonably from the viewpoint of crack closure behavior, and crack tip plastic zone characteristics under impact fatigue loading were discussed tentatively based on the variation trend of effective stress range, U, or crack opening stress intensity factor, K_op, during crack growth process.

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The authors proposed in this paper a new method using X-ray diffraction to measure the distributions of three principal residual stresses in a hollow cylinder. The procedure involves the uniform removal of successive thin layers from an inner or outer surface of a hollow cylinder and surface stress measurements by X-ray on the inner and outer surfaces of it. Residual stress distributions are calculated from both surface stresses. The new method has a special feature of simple formulas. The authors give an example of measurement by applying the new method to a heat treated hollow cylinder (STPT 38).

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The torsion problem of a cylindrical rod, which is composed of semi-infinite solid and hollow cylinders bonded completely at each end, is studied. A stress singularity appears at the corner of the connected rod. The problem is solved by the method of series expansion in consideration of the stress singularity at the corner. The distributions of the displacements and the stresses for various ratios of the radii and for various ratios of the shear moduli are obtained.

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The present paper is concerned with the propagation of elastic waves in a finite length bar with a variable cross section subjected to an arbitrary longitudinal impact loading. The solution is obtained by the application of the Laplace transform. The results of this analysis can be applied only to a thin bar with small changes of area and to waves which are long compared to the lateral dimensions of the bar. Numerical calculations are carried out for the case of truncated cones, and strain wave histories at various stations along the bar are shown for two kinds of impact loading. The corresponding experiments are also performed for two different truncated cones. The theoretical predictions are found to be in good agreement with the experimental results.

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Stress state in an elastic hollow cylinder reinforced with a rigid ring is considered within the framework of the three dimensional elasticity theory. Perfect bond between the cylinder and the ring is assumed and satisfaction of the mixed boundary conditions through the method of Fourier transforms then leads to two pairs of dual integral equations which are reduced to an infinite set of algebraic equations. Comparing the present solutions with those of a frictionless bonded contact problem, authors examined the effects of the presence of friction on the stress distributions.

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The stress distribution in a compact specimen for fracture testing is numerically computed by the analytic method. The condition of free surface on the outer boundary in the state embedded in an infinite plate is expressed by a discrete arrangement of edge dislocations, and that on the crack plane is expressed by point forces acting on the plane of finite crack in an infinite plate. The dislocation distribution is obtained through a successive approximation developed empirically. The computed results are shown by contour maps of stresses, and by distributions of dislocations, surface stresses, and displacements on the external boundary. The stress intensity factor, the stress on the back face, and the displacement at the crack entrance are given as functions of crack length.

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Contact stresses between two rectangular plates and a sandwiched solid-metal flat gasket are studied to discuss the sealing behavior of the gasket. Assuming that the gasket is an elastic body, the two dimensional theory of elasticity is used to analyse the contact stresses and the deformations in three laminated dissimilar rectangular plates whose both sides are compressed with locally distributed loads. By neglecting shearing stresses on the contact surfaces, an exact solution satisfying the remaining boundary conditions is obtained. Numerical calculations are carried out for various rigidities and thicknesses of the rectangular plates under various loading conditions. In order to examine the results of the theorectical analysis, the contact stress is measured experimentally by using pressure-sensitive pins attached to a rectangular plate. It is confirmed that the theorectical results agree well with the experimental ones except the vicinity of the loaded area.

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Gaskets have been usually used in bolted joints in mechanical structures such as pressure vessels and pipe flanged connections. But a design of bolted joints with gaskets almost depends on experience and the sealing performance is not theoretically clarified. In this paper, a bolted joint in which a metal flat gasket is interposed between two hollow cylinders is studied. At first, a contact stress, which governs the sealing performance is analyzed as a three body contact problem using the three-dimensional theory of elasticity. Effects of the stiffness and the thickness of gaskets on the sealing performance are shown by numerical analyses. Next, the force ratio of bolted joints with gaskets, that is a ratio of an increment of bolt axial force to an external load, is analyzed. Corresponding to this analysis, experiments are carried out. Analytical results fairly coincide with experimental ones.

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Elastic-plastic stress states on three-point bending fracture toughness specimens are analyzed by the three-dimensional finite element method. Effect of side grooves on the stress state around the crack tip is discussed on specimens about 30 % side-grooved in U, V, and slit types comparing with a regular flat specimen. Side grooves restrict the plane stress type deformation, which is commonly observed near the side face of a flat specimen. Consequently, over 80-90 % of the thickness of the side-grooved specimens, practically even distributions of the stress intensity factors, plastic zone geometries, crack tip dilatant stresses, and three-dimensional J integrals are achieved.

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Bifurcation phenomenon of an elastic-plastic thin-walled tube which is subjected to internal pressure and axial tension is analysed as a variational problem formulated by Hill's sufficient condition for the uniqueness of solution. Proportional loading is assumed for the stress state in uniformly deformed pre-bifurcation state and a generalized Prandtl-Reuss equation is used as a constitutive equation for the elastic-plastic material. A characteristic equation which determines the bifurcation stress is derived and dependences of the bifurcation point for axisymmetric and non-symmetric modes of various orders on the stress ratio are discussed in some numerical examples.

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This paper reports a series of experimental studies on the dynamic behavior of the gas-liquid interface. These studies are concerned with the liquid sloshing phenomena induced by vertical vibration of a cylindrical container containing a liquid. The disappearance of the harmonic surface wave motion, the formation of 1/2-subharmonic motion, the mechanism of the surface disintegration had the behavior of spray-excited low frequency waves are investigated. The effect of the liquid height in the container on the surface disintegration was a decrease in the threshold excitation amplitude for the disintegration with an increase in liquid height. Splay-excited low frequency waves were observed over a wide range of excitation frequencies. It was also found that a violent surface agitation might occur due to a bubble cluster formed by the air injection, although the excitation acceleration was relatively low.

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The interrelationship was experimentally studied between the performance of a centrifugal pump with an air-water two-phase inlet flow and the distribution of void fractions in the impeller. Void fraction was measured by the electric resistivity probe method at twenty-four locations in the impeller, i.e., eight needle tip void probes adjustable in their positions from the boss to the shroud-side were introduced. The distribution of void fractions is closely related with the pump performance, especially with the transition process to a 'breakdown', under which the performance drastically degrades. The slip ratio estimated from the information on void fraction decreases to less than unity with increasing volumetric inlet quality, which implies not only an increase of the amount of air dwelling near the inlet of the impeller, but also is an indication of breakdown. A possibility is suggested that parameters linked with void fraction will be effective as a quantitative tool for analyzing the pump performance.

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The effect of radiation on forced convective film boiling heat transfer from a vertical plane to a subcooled liquid is analyzed by the integral method of boundary-layer. Numerical solutions are obtained for water under the atmospheric pressure. The effect of radiation is discussed using some parameters used in the conventional analyses of film boiling and a new parameter for radiative contribution, and the method which Bromley proposed to estimate the radiation effect on total heat transfer is examined.

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Unburned ethanol, formaldehyde, acetaldehyde, hydrocarbons, NO and NO₂ concentrations along the exhaust tube of an ethanol fueled single cylinder S.I. engine were measured for various equivalence ratios and ignition timings. Experiments showed that periodical changes in concentrations of each species in the exhaust tube corresponded to the engine stroke cycle, and to a distribution of the species in the cylinder. Moreover, the changes were overlapped with the resulting oxidation of unburned ethanol. Formaldehyde and acetaldehyde were formed at the same time with the oxidation during the exhaust process. Using a temperature controlled reactor tube, characteristics of aldehyde formation were verified. It is found that aldehyde accumulation in exhaust system occurs at a temperature around 80 K.

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A numerical analysis of the motion of a single capsule through horizontal pipeline is made by taking account of air leakage through the clearance between the pipe wall and the capsule. The boundary condition at the inlet and outlet of pipeline is the pressure being constant. Compared with an analysis ignoring the air leakage, the prediction of the time history of pressure at the pipeline and of the mean velocity of capsule over the pipeline is improved.

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Dynamic analysis of a very large group of rods in a fluid is of great importance, particularly in the seismic design of nuclear reactor cores. A practical approximate method of analysis of a group of rods in a fluid is presented in this paper. A simplified model of the rod/fluid system - which will be refered to as a single-mass-point model - is presented and its applicability to practice is verified through theoritical and experimental analysis.

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Dynamic analysis of a very large group of rods in a fluid is of great importance, particularly in the seismic design of nuclear reactor cores. A simplified model of the system was presented in the previous paper, and proved to be valid for a cluster of rods whose elements were arranged to form a circle as a whole cross-sectionary. In this paper a group of rods is treated as if it were a continuous body as a whole. A more generalized and widely applicable model of the rod/fluid system is presented, and its validity for practical use is shown through experiment.

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In this paper, we analyze, by using the thin shell theory, the axisymmetric vibrations of thin barrel-like shells of revolution which have been used for pressure vessels of reactor, various chemical devices and others. The equations of motion and boundary conditions are determined from the sationary conditions of the Lagrangian of vibrations during a period of the shell of revolution. The equations of motion are solved exactly by a series solution. As numerical examples, the frequencies and the mode shapes are obtained for symmetric shells with both ends clamped, simply supported and ones with one end clamped and the other simply supported. And the characteristics of the frequencies and the mode shapes are clarified.

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In this paper, by an improved thick shell theory, we analyze the axisymmetric vibrations of barrel-like shells of revolution, which have been much used in various chemical plants, atomic plants and so on. We solve the equations of vibration exactly by a series solution. As numerical examples, we obtain natural frequencies and mode shapes of symmetric shells of revolution with both ends clamped and with both ends simply supported to clarify their characteristics. The results by the present theory are compared the ones by the thin shell theory and the effects of the shear deformation and the rotatory inertia upon the natural frequencies and the mode shapes are clarified.

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In this paper, as the first step to get a key to clarification of the mechanism of scoring in gear pairs, effect of surface roughness on the seizure limit of non-additive gear oil was examined by two-cylinder tests. As the result, the following conclusions are deduced : (1) In the lower range of specific slidings and the slower range of sliding velocities where seizure occurs in boundary lubrication, the seizure limit is not affected by surface roughness or rather it increases as surface roughness increases. (2) In the higher range of specific slidings where seizure tends to occur in mixed or full elastohydrodynamic lubrication regardless of surfaced roughness, the seizure limit decreases as surface roughness increases. (3) In order to increase the seizure limit in the higher range of specific slidings and the faster range of sliding velocities where seizure occurs easily and to decrease the frictional power loss, finishing the surface roughness fine is an effective means.

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A root stress analysis by means of the two-dimensional finite element method (FEM) and a bending fatigue test for planet and idle gears were carried out. The effects of rim thickness and internal pressure due to a press-fitted bush on the root stresses and the position of the fatigue crack initiation were investigated. In thin-rimed planet and idle gears considerably large stresses occur near the bottom of every unloaded tooth as well as two loaded teeth. The root stresses increase at the tensile side and decrease at the compressive side with a decreasing rim thickness. The fatigue crack of a planet or an idle gear with a press-fitted bush may occur near the tooth bottom due to the effect of residual tensile stress produced by press-fitting.

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The kinds of materials have different effects on gear distortions caused by hardening, even if heat-treatments of the raw material and gear are the same. In this experiment, the test gears which were made of steel materials containing different amounts of some chemical compositions in two kinds of steel were case-hardened. And from the measurements of gear distortions, namely, change of tip cylinder diameter and of face width, it became clear that there exists a relationship between ideal critical diameter of the test material, and the gear distortions. Also grain sizes were changed through annealing process. Originally the hardenability is a criterion for the thickness of hardened layer. It is confirmed from this experiment that the hardenability is related with gear distortions caused by hardening.

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This paper deals with tooth form accuracy of roll-finished involute helical gears with addendum modification. The calculated and measured results indicate that a difference in flexural rigidity between the die-wheel tooth and the work-gear tooth induces a pressure angle error on the roll-finished tooth form : when the tooth rigidity of die-wheel is too large, a positive pressure angle error is induced ; on the contrary, when the tooth rigidity of die-wheel is too small, a negative pressure angle error is induced. It is concluded, therefore, that the difference in flexural rigidity between the die-wheel tooth and the work-gear tooth must be kept minimum, in order to improve the tooth form quality of profile shifted helical gears made by roll-finishing.

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A method of roll-finishing the involute helical gears in a crossed axes system is described, and the prospect of this system has been studied experimentally. The results indicate that the crossed axes system is capable of roll-finishing the involute helical gears under loading lower than that for the ordinary parallel axes system, the tooth form accuracy is therefore improved to a little greater extent. Furthermore, it is found that with this system the lead accuracy is also improved markedly, that is, a dull-rounding down at both tooth flank side ends is hardly observed.

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A dimensional synthesis of three types of planar six-link adjustable function generators is carried out in succession to the path generators in part 1. The relations between adjustable parameters and input-output displacement curves are classified, and four characters are suggested in order to deal with the relations quantitatively. Then the kinematic conditions satisfying each character above are obtained, and a systematic synthesis of adjustable mechanisms has become possible.

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This paper discusses analytically on the condition for modification of the work roundness error and improvement to the value of about 0.1 μm by a simple conventional cylindrical lapping method, considering that it has been very difficult to machine a cylindrical workpiece at its top position supported with two free rotating rollers. The analysis points out that there is a suitable machining condition for modification of roundness error by which the effect of the random and periodic deflections of the supporting roller surface and its rotating axis on the work roundness can be decreased. The paper describes the analytical result and a few experiments carried out for confirmation yielding an out-of-roundness value of 0.2 μm.

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This paper presents an algorithm to analyze the calculation of a large scale GERT network by means of the method of graph theory. The detection of path is made by applying latin square multiplication and the detection of circuit and loop is made by applying the Boolean matrix, reachability matrix and strongly connected matrix. A method is shown to obtain the determinant of network Δ(s) by the matrix L of touching circuit and loop as well as latin multiplication, and further to obtain Δ_k(s) by the calculated HP_j of the matrix of touching path, circuit and loop by using the coefficient of (l - γ_ij). A numerical investigation demonstrates the applicability of the described method.

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The dynamic characteristics of the annular pressure seal employed in pumps have been theoretically deduced with consideration for the effect of eccentricity of rotor. Turbulent flow is assumed in both circumferential and axial directions, and effect of inertia of the fluid is considered. An equation for the pressure increment due to journal translation is derived in terms of the effective viscosities, based on the rotational and axial flow Reynolds numbers. Comparisons are made between the stiffness, damping and add mass coefficients derived herein and the previousely published theoretical and experimental results without eccentricity. It is shown that the numerically obtained value is in reasonable agreement with experiment.

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