Cold-worked copper and α-brass, which have wavy and planar slip modes, respectively, were low cycle fatigued, and the relation between the fatigue life and the cyclic softening behavior was discussed in terms of the slip mode. The amount of cyclic softening is much larger in copper than in α-brass, and the fracture ductility in the latter is much more influenced than in the former by the cold-work. The cyclic softening behavior and the cold-work dependent fracture ductility might be interpreted by a common factor of the relative difficulty in the cross slip of the screw dislocation. The decrease in the low cycle fatigue life caused by the cold-work is closely related with the above cyclic softening characteristic and the fracture ductility. On the other hand, the microscopic configuration of slip line is also important for understanding the cold-work dependent fatigue life.

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The problem of determining the shape of an elastic cantilever with a cross section varied stepwise is discussed. The criterion is the minimization of the strain energy of the cantilever under the constraints of given length and volume. The beam is subject to the load distributing proportionally to the power of the distance from the free end. The length of each beam segment as well as the size of its cross section is taken into consideration as the design variable. The dynamic programming procedure is used to obtain a recursive equation which is modified into an appropriate non-dimensional one to decide optimal values independently of the magnitudes of constraints (or, total volume and length) at every decision stage. Beams with a rectangular cross section of a constant width and beams with a circular cross section are treated in numerical examples. Moreover, from a viewpoint of optimization through discretization the results are compared with the analytically optimized beams with a continuously variable cross section.

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Experimental investigations of rotating cascades operating under circumferential inlet-distortion flows are described. Systematic measurements of flow fields near a rotating cascade are made and attenuation of the distorted flows is evaluated quantitatively. Then, transfer of distorted velocity profiles through a cascade and unsteady responses of flow angles behind a cascade are calculated with an aid of a linear theory. Circumferential inlet-distortions are attenuated by a cascade at both the design and the off-design points, and the attenuation ratios diminish with an increase in the number of distortions and with a decrease in flow rates, but the rotational speed has a little influence on the attenuation effect. Attenuation ratios at the design and the off-design points under various operational parameters can be represented uniquely by the use of a reduced frequency. Transfer of distorted velocity profiles can be obtained from the actuator disk model and unsteady changes in relative outlet flow angles agree relatively well with theoretical ones ca1cu1ated from unsteady cascade theory on thin airfoils.

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Unsteady flow fields behind an isolated airfoil and a cascade oscillating in pitch about their mid-chords are determined from a computer aided measurement. Behavior of shedding vortices is investigated and validity of the Kutta condition for a pitching airfoil is examined. Then, the response of a boundary layer on an airfoil under both stalled and unstalled conditions is studied by the wake analysis. The Kutta condition holds quite strictly for an airfoil pitching at reduced frequencies up to 0.45. Shedding vortices are conveyed downstream on a wake center in the form of a quite small-sized vortex or a vortex sheet. As long as a flow separation on an airfoil does not occur influence of pitching motion on a boundary layer is very small. When a separation occurs, however, the boundary layer is affected severely by pitching motion and a dynamic stall appears remarkably with an increase in a reduced frequency. An unsteady response of a boundary layer under a dynamic stall condition can be represented relatively well by the dead lag model.

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The effect of a free-stream turbulence of high intensity on the flow past a rigid circular cylinder was experimentally studied in a Reynolds-number range 7.9×10³∼5.4×l0⁴. Square-meshed grids were used to produce homogeneous turbulent-flow fields. The intensity and scale of a turbulent flow in which the cylinder was immersed were varied by positioning the cylinder at various locations downstream of the grid. Measurements were made of the time-averaged drag coefficient, Strouhal number of the vortex shedding, spanwise correlation length and length of the vortex formation region in the wake of the cylinder. These properties of flow around the cylinder were found to be considerably different from those measured in a smooth flow.

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Firstly the freestream Mach number for subsonic liquid flow is defined as being smaller than the lower critical Mach number in which the critical condition can be found on the cavity streamline The governing equation of elliptic type for velocity potential is solved by local linearization technique and then the corresponding relation are derived between subsonic and incompressible liquid f1ows. Compressibi1ity effects are minutely discussed on the cavity characteristics of symmetrical wedge through the Mach number range and also comparisons are made with the former linearized analysis.

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Some notable features of normal and oblique shock waves of supersonic liquid flow are clarified and also the close relations of cavity streamline to the flow turning by expansion wave are pointed out. And then after defining the Mach number range for transonic and supersonic liquid flow by using the critical Mach number, the governing equations of parabolic and hyperbolic types for velocity potential are analytically solved by local linearization technique. Compressibility effects on the cavity characteristics of symmetrical wedge are clarified through the Mach number range . Comparisons are also made with the results from oblique shock relations.

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One of the important factors affecting the diffuser performance is the shape of the inlet velocity profile. In this report, the results of measurements on a conical diffuser having various asymmetric uniform shear inlet flows are presented. Velocity distributions and pressure distributions were measured for four cone angles of diffuser and four degrees of shear of inlet flow for each diffuser. The main results obtained are as follows. Diffuser performance is decreased with an increased shear of inlet flow, and the reduction rate is maximum for a diffuser which has nearly an optimum shape for a uniform inlet flow without shear. With an increase of the inlet shear, a fixed large back-flow forms on the wall of the lower velocity side in the diffuser. This results in a decrease in the pressure recovery in the diffuser and also causes an increase in the outlet energy loss. A diagram indicating an equivalent cone angle of diffuser corresponding to that of one which has an inlet uniform flow is produced for the inlet shear.

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Viscous flow induced in a half space by two sources with different strengths on a wall is studied theoretically using Stokes' approximation. It is assumed that the flow is two-dimensional and incompressible. The forms of the separating streamline which divides the fluid coming out of one source from that of other source are obtained. That streamline becomes a closed curve in the case of the flow according to the source and sink. The area of the space bounded by this closed curve is very important in connection with fluid mixing and ventilation. That area in case of a viscous flow is larger than that of a potential flow.

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In axisymmetrical jets of KC1 solution emerging into otherwise quiescent water, samples were sucked through capillaries and the concentration of material (KC1) contained in the nozzle fluid was determined from the electric conductivuty of the sample. From the experimental results using four capillaries with different diameters, it was found that the concentration or a sample is equal to that of the measuring point without disturbance only when the sampling velocity is equal to that at the measuring point. Dimensional analysis is made to investigate the error in measured concentration (e.g., sample concentration) and an experimental formula is proposed to estimate the error in the sampling method applied to concentration measurements in a shear flow with a concentration gradient.

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Flow characteristics of a two-dimensional air jet issuing from a nozzle of 5mm in width which is parallel to a horizontal wall with the vertical distance L have been experimentally and analytically investigated. The adjacent wall jet consists of three regions in the flow direction and the velocity profiles in each region are approximately composed of a free jet profile and a one-fifteenth power law profile. The flow characteristics are independent of Re (=u_o·L/ν=2.3×lO⁴∼4.0×1O⁴, u_o ; maximum of u at the upper end of the wall, ν ; the kinematic viscosity) and are of similarity. The bend of the main stream line, that is, the locus of the maximum velocities, was analyzed by using the momentum equations and the energy equations, The results agreed with the experimental results.

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This paper presents the PVT-surface of water for temperatures from 273 to 1123 K up to a maximum pressure of 1 GPa given as a set of selected values. These selected values are derived from 6780 measured values by applying the method of error analysis previously proposed by the authors. In order to confirm the reliability of the method applied, the confidence intervals of the selected values as well as a result of the error analysis with respect to each set of measured values are closely examined. The validity of the selected values and their confidence intervals obtained as a result of this work are also confirmed both by examining the behavior of the proposed PVT-surface and comparing the selected values with the measured values.

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Two types of unstable vibrations occur because of the asymmetry in the shaft stiffness. To understand the mechanism for the occurrence of these unstable vibrations, the authors clarify the conditions necessary for their occurrence. A torque applied to a shaft end tends to increase the whirling amplitudes of the shaft. The conditions for instability of free vibration thus obtained are ascertained by an analog computer. If the higher order of small quantities, that is, the rotating asymmetry of shaft stiffness and inequality of pedestal stiffness, is taken into consideration, a number of very narrow instability regions can be made to occur.

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The lateral vibration and bending stress of a boring-rod induced by drifting and rolling motions of a drilling vessel floating on the deep sea were analyzed theoretically.The results of this study predict when and where the maximum displacement and bending stress occur along the rod, depending on a given damping factor of the surrounding water.When the non-dimensional damping factor, N, defined in this paper, is less than about 1.0, resonant vibrations of the rod are caused bya the vessel-motions, whereas they disappear when N exceeds the above value.Inthis case, however, the maximum bending stress increases with an increasing fequency of vibration of the rod.Finally, the analysis, applied to practical cases, has revealed that the present rule of thumb for the safety operation of an off-shore boring is not applicable to all cases encountered in ocean engineering.

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This paper presents a study on the effects of addendum modification on bending fatigue strength of spur gears of cast iron and cast steel. Analysis is made regarding the effects of addendum modification on the true stresses at the fillet in connection with the worst loading point and also on the bending fatigue strength of gear teeth. Bending fatigue strength of cast iron and cast steel gears can be improved by selecting the proper amount of addendum modification. Addendum modification factor B_χ 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. Furthermore the effects of addendum modification on both the contact ratio and the contact ratio factor are also discussed.

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The noise level of toothed belt drives is affected by the interference of belt and pulley teeth at the point where meshing on the driving pulley begins. A preferable amount of interference can be obtained by a suitable selection of the pitch difference between belt and pulley. The smaller the radius of the rounded tip corners of the pulley teeth, the lower the noise of the belt. Vibration due to the impact of the belt and pulley teeth at the point where meshing begins is almost never transmitted to the pulley.

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In this paper, the practical equations to calculate maximum contact surface temperature in Two Cylinder test were proposed. Moreover, for non-EP additive mineral oil, the effect of sliding velocity on the seizure behavior under pure sliding contact condition using through-hardened cylinders of S45C steel and the relation between seizure and temperature were investigated. As the result, the following conclusions are deduced : Bulk temperature of outer surface of cylinder can be approximated by the temperature at r^^-=0.97 and the circumferential position of ψ where bulk temperature rise of outer surface of cylinder is defined in the transverse section which passes through the end of contact region in axial direction. Seizure behavior is classified into two forms. One is such a form that when sliding velocity ν_s ≨ 1.26 m/s initial and destructive seizures occur at different loads after lasting boundary lubrication condition, and the other is such a form that when ν_s > 1.26 m/s destructive seizure suddenly occurs with a metallic sound from the state that oil film is retained and coefficient of friction is small. Thermal resistance of boundary lubrication film in initial seizure is related to maximum contact surface temperature.

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Elastohydrodynamic squeeze problem of two rotating cylinders is analyzed under the conditions of both flooded and starved lubrication in this paper. The Reynolds equation and an elastic equation are solved simultaneously by the Newton-Raphson method and their solutions show that the approaching velocity decreases with a decrease of the film thickness for a certain rolling velocity and load capacity, and an entrapment appears in the film profile for a large approaching velocity. Under the condition of starved lubrication, it is made clear that the load capacity and the frictional force for a certain film thickness and rolling velocity under a small approaching velocity decrease largely when the inlet coordinate comes closer to the contact center and that the effect of the inlet coordinate on them is small under a large approaching velocity.

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This paper deals with formation mechanism of ground white layers in relation to grinding temperature and grinding heat energy. Obtained results are as follows : 1) A ground white layer is formed during a rapid cooling process of a workpiece, which follows the generation of grinding heat energy. 3) The structure Of the ground White layer consists of fine α-phase, α'-phase, fine recrystalized γ_R-phase and fine secondary Fe₃C-phase, Fe₃O₄ and FeO-phase. 3) Hardness of ground white layers is increased because (1) fine untempered martensite contains a greater quantity of carbon in the super-saturated state in the base α-phase, and (2) the fine secondary Fe₃C-phase precipitates.

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The temperature at the cutting edge of a tool in machining glass-fiber-reinforced-plastics was measured by a special thermocouple method, in which two insulated wires were embedded in the workpiece, and the hot junction of the thermocouple was established when these wires were cut together with the workpiece. The temperature distribution along the cutting edge, and the relation between the physical property (thermal conductivity) of tool materials or cutting speed (spindle speed) and the temperature at the cutting edge were analyzed to estimate the relation between the cutting temperature and the flank wear of cutting tools.

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