A comprehensive study has been made, using the laminated plate-photoelastic technique, of the bending moment distributions in a thin skew plate subjected to a uniformly distributed load or a concentrated load and simply supported along its two opposite sides. The distribution of sums of principal bending moments was determined by solving Poisson's equation numerically with the boundary conditions obtained photoelastically. The effects of the membrane stresses and twisting moment were corrected satisfactorily. The distribution of the principal bending moments, sum and difference of the principal bending moments and twisting moments over the entire area of the plate together with the map of directions of principal bending moments were obtained in each of about 260 combinations of shape factors of the skew plate and loading parameter. An analytical solution for a special case of square plate under a concentrated load was worked out to verify the accuracy of the experimental procedure employed and the comparison of the results obtained experimentally and theoretically indicates that the accuracy of the procedure is satisfactory. In the present first part of the paper, the basic principle, experimental techniques and the theoretical verification of the procedure are described in detail. The particular data obtained by the systematic experiments will be given in the succeeding parts.

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The stress analysis near an oblique circular hole boundary in a plate subjected to tension is one of the important problems in collecting basic data for machine design. However, for various dimensions of plate widths, oblique angles and plate thicknesses, sufficient information on the stress-concentration due to the oblique hole boundary has not been presented. Accordingly, it is necessary to obtain sufficient data on the stress-concentration around the oblique hole by performing further systematic investigation. In the present paper, the stress distribution near the oblique hole boundary and the stress-concentration factor are measured in detail by using the photoelastic stress freezing method.

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The work-hardened surface layer induced by machinig is generally thought to improve the fatigue strength in metallic materials. However, at high stress levels, the specimen B with thin work-hardened layers by turning has proved to have a lower fatigue strength than the specimen A whose surface layers are removed electrolytically, namely the S-N curves of the specimens A and B cross each other, in the rotating bending and the constant strain torsional fatigue tests, using the structural steels S30C and S35C. However, the torsionally pro-strained specimens with deep work-hardened layer have proved to have a higher fatigue strength at all stress levels than the virgin specimens. These results are well explained by applying the concept in the formula for the axial strain cycling by S.S. Manson, to the constant stress fatigue behavior.

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Stress analysis for a circular cylindrical shell having two circular rigid inclusions of equal size is worked out. The method of solution for a circular cylindrical shell having two circular cutouts of equal size published by us is extended to this problem. The following four cases are treated : A circular cylindrical shell having two circular rigid inclusions of equal size (a) in a longitudinal direction under uniform tension, (b) in a circumferential direction under uniform tension, (c) in a longitudinal direction under internal pressure and (d) in a circumferential direction under internal pressure. Numerical solutions are obtained for three kinds of diameters and four kinds of center-distances of the inclusions. Especially, in the cases of (a) and (b), the results are compared with those for a flat plate by Shioya.

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This paper deals with a method of approach by means of three stress functions to axially symmetric problems of the dynamical theory of elasticity in cylindrical co-ordinates. The principal results are as follows : (1) The solution presented in the paper is a complete one for problems associated with both torsional deformations and body forces as well. (2) In the case of no body forces, it is possible to drop a stress function (not arbitrary) form three stress functions without loss of generality. (3) Stress functions for dynamical body force problems and for initial value problems are presented and examples of their application are investigated. (4) As a special case of the solution shown in the paper Love's solution for elastostatics can be obtained.

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This paper describes the yielding of a mild steel rotor having blades on its periphery under rotation. In this experiment a uniform thickness disc having narrow slits on its periphery is used as the model rotor having blades, and the following conclusions are drawn from the experiments and its considerations. (1) By a photoelastic experiment using stress freezing method on the model rotor having blades made of epoxy plate, it is proved that the centrifugal force of the part corresponding to blades under rotation acts on the rotor approximately as external pressure as the number of slits increases. (2) There are two modes in the yieldings of mild steel rotors having blades ; one is the yielding caused under a constant number of revolutions, and the other is the mode that the yielding does not spread unless the number of revolutions increases. And the criteria of the yieldings of these rotors as well as those of the uniform thickness discs can be explained by Nakanishi's theory on the yielding of mild steel.

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An analysis of the wave modes in compound elastic circular rods, which consists of a circular matrix rod and a circular sheath tube made of different materials, was executed. Results of numerical evaluations of the frequency equation are as follows. (1) Frequency spectra for a compound circular rod of which the sheath material is similar to the matrix material are substantially equal to the frequency spectra for a uniform circular rod. (2) The larger Young's modulus of the sheath tube becomes with Young's modulus of the matrix material kept constant, the larger the phase velocity of each mode becomes. Otherwise, when Young's modulus of the sheath tube becomes large with the average Young's modulus of the compound material kept constant, there appears region in which the phase velocity of each mode inversely becomes small.

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In design of a transportation system with guidance, it is important to give quickly the specifications of the lateral control system in accordance with the vehicle, its velocity and the guideway given by the transportation plan. This paper concerns the mechanical guidance which stress the front wheels of a pneumatic-tired vehicle by contacting the guide-followers with the guide-track. A mathematical model of the running vehicle which includes the coupled dynamics of the steering mechanism and the guideway is developed, and the validity of it is proved by the test data. And applying the model, the effects of the four functional parameters d, g, k and γ of the guidance on the behaviors of the vehicle are examined theoretically from the "design" point of view.

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On a blade row in turbomachinery, the unsteady force comes out owing to the following two main sources, i.e. the wake effect and the circulation effect. This paper is planned in order to make clear theoretically the wake effect on the blade. When a cylinder is moving near a stationary blade, the wake sweeps downstream through the blade. The velocity profile in the wake shed by the moving cylinder is approximated by the stationary counterpart. Calculations are done for various values of the velocity of the cylinder and axial spacing, while taking account of wake varying with distance from the cylinder. The cylinder is represented by a doublet traveling in a free-stream in order to predict the unsteady force on the blade due to the theoretical cylinder-thickness effect. The computed unsteady force on the blade due to the wake effect and the cylinder-thickness effect is added and compared with the experimental one. The reason why discrepancies arise is also considered.

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In order to know the characteristics of turbulence immediately before the initiation of combustion in an engine cylinder, it must be known, in addition to the decay-law for the relaxed period, how the initial conditions of generating turbulence have influences on the decay process of turbulence or how long the significant characteristic of incipient turbulence continues. In this respect, the authors carried out an experimental study to find out the relation between the relaxation time (duration before relaxation) and the various related conditions of generating turbulence in a closed vessel. The results obtained show that the relaxation time increases with an increase in the interval of orifices in the turbulence-generating disc, a decrease in the diameter of orifice, a decrease in velocity of gas blowing out of orifices, an increase in the diameter of the vessel and an increase in the eccentricity (distance from the center of the turbulence-generating disc) in the case of single orifice.

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The authors carried out the numerical integrations with several initial shapes of spectra and with varied initial values of Reλ according to the Kraichnan theory which was introduced in order to complete the series of equations expressing decay of turbulence in free space. By comparing the results of calculation with the experimental results obtained for the decay of grid-turbulence in a steady tunnel flow carried out by Van Atta et al., it was first proved that the validity of Kraichnan theoty was satisfactory. It was found that the asymptotic line of the decay-law of turbulence resulting from the theoretical computations was able to be approximated by the line of decay-law experimentally obtained by the authors for the relaxed turbulence in closed vessel. It was also found that (1) depending on whether the peak in the initial spectrum was too high or too low, the approaching manner toward the asymptote was reversed, and the influence of the manner on the time variation of turbulence characteristics was significant ; and (2) there existed the most conformable form of spectrum for a turbulence field with respect to the existing turbulence intensity and viscosity, and the peak of the spectrum grew steeper as decay of turbulence progressed.

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Mean velocity and turbulence together with pressure distributions in a radial free jet flows were studied. By changing diameter and width of nozzles and discharge velocity, the flow pattern were measured. The concept of the equivalent nozzle width which contains the diameter and width of the nozzle can be usefully applied to describe both maximum flow velocity decay and growth of the jet half width with distance from a nozzle outlet. The maximum flow velocity decay and the growth of the jet half width lie on a single curve according to this equivalent nozzle width. In the main region at large nozzle Reynolds number, the maximum flow velocity decays following the same rule as in circular jet, and the growth of the jet half width is in good agreement with that in the two-dimensional jet.

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This is an investigation of flow characteristics of a wall jet produced by gases impinging on a plate from an axisymmetric nozzle. Air, hot air, and carbondioxide were used, and the distances from the nozzle to the plate were fixed equal to the nozzle diameters. Experiments were carried out at exit Reynolds numbers from 1300 to 21000, for various nozzle diameters and exit velocities. Velocity, temperature and concentration profiles become similar at various distances X from the impinging center, for the same exit Reynolds number. Experimental relations between X and maximum values of temperature, concentration and velocity were obtained. Mixing length, eddy viscocity and entrainment of surrounding air were given in comparison between impinging and free jets.

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In the previous paper, a statistical method of evaluation of the relation between transmission errors and dynamic loads on a pair of spur gears was established neglecting shaft stiffnesses. A more advanced study considering the shaft stiffness is developed in this paper. A Fokker-Planck equation is derived and the mean and the variance of dynamic loads are calculated numerically by applying statistical linearization to nonlinear terms. Monte-Carlo-Simulation is also performed to find maximum dynamic loads by means of an analogue computer. The result shows that the shaft stiffness affects the dependency of the mean and the variance of dynamic loads on gear speed significantly.

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In the present paper, to improve the controllability of machine tool feed drive, the dynamics is studied by the method of linear analysis. The results are represented by a special pole-zero locus graph by which the effects of the components on the dynamic behaviour of the drive can easily be understood. By means of this graph, the design of drive with higher performance is discussed and particular attention is paid to the problems caused by the low load damping in this class of drive. Also, the introduction of a specific tachometer feedback network is suggested.

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