We conducted bursting and deformation tests of aluminium rotating disks. Considering the relation between the number of revolutions and strain of the disk, we proved that the strain-path of any point on the disk was approximately a straight line in the strain- space, and that the deformation-theory might be applicable to the stress-strain equation of the plastic deformation of the rotating disk. We measured Vickers hardness numbers, and compared them with the values determined from the deformation test and the hardness-strain curve.

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In the whirling of a shaft supported by bearings having the radial clearances, the locus of any point on the shaft is circle, so the behaviour of the motion differs from the reciprocal vibration on the straight line which takes place in the vibratory system with the backlash. In this paper, the stability criterions of the forced vibrations of a shaft, the response curves and the jump phenomena are discussed.

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A theoretical analysis is presented for the lateral vibration of wire or belt form materials in case of axial movement through two supporting points under the condition of fixed slope at these points. The report contains the theory of critical speeds, the characteristic equations for the materials with flexural rigidity and the analysis of frequency curves for some special conditions.

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In this report the author wishes to propose the following classification of the generalized terminal condition on which a shaft is supported on each end.[table] The auther shows the characteristic equations for determining the natural frequency, the position of nodal points and the position of loops of a lateral vibration of a shaft which is supported on the generalized terminal conditions. Several features of the vibration deduced from the characteristic equation shown above are also shown.

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In this paper, an experiment on the oscillation of chain suspended at both extremities is informed. The one end is fixed, while the other is forced to displace periodically by a crankmechanism driven by a variable speed alternating current motor and the modes of the oscillation are observed from the photograph taken by cameras set up several meters apart. The followings are concluded : (1) The natural frequencies of chain diminish rapidly as the statical deflection of suspended chain becomes large. (2) In all cases, the natural frequencies of chain increase in almost proportional to the orders. (3) The curves representing the modes of the vibration become sharper than the sinecurves of the modes of string. (4) The experimental results of the chain vertically hung from the one end only agree with the well known theory.

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Impact value is the sum of energy W₁ required to initiate a crack in specimen and the energy W required to spread the crack. The magnitude of W₁ can be estimated from tension test data but W cannot. In this experiment, round bars with a circumferential crack were fractured in tension and the thickness of the plastically deformed layer adjacent to the fractured surface (which was brittle) was estimated by taking X-ray reflection patterns. Thus the energy absorbed in that layer in the course of fracturing was estimated. This energy has close relation to W. It was shown, in steel, that the smaller the values of energy absorbed in the fractured surface, the more apt is the material to fracture in brittle manner even if a tiny crack is present. In steel this tendency can be foreseen, in some degree, by the magnitude of impact value of the material.

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An analytical investigation is developed on a problem of lateral mass-impacts applied at the end of a semi-infinitely long bar under assumptions similar to the previous retort⁽3). The difficulty that occurs when one determines the roots of the characteristic equation (Eq.10a) has been conquered by application of a statistical treatment. The phenomena subsequent to the impact are discussed and computed mainly referring to the shearing strains and bending strains. It can be qualitatively explained that the larger the velocity of impact becomes, the nearer approaches the point of failure to the struck end, if the failure is assumed to depend only on the amount of bending stresses.

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It is generally considered that stress-strain curve is smooth in plastic range, but the author found that it is not smooth when strained very slowly. From the auther's experiments with solid round bars and thin hollow cylinders under torsion, and with round bar under tension, the following are concluded. 1. Stress-strain curve in plastic range is discontinuous ; it consists of several branches convex downward. 2. Yield point of mild steel is the first discontinuous point. 3. The difference between the stress-strain curve of solid cylinder and that of hollow one, as shown in Fig.5, is due to the influence of stress distribution. 4. The stress-strain relation at the ultimate strength under tension is just similar to the yield point of mild steel.

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Previously, the solution for the problem of distribution of stresses in a semi-infinite strip under the normal compressive forces applied opposite at its end were published by prof. S.Higuchi. In this paper, using the similar method, we will treat the problem of a same strip mentioned above under the normal compressive forces applied alternately on the opposite surfaces of the strip. By using the stress function, solution to this problem is first obtained and calculating it numerically, we have obtained finally the state of stress in the strip. Thus, main characteristic properties of the distribution of stress in the present problem are inquired and discussed.

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This paper treats the bending of sectorial plates under a concentrated load in the following cases : (1) central angle=(π/n), (i) the circular edge is clamped, and two straight edges are free supported, (ii) all edges are free supported, (iii) all edges are clamped, (iv) the circular edge is free supported and two straight edges are clamped, (2) central angle=(π/2n), (v) the circular edge is clamped, one of the straight edges is clamped, and the other is free supported, (vi) the circular edge is free supported, one of the straight edges is clamped, and the other is free supported.

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In this papaer, some mechanical properties of the electric-wires burnt by a fire were examined to know whether it is possible to use them for construction works, and the relations between the properties and the annealing temperatures or times for the cold-worked copper-wires were investigated to deduce the temperatures and states in which the burnt electric-wires had been exposed. Then the following conclusions were drawn. Regardless of the condition of fire, the properties of the burut electric-wires remained almost unchanged, and the cold-worked copper-wires concluded the recrystallization even after the very short-time annealing, and after recrystallization the properties were remarkably reduced. Velocities of cooling after heating, and the methods of heating did not influence to the properties. And therefore, we learnt that it is impossible to deduce the temperatures and states of a fire from the strength-results of the burnt e1ectric-wires.

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Although this is not the proper way of its application, the Shore scleroscope is often used for the commercial measurement of hardnesses of sheet metals because of its character. The present report discusses the influence of the hardness of the anvi1 of the scleroscope and the way of mounting of specimens on the measured va1ue of the hardness of a thin plate as well as the variation of the hardness number of a laminated specimen with its thickness. The results of this investigation are as follows : i) The hardness of a thin metallic specimen should be measured on a single sheet, unless the specimen is laminated to a certain thickness. ii) If the hardness is measured in the way mentioned above, the hardness value given by the instrument remains approximately constant independent of the hardness of the anvil, if the anvil is only harder than the specimen. iii) Thus the indicated value of the hardness of sheet metals may be influenced by the hardness of the anvil, but as it does not remarkably change with the variation of the hardness of the anvil, this value may be used for commercial purposes.

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On the problem of Beam for various shapes, many cases have been solved. But there studied a little for general enclosed one except the case for Ring against symmetrical loads. To solve them approximately, the author has attempted to calculate the amount of these stresses and deformations, as one of the cases where their enclosed ring with any shapes not only uniform cross section, but also irregular one, was acted against various loads ; inner or outer fluid pressure, some different concentrated loads, stiffeners of stay bolt and others, by means of Castigliano's theory, standard system and graphical integrations. As 1st Report the author has attempted to solve the case against inner fluid pressure, in these special cases the stress calculation of the sluice valve body are considered.

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In this paper, the author has attempted a method of approximate solution of the stress and deformation against four outer different concentrated loads, under sufficient condition of funicular polygon. As a special case, the stress calculation of the large cast iron pipe for city water use is considered.

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In this paper, the author has attempted a method of approximate solution of the stress and deformation against inner fluid pressure under three stays, assuming the end of stiffener be hinged. As a special a case, the stress calculation of the body and stays about large Y pipe be considered. Through the three Reports, the problem of fluid pressure, concentrated loads and stiffeners have been solved, therfore another case of several conditions is able to be solved approximately as one of the application of general case.

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