Transactions of the Japan Society of Mechanical Engineers

The Micro Plastic Stress-Strain Hysteresis Loops of Steel during the Fatigue Process : II. The Effects of Strain Aging

Shigemi SASAKI

1963 Volume 29 Issue 206 Pages 1507-1514
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1507

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In order to investigate the effects of strain aging on the fatigue process of steel, the stressstrain hysteresis loops were measured through all stages of fatigue process by wire strain gauges 3 mm in length. Two kinds of killed steel have been used in the experiment; (e.g. 0.18% C and 0.12% C), all of them were sufficiently heat-treated to reduce the interstitial atoms C and N, thus varied the strain aging effects. The main results obtained are as follows : (1) The magnitudes of hysteresis loop decrease, being caused by the strain aging effects. (2) The materials tested under the strain aging effects are stronger than the materials free from the effects and the hysteresis energy accumlating until fatigue failure increase. (3) At the initial stage on the fatigue process, the maximum value of the strain aging effects appera.

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On the Relationship between the Fatigue Stages of Steel and the Micro Stress-Strain Hysteresis Energies

Shigemi SASAKI

1963 Volume 29 Issue 206 Pages 1515-1523
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1515

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In the previous paper, it was reported that the fatigue being measured by the wire strain gauges of 3 mm in length on the micro stress-strain hysteresis loops was observed at three stages. In this paper, the fatigue stages of steel was observed and concluded as follows : (1) At the 1st stage, the yield point observed on hysteresis loop and the strain hardening varied. (2) At the 2nd stage, slip and recovery varied. (3) At the 1st stage, the fatigue damage was recovered at 600°C but at the 2nd stage it was not recovered. (4) The microcrack started at the beginning of the 2nd stage. (5) We proposed that the unstable state ξand the metastable state ηseemed to be produced by the distortion of crystal lattice, and micro hysteresis loops were caused by their accumulation. (6) The fatigue lives were prolonged when the variance of ξon the 1st stage and of ηon the 2nd stage was minimized.

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Research on the Reinforcement by the Rib : 4th Report, The Stress Concentration at the Reentrant Corner of Trapezoidal Rib

Kunio NISHIOKA, Nobuyoshi HISAMITSU

1963 Volume 29 Issue 206 Pages 1523-1528
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1523

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The authors have studied the stress concentration at the reentrant corner of trapezoidal rib under pure bending by the two dimensional photoelastic method. Thus the influence of the fillet radius at the reentrant corner, the thickness of member and the height of rib on the stress concentration factor were clarified. The results obtained were as follows : (1) the stress concentration factor decreased gradually with the increase of height of rib so long as the height was relatively large, and the stress concentration factor decreased drastically when the height of rib became small. (2) The stress arised in the rib increased with the decrease of height of rib. Below a certain height, the maximum stress in the rib exceeded the one at the reentrant corner of rib. This critical height of rib increased as the fillet radius or the thickness of member increased.

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Deflections of the Bent Cantilever

Masayoshi AOKI

1963 Volume 29 Issue 206 Pages 1529-1537
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1529

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The bent cantilevers, namely, the bent leaf springs are assembled in a wire spring relay to push the armature to the core. In designing of this relay, it is necessary to use a spring having a proper force-deflection relationship. First, the deflections of the bent cantilevers are analyzed on the basis of the theory of small deformations, and it has been clarified that the effect of curvature at the bending points on the deflection is negligible. Second, a force-deflection relationship is analyzed, and a correction basing on consideration of the change of the arm length of bending moment is found. The nonlinear characteristic of springs depends upon the bending angles, the bending positions, and the magnitude of the deflection. The theoretical predictions show excellent agreement to the experimental results.

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On a Contact Problem of an Elastic Half-Plane with a Circular Hole

Osamu TAMATE

1963 Volume 29 Issue 206 Pages 1538-1544
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1538

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A two-dimensional solution is given for the stresses produced by the indentation of the plane boundary of a semi-infinite elastic medium with a circular hole by a flat-ended rigid stamp. It is assumed that the stamp is placed on the segment of the straight boundary, just above the hole, and pressed into the half-plane by a given force, perpendicular to the boundary, and that the friction between the stamp and the elastic body is so great that no slip can occur. The complex potentials, which have singularities at the center of the hole and do not disturb the boundary conditions along the straight edge as well as at infinity of the half-plane, are added to the solution of the contact problem of a half-plane without hole and the parametric coefficients attached to the potentials are then adjusted, so as to satisfy the conditions at the rim of the hole. Numerical examples are worked out and compared with results available.

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On the Simple Tension of a Semi-Infinite Plate with Partially Stiffened Edge

Osamu TAMATE, Takeshi KAMADA

1963 Volume 29 Issue 206 Pages 1545-1549
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1545

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A two-dimensional solution expressed in finite terms is given to the problem of the extension of a semi-infinite plate, to which a perfectly rigid stiffner of finite length is attached along the straight edge. The solution of the mixed boundary-value problem, stated above, is reduced to the search for a function φ(z), continued analytically into that part of the z-plane not occupied by the material through the unloaded parts of the boundary. The integral of the Cauchy type is used to find φ(z). The introduction of φ(z), instead of Φ(z)=φ'(z) that is commonly used by N.I. Muskhelishvili and his Russian collaborators, has the advantage that in constructing the boundary equations, involving the boundary values of the displacements, one is not obliged beforehand to differentiate these values. Expressions for the displacements and stress in the semi-infinite plate are found and plotted in a non-dimensional form.

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Bending Stress Analysis of Swept-Back Plates of Variable Thickness

Eiichi MATSUMOTO, Tsuyoshi SEKIYA, Hiroshi INAGAKI, Koji NAKAI

1963 Volume 29 Issue 206 Pages 1550-1559
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1550

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A numerical method is presented for the problem of the bending stress of thin elastic cantilevered plate of variable thickness, having arbitrary swept-back angle and taper and being subjected to the pressure load on its surface and the temperature distribution in itself. Three examples are solved by relaxation method; Examples 1 and 2 treat the solid wing plates of variable thickness and swept angle of tan^-1(3/4). The former is supported simply at four points and the latter is fixed at the root. Example 3 treats the tapered solid wing plate which is fixed at the root. For all of these examples the loads are assumed to be uniformly distributed. Furthermore, experiments for the above three examples are carried out. Fair agreement is observed between the numerical and the experimental results.

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Numerical Analysis for Sandwich Plates by Difference Method : 1st Report, Analysis of Flexure Problems

Masaaki OKAMOTO, Tsuyoshi SEKIYA, Motoki IKEGAWA

1963 Volume 29 Issue 206 Pages 1560-1568
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1560

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Although a great many investigations for the strength and the stiffness of the flat sandwich plates have been reported, most of them show only the basic equations or the solutions which are applicable only to certain particular cases. In the present paper, we extend Hoff's energy method to the case of the cylindrical coordinates with the view of applying to the circular and sectorial plates, and on the other hand we propose to apply the difference method to the present problem in order to treat the plates with the arbitrary forms of the boundaries under the arbitrary loads and the mixed boundary conditions. The numerical calculations were worked out for the deflections and the stresses of several plates. From these results, it has been shown that our calculations coincide fairly well with our experiments and also coincide with the results obtained by means of the other theories.

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Elastic-Plastic Bending of a Built-in Circular Plate under Circularly Distributed Load within a Concentric Circle

Yoshio OHASHI, Sumio MURAKAMI

1963 Volume 29 Issue 206 Pages 1569-1575
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1569

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AS an extention of the preceding paper, in which the elastic-plastic bending of a circular plate fixed at its periphery and subjected to a uniform load was treated, problems of the elastic-plastic bending of the same plate under partial loading by a distributed load in various concentric circles are analyzed. Though the method of approach is almost same as described in the preceding paper, in this case, however, a special consideration for the condition at the boundary of loaded region becomes necessary. The results of calculation show that the distributions of the bending moments and deflections and the developments of plastic range are remarkably affected by the change of the loading circles.

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Elastic-Plastic Bending of a Simply-Supported Circular Plate under Annular Load

Yoshio OHASHI, Sumio MURAKAMI

1963 Volume 29 Issue 206 Pages 1575-1581
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1575

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Elastic-plastic bending of a thin circular plate under lateral load by a rigid circular punch is a foundamental example of the various practical problems such as the incipient state of the drawing of a plate and the heavy loading of it. In particular, when a thin circular plate is bent by a punch, as the central part of the plate is not affected by the punch on accout of its deflection, the plate is subjected to a load along the periphery of the punch just like an annular load. In the present paper, elastic-plastic bending of a simply supported thin circular plate under an annular load is researched by an electronic computer for the material which follows Mises' yield condition and Hencky's stress-strain relation. The results of calculation are discussed for the development of plastic region and distributions of the bending-moment and deflection.

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Elastic-Plastic Bending of Circular Plates with the Membrane Forces : 1st Report, One-Side Elastic-Plastic Bending of Simply Supported Circular Plates Subjected to the Uniform Lateral Loads and Uniform Radial Forces

Yoshio OHASHI, Sumio MURAKAMI

1963 Volume 29 Issue 206 Pages 1581-1591
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1581

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The present authors intend to research axis-symmetric problems of elastic-plastic bending of plates in regard to non-hardening elastic-plastic material following Mises' yield condition and Hencky's stress-strain relation, taking into account the membrane forces and development of the plastic region in the meridian section of the plates, and using the Sokolovsky's representation in regard to the principal tensile strain e_r, e_θ and the principal curvature α_r, α_θ. In the present paper, as an example of the problems, one-side elastic-plastic bending in which one surface of the plate is in plastic range while the other surface is still in elastic range is investigated for the circular plates which are simply supported at the periphery and subjected to uniform lateral loads and uniform radial forces. Distributions of bending moments and membrane forces, deflection of the middle plane, radial displacement and development of the plastic region are also calculated.

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On the Experiment of Elastic-Plastic Bending of Simply Supported Circular Plates under Annular Load

Yoshio OHASHI, Sumio MURAKAMI

1963 Volume 29 Issue 206 Pages 1591-1597
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1591

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The paper is concerned with the experiment of elastic-plastic bending of plates of 0.13% C carbon steel which are simply supported and subjected to annular load. In the experiment, deflection of the plate, distribution of strain components and development of plastic range were examined and they were compared with the results of the calculation which had been formerly reported by the authers. It has been verified that the results of calculation and experiment coincide almost completely not only throughout the purely elastic stage of bending, but even in the elastic-plastic stage up to 75% of the collapse load.

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Bending of an Eccentric Circular Ring with a Cut Out Portion Undergoing Forces and Bending Couples at the Both Ends

Kyohei MORI

1963 Volume 29 Issue 206 Pages 1598-1605
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1598

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To solve the problem of bending action of piston rings or crane hooks, we considered an eccentric circular ring with a cut out portion undergoing forces and bending couples at the both ends. Using the theory of elasticity for plane stress and applying bipolar coordinates, we obtained correct solutions for the above problem and compared the solutions with those by the usual elementary theory for curved bars. From the results of calculations, we have a conclusion that the solution by the usual elementary theory is very reliable, only when the eccentricity between the centers and the difference between the radii of two circles of the boundaries are small.

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Thermal Stresses in an Infinite Circular Cylinder Heated through Moving Heat Sources

Rokuro MUKI, Kenji AKIYAMA, Yoshikazu NAKANO, Kenichi BANZAI

1963 Volume 29 Issue 206 Pages 1606-1614
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1606

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This paper deals with the thermal stress analysis of an infinite circular elastic cylinder heated on the surface axisymmetrically through heat sources, which move at a constant velocity in the axial direction. The underlying heat conduction problem as well as the thermoelastic problem is attacked by the aid of complex Fourier transforms, assuming that the cylinder is homogeneous and isotropic with respect to both thermal and elastic response and the temperature distribution on the surface is prescribed. The general solutions for both temperature and stress distributions are obtained in the forms of infinite integrals. Numerical examples, which are carried out for two special distributions of temperature, show a marked influence of the velocity of the heat sources on the distribution of the thermal stresses.

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Theoretical Analysis of Critical Conditions of Stick-Slip in Hydraulic Driving Mechanism

Atsushi MATSUZAKI

1963 Volume 29 Issue 206 Pages 1615-1625
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1615

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Stick-slip is often observed in the sliding surfaces of machine tool. It was shown in the previous paper that the result of theoretical analysis of stick-slip in the hydraulic driving mechanism coincided with the experimental results. This paper deals with the theoretical analysis of critical conditions of stick-slip. The range of stick-slip occurrence is represented graphically in a non-dimensional form. The conditions whether stick-slip occurs or not are given in terms of the mass of moving part, the friction-velocity relation of slide-way, the pressure-flow characteristic of flow control valve, oil compressibility and others. Furthermore the influence of change of these parameters are discussed, and it is shown that the more rarely the stick-slip occurs, the smaller the mass of moving part, the difference between static and Coulomb friction and the oil compressibility are, and the larger the coefficient of viscous damping and oil flow through the cylinder are.

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On the Fatigue Strength of Shallow-Notched Specimens of Commercially Pure Titanium

Katsuzi TAKEUCHI

1963 Volume 29 Issue 206 Pages 1626-1631
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1626

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The rotating-beam fatigue tests with comparatively shallow notches are conducted on two grades of commercially pure titanium and the fatigue strengths are measured at 10⁷ cycles. The notched fatigue strength increases beyond that of unnotched specimen as it iocreases remarkably in sharpness of the notch untill the theoretical stress concentration for the notch reaches 1.2 and decreases gradually with further notching. The notched fatigue strength for theoretical stress concentration of about 2.0 or less is higher than that of the unnotched specimen. In the case of shallow-notched specimens with theoretical stress concentration less than 1.2, an internal heating phenomenon same as in the case of unnotched specimens is observed. When those specimens are tested in water, the increase in fatigue strength is not exhibited on account of the cooling effect. It is considered that the increase in fatigue strength of shallow-notched specimens is related to the internal heating phenomenon.

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High Frequency Fatigue Behavior of Notched Specimens at Elevated Temperatures

Minoru KAWAMOTO, Tsuneshichi TANAKA, Hideo NAKAMURA

1963 Volume 29 Issue 206 Pages 1632-1639
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1632

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Cantilever beam type rotating fatigue test was conducted at the temperatures of room temperature, 300°C and 500°C at a frequency of 10 000 rpm, and as the check test, same type fatigue test was carried out at room temperature at the frequency of 2 450 rpm. The material used here was 0.26% carbon steel. Specimens tested were three types of different stress concentration factors; α_κ=1.0, α_κ=1.8 and α_κ=3.0 (these values are Neuber's calculation). The following is the summarized conclusion of the experimenta1 results. In the high frequency fatigue, the sharper the notch, the more decreasing the fatigue strength; as the notch is sharper, the fatigue notch factor has larger value than that of the stress concentration factor, especially at elevated temperatures.

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Notch Effect of High Carbon Steel on the High Temperature Fatigue

Minoru KAWAMOTO, Tsuneshichi TANAKA, Toshinobu SHIBATA, Takahisa OKUDA ...

1963 Volume 29 Issue 206 Pages 1640-1646
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1640

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The authors already reported⁽¹¹⁾ the effect of the notch on the fatigue strength of the low carbon steel at the high temperature. On the low carbon steel it was indicated that at about 300°C the smooth specimen takes the highest fatigue strength, and as the notch becomes sharper, the temperature where the highest strength appears is gradually elevated. In this paper the same rotating bending fatigue tests were performed on the 0.72% C carbon steel, and the effects of the test temperature, the test speed and the notch sharpness on the fatigue strength and the notch factor were studied. The data indicate that on the high carbon steel also the temperature, where the increase of the fatigue strength occurrs based on the bluebrittleness, is elevated as the notch becomes sharper. At the high temperature the notch factor takes constant value when α_κ>2, The notch factor is not so much effected on the high carbon steel as on the low carbon steel by the test speed and by the number of revolutions to fracture at the high temperature.

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Torsiona1 Fatigue Test of Ni-Cr-Mo Steel at Room Temperature and High Temperature (350°C)

Minoru KAWAMOTO, Koji KOIBUCHI, Yasuhiko YAMAJI

1963 Volume 29 Issue 206 Pages 1647-1652
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1647

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In this paper, both the cyclic straining test and the cyclic stressing test of the Ni-Cr-Mo steel were carried out completely reversed in torsion, at room temperature and at high temperature (350°C), for the investigation of the plastic fatigue phenomena. At room temperature, the stress amplitude decreases with the number of cyclic straining, and the strain amplitude increases with the number of cyclic stressing. The fatigue lives of both tests were compared on common setting-up cycle. Then the fatigue lives of cyclic straining test are longer than those of cyclic stressing test. On the other hand, the same phenomena were amplitude observed, at high temperature, but the changing aspect of the strain amplitude and the stress are not so large as in case of room temperature. The difference of the temperature influences the fatigue life so much. That is, for the same setting-up stress, the fatigue lives at room temperature are longer than those at 350°C, due to the lower stress-strain curve at 350°C, but for the same setting-up strain, the fatigue lives at 350°C are longer than those at room temperature, due to the annealing effect.

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Rotating Bending Fatigue Tests of Steel in the Plastic Range at Elevated Temperatures

Minoru KAWAMOTO, Yukihiko IBUKI, Hideo NAKAMURA

1963 Volume 29 Issue 206 Pages 1653-1662
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1653

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Constant stress and constant deflexion cantilever rotating bending fatigue tests of annealed 0.35% Carbon steel were carried out at a frequency of 62rpm at the temperatures of room, 200°C, 350°C and 500°C. In the constant stress test, the change of vertical and horizontal deflexion of specimen was observed; in the constant deflexion test, the change of stress was also recorded. Consideration was given to S-N diagram, δ_ν-N diagram, change of deflexion and stress, hysteresis energy and so on. The main conclusions of the paper are as follows : in the constant stress and constant deflexion tests, S-N diagram shows considerably same tendency; the change of deflexion and stress differs much at different temperatures, and so does hysteresis energy; the fatigue life of the constant stress test is longer than that of the constant deflexion test in the plastic range, comparing on the bases of the static bending test.

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Very High Speed Plane Bending Fatigue Test : 3rd Report, Theoretical Analysis of the Speed Dependency of Fatigue, Part 1

Masami YAMANE

1963 Volume 29 Issue 206 Pages 1663-1673
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1663

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Remarkable dependency of fatigue properties on speed, and that it is closey related to the internal friction in the specimen, were shown from testing several kinds of steels by means of the High Speed Fatigue Testing Machine developed by the author, as described in the 1st and 2nd reports. A model concerning the preyield plastic microstrain was developed here to explain the mechanism of this dependency of fatigue on speed, and from the analysis of this model subjected to periodical stress, the similer tendency in the amplitude-dependency and the speed-dependency of internal friction with those experimentally obtained was exhibited. From this, the model developed here may be considered to be acceptable. Next, the speed-dependency of fatigue obtained from the analysis, assuming that a certain amount of plastic strain is required to cause fatigue in the specimen as could be supposed from the expermental results, also shows the similer behavior with that experimentally obtained. Hence it could be concluded that the speed-dependency of fatigue is due to the time lag of the preyield plastic microstrain.

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The Effects of the Shapes and the Distributions of Inclusions on the Fatigue Strength of Bearing Steels in Rotary Bending

Yuichi KAWADA, Hajime NAKAZAWA, Syotaro KODAMA

1963 Volume 29 Issue 206 Pages 1674-1683
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1674

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The relations between the fatigue strength of bearing steels in rotary bending and the shape and the distribution of inclusion were investigated. The material used were normal steel (N), normal Swedish steel (S) and steel melted in vacuum (V). Plane specimens and specimens with two kinds of groove were made from each sort of steel. The results obtained were as follows : (1) When the steel had less and smaller inclusions, its fatigue strength became higher. (2) In this experiment, the inclusion whose mean diameter was smaller than 8 μ did not affect the fatigue strength. The mean diameters of detected inclusions were 10∼40 μ for S-steel, 30∼70 μ for N-steel and 35∼130 μ for V-steel. (3) It was clarified that the fatigue life of bearing steel was affected by the mean diameter, the shape of inclusions and the distance from the surface of specimens to the inclusion. (4) The inclusions found on fatigue fracture surfaces were inspected by X-ray analyzer and it was clarified that they were composite of Si and Mn.

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Standardization of Shore Hardness Scale for Soft Metals

Kozo IIZUKA

1963 Volume 29 Issue 206 Pages 1684-1692
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1684

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A study is made on the standardization of Shore hardness scale below 30 by using a number of Shore hardness testers of various types, which, above 30, agree with the standard of JIS, set in terms of the conversion from Vickers hardness. As the result of extensive experiments on various soft metals, it is found that annealed mild steel with C of 0.13 to 0.31% (Hs &cong; 17∼22) and pure copper Of 99.8% or better (Hs &cong; 7) exhibit a well coincident Vickers-Shore relationship with the extension of the conversion formula prescribed in JIS. The use of standard hardness blocks made of these materials for the calibration of Shore hardness testers proves the possibility of standardizing Shore hardness scale below 30 as accurately as that above 30.

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Fatigue Damage of 7-3 Brass Specimens

Tadasi ISIBASI

1963 Volume 29 Issue 206 Pages 1693-1701
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1693

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The nature of the fatigue damage of 7-3 brass specimens is quite the same as what occurs in 6-4 brass or in low carbon steel specimens. The damage is confined within a thin surface layer of the specimen and cannot be removed by stress relief annealing. The thickness of the damaged layer becomes greater when the applied stress is high and the number of the stress repetitions is large. The fatigue stressing hardens the material which, however, disappears by stress relief annealing. By taking x-ray diffraction patterns of the surface as well as of the portions beneath the surface of the specimens, it was revealed that the distorsion and fragmentation of the grain in fatigued specimens decrease as the distance of the irradiated grain from the surface increases and it was concluded that, as the thickness of the severely damaged layer reaches some threshold value (of one or two grains thickness), fatigue cracks develop there which, in most cases, lead the plain specimens to break down eventually.

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A Study on the Strength Calculation for Electric Railcar Body

Masaki WATANABE, Kunihiko SATO, Yutoro URATSU, Shin'ichi ISHIZUKA

1963 Volume 29 Issue 206 Pages 1702-1712
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1702

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The present investigation deals with practical calculation for the strength of electric railcar body. A new calculation method for the end shock on underframe was established as a result of the investigations of clashed railcar bodys. Two solutions were obtained on the strength of railcar body considering sideframe as both Vier endeel Rahmen and sandwiched beam. A solution as Vierendeel Rahmen was obtained by modified slopedeflection method, in which the effect of shear deflection and the joint area of each member was considered. Another solution as sandwiched beam was obtained under the assumption that each post in sideframe is substituted for elastic layer in the sandwiched beam. Three factors were found important on the practical strength calculation of electric railcar body, that is, (1) Ratio of the length of overhang to the distance between bolsters, (2) Arrangement of side doorways and (3) Rigidity of posts.

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Dynamics of Pressure in Forced-Flow Evaporator System

Kotohiko SEKOGUCHI, Minoru SAKASAI

1963 Volume 29 Issue 206 Pages 1713-1724
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1713

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Some theoretical solutions are here intrcduced which may be applied to the analysis of dynamics in forced-flow evaporator systems. Some basic forms of the various transient response curves are illustrated by using the above solutions. As a main result, it was made clear that the dynamic behavior of system pressure is subjected to two factors. The first factor has such a physical meaning as a lumped parameter corresponding to drum-type boilers, and the second as a distributed parameter. It is found, however, that the transient response of pressure is almost determined by the lumped parameter.

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Vibration of a U-bar Perpendicular to its Plane

Shin TAKAHASHI

1963 Volume 29 Issue 206 Pages 1725-1733
Published: October 25, 1963
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.29.1725

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The vibration of a U-bar which occurs perpendicularly to its plane is studied. The U-bar is consisted of one circular arc bar and two straight bars or of three straight bars. The ends of U-bar are clamped and two legs of it are the same with respect to the dimensions and the material. The frequency equations and the boundary values are obtained by minimizing the Lagrangian. The frequencies of U-bar with an arc in the symmetric vibration are calculated and shown in Figs. 5, 6, 7 and 8, and its material and sectional dimensions are homogeneous and uniform respectively. The experiments are carried out and their results are compared with the theoretical results.

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