材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
26 巻 , 283 号
選択された号の論文の14件中1~14を表示しています
  • 田中 稔, 橋詰 源蔵, 松井 博
    1977 年 26 巻 283 号 p. 309-318
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 田中 道七, 服部 修次
    1977 年 26 巻 283 号 p. 319-321
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    This study was to investigate the relation between the stress-strain hysteresis energy and the temperature rise of a specimen during the usual fatigue test. The experiment was carried out using S50C steel, and the simultaneous measurements were made on the temperature rise and the hysteresis energy of the specimen. The results were compared with the solution obtained by solving the Fourier's equation of heat transfer.
    The conclusions obtained were as follows:
    (1) The hysteresis energy W is completely transformed into heat energy, which contributes to the temperature rise of the specimen. The temperature rise θ is given by the equation as a first approximation;
    θ=αWf,
    where f is the testing frequency and α is a geometrical parameter determined by the shape of the specimen and the gripping condition.
    (2) The generation of hysteresis loop is not confined on the surface layer but it is a bulk phenomenon covering the total volume of the specimen.
  • 蒲地 一義, 峠 睦, 中乗 敬之
    1977 年 26 巻 283 号 p. 322-328
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Electrolytical charging of hydrogen into austenitic stainless steels induces a phase transformation from austenite to martensite and hydride formation. The behaviours of these phases have been studied by X-ray diffraction analysis.
    Hydrides formation was found to be dependent on the nickel content and charged hydrogen concentration in steel. Diffraction analysis of the specimen cathodic-charged at 60°C revealed the formation of hydride phases [ε'(c.p.h.) and Y1, Y2 (F.C.C.)]. The hydride phases were stable at -78°C, but as temperature is raised gradually from -78°C to room temperature, they become unstable and the martensitic phases were formed.
    The order of the phase transformation by catholic charge of hydrogen was
    [γ→hydrides (ε'+Y)→α'H→α'HH]
    in the charging process, and
    [γ→hydrides (ε'+Y)→εH→εH+α'H]
    in the aging process.
  • 有馬 道男, 蒲地 一義
    1977 年 26 巻 283 号 p. 329-333
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    In the study of fracture, X-ray stress measurement is generally used to analyze the stress distribution at a crack tip or notch root. Most of practical metallic materials have lower strength of one-tenth or one-hundredth than the theoretically calculated values.
    In the macroscopic X-ray stress measurement, this discrepancy is attributed to the propagation of cracks, initiated at the pre-existed crack tips, and the stress and strain distributions around these cracks or notches are investigated. But little experimental approach from microscopic point of view have been made. Therefore, in this paper, the stress distribution at the vicinity of a notch and crack is measured by the X-ray stress measuring method, and compared with theoretical values.
  • 徳岡 辰雄
    1977 年 26 巻 283 号 p. 334-338
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The constitutive equations of a plastic material with kinematic work-hardening are proposed. A symmetric tensor internal state variable, called the translation tensor, is introduced. The plastic potential is assumed to be a scalar function of the translated stress, which is the difference between the stress and the translation. A rate type mechanical constitutive equation is defined which relates linearly the stress rate to the stretching and has a coefficient depending on the translated stress, and a rate type evolutional equation is also defined which is the linear relation between the translation rate and the plastic stretching. The loading, the neutral and the unloading states are defined, respectively, by the positive, zero and negative values of the deviatoric translated stress power. The constitutive equation and the evolutional equation are newly defined in the above three states. From the mechanical constitutive relation in the loading state the yield criterion and the plastic flow rule are derived. The criterion obtained shows the kinematic work-hardening.
  • 徳岡 辰雄
    1977 年 26 巻 283 号 p. 339-342
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Here the behaviors of the incompressible Prandtl-Reuss plastic material with the kinematic work-hardening are investigated theoretically for the steady simple extension. The material was derived in the preceding paper and has a symmetric tensor internal variable, i.e., the translation tensor. The stress- and the translation-logarithmic strain relations are formulated analytically. In order to estimate the behavior of the material for the work-hardening, the equations are solved approximately and the linear relations between the stress and the translation increments and the strain increment are obtained. The exact solution is also obtained, and its numerical calculations are depicted in the figures. The results show the remarkable rounding phenomenon for the reloading curve and the Bauschinger effect.
  • 粟谷 丈夫, 松波 康二
    1977 年 26 巻 283 号 p. 343-347
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    As well known, a non-propagating fatigue crack is easy to be formed at the root of a notch as the radius of curvature of the notch decreases. Although a crack may be considered to be an extremely sharp notch with an infinitesimal radius, it is not clear yet whether non-propagating cracks are developed at the tips of the cracks or not. To clarify this, some experiments were made on two kinds of specimens, the plain specimen with a crack and the notched specimen with a crack. It was found that a non-propagating crack could not be developed at the tip of the crack in the former specimen, but could be in the latter specimen.
    For the interpretation of these results, the experimental facts found by Frost are referred to, which show that crack initiation is governed by the alternating stress amplitude (independent of mean stress), and crack propagation is determined by the maximum tensile stress in the cycle. Since the crack existing in the plain specimen does not bear the compressive stress concentration, the alternating stress at the crack tip will be relatively low. On the other hand, the alternating stress will be larger at the tip of the crack existing at the notch root, because of the stress field associated with the notch, operating even in the compression phase. From such a difference in stress conditions, coupled with cyclic hardening, satisfactory explanation for the experimental results can be derived.
  • SUS 304B材の場合
    岡崎 章三, 中村 宏, 苧野 兵衛
    1977 年 26 巻 283 号 p. 348-354
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The rotating bending fatigue tests were carried out on the tufftrided smoothed specimen (ρ=100R), U-notched specimen (ρ=5R), and nitrogen contained smoothed specimen made of SUS 304B stainless steel.
    The results obtained are summarized as follows;
    (1) The ratio of the fatigue strength of the tufftrided smoothed specimen to that of the non-tufftrided specimen was at most 1.1 even if it was tufftrided for 240min.
    (2) The fatigue strength of the U-notched tufftrided specimen was higher than that of the tufftrided smoothed specimen.
    (3) The fatigue strength of the nitrogen contained smoothed specimen was higher than that of the tufftrided smoothed specimen.
    (4) The fatigue limit of the U-notched specimen (ρ=5R) can be estimated approximately using the hardness distribution obtained from the specimen after the fatigue test.
  • 黒部 利次, 上田 勝宣, 戸水 晴夫
    1977 年 26 巻 283 号 p. 355-360
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The fatigue test has been carried out on 0.18%C carbon steel in order to investigate the effect of atmosphere on its fatigue strength. The experiments were conducted under reversed plane bending at the vacuum levels ranging from ambient pressure to 8×10-5 Torr. The difference of fatigue failure modes at these environmental conditions was observed by means of electron- and scanning electron microscopies, and furthermore, the surface roughness of specimens subjected to stress cycling was traced using a surface profilometer. The influence of atmospheric-corrosion on the fatigue failure of low carbon steel was discussed from mechanochemical viewpoints. The main results obtained are as follows:
    (1) The fatigue life of carbon steel has prolonged with evacuating the air surrounding of a specimen. The endurance limit was observed in the specimens in vacuum in which the value of applied stress at the endurance limit was higher than that in air, and the number of cycles to the endurance limit observed in vacuum was not so much different from the value in air.
    (2) The prolongation of fatigue life of carbon steel, which was found to be dependent on the degree of test pressure, was analyzed theoretically using a capillary model.
    (3) The surface roughness of specimens subjected to fatigue stressing has increased in three stages. The surface roughness of specimens tested under a constant stress level has increased with reducing the pressure of test environment.
    (4) Many cracks of trans-granular type were observed in the specimens tested in vacuum, while those of inter-granular type existed in the specimens tested in air.
  • 夏目 喜孝
    1977 年 26 巻 283 号 p. 361-366
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The objective of this paper is to provide some information on the microscopic structural changes occurred during quenching and tempering processes. The effect of X-ray diffraction integral breadth on static bending strength and the correlation between static strength and endurance limit are investigated. The results summarized are:
    (1) Behavior of the stress-strain relation, and the bending strength can be formulated in terms of integral breadth and macroresidual stress as follows:
    σεB0B≅{23ε+(-0.15)ε·σr}(b-b0)
    σBB0B≅{58.5+(-0.26)σr}(b-b0)
    (2) In the analysis of the correlation between static strength and endurance limit, it is necessary to evaluate it under the same stress distribution.
    (3) The increase in static strength is higher than that of endurance limit, and the ratio of endurance limit to static stress for induction hardened steel is indicated as 0.2 to 0.4.
  • 田代 忠一, 新谷 達夫, 美世 昭博
    1977 年 26 巻 283 号 p. 367-371
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The test prisms of 10×10×40mm were made of Ba2SiO4 mortars with a Ba2SiO4-sand ratio of 1:2 and a water-Ba2SiO4 ratio of 0.65. After humid air curing for 3 days, the test prisms were immersed in 0.1, 0.3, 1.0, 3.0, 10.0 and 30.0wt. % H2SO4 solution for 1 to 28 days. The sulfuric acid resistance was estimated from the compressive strength and the change in weight of immersed test prisms. The reaction products were identified by X-ray diffraction method and microscopic observation.
    The results obtained were summarized as follows.
    (1) When the test prisms were immersed in 0.1 and 0.3% H2SO4 solutions for 28 days, their compressive strengths fell respectively to 13 and 12kg/cm2 from 313kg/cm2 and their weight decreased. On the other hand, when the test prisms were immersed in 3.0 and 10.0% H2SO4 solutions for 28 days, their compressive strengths became 148 and 84kg/cm2 respectively and their weight increased.
    (2) The above mentioned high resistance against 3.0 and 10.0% H2SO4 solution resulted mainly from the compact textures of BaSO4 and amorphous silica, which were formed by the reaction between Ba2SiO4 and H2SO4.
    (3) The low resistance against 0.1 and 0.3% H2SO4 solutions was mainly due to the porous textures of BaSO4 and amorphous silica. These porous textures were formed by the reaction of H2SO4 and barium silicate hydrate which were produced from Ba2SiO4 during the period of immersion. They were also formed by precipitation of BaSO4 on the outer parts of test prisms.
  • 徳田 弘, 川上 洵, 加賀谷 誠
    1977 年 26 巻 283 号 p. 372-377
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The recent trend of civil engineering to make larger structures has brought the increase in number of constructions of massive reinforced concrete members. Since higher strength is required for these structures than for concrete dams, the rich mix concrete must be used for them. Thermal stabilization of these structures is of prime importance, but any of the methods used for preventing thermal cracks in dams is not generally applicable to them for several reasons. The data of thermal properties of rich mix concrete are needed to establish a suitable method.
    The thermal diffusivity, coefficient of thermal expansion, and compressive strength of concrete specimens with cement contents from 250 to 700kg/m3 were measured in this study. These properties were influenced considerably by the cement content: with increasing cement content, the diffusivity tends to decrease and the expansion and the strength to increase. Stronger concrete usually exhibits lower diffusivity and higher expansion, so that it is more liable to cracking.
    Concrete can be regarded as a composite material composed of cement paste and aggregates. The diffusivity of the paste is lower than that of aggregate and its expansion is higher. Furthermore, the higher the water cement ratio of the paste, the lower the diffusivity and the higher the expansion slightly. For the constant consistency of concrete, however, the higher the water cement ratio, the higher the diffusivity and the lower the expansion, because of the less mix quantity of the paste per unit volume of concrete. To improve the thermal properties, a polycyclic sulfonate, a powerful water reducing agent, was tried in this experiment. As the result of admixing it, a marked improvement in thermal properties was achieved without changing consistency and strength of concrete.
  • 大岸 佐吉, 小野 博宣, 岩本 威生, 松永 勝己
    1977 年 26 巻 283 号 p. 378-384
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Since the accelerated electron has by far a higher dose rate than gamma-rays, the electron polymerizing method is more suitable for the efficient fabrication of polymer-impregnated concrete (PIC) with a thin cross section. However, there are few published papers on the manufacturing process of PIC polymerized by electron beam.
    This experiment was carried out to investigate the effects of density of cement mortar, dose rate of electron beam (4MeV), total exposure dose and other factors which have influences upon the strength of MMA-PIC. The density of mortar, size of cross section of mortar specimens, dose rate of electron, total exposure dose and irradiating time interval were varied respectively as follow; ρ=1.55∼3.13g/cm3 (the kinds of aggregates in cement mortar used are perlite, artificial light weight aggregate, normal river sand and iron sand), t=3.5∼40mm in thickness, 0.55 or 1.10 Mrads/sec, 12.5∼100 Mrads per face, and 15∼60sec/cycle.
    The test results of mechanical strength of PIC show that the optimum total exposure dose is about 40Mrads at 0.55Mrads/sec rate and 50Mrads at 1.1Mrads/sec in the ordinary mortar. It is also shown that the impregnation depth from the surface of specimen has a linear relation with the density of cement mortar, and that its depth is about 1cm in conventional mortar.
  • 斎藤 孝平, 坂上 ハツ子, 篠原 拓男, 福澄 哲夫
    1977 年 26 巻 283 号 p. 385-392
    発行日: 1977/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    For the purpose of investigating the effects of addition of glycerol to tobacco laminae on three characteristics of shreds“Y”(fragility, filling capacity and equilibrium moisture content), an experimental plan was set up by using the glycerol addition“G”(0∼6%) and the environmental humidity “h”(43∼80%RH) as two main factors and the shreds length as a subsidiary factor. The tests were carried out with Flue-cured and Burley tobacco varieties. By means of statistical analysis of these experimental data, the relations among“Y”, “G”and“h”were represented with experimental formulae. Moreover, the analysis of multiple regression for fragility and filling capacity was performed with two independent variables of real glycerol content“GR”and moisture content in tobacco shreds.
    The important results obtained were as follows:
    (1) When the“G”or the“GR”increased, the equilibrium moisture content of shreds increased, the filling capacity decreased and the fragility of shreds decreased.
    (2) The addition of glycerol to tobacco had a very large effect on the fragility of shreds, medium on the filling capacity and slight on the equilibrium moisture content.
    (3) The“GR”in the shorter part obtained by sieving shreds appeared to be larger than that in longer one.
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