Journal of the Society of Materials Science, Japan
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
Volume 24 , Issue 263
Showing 1-11 articles out of 11 articles from the selected issue
  • Kozo IKEGAMI
    1975 Volume 24 Issue 263 Pages 709-719
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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  • Tomomichi TOMIIE, Masakazu KAGAWA
    1975 Volume 24 Issue 263 Pages 720-725
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The objective of the present study is to see the applicability of hardness test in order to grasp the mechanical characteristics of plastic pipes. In this paper, the relation between hardness and deflection appearing in a direction parallel or perpendicular to the axis of a plastic pipe has been clarified.
    The results obtained are as follows:
    (1) Hardness should be measured on the spots at least 20mm apart from the edge of pipe.
    (2) Both Vickers and Shore hardness testers can be applied for testing plastic pipes.
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  • Noriyoshi YAMADA, Kazuhiko YONEDA
    1975 Volume 24 Issue 263 Pages 726-732
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Flexural creep tests on several engineering plastics were carried out for more than three years at room temperature.
    Deflections after two or more than three years were estimated from the data in the first stage of the creep tests, and the accuracy of estimation was discussed by comparing the estimated values of deflections with observed ones.
    The results obtained are as follows:
    (1) Using the five data points obtained in the period from 96hrs to 504hrs (three weeks), the total deflection after two or more than three years can be estimated within about 5% error.
    (2) The following two equations are applicable for the estimation:
    logY=alogt+b (1)
    log(Y-Y0)=a'logt+b' (2)
    where Y is deflection, Y0 initial deflection, t time, and a, b, a', and b' are constants.
    The values calculated from equation (2) are larger than those from equation (1), and equation (2) is better than equation (1) especially for estimating the deflection of glass-fiber reinforced thermoplastics.
    (3) The constants a and a' in the equations are related to the rate of increase in total deflection and the creep speed and are independent of stress. Especially, the constant a' is almost independent of glass-fiber contents, and it takes a particular value for each plastics.
    The constants b and b' depend on the modulus of specimen, so that their values are controlled by the loading stress.
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  • Shuji TAIRA, Keisuke TANAKA, Toshinori YOKOMAKU
    1975 Volume 24 Issue 263 Pages 733-740
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    Bilby-Cottrell-Swinden model of the plastic deformation near the tip of a notch or crack gives two important parameters, i. e., the plastic zone size and the crack tip opening displacement, for analyzing fatigue and fracture problems. For several cases of specimen geometry which are significant in the field of engineering, analytical solutions of BCS model have not yet been obtained. In this paper, the authors discuss some approximations of BCS model analysis in order to incorporate the effects of the specimen finite width and the notch on the plastic zone size and the tip opening displacement. These approximations will be valuable to the engineering analysis of the problems of fatigue and fracture.
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  • Atsushi FUKUSHIMA, Shigenori KINOSHITA
    1975 Volume 24 Issue 263 Pages 741-746
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    As a probability model of rock failure, the weakest link model has been usually used in pure tension. In compression, however, recent laboratory investigations show that most rock specimens can have the load bearing capability if subjected further displacement after the peak load has been reached. In order to explain the complete stress-strain characteristics of rock in compression, the weakest link model is not adequate to be applied.
    In this paper, a new model is proposed for compression of rocks on the assumption that the strain in compression consists of the permanent strain (εp) and the elastic strain (εe), the ratio of permanent strain to the total strain being increased according to the Weibull's cumulative distribution function and that the bearing stress of a rock specimen at any deformation is proportional to the amount of elastic strain being survived.
    By these hypotheses, the following equation can be derived to express the complete stress-strain relation for uniaxial compression of rock.
    σ=E(1-F(ε))ε
    where, E=Young's modulus,
    F(ε)=εp/ε=1-exp(-εm/α)
    The results computed for various values of inhomogenity parameter p(=m=α) are shown Fig. 3 (a) and (b).
    By expanding the idea to the dilatancy of rock in uniaxial compression. an equation to represent to volumetric strain (εV) over the whole range of pre-and post-failure regions can be derived. The equation is as follows.
    εV={(1-2ν0)(1-F(ε))-CF(ε)}ε
    where, ν0=intrinsic poisson's ratio
    C=dilatancy coefficient
    The effects of dilatancy coefficient C and the parameter p on the complete stress-volumetric strain curve are shown in Figs. 5, 6 and 7.
    According to the present analysis, the apparent secant modules and the apparent poisson's ratio are found to be
    E*=E(1-F(ε))
    ν*=1/2(2ν0+(1-2ν0+C)F(ε))
    They are shown in Figs. 8, 9, 10 and 11.
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  • Akio TAKADA, Masateru OHNAMI, Yoshiteru AWAYA, Kiyoshi UMEDA
    1975 Volume 24 Issue 263 Pages 747-752
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The objective of the present study was to elucidate the effect of strain restriction resulting from the difference in notched section form of metallic specimens on creep rupture life at elevated temperatures and also the effect of vacuum environment on rupture life. From the results of tensile creep rupture tests on notched plate specimens of 1Cr-1Mo-1/4V steel in both atmospheric pressure and vacuum at 600°Cand of numerical calculations by use of the finite element method, the following conclusions have been derived.
    (1) When the present results of notched plate specimens were compared with those of notched cylindrical specimens reported previously, the creep rupture life of a notched cylindrical specimen was longer than that of a notched plate specimen in the region of notch-strengthening, but there was little difference between both data in the region of notch-weakening. This may be interpreted on the basis of the difference in the equivalent stresses or the strains at the notch bottom of cylindrical and plate specimens.
    (2) The creep rupture life of a notched plate specimen in vacuum was almost the same as that in atmospheric pressure in the region of notch-strengthening, but in the region of notch-weakening the former was shorter than the latter.
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  • Hiroshi KOGANEI, Satoshi TANAKA, Tadakazu SAKURAI
    1975 Volume 24 Issue 263 Pages 753-760
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The changes in mechanical properties of carbon steel fatigued ultrasonically at 17kHz have been investigated. The results were compared with those fatigued by the rotary bending test at 3000rpm.
    The following conclusions are obtained:
    (1) The fatigue life of carbon steel cycled at 17kHz is longer than that of the same material fatigued at 3000rpm. This is more pronounced in annealed (An.) materials than in low-temperature quenching (LTQ) ones.
    (2) The variations of hardness Hv and residual stress σi during the fatigue test are smaller at 17kHz than at 3000rpm fatigue.
    (3) The variations of both Hv and σi for S10C (0.1%C) during the faigue test at 17kHz are slightly smaller than those for S45C (0.42%C). In the case of 3000rpm fatigue, however, these variations values for S10C are fairly larger than those for S45C.
    (4) In both 17kHz and 3000rpm tests, the amounts of change in Hv, σi and E become larger as the stress amplitude increases.
    (5) In the fatigue process at 3000rpm, the amount of change in Hv of LTQ specimen is larger than that in Hv of An. specimen. However, there is no significant difference between them in the process of 17kHz fatigue.
    (6) The number of slip lines produced on the specimen surface fatigued at 17kHz is far fewer than that at 3000rpm, especially in LTQ materials. However, the number of cracks is not so different between them. It is confirmed that those characteristics may influence the hardness and Young's modulus.
    (7) The relationship between the hardness and the residual stress can be expressed as follows:
    Hv=Hv0+ei
    where k is a constant which depends upon the kind of materials, working conditions and fatigue testing conditions. This equation, however, is not applicable to the later stage of the fatigue test nor to the quenched materials.
    (8) The relationship between the residual stress and Young's modulus can be expressed as follows:
    σi=K1EtEst/ΔE
    i>0.5kg/mm2 in carbon steel)
    where ΔE=Est-Et; Est being Young's modulus in saturation magnetization and Et being Young's modulus in non-magnetization.
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  • Sadahiro INOUE
    1975 Volume 24 Issue 263 Pages 761-768
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    The main purpose of the present study is to obtain an epoxy resin mortar which can be used safely in environments below freezing point. The mechanism of curing of the binders used in the experiment consists of the ring opening of the epoxy radical by amine as the electron donor and the subsequent addition polymerization.
    The tensile test specimens were briquets of ASTM C 190, while the bending test specimens were prisms of JIS R 5201 or prisms of 2×2×10cm. The compressive test specimens were fragments of prisms of JIS R 5201 or of cylinders of 2.5cm (diameter)×5cm (height). The aggregate used was absolutely-dried sea sand. The binder content was 15per cent.
    The experiments to find (1) properties of binders, and (2) short period strength development were conducted using 20 kinds of test manufactured products at -6°C. As for (1), the viscosity ranged from 400∼557000cps, the gel time from 35∼161min, and the maximum exotherm temperature from -1∼+195°C. The consistency, stench, and exotherm profile at +4°C or -1°C were also examined. As for (2), the curing time was 1, 2, 4, 8, or 16 days. The strengths in 8 day's curing were 22∼130kg/cm2 (tensile), 63∼360kg/cm2 (bending), and 128∼645kg/cm2 (compressive), and it was possible to regard these value approximately as equilibrium values. The cured materials which showed good flexibility generally exhibited high strengths.
    An epoxy resin mortar which showed the most prominent performance in these experiments was used for the experiments to find (3) long period strength development at -6°C, and (4) strength development at fluctuating temperatures. As for (3), the curing time was 0.5, 1, 2, 3, 4, or 6 months. The maximum strengths were 151kg/cm2 (tensile, 0.5 month), 417kg/cm2 (bending, 1 month), and 808kg/cm2 (compressive, 4 months). As for (4), the curing conditions were chosen from the combinations of -15°, -6°, and +10°C. Sufficient strengths for practical applications were obtained under all the curing conditions.
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  • Kohei SAITO
    1975 Volume 24 Issue 263 Pages 769-775
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    For the purpose of defining quantitatively the influence of soluble sugar content“S”in tobacco on the tensile characteristics“Y”of tobacco leaves, the following multiple regression formula, with three independent variables (temperature“t”, moisture content “w”and “S”), was statistically determined by using the experimental data obtained on flue-cured tobacco cultivated in Japan.
    Y=ko+kt·t+kw·w+kS·S+kl
    Furthermore, the variation of“Y”caused by the change in “t”, humidity, water extraction of tobacco, leaf position on a stalk“p”and direction of specimen on a leaf“l”, were statistically analyzed by five-way classification. The“Y”represented the tensile strength, elongation percentage, elastic modulus or elasticity per unit dry weight of tobacco. The results obtained were as follows;
    (1) Tensile strength“Pm”.
    The influences of“p”and“l”on“Pm”were greater than those of“t”, “w”and“S”. The value of“Pm”increased with increasing“p”.
    (2) Elongation percentage“ε”. The influences of“S”and“w”on“ε”were higher than those of“t”, “p”and“l”. The value of“ε”increased with increasing“S”and“w”.
    (3) Elastic modulus“E”and elasticity per unit dry weight“EG”. The influences of“S”on“E”and“EG”were stronger than those of“w”, “t”, “p”and“l”. The values of“E”and“EG”decreased with increasing“S”.
    (4) In conclusion, the effects of“S”on“E”and“EG”was greater than those on the other tensile characteristics, and the effect of“S”on“ε”was greater than that on“Pm”.
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  • Osamu HAGA, Noriyuki HAYASHI, Kazuo KASUYA
    1975 Volume 24 Issue 263 Pages 776-782
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
    A new type of Biaxial testing machine utilizing flat specimens has been assembled to investigate the mechanical behaviours and failure strength of glass cloth reinforced plastics under a combined tension-compression biaxial stress state. This machine is composed of the tension and compression devices which have the mechanism of preventing shifting of the center of a specimen during biaxial test.
    The structure of this machine is described in the paper. The experimental results of failure strength of glass cloth reinforced plastics under a biaxial stress state are compared with those caluculated by using the interaction formula. The observed values were found not to agree well with the calculated results, and a criterion such as Hill's was not applicable to this case.
    From the consideration of the failure mode, some suggestions have been made to obtain the way to find a more exact failure criterion.
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  • H. Ishikawa
    1975 Volume 24 Issue 263 Pages 783-788
    Published: August 15, 1975
    Released: June 03, 2009
    JOURNALS FREE ACCESS
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