材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
25 巻 , 277 号
選択された号の論文の13件中1~13を表示しています
  • 小林 一輔
    1976 年 25 巻 277 号 p. 937-945
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 井上 貞弘
    1976 年 25 巻 277 号 p. 946-952
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The accelerated weatherability (40°C, 2000hrs), heat resistance (100°C, 2000hrs), and water resistance (20°C, 2000hrs) of jointings of successive pours of cement mortar-epoxy-resin mortars (8 kinds), and jointings of successive pours of cement mortar-K cement mortar with epoxy resin adhesives (11 kinds) were investigated. The curing condition of test specimens was 4°C for 28 days. Their strength retentions (tensile bond, bending bond, compressive: mortar) and variation of failure states were examined.
    The results obtained are summarized as follows:
    (1) All of the original test specimens showed good performance for practical use.
    (2) All types of test specimens showed a correlation between the strength after exposure to weather meter and the strength after water soaking.
    (3) The retention of bond strength of jointings of successive pours of cement mortar-epoxy resin mortars after the weather meter test and the water soaking test was satisfactory for the combinations of DGEBA or modified DGEBA and modified ALP, but not so for the combination of DGESPA and modified XDA.
    (4) The retention of bond strength of jointings of successive pours of cement mortar-K cement mortar by epoxy resin adhesives after the weather meter test and the water soaking test was good for the combinations of DGEBA or modified DGEBA and modified ALP, blend of ALP or blend of modified ARP, but not good for the combination of DGESPA and modified XDA.
    (5) As the result of decrease in strength of cement mortar and K cement mortar near the interface by the Geer oven test, the bond strength retention was found to be lowered for all jointings (with one exception).
    (6) Only the epoxy resin mortar which comprised of the combination of DGESPA and modified XDA as the binder showed a remarkable decrease in compressive strength by the Geer oven test.
  • 佐々木 茂美, 越智 保雄
    1976 年 25 巻 277 号 p. 953-959
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Rotating bending, push-pull and plane bending fatigue tests were carried out in the high cycle fatigue region with unnotched specimens of five kinds of carbon steel at room temperature. The results obtained are as follows.
    (1) The fatigue process was divided into three stages based on the variation of plastic strain range εpg. In the first stage, εpg increased with the number of stress cycles n and reached to the maximum value εpgM at stress cycles nM. In the second stage, εpg decreased with n and reached to the minimum value εpgV at nV. In the last stage, εpg was almost constant or increased slightly.
    (2) The ratio of εpgV to εpgM was nearly constant for various stress amplitudes σg as follows,
    pgVpgM)=C1
    where C1 was an experimental constant dependent upon the kind of test materials.
    (3) The increase of εpg during the first stage and the decrease of εpg during the second stage corresponded with the decrease of fatigue life N, and the relations between the maximum increase εpgM and nM, and between the maximum decrease (εpgMpgV) and (nV-nM) were as follows,
    εpgM·nMm2=C2
    pgMpgV)·(nV-nM)m3=C3
    where m2, m3, C2 and C3 were experimental constants and nM and nV corresponded with the numbers of stress cycles at micro-crack initiation and macro-crack initiation, respectively.
    (4) With regard to fatigue damage, the damage (D12) for the first and second stages was related to the variations of plastic strain range εpg1 in the first stage and εpg2 in the second stage as follows,
    D12=(εpg1pgM)·(D1)max.+{εpg2/(εpgMpgV)}·(D2)max.
    where (D1)max. and (D2)max. were the maximum values of fatigue damage for the first and the second stages, respectively.
    (5) With regard to fatigue life, the relation between the life N and εpg was shown as,
    pgM+(εpgMpgV)}·Nm5=C5
    where m5 and C5 were experimental constants and m5≈0.5, C5≈εFF: tensile ductility) in this study.
  • 徳岡 辰雄
    1976 年 25 巻 277 号 p. 960-966
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The constitutive equations of a plastic material with isotropic work-hardening are proposed. The plastic potential is assumed to be a function of the stress and the scalar internal state variables. Here four restrictions are taken into consideration, that is, (1) linear elasticity, (2) pressure-insensitivity, (3) no generalized Bauschinger effect, and (4) grade two for stress. A rate-type mechanical constitutive equation is derived which relates the stress rate to the stretching and has a coefficient depending on the internal state variables. Evolutional equations, which govern the temporal variations of the internal state variables, are also derived. From a point of view of the theory of ordinary differential equation the number of the variables is reduced to one. From the constitutive equation the yield criterion and the flow rule are naturally specified, and a generalized Huber-von Mises yield criterion with isotropic work-hardening and the Lévy-St. Venant flow rule are obtained.
  • 徳岡 辰雄
    1976 年 25 巻 277 号 p. 967-973
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Here the loading and unloading behaviors are investigated theoretically for the Prandtl-Reuss plastic material with the isotropic work-hardening, which was derived in the preceding paper. The constitutive equations consist of the mechanical equation of rate type and the evolutional equation of a scalar internal state variable α. The steady extension is analyzed and the stress-logarithmic strain relations are formulated, where α plays as a parameter. The steady extension in the uniaxial stress is also analyzed for the incompressible material. The material function of the type M(α)=M0(1+aα)n is adopted, where M0, a and n are the material constants. The function specifies the yield phenomenon and the work-hardening. The constants a and n represent, respectively, the magnitude of the work-hardening and the variation of it. The results of the numerical calculations are depicted.
  • 北川 正義, 小河 弘
    1976 年 25 巻 277 号 p. 974-978
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The crazing phenomenon is one of the most interesting problems in the field of polymer engineering science. Many investigations have been carried out to clarify a criterion for craze initiation. The experiments under conditions of uniaxial and biaxial stress states have showed a critical stress or strain criterion. Almost all of these experiments have been carried out by use of isotropic polymers.
    It is the purpose of this paper to investigate the craze initiation criterion and yield behavior of anisotropic polycarbonate plates obtained by cold rolling. The stresses of craze initiation and yielding and the craze direction were measured as a function of orientation angle between the tensile axis and the rolling direction, under tension in the presence of kerosene.
    The results are summarized as follows.
    (1) Elastic modulus increases with an increase in rolling reduction.
    (2) Critical crazing strain for rolling direction increases considerably with an increase in rolling reduction.
    (3) Craze direction varies with the orientation angle. This trend can be explained by the maximum principal strain theory.
  • 北川 正義
    1976 年 25 巻 277 号 p. 979-983
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    Craze and crack growth in polycarbonate, polyvinyl chloride and polymethyl methacrylate have been investigated under the presence of kerosene. The experiment for craze growth was carried out under the conditions of both constant rate loading and cyclic loading since the results under dead weight and step-wise loadings had previously been obtained. The delayed crack growth rate was investigated as a function of stress intensity factor.
    The experimental results were compared with the theoretical predictions derived from a model taking creep into account, which was proposed by the author.
    The results are summarized as follows.
    (1) The theory seems to hold also for the craze growth under constant rate and cyclic loadings.
    (2) The delayed crack growth may be classified in two types. One is the fibrous fracture type and the other is the quasi-brittle fracture type. The former type crack growth can be explained by the modified Knauss theory with the same time function as that of craze growth.
  • 増田 雄市郎
    1976 年 25 巻 277 号 p. 984-990
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    One and two-stress level fatigue tests have been conducted to investigate the fatigue properties of glass fiber reinforced plastics, especially the relation between cumulative fatigue damage and residual strength. The materials used for the experiment were FRP laminates made of polyester resin and plain woven roving glass cloth. The tests were performed in repeated tension with the minimum value of cyclic stress equal to 5 percent of the cyclic stress amplitude.
    The tensile strength of the material under fatigue loading decreased with increaing the number of stress cycles, and fatigue failure occured when the residual strength became equal to the maximum value of cyclic stress.
    The reduction of the residual strength at a given stress level has been determined as a function of number of cycles. The experimental results show that for the high-low stress cumulative damage test the Miner's sum, (n1/N1)+(n2/N2), is greater than unity and for the low-high stress test less than unity.
    These observations agree both qualitatively and quantitatively with the predicted values of fatigue lives based on the strength reduction theory.
  • 大南 正瑛, 今村 龍三
    1976 年 25 巻 277 号 p. 991-997
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The creep-rupture properties of SUS 316 stainless steel were studied in both air and vacuum of 10-3 torr at 600°C. In the test, unnotched and notched cylindrical specimens were used.
    The following conclusions were obtained.
    (1) The rupture lives of both unnotched and notched specimens in vacuum were shorter than those in air. Especially, a larger environmental effect was observed for unnotched specimens.
    (2) The rupture time ratio, tr (notched) /tr (unnotched), in vacuum was larger than that in air. The environmental rupture time ratio, tr (air) /tr (vacuum), decreased with increase of stress concentration factor Kt.
    (3) No difference between the structure of the crept unnotched specimen in air and that in vacuum was observed in terms of intergranular cracks, densities of elements in oxide layer, the size and distribution of precipitated Cr23C6 in the grain boundaries.
    (4) It was considered that the remarkable increase of steady state creep rate in vacuum resulted from the increase of dislocation density or the associated lattice strain on the basis of the measurement of micro strain by X-ray diffraction technique.
  • 平 修二, 田中 啓介, 横幕 俊典, 中川 幸長
    1976 年 25 巻 277 号 p. 998-1004
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The relationship among notch-tip opening displacement, notch-tip contraction and J-integral below and beyond general yield was experimentally established based on the results of tension tests on 7075-T6 Al alloy, 3%Si-Fe and 0.04%C steel sheet specimens with various values of thickness and notch depth.
  • 宮内 信之助, 大宮 行雄, 横塚 正俊, 大北 熊一
    1976 年 25 巻 277 号 p. 1005-1009
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
    The polymers containing furnace black grafted with n-butyl acrylate or acrylic acid were cured with a peroxide (di-t-butyl peroxide, cummene hydroperoxide or di-cumyl peroxide) and a divinyl monomer (ethylene dimethacrylate), and their degree of crosslinking was determined by the measurement of gel fraction. Di-cumyl peroxide-ethylene dimethacrylate system was found to show the highest crosslinking efficiency. Then, the resistors were made from the polymers with different degrees of crosslinking by coating the carbon black-graft polymers dispersed in acetone on porcelain plates and heating them at 150°C for 5hr., and their electric resistance were measured.
    The following results were obtained:
    (1) The volume resistivity was in the range of 6∼8Ωcm.
    (2) The temperature coefficient was nearly equal to zero, regardless of the degree of crosslinking.
    (3) The hysteresis of resistance against temperature was smaller than that of the resistors made from the polymers crosslinked with epoxy resin and it decreased with increasing crosslinking.
  • 1976 年 25 巻 277 号 p. 1010-1019
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 藤井 太一
    1976 年 25 巻 277 号 p. 1020-1029
    発行日: 1976/10/15
    公開日: 2009/06/03
    ジャーナル フリー
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