材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
38 巻 , 427 号
選択された号の論文の19件中1~19を表示しています
  • 平井 恒夫, 片山 傳生, 平井 三友, 経澤 昌芳
    1989 年 38 巻 427 号 p. 334-340
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of this study is to establish a quantitative deformation analysis of the out-of-plane deflections occurring in a product when released from the mould.
    At first, it was investigated how the thickness of the skin layer is influenced by the mould temperature, by using thermal conduction analysis and experiment. Secondly, fibre orientation in the skin layer was made clear by soft X-ray photograph and visualization. Finally, a deformation analysis was attempted with consideration for the fibre orientation in the skin layer.
    The following conclusions were obtained.
    (1) It became clear that skin layer formation has two patterns; one is to rotate the fibre in a 180-degree arc and another is not to rotate. The fibre in the core layer is taken into the skin layer after reaching at the flow front.
    (2) As the fibre orientation is different in the skin layer from that in the core layer for injection moulding of FRTP, it is desirable to consider the influence of the fibre orientation in skin layer on the material constants.
    (3) By comparing the analytical results with the experimental results, it appears that this flow analysis considering thermal conduction gives satisfactory prediction for the thickness of the skin layer.
    (4) By comparing the analytical results with the experimental results of deformation, it appears that this deformation analysis considering the skin layer gives satisfactory quantitative prediction.
  • 平井 恒夫, 片山 傳生, 平井 三友, 川釣 正哉
    1989 年 38 巻 427 号 p. 341-346
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The purpose of the investigation is to devise a procedure for the computer aided design of the injection moulding process for FRTP (Fibre Reinforced Thermo-Plastics), taking the fibre orientation into consideration.
    This system consists of a series of analyses of flow, the flow fibre orientation and warp. The state of the composites in the core layer is two-dimensionally analysed by taking the friction against the upper and lower skin layer into consideration. The fibre orientation analysis is carried out, where it is assumed that the fibres are tracked rotating according to the velocity gradient tensor obtained in each element from the numerical results of the flow state analysis. The relationship between the fibre orientation factor and temperature depending material constants are determined and the warp occurring in a product is simulated. The above system was applied to two-dimensional thin plates.
    In this paper, analysis of the flow state of the three-dimensional structure of plate construction, such as a box was tried out. Two-dimensional analysis was used in each plate and constructed by the coordinate transformation along the edge element. In consideration of the flow state on the edge, the frictional resistance was varied in the element. The result was in good agreement with the experiment.
  • 網島 貞男, 藤井 透, 佐上 太介, 松岡 敬
    1989 年 38 巻 427 号 p. 347-353
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Static tests under tension/compression-torsion biaxial loading were conducted using tubular FRP specimens reinforced by plain woven glass cloth. Stress-strain curves were observed with a biaxial extensometer developed by the authors. In order to take account of the large deformation which is one of the unique charactaristics of FRP, the strength and S-S curve were evaluated with the Piola-Kirchhoff stress tensor and the Green-Saint Venant strain tensor, and these results were also compared with the S-S curves based on the nominal stress and nominal strain. The effects of normal stress to shear stress ratio (i.e, combined stress ratio) on both strength and steess-strain relations were also investigated. The following results were obtained;
    (1) For orthotropic materials having large deformation capability, their properties (strength and stress-strain relations) must be evaluated with Piola-Kirchhoff stress tensor and Green-Saint Venant strain tensor.
    (2) The combined stress ratio has no effect on the stress-strain relation within an elastic range, but it affects not only on the stress level where the yield point appears but also on modulus decay after yielding.
  • 逢坂 勝彦, 福田 武人, 小泉 明久
    1989 年 38 巻 427 号 p. 354-359
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this paper the strength and the process to failure of the cylindrical adhesively bonded joints of fiber reinforced plastics have been investigated under combined bending and torsional loading conditions. Experiments were performed with an apparatus capable of applying bending and torsional moments in various proportions. From the results of the strength under combined bending and torsional loading, it was found that the failure criterion of cylindrical joints of FRP was expressed by an elliptic form equation. In order to know the extent of damage in the joint, strains and AE in this part were measured in tensile, bending, torsional and combined bending and torsional loading tests. From these results it became clear that the failure of cylindrical adhesive joints was mainly in the adhesive layer under tensile loading, while under other loading conditions damage was undergone in adherent. It was also found that the damage region in the joint was characterized by the loading conditions. It was observed that under the bending condition the central area of the joint was mainly damaged and with increase of the ratio of the torsional moment to the bending moment, the main damage area was extended to the joint end.
  • 孫 峰, 岩本 正治, 自念 榮一, 鈴木 惠
    1989 年 38 巻 427 号 p. 360-366
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The fracture mechanisms of plain woven fabric laminated composites were studied by load-displacement curves, AE behavior, and macro- and micro-observations in tensile tests. The results obtained are as follows:
    (1) The failure processes which are accumulative can be divided into three stages on the load-displacement curves of the composites. The stage I is elastic. In the stage II, the debonding in weft takes place. The stage III mainly corresponds to the matrix cracking and the separation between wefts and warps. They depend on the weave structure strongly but are related little with the ply number of laminates.
    (2) The boundaries of the stages I to II and II to III have some relations to the point where the AE event count rate can be detected first and the point where the rate increases rapidly, and thus the dominant failure mode can be well traced from the patterns of the AE event count rate and the AE energy curve.
  • 武田 展雄, 東藤 貢, 桜田 泰弘, 高橋 清
    1989 年 38 巻 427 号 p. 367-371
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The degradation behavior of high-energy electron irradiated epoxy based FRP composite laminates was studied using the Mode II interlaminar fracture toughness GIIC, measured by ENF tests. The radiation-induced degradation mechanisms were investigated with GIIC and the scanning electron micrographs of fracture surfaces.
    For GFRP the significant decrease in GIIC was found. Debonding of glass fibers and epoxy matrix (or degradation of silane coupling agents) plays an important role in degradation in addition to resin degradation. Thus, the improvement of the radiation resistance of fiber-resin interfaces as well as matrix itself is of supreme importance in order to increase the radiation resistance of GFRP.
    For CFRP, on the other hand, no degradation in fiber-resin interfaces was found and the slight decrease in GIIC seems to be due to the resin degradation.
    The sensitivity of radiation-induced degradation was more pronounced in the Mode II Interlaminar fracture toughness than in the interlaminar shear strength, for both GFRP and CFRP. Consequently, interlaminar fracture toughness measurements were found necessary for evaluating properly the radation-induced degradation of FRP composites.
  • 東 健司
    1989 年 38 巻 427 号 p. 373-383
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 加藤 寛, 中村 一明, 小林 一夫, 吉川 敬治
    1989 年 38 巻 427 号 p. 384-390
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Al-4wt% Cu alloy ingots with solute segregation were produced by iterative casting with seed, and their structures and mechanical properties were measured. The grain size increased with the iterative casting, and the ingot after the 4th iterative casting consisted of almost one grain. The primary arm spacing λp and the secondary arm spacing λs had relations with the cooling rate V and the local solidification time θ; λp[mm]=0.17·υ-0.56[K/S], and λs[mm]=0.015·θ0.29[S]. These agreed well with the previous results for alloys consisting of columnar grains or equiaxed grains. The yield strength σy, the ultimate tensile strength UTS and the elongation of 4th ingot decreased with primary arm spacing λp. After heat treatment, there was no dependence of σy and UTSL (parallel to primary arms) on the spacing λp, but UTST (perpendicular to primary arms and parallel to secondary arms) and the elongation varied with λp. These results imply that σy and UTSL are largely affected by the solute segregation, and UTST and the elongation are largely affected by cavities and micro-cracks created during solidification.
  • 池内 保一, 藤原 晴夫
    1989 年 38 巻 427 号 p. 391-397
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Since there is a considerable degree of thermal expansion mismatch between fiber and matrix in a γ-Al2O3/Al composite, this system inevitably is in a residual thermal stress state after cooling down from its fabrication or annealing temperature. In this study a programmable automated system of X-ray stress analysis with a para-focusing Ω-diffractometer was developed and applied to in-situ measurements of the matrix thermal stress during the thermal cycling process of the composites. The results obtained are as follows:
    (1) X-ray diffraction technique is found to be an effective method for determining thermally induced stresses in the Al matrix of this composite system.
    (2) On cooling the composite from the annealing temperature of 600K to room temperature (RT) the Al matrix showed a tensile residual stress of 30Mpa. Thereafter, on cooling the composite to liquid nitrogen temperature and heating back to RT a compressive residual stress of -27Mpa was observed in the matrix. On the subsequent reheating process from RT to 530K the matrix plastically deformed in compression.
    (3) When the composite underwent a change in temperature, the Al matrix deformed in such a way as to modify thermal expansion mismatch between fiber and matrix. In the case of reheating process after cooling the composite from 530K to RT, the Al matrix showed a remarkable Bauschinger effect.
    (4) During the repeated thermal cycling between RT and 530K, the Al matrix plastically deformed and a steady state of the thermal stress-temperature hysteresis loop was observed after only one cycle.
  • 三木 武司, 戸田 正弘
    1989 年 38 巻 427 号 p. 398-403
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Work hardning of a steel in the cold forging process affects strongly the tool life. In the present paper, work hardening behaviors of various kinds of steels in three typical processes, upsetting, forward extrusion and backward extrusion were studied by the measurements of a change in the forming load and the half-value breadth of X-ray diffraction profile which reveals approximate dislocation density.
    It was found that a significant Bauschinger effect appears with the combination of drawing and upsetting, but rarely appears with the other combination such as drawing and forward extrusion, and drawing or upsetting and the subsequent backward extrusion.
  • 平均応力波形の影響
    鎌田 敬雄, 西田 新一
    1989 年 38 巻 427 号 p. 404-409
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Push-pull fatigue tests were conducted on 80kgf/mm2 steel under the combination of regularly applied understresses and intermittently applied overstresses. The mean stress superimposed on understresses changed periodically to form a overstress range pair at the time of the mean stress change. The effects of understress application, mean stress superposition on understresses and the mean stress wave form on the crack growth rate were investigated. Crack initiation and propagation lives in the tests conducted under the combination of over- and under-stresses were much shorter than expected when only the overstress cycles were counted, neglecting the damage of understresses. The stress amplitude even about 50% of the endurance limit of the steel was judged effective to make both of crack initiation and growth lives shorter. Crack initiation and growth lives in the tests with the sporadic down-spike stress change and with the rectangular stress change seemed almost equal to each other, and much shorter than those for the constant amplitude test. In two-step P-N interval tests, the crack growth rate was higher than that for the two-step N-P interval test, and even crack growth rate for the N-P test was higher than that for the completely reversed constant amplitude test at relatively smaller values of ΔK.
  • 升田 博之, 松岡 三郎
    1989 年 38 巻 427 号 p. 410-415
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to predict the most reliable fatigue life under variable loading conditions such as survice environments, a new fatigue test method was developed, and by using it the fatigue crack propagation properties were studied for HT80, SM50B and SUS 304 steels.
    The test results show that, although no crack closure occurred in both the variable and constant loading tests, the crack propagation rate under the variable loading test condition was much faster than that under the constant loading test condition for all tested alloys especially at low ΔK regions.
    The maximum acceleration of the crack propagation was dependent of the variable loading amplitude. When the variable load was frequently applied, the crack propagation rate became proportional to second power of ΔK.
    From these results, it can be said that the new fatigue test method is one of the best methods to predict the most reliable fatigue life under variable loading conditions.
  • 新田 明人, 緒方 隆志, 桑原 和夫
    1989 年 38 巻 427 号 p. 416-422
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The authors have conducted in-phase and 90° out-of-phase push-pull and torsion fatigue tests on SUS304 stainless steel at 550°C and investigated its fracture mechanism and fatigue failure criterion. This paper assesses the results of the push-pull and torsion fatigue tests which have the shear strain to normal strain ratio of 1.5 with 30°, 45°, 60° phase difference at 550°C and discusses the transition condition of the fracture mode and the low cycle fatigue failure criterion for the biaxial fatigue data obtained in this study as well as for those in the previous study. From the strain analysis and the fracture surface observation in the in-phase and out-of-phase tests, the fracture mode transition condition which depends on both the values of Δεmax/Δγmax and Δεn/Δγmax was determined, and the biaxial fatigue fracture mode map for a SUS304 stainless steel at 550°C was drawn on the basis of these values. Equivalent strain energy, ΔE, was defined by iso-fatigue life evaluation from a plane with tensile strain energy, ΔEI on the y-axis and shear strain energy, ΔEII, on the x-axis. Fatigue failure life under out-of-phase straining conditions could be correlated well with equivalent strain energy.
  • 新田 明人, 緒方 隆志, 桑原 和夫
    1989 年 38 巻 427 号 p. 423-429
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to investigate the fracture mechanics law of macroscopic crack propagation in thermal fatigue, strain-controlled thermal fatigue tests on Cr-Mo-V rotor steel and SUS304 stainless steel were carried out by using a notched specimen. A smooth specimen was also employed for thermal fatigue tests under the same conditions as the crack propagation tests to discuss the applicability of the fatigue life law (i.e., the strain-energy-parameter approach) derived from the macroscopic crack propagation law to thermal fatigue life evaluation.
    The results obtained were summarized as follows:
    (1) The characteristics of thermal fatigue crack propagation could be classified into two types (i.e., cycle-dependent and time-dependent) by applying the transition criterion between the types.
    (2) The fracture modes in the cycle-and time-dependent thermal fatigue were of transgranular and intergranular types, respectively.
    (3) The fatigue J-integral range, ΔJf, was a fracture mechanics parameter controlling the crack propagation rate, dl/dN, in the cycle-dependent thermal fatigue, while the creep J-integral range, ΔJc, in the time-dependent thermal fatigue. In this case, rapid straining could be successfully applied to the partition of the inelastic strain into plastic and creep components for evaluating the ΔJc-value. The crack propagation law (i.e., the dl/dNJf and dl/dNJc relations) in thermal fatigue was identical with that obtained in isothermal fatigue.
    (4) The thermal fatigue failure life of the smooth specimen was correlated with the strain-energy parameter, and the correlation agreed with that in isothermal fatigue. Also, it could be predicted from the crack propagation characteristics obtained by using the notched specimen.
  • 安部 英昭, 下屋敷 重広, 前田 納
    1989 年 38 巻 427 号 p. 430-436
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    In order to investigate the fatigue strength of bellows at elevated temperature, fatigue tests at room temperature and 500°C, and stress analyses have been conducted on the manufactured bellows. The manufactured bellows are a two-ply type, in which strain can be decreased by axial extension and compression without loss of stiffness against pressure.
    It was found that the strain distribution changed with the bellows thickness and usually the maximum strain appeared at the outer surface of the root in the outer bellows. In order to estimate the fatigue lifetime of bellows, the octahedral shearing strain derived from both the axial and circumferential strains was found to be more effective than the estimation with only the axial strain, which is commonly used. Fatigue cracks were produced in the maximum strain area, and the cracks propagated from the outer surface to the inner surface of the bellows. It seems that the strain intensity factor obtained from the measured strain is effective for estimation of fatigue crack propagation rates.
  • 田中 道七, 山元 茂, 岡部 永年, 中山 英明, 福地 雄介
    1989 年 38 巻 427 号 p. 437-443
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    Engineering ceramics have two opposite aspects in their mechanical properties; low fracture toughness and high compressive strength together with excellent wear properties. The aim of this study is to develop a method of determining the compressive fracture strength of engineering ceramics precisely by using a simple loading device. In compressive fracture tests, attention must be paid not to introduce tensile stress at fracture originating locations, since ceramics are typically about 10 times stronger in compression than in tension, fracture may occur by tensile stress even in compressive loading when intensity of tensile stress field reach some critical condition.
    In the experiments, investigated was the effect of some factors, such as thin steel sheet inserted between an anvil and specimen and the size of chamfer at the corner of cylindrical specimen, on compressive strength and fracture mode. The results on two engineering ceramics, Si3N4 and SiC, indicate the following features on fracture strength and fracture mode: (1) When radial and tangential tensile stresses are generated in the end face layer of specimen, vertical cracking type fracture occurs, and such stress distributions are due to the elastic deformation of the thin steel sheet with low elastic modulus in comparison with the cramics studied. (2) When the above stress condition can be avoided, the specimen shows crushing type fracture following cleavage cracking of small flakes at the side face near the corner edge of specimen where tensile radial stress of high intensity is generated, and such a stress condition is attained when specimen end faces are directly loaded compressively without the thin sheet so as to constrain the radial deformation of specimen end face not to occur.
  • 椿 隆行, 後藤 幸光
    1989 年 38 巻 427 号 p. 444-450
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
    The effect of fiber content on the fundamental properties of heat insulators in the vermiculite-fibriform material-phosphate system was investigated by measuring their apparent porosity, compressive strength and thermal conductivity. The granular aggregates used were the raw vermiculite from Fukushima Prefecture, Japan and Palaboroa area, N.E. Transvall, S. Africa, and the fibrous aggregate used were the amosite asbestos from Lydenburg area, N.E. Transvall, S. Africa, commercial rock wool and fiber glass. The bonding material of aggregates was sodium metaphosphate, and magnesium dihydrogen phosphate was mixed as the additive.
    A remarkable increase in compressive strength was observed when a small quantity of amosite asbestos or rock woll was added to the vermiculite-sodium metaphosphate system. This was attributed to the formation of bridge bonds due to the reactions of magnesium oxide component in vermiculite and amosite asbestos or rock wool with sodium metaphosphate. This was explained by the X-ray diffraction evidence that sodium metaphosphate reacted with vermiculite and amosite asbestos or rock wool. Scarce increase in compressive strength was observed when a small quantity of fiber glass was added to the vermiculite-sodium metaphosphate system. This was explained by the X-ray diffraction evidence that sodium metaphosphate did not react with fiber glass.
    The thermal conductivity was decreased when a proper quantity of fibriform material was added to the vermiculite-phosphate system. This corresponded to the apparent porosity increase caused by the mixing of fibriform and granular aggregates. On the other hand, the thermal conductivity was decreased when a proper quantity of magnesium dihydrogen phosphate was added to the vermiculite-fibriform material-sodium metaphosphate system. This was attributed to the porosity increase due to the dehydration reaction of the magnesium dihydrogen phosphate on firing.
  • 3. 三次元強化複合材料
    前川 善一郎
    1989 年 38 巻 427 号 p. 451-457
    発行日: 1989/04/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 1989 年 38 巻 427 号 p. 464
    発行日: 1989年
    公開日: 2009/06/03
    ジャーナル フリー
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