著者
布施 洋一
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.43, no.492, pp.1181-1182, 1994-09-15
著者
妹尾 允史
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.41, no.462, pp.396-397, 1992-03-15
著者
熊倉 郁夫
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.52, no.5, pp.552-553, 2003-05-15
著者
荒川 正文
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.16, no.164, pp.319-321, 1967-05-15
被引用文献数
2

粉体粒子の付着、凝集の程度を知るためにいくつかの方法が試みられているが、その中で粉体充てん層のせん断応力と荷重の関係からクローン式により粒子間凝集力を測定する方法を試みた。この方法で得られる凝集力はせん断面あたりの力であるが、これに充てん層の空隙率、試料粒子の平均粒子径、粒子1個に対する隣接粒子の平均接触点数を考慮すれば粒子接触点1個の凝集力を計算することができる。粒度の異なった数種のホワイトアランダムを試料としてこの方法で粒子径と粒子間凝集力の関係を調べた。その結果、この試料では脂肪酸処理による粒子の表面の疎水化の効果はほとんど認められない。また、粒子径が小さくなるほど凝集力も減少するが、その力は吸着層を伴ったvan der Waals力の範囲である。しかし、van der Waals力による凝集力は粒子径に比例するといわれるが、この実験では微粒子では粒子径が1/10になると凝集力が1/100程度になった。これは、充てん層のせん断面あたりの凝集力を粒子接触点1個あたりに換算するときに用いたRumpfの仮定に誤りがあると考え、実験結果から逆に補正をすると高空隙率充てんの微粉体では粒子1個の平均接触点数が約2.3となり、微粒子の凝集は珠数状の連りで、かさ高い網状構造を形成していることが推定される。
著者
佐藤 千之助 車田 亮 岩城 英彦 小松 靖門
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.35, no.397, pp.1144-1150, 1986-10-15
被引用文献数
1

Two kinds of carbon felt reinforced carbon composite of pitch fiber (C/C-A) and of PAN fiber (C/C-B) have been developed to improve the fracture mechanics properties of regular grade graphite. The tensile properties and the fracture toughness values of these new composites were determined as function of temperature up to 2400℃. These results were compared with those of a carbon fiver cloth reinforced carbon composite of rayon fiber (C/C-C) and fine grain isostatic graphite (IG-11), and these distinctive features were discussed.
著者
中村 孝
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.55, no.4, pp.445-446, 2006-04-15

筆者は2004年10月から2005年7月まで,カナダのアルバータ大学機械工学科で在外研究を行う機会を得た.アルバータ大学はアルバータ州の州都エドモントンにある学生数3万人以上の総合大学であり,世界45ヵ国170校と提携を結んでいる.特に,機械工学科は筆者の所属する北海道大学機械系専攻と実質的な交流を続けている.筆者は約10ヶ月の間,Advanced Composite Materials Engineering (ACME) Groupに在籍し,Fernand Ellyin教授とZihui Xia助教授の指導の下でCFRPの環境強度に関する研究に携わった.研究内容については,論文等で紹介する機会もあると思うので,本稿では印象に残った身の回りの出来事を綴ってみたい.
著者
村瀬 勝彦 ジョーンズ ノーマン
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.42, no.483, pp.1420-1426, 1993-12-15
被引用文献数
5 5

Progressive plastic buckling appears in the axial symmetric behavion of circular tubes subjected to static loads or low velocity impacts,when the inertia effect is neglible.For high velocity impacrs in which imertia cannot be neglected,the studies.However,a series of impact tests on tubes by Florence et al.recorded thephenomenon of dynamic plastic buckling in which the deformation consists of many waves superposed on a uniform plastic deformation.This phenomenon was found for moderately thick circular tubes subjected to high velocity axial impacts.Ren et al. observed that dynami plastic buckling developed on thin circular tubed.Thus,the plastic buckling behavior for high velocity impact tests on circular tubes consist of both progressive plastic buckling and dynamic plastic buckling,but the deraied behavior is not clear yet.The purpose of this study is to clarify the characteristics for the transition process from progressive plastic buckling to dynamic plastic buckling.In particular,the following features are examined:(1) The comparison and consideration of various experimental methods used in the pervious impact test results.(2) The influence of end condition on the static buckling behavior of circular tubes.(3)The consideration of some impact test results.
著者
林田 建世 福本 博明 山口 明
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.22, no.243, pp.1104-1109, 1973-12-15

The stationary viscoelastic properties of general purpose polystyrene (GPPS) and high impact polystyrene (HIPS) melts were measured by means of a screwless extruder. Since the cone rim pressure was not equal to the atmospheric pressure, some theoretical considerations were necessary to derive an approximate relation for calculating the first normal stress difference from the profile of Weissenberg's pressure and the value of pressure at the cone rim. Measurements of Weissenberg's pressure were performed in a stationary state which occur-red at 7〜10 min after the starting of the rotor and continued for about 5 min. The first normal stress difference observed for low density polyethylene (M.I.=2.0, 190℃) showed a fairly good agreement with the literature values. The first normal stress difference for GPPS was slightly greater than that for HIPS at the same shear rate. Some flow properties were measured with an extruder-type rheometer according to both Bagley's and the pressure gradient methods, which gave the same results. The apparent viscosity of HIPS was somewhat greater than that of GPPS at the same shear rate. The rigidity, calculated from the first normal stress difference and the apparent viscosity for HIPS, was considerably higher than that for GPPS at the same shear rate. The correlation between the Weissenberg effect data and the exit pressure data was also examined.
著者
長嶋 晋一
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.32, no.358, pp.705-715, 1983-07-15
被引用文献数
2 1
著者
中井 博 北田 俊行 穐山 正幸 三田村 武 小林 剛 島本 明
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.48, no.6, pp.623-628, 1999-06-15
参考文献数
7

Investigated in this paper is a new hybrid cable-wire consisting of outer new Fiber Reinforced Plastic(FRP)and a steel wire as a core. First of all, a design method of cross section of the new hybrid cable-wire is proposed on the basis of the safety factors of 1.7, 3.0 and 1.1 against the yield limit state of the core steel wire, the ultimate limit state of the hybrid wire and the hazard state corresponding to the breaking of the outer FRP by accidents from standpoint of fail safe, respectively. Next, the mechanical properties of carbon-steel hybrid wires are dealt with, which consist of outer CFRP containing parallel carbon fibers and a core steel wire, and are dimensioned by the design method and produced by a method called the pultrusion method for trial. Results of a static tensile test, bending test, lateral pressure test and fatigue test prove the possibility of their application to structural cables and the necessity of further study for developing reliable anchorage systems of hybrid cables. A corrosion test emphasizes the importance of investigation on countermeasures against galvanic corrosion of carbon-steel hybrid wires.
著者
山口 章三郎 大柳 康 辻川 洋三郎 高橋 義男
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.23, no.250, pp.588-592, 1974-07-15

The effects of dimensions and supporting conditions on the compressive strength and deformation of polyvinylchloride pipes under external pressure were discussed. The following four kinds of pipe supporting conditions were used; (A) compression between two steel plates, (B) compression between a steel plate and a concave wooden block, (C) compression between two concave wooden blocks, and (D) compression between two concave hard rubber supporters. The main results obtained are as follows. (1) The relation between the compressive strength P and the dimensions of PVC pipe is given by the following formula, similar to the mid load bending for a both end flxed straight beam with a rectangular section; P=(4σ_b・l・t^2)/(3・Dm)・c_1 (a) where, l, t and D_m are the length, thickness and diameter of pipe, respectively, c_1 the correction coefficient according to pipe supporting conditions, and σ_b the bending stress in kg/mm^2. The value of correction coefficient c_1 was 0.81〜1.35 for A-method, 1.35 for B-method, 8.0 for C-method and 2.3 for D-method, respectively. (2) The deflection δ under elastic deformation is given by the following formula; δ=(P・D_m^3)/(8E・l・t^3)c_2 (b) where, E is Young's modulus in kg/mm^2 of pipe material, and c_2 the correction coefficient similar to c_1. The value of c_2 was 2.22 for A-method. (3) It seems reasonable, therefore, that the theory of straight beam may be applied to the compressive strength and deflection of plastics-pipe under external pressure by using the correction coefficient c_1 or c_2.
著者
市川 昌弘 高松 徹 松尾 貴史 岡部 永年 阿部 豊
出版者
社団法人日本材料学会
雑誌
材料 (ISSN:05145163)
巻号頁・発行日
vol.42, no.483, pp.1406-1411, 1993-12-15
被引用文献数
2 1

Rolling fatigue tests were carried out on hot isostatically pressed silicon nitride bearing balls.At three load levels of the maximum Hertzian contct pressure p_<max>=5900,6740 and 7110 MP_a,13 balls each were tested,and the life distribution was studied.It was found that the rolling fatigue life followed approximately a 2-parameter Weibull distribution with the shape parameter of a 〓 1 at each load level.The relationship p^k_<max>L_<50>=const(x〓10) was found between p_<max> and the median life L_<50>.Microscopic observationof flaking was also performed,and two types of flaking were found.One is flaking with the depth of the order of 100μm,and the other is a shallower one.The depth of the former type was found to coincide aproximately with the depth at which the maximum shear stress ocurred.At lower load levels,the former type was dominant.Frequency of appearance of the latter type increased with an increase in load level.Comparing the shape parameter of a〓1 and the exponent of x〓10 mentioned above with those for the cylic bending fatigue of plain specimens of silicon nitride,it was suggested that the mechanism of rolling fatigue of silicon nitride was different from that of cyclic bending fatigue of the same material.