著者

上田 敏郎 島村 佳伸 東郷 敬一郎 藤井 朋之 岡島 いづみ 平松 正敬 佐古 猛

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.59, no.12, pp.964-969, 2010

被引用文献数

2 5

---

Carbon-fiber reinforced epoxy was decomposed using subcritical water and supercritical methanol to reclaim carbon fibers. The tensile strength of the reclaimed carbon fibers was measured. Then SEM observation, XPS, and Raman spectral analysis were conducted to elucidate the change of tensile strength caused by decomposition. The tensile strength decreased by 6% in the case of decomposition with supercritical methanol, and by 12~17% with subcritical water. The surfaces of reclaimed carbon fibers were resin-free. Decomposition did not affect the fiber surface and fracture surface morphology. Subsequent XPS analysis revealed that functional groups of the carbon fiber surface had been removed. Raman spectral analysis showed decreased graphitization of the carbon fiber surface. These results imply that the fracture toughness of the carbon fiber surface decreased because of breakage of carbon-carbon bonds in the carbon fibers as a result of decomposition.

著者

斎藤 博

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.40, no.449, pp.249-250, 1991-02-15

著者

守屋 慶隆 太田 晃

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.491, pp.919-929, 1994-08-15

被引用文献数

3 7

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.31, no.351, 1982-12-15

著者

渡辺 孝司

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.28, no.309, pp.529-534, 1979-06-15

被引用文献数

1

---

Yield behavior of low-carbon steel sheets (0.07% C) has been examined under the strain rate of 10^<-4> to 10^<-1>/sec at room temperature using an Instron tensile machine. Stress-strain curves have been recorded by using a transient converter (NF, E-5001:8 bits×1024 wards) , since the response of a X-Y, T recorder is not sufficient for the measurements under high strain rates. The experimental results by the transient converter show that the upper and lower yield points appear clearly before the crosshead speed reaches to a given value of high strain rate. The transient converter is found most desirable in order to observe the yield behavior under high strain rates, The results also show another break point of the strain rate dependence of yield stress at the strain rate of 〜3×10-3/sec, which is different from M. J. Manjoin (1944)'s strain rate i.e. 〜10^<-1>/sec. The strain rate dependences of yield stress, yield point elongation, and tensile strength in the range of high strain rate above 〜3×10^<-3>/sec are larger than those at lower strain rates. The yield stress is much more sensitive to the strain rate as compared with the tensile strength.

著者

中野 詔彦 長谷川 澄子 中尾 幸道

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.480, pp.1072-1076, 1993-09-15

被引用文献数

2

---

The effect of reinforcement of elastic modulus in polymer composite materials filled with ultramicroscopic particles has been investigated by taking an example of polymethyl methacrylate-palladium cluster composites.The singularity that makes the elastic modulus increase twice has been indicated by filling up the microscopic fine particles of 10〜20A in spite of a little volume which is 05%.This singularity is caused by the fact that the microscopic particles and the matrix,are perfectly unificated in the materials.The reinforcement of elastic modulus can be explained by the perfect parallel model in consideration of the interface restriction regions.It is clearly shown that such singularity is brought in only by the relative size effect of microscopic particles in such perfect composite materials.

著者

池尻 忠夫

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.16, no.165, pp.394-400, 1967-06-15

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高電圧小電流アークによる劣化の性質を放電形式、電極配置、絶縁材料の種類を種々変えた場合について調べた。そしてアーク劣化ではいくつかの劣化の形式が存在することを明らにした。またその劣化機能についても考察した。その結果、次のような結論を得た。(1)アーク劣化は放電形式により影響されるところが大で、孤光状花火では劣化は大きく、せん光状火花の場合では劣化の程度はきわめて小さく炭化は起こらない。(2)アーク劣化は電極配置により異なり、特異焼損図形を伴いトラッキングにより劣化する場合、電極軸にほぼ直角方向に生成される炭化侵食部を生じ、最終的にはトラッキングに進展する場合、アークの腹により燃焼蒸発を起こし内部に向かい劣化する場合などのいくつかの形式がある。(3)絶縁材料の種類により、劣化は炭化する場合、溶融炭化する場合、溶融するが炭素を遊離しない場合の三つの形式が存在する。そして、絶縁材料の分子構造中のフェニール基の有無やC/H,C/F(個数比)などとこれらの劣化形式がかなり関係あることが推察される。(4)高電圧小電流アークによる劣化では高電界の影響が存在する。

著者

斉藤 秀雄 田中 穆 林 実 鴨先 実 渡辺 忠彦 田中 孝男

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.13, no.132, pp.711-716, 1964-09-15

被引用文献数

1

---

Studies were carried out on the improvement of radiographic relative fault sensitivity, and attempts were made to find out a suitable penetrameter in order to establish a technique on the radiographic inspection by X-rays for solid composite propellants up to 400 mm in diameter. The solid rocket propellants have small absorption coefficient for X-rays, so it is necessary to use lower energy X-rays in comparison with the thickness of the metals and to perform the testing in as low W-ray voltage as possible. The relative fault sensitivity thus obtained is 0.5 to 1.0 percent for the solid composite propellants of 400 mm in diameter. It has been found that the hole type penetrameter is the most suitable for the solid composite propellants among various sorts.

著者

堀川 教世 中山 英明 境田 彰芳 田中 道七

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.49, no.4, pp.426-432, 2000-04-15

被引用文献数

2 4

---

Load-controlled fatigue tests were carried out on PAN-based monofilament carbon fibers under cyclic tensile load conditions at a frequency of 10Hz.Fatigue strength data are obtained under pre-determined maximum load P_max with three different stress ratios of R(=P_mix/P_max)=0.1, 0.5 and 0.7.The maximum load P_max is not an appropriate parameter to evaluate the fatigue strength behavior because the cross-sectional area of monofilament carbon fiber is not constant and varies along the longitudinal direction.This fact results in a large scatter of fatigue lives when the data are plotted on P_max-N_f diagram.In order to evaluate the evaluate the fatigue strength behavior more precisely, the fatigue strength data must be plotted on S-N diagram by using the maximum tensile stress σ_max determined from the crosssectional area of the fracture surface.It is found that S-N properties of monofilament carbon fibers clearly show the fatigue behavior, depending on the stress ratio R.It is also found that the fatigue strength of monofilament carbon fiber is governed by two parameters such as the maximum stress σ_max and the stress amplitude σ_a, and that the combined stress parameter σ_max~(1-α)×σ_a~α is useful to describe the fatigue strength behaviors of the different stress ratios.

著者

石栗 太 川島 麻里 飯塚 和也 横田 信三 吉澤 伸夫

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.55, no.6, pp.576-582, 2006-06-15

被引用文献数

2 14

---

In the present study, to clarify the relationship between stress-wave velocity of standing trees and their wood quality, stress-wave velocity of 122 standing trees in 27-year-old Hinoki (Chamaecyparis obtusa Endle.) plantation were measured by using a commercial hand held stress-wave timer (FAKOPP). Ten trees were cut down for examining the anatomical properties, static bending properties of small-clear specimen, and quality of square timber (1700 by 55 by 55mm). Stress-wave velocity of standing trees appeared to be affected by wood quality, especially by basic density and Young's modulus in juvenile wood. Significant relationships between stress-wave velocity of standing trees and dynamic Young's modulus or modulus of elasticity in static bending of square timber were found. However, it was very difficult to evaluate the modulus of rupture in static bending of square timber by stress-wave velocity of standing trees, because square timber had some defects such as knots. These results suggested that modulus of elasticity in static bending of square timber can be predicted by the stress-wave velocity.

著者

升田 利史朗

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.28, no.312, 1979-09-15

著者

藤原 源吉

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.45, no.1, pp.2-8, 1996-01-15

被引用文献数

13

---

This article describes the findings of research for some recent transport airplane's accidents related to fatigue cracks. One is a B747SR's accident due to crack initiating at the fastener holes (to say Multiple-Site Damage). The other describes the crash of UAL's DC10-10 (N1819U), in Sioux City, Iowa, U.S.A., on July 19, 1989, which experienced a catastrophic failure of the No.2 tail-mounted engine during cruise flight. The third explains the in flight separation of the No.2 engine and engine pylon from B747-100F, shortly after departure from Anchorage International Airport, Anchorage, Alaska, on March 31, 1993. As a result of investigation for B747-100F's accident, National Transportation Safety Board made some important recommendations (One is to amend the design load requirements of Title 14 Code of Federal Regulations Part 25 to consider multiple axis loads encountered during severe turbulence) to the Federal Aviation Administration. Also, current aging airplane service data have identified that there are more cracked airplanes with increasing fleet edge, and possibly several fatigue cracks in some of the cracked airplanes. Especialy, MSD helped focus the attention of the aeronautical field on the problems of operating an aging transport airplanes. Therefore, FAA proposed to rivise the Advisory Circular No.25·571-1A (Damage tolerance and fatigue evaluation of structure) on 3/5/1986. This article describes one operator's viewpoint on the means to maintain the safety of aircraft structures in consideration of the revised structural fatigue evaluation standards.

著者

藤原 源吉

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.493, pp.1188-1194, 1994-10-15

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Well Over 32 percent of the commercial air carrier fleet, worldwide, are beyond their original 20-year design life goal. In the past, 20-year old aircraft were most often replaced by newer aircraft for airline service. However, this is no longer true, and by the turn of the century, 64 percent of the current fleet will be at least 20 years old. This is because economic and market conditions have resulted in the use of commercial jet airplanes beyond their original economic design life objectives. As aircraft exceed their economic design life objectives, the incidence of fatigue increases and corrosion may become more widespread. The purpose of this paper is to discuss our experience with aging aircraft, the basic considerations of fracture mechanics treatment of cracks initiating at rivet holes(to say Multiple-Site Damage) and some problems due to fatigue cracks in aircraft components from the operators viewpoint.

著者

丁 勇 尾坂 明義 三浦 嘉也 難波 徳郎

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.489, pp.618-623, 1994-06-15

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Precipitation of LaBO_3 on the surface of a glass of composition 0.1Cr_2O_3・25Li_2O・10La_2O_3・65B_2O_3 (in mol%) was enhanced due to ultrasonic surface treatment (UST) with aqueous and ethanol suspensions of LaBO_3 particles. The aqueous suspension gave a higher efficiency than the ethanol suspension. The crystallites were almost uniform in size distribution, and grew irregularly : increase-decrease-increase in size when heated at 580℃. Preferred growth of (200) was detected. The mechanism of UST enhanced crystallization is proposed.

著者

内藤 武志 植田 秀夫 菊池 雅男

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.32, no.361, pp.1162-1166, 1983-10-15

被引用文献数

8 23

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Rotating bending fatigue tests were conducted on the gas carburized specimens with internal oxides and non-martensitic microstructure beneath the surface. The fracture surface and the axial section at the fatigue fracture origin were observed using a scanning electron microscope. The following results were obtained. (1) The S-N diagram of gas carburized steel with internal oxides and non-martensitic microstructure revealed two knees on its curve. The test results appeared to be divided into two groups: a group with the number of cycles to failure N_f under 10^5, and that with N_f over 10^6. (2) The fractographic feature of the group with N_f<10^5 was intergranular fracture from the surface to the depth of 25μ, followed by transgranular fracture reflecting martensitic microstructure. (3) For the group with Nf>10^6, fracture surface inclined about 45° to the specimen axis was observed. This surface was smoothened by rubbing each other with another surface during the fatigue test. The depth of the inclined smooth fracture surface reached to the depth of 100μ from the surface. It was concluded that the inclined smooth fracture surface consisted of the Stage 1 cracks and Stage 2a cracks.

著者

稲田 貞俊 花岡 公司 近藤 正多嘉

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.170, pp.883-889, 1967-11-15

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We designed the measuring instrument of thickness variation of bulged foil, and by using this apparatus, studied the configuration of bulged surface of aluminum foil. (1) The bulged surface of aluminum foil is composed by two parts; one part near the appex is spherically constant in thickness, the other part is settled inside the sphere. (2) The instable state of bulged surface of alumium foil occurs before the initiating point destructions. (3) The bulged height corresponding to the initiating instable state is detected by measuring the thickness variation.

著者

津田 紘 臺丸谷 政志 小林 秀敏

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.54, no.7, pp.734-740, 2005 (Released:2006-04-07)

参考文献数

15

被引用文献数

5 5

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In this research, the effect of pre-fatigue on the impact tensile properties of the welded butt joint of high strength steel plates, HR590 and HR780, was investigated by means of the split Hopkinson bar method for tensile test. For comparison, quasi-static tensile tests were also performed to examine the effect of strain rate on the strength and the elongation. It was found that the effect of pre-fatigue on the tensile strength of welded butt joints is quite small if the applied stress in the pre-fatigue is less than the apparent yield stress of the welded butt joints. In the results of quasistatic and impact tensile tests for the welded butt joint of HR780 steel, however, the fracture strain of the specimens subjected to high cycle pre-fatigue was larger than that of the virgin specimens. This may be caused by the increase in hardness due to pre-fatigue observed in the weld zone of the joints.

著者

秋庭 義明 木村 英彦 原 航平 田中 啓介

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.54, no.7, pp.698-703, 2005 (Released:2006-04-07)

参考文献数

13

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Single edge notched specimens of a unidirectional SiC long fiber reinforced titanium alloy were fatigued under four point bending. Propagation behavior of fatigue cracks was observed on the basis of the effect of the fiber bridging. The branched fatigue cracks were initiated from the notch root. The crack propagation rate decreased with crack extension due to the crack bridging by reinforced fibers. The longitudinal stress in the reinforced fiber was measured by using high spatial resolution synchrotron radiation. The interfacial frictional stress between the matrix and the fiber could be directly determined by X-ray method. The bridging stress was also measured as a function of a distance from a crack-tip. The stress intensity factor range corrected on the basis of the shielding effect agreed well with that for the monolithic titanium alloy, when compared at the same crack propagation rate.

著者

上野谷 敏之 水谷 義弘

出版者

公益社団法人 日本材料学会

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.55, no.3, pp.341-347, 2006 (Released:2006-04-26)

参考文献数

50

被引用文献数

1