著者
神谷 友裕 水谷 忠均
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.66, no.4, pp.275-281, 2017-04-15 (Released:2017-04-20)
参考文献数
23
著者
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.60, no.7, pp.668-673, 2011-07-15 (Released:2011-07-20)
参考文献数
12
被引用文献数
1

The Japanese sword is interesting not only from the viewpoint of traditional crafts of arts, but also from the aspect of modern science and technology because the way of making and its functionality as a weapon are really consistent with modern science. The present study is concerned with the joint between tohshin (blade) and tsuka (hilt) of the sword. Only one mekugi-take (retaining peg made of bamboo) with about 5mm in diameter holds Nakago (tang) in the hilt. However the slender mekugi might not be broken, even in the case of violent sword-fighting. This fact has been historically demonstrated in many battles by Japanese swords. In this study, using a Japanese sword model, it is examined theoretically and experimentally why a mekugi used in Japanese swords might not be broken from the viewpoint of impact engineering. Consequently, it is presumed that such a strong force as breaking mekugi-take does not act on it, because of the location of mekugi-ana (a hole for mekugi) in the tang, which has been made by following the traditional code of swordsmiths.
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
藤原 源吉
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.45, no.1, pp.2-8, 1996-01-15 (Released:2009-06-03)
参考文献数
10

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
菅田 淳 齊藤 和宏
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.59, no.2, pp.171-177, 2010-02-15 (Released:2010-02-19)
参考文献数
27
著者
竹田 憲生 成瀬 友博 河野 賢哉 服部 敏雄
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.52, no.2, pp.204-209, 2003-02-15 (Released:2009-06-03)
参考文献数
9
被引用文献数
4 4 2

Silicone gel is usually applied to electrical automotive devices to protect them from corrosion. However, under a vibration environment, the silicone gel vibrates bonding wires in the devices, thus, to evaluate the reliability of the devices, the vibration analysis of the gel/wire structure is indispensable. In this study, we clarify the relation between the fatigue life of gel-protected bonding wires and the geometry of the gel and bonding wires experimentally. It was founded that the diameter of wires and the thickness of the gel have a significant influence on fatigue life. Then, we developed a method, based on a vibration analysis model that takes into account the visco-elasticity of a gel, for predicting the fatigue life of the wires. It was confirmed that the predicted fatigue life showed good agreement with the measured fatigue life. Finally, we developed a design tool for easily calculating the fatigue life of the wires. This tool estimates the strain range by using a response surface, i. e., a neural network. As Bayesian regularization was executed in learning of unknown parameters in the neural network, we could make the response surface and ensure good generalization ability.
著者
三木 五三郎
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.19, no.205, pp.900-904, 1970-10-15 (Released:2009-07-09)

Special attention must be paid to the fill construction where coal ashes are used because they have particular geotechnical properties.Coal ashes are sandy coarse silt and have no plasticity. They have such small specific gravity as 2.1. Compacted coal ashes have strong shearing resistance at the optimum moisture content, but loose coal ashes have the risk of liquefaction when they are saturated.In Hisasue valley in Kawasaki city, an extensive flow slide of fill construction where coal ashes were used occurred in June, 1965. The fill consisted of loose dumping ashes and it collapsed just when it had been saturated by the seeping groundwater to the critical state.In Hodogaya in Yokohama city, a large fill construction has been built with coal ashes with special attention paid to the drainage of groundwater and to the compaction of fill material. The work has proved a success.
著者
井上 達雄
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.66, no.11, pp.804-810, 2017-11-15 (Released:2017-11-20)
参考文献数
10
著者
熊谷 正芳
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.67, no.8, pp.828, 2018-08-15 (Released:2018-08-20)
参考文献数
3
著者
畑 敏雄
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.17, no.175, pp.322-325, 1968-04-15 (Released:2009-07-09)
参考文献数
12
被引用文献数
2 2

Two theories of fracture of viscoelastic materials are hereunder proposed, the one based on a simple model and the other generalized thereupon, and an attempt is made to explain the dependence of stress and strain at break on temperature and strain rate as particularly was called the failure envelope by T.L. Smith.The model of the first simple theory consists of two Maxwell elements (system 1 and 2) connected in parallel and the following criteria for fracture are introduced.(1) Fracture occurs first at the system 1, and then at the system 2 where the whole load is applied.(2) Fracture of the system 1 occurs either when the spring reaches the critical strain ε11c (in the case of large strain rate) or the dashpot does so to ε12c (in the case of small strain rate).For the deformation of constant rate R, the following results are obtained, which explain the experimental behaviors well at least qualitatively.at larger strain ratesat smaller strain rateswhere σ, ε, G and τ follow the ordinary use and suffices 1 and 2 mean system 1 and 2 respectively and the suffix b does so "at break".Next the above model theory is so extended to the generalized Maxwell bodies as to read that the stress of deformation at constant rate is expressed by the equationIn this case the storage energy Wst and the dissipation energy Wdis of deformation are calculated after Landel, and the following criterion is introduced, that is, the sample breaks either when the elastic part with its own modulus G0 (the instantaneous modulus) reaches the critical strain ε1c or the viscous part with its steady flow viscosity η0 reaches the critical strain ε2c.The results are given asat larger strain ratesat smaller strain rateswhere G' and η' are dynamic modulus and viscosity respectively. Considering the dependence of G' and η' on shear rate and temperature, the failure envelope can be explained with these equations.
著者
宮田 昌悟 田中 基嗣
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.63, no.9, pp.684-689, 2014-09-15 (Released:2014-09-20)
参考文献数
39
著者
牧 正志 田村 今男
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.30, no.329, pp.211-217, 1981-02-15 (Released:2009-06-03)
参考文献数
35
被引用文献数
8 7
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
岡島 智史 泉 聡志 酒井 信介
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.57, no.4, pp.401-407, 2008 (Released:2008-04-18)
参考文献数
6
被引用文献数
1 1

Because of the lessening number of maintenance experts, a method to rationalize pipe inspection interval is desired. For this purpose, the evaluation method for the pipe integrity in the form of failure probability has been developed based on the Bayesian inference method in the previous paper. In this paper, the previous method is called the linear-Bayes method. The linear-Bayes method assumes wall thinning due to Flow Accelerated Corrosion (FAC) as the principal damage mechanism, and it can define the safety margin of a pipe's residual life depending on the number of inspections. However, the linear-Bayes method ignores the corrosion rate fluctuation against time, which may be caused by the change of environment such as water chemistry and flow velocity. Therefore, the linear-Bayes method may underestimate the failure probability of the pipe segments if the online monitoring of the environments is not used. In this paper, the linear-Bayes method is extended for the wall-thinning model with the corrosion rate fluctuation. The extension is carried out through following two approaches : correction-term and error-term approaches. In this paper, the formulation and the procedure for each approach are shown at first. And then, the accuracy and the merit of the extended method are examined through the evaluation using the artificial and the actual inspection records. Through the examination, it is confirmed that the extended method makes the evaluation of the pipe integrity available in view of safety margin for the corrosion rate fluctuation, keeping the merits of the linear-Bayes method.
著者
菊地 慎二 平島 健一 杉坂 憲明
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.47, no.9, pp.887-891, 1998-09-15 (Released:2009-06-03)
参考文献数
6
被引用文献数
2 1

This paper presents a unified analysis of isotropic out-of-plane shear problems with concentric circular elastic inclusions. The applied disturbances considered in this paper are longitudinal shear stress at infinity, analysis is based on the complex variable method using the Möbius transformations by Honein and Herrman. Several numerical examples are given by many graphic representation.
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
保田 昌樹 日根 文男
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.31, no.340, pp.22-27, 1982-01-15 (Released:2009-06-03)

Formation of corrosion tubercles on carbon steels were carried out in the aerated neutral solutions composed of boric-borate buffer (0.01M) and water with some suspensions of CaCO3 and CaSiO3 powders at pH=7.5-8.8. The solutions containing NO2-, CrO42-, or HS- of less than 50ppm in concentration were also examined. The solution temperature was at 60-65°C.The tubercles thus formed were classfied into three types: the active passive, the general corrosion, and the sulfide initiative, depending on the potential. The active passive-type tubercles formed at the potential range where the second peak of current appeard on the anodic polarization curve. On the other hand, the general corrosion-type tubercles grew at the potentials where general corrosion of steels tested appeard. In the latter case, calcium scale deposited on the steel surface, but the corrosion spots formed partially at which the scale deposition was insufficient.The mechanism for the sulfide initiative-type tubercles is unclear whereas it forms certainly in aerated and neutral solutions containing HS- at the potential range -0.50 to -0.55V vs. Ag/AgCl.