著者

長野 博夫

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.27, no.294, pp.309-314, 1978-03-15 (Released:2009-06-03)

参考文献数

23

被引用文献数

3

著者

遠藤 達雄 安在 弘幸

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.328, pp.89-93, 1981-01-15 (Released:2009-06-03)

参考文献数

3

被引用文献数

2 13

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This paper reports in detail a fundamental concept of a P/V difference method which is one of rainflow algorithms. The method is one of cycle count procedures which are useful for analyzing a complex strain time history.A strain time history should be analyzed keeping in mind the stress-strain behaviour in the background. Based on this concept, the rainflow algorithm subtracts from a strain time history the parts which correspond to closed hysteresis loops in the stress-strain relation. The subtracted parts and the residual parts are successively processed for fatigue damage evaluation.The algorithm given in this paper is simpler than the ones already presented, by the use of successive absolute differences between neighbouring peaks and valleys called P/V differences.The simplicity enabled us to make a real-time on-site fatigue damage indicator.

著者

田中 啓介

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.38, no.432, 1989-09-15

著者

大塚 昭夫 宮田 隆司

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.33, no.364, pp.97-103, 1984-01-15

著者

小林 英男

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.363, pp.1410-1415, 1983-12-15

著者

青木 繁

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.33, no.365, pp.229-235, 1984-02-15

被引用文献数

1

著者

屋代 如月 西村 英晃

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.2, pp.155-162, 2014-02-15 (Released:2014-02-20)

参考文献数

20

---

For a new insight on solid lubricant of fullerenes and onion-like carbons (OLCs), we have performed scratch simulations on isolated fullerenes/OLCs and monolayer film of their array. Here, molecular dynamics simulation may overestimate bond-forming between the scratch surface and target carbons, so that we consider only the van der Waals interaction between the rigid diamond and fullerenes/OLCs. On this condition, both the isolated/layered fullerenes/OLCs doesn't show rotation but slip on the perfect (001) diamond surface, showing frictional coefficient lower than μ=0.05. On the other hand, the fullerenes/OLCs show rotation and higher frictional coefficients of μ=0.1∼0.3, if we set surface roughness on both scratch walls. In this rotational friction, larger fullerenes/OLCs show smaller frictional coefficients, and the fullerenes shows higher frictional coefficient than OLCs of same size.

著者

矢野 浩之 椋代 純輔 大西 一広

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.39, no.444, pp.1207-1212, 1990-09-15 (Released:2009-06-03)

参考文献数

12

被引用文献数

6 8 2

---

The top plate of guitar is usually made from two wood species which belong to different genus, that is, german spruce (Picea abies) and western redceder (Thuja plicata). To clarify the characteristics of these species and of the wood materials for guitar top plate, the acoustic properties of the specimens prepared from the neighbour portion of the top plate were measured by means of free-free flexural vibration method. The results were compared with the evaluation by an expert of guitar manufacture.The mean values of specific dynamic Young's modulus (E/γ) and tanδ of german spruce were higher than those of western redceder, while among various wood species these two had higher E/γ and lower tanδ in the longitudinal direction. These characteristics were particularly pronounced in the specimens which were judged by the expert to be high grade. Moreover, the standard deviations of the acoustic properties of the high grade specimens were smaller than those of the medium or low grade ones regardless of the species.The value of E/γ in the longitudinal direction, which can be obtained easily, seemed to be a convenient criterion for selecting the wood material suitable for guitar top plate. Because it correlated highly with tanδ in the longitudinal direction, and also with the ratio of tanδ in the radial direction to that in the longitudinal direction. Evaluation using both E/γ and tanδ in the longitudinal and radial directions was more appropriate, because the experimental values of E/γ and tanδ in any grain angle agreed with the values calculated based on Hankinson's equation.

著者

臺丸谷 政志 小林 秀敏

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.60, no.7, pp.668-673, 2011

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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 <i>tohshin</i> (blade) and <i>tsuka</i> (hilt) of the sword. Only one <i>mekugi-take</i> (retaining peg made of bamboo) with about 5mm in diameter holds <i>Nakago</i> (tang) in the hilt. However the slender <i>mekugi</i> 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 <i>mekugi</i> 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 <i>mekugi-take</i> does not act on it, because of the location of <i>mekugi-ana</i> (a hole for <i>mekugi</i>) in the tang, which has been made by following the traditional code of swordsmiths.

著者

北川 浩

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.21, no.230, pp.969-977, 1972-11-15 (Released:2009-06-03)

参考文献数

26

被引用文献数

1 1

著者

上原 拓也 井上 達雄

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.44, no.498, pp.309-315, 1995-03-15

被引用文献数

1 9

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The quenching process of a Japanese sword is simulated by a CAE system "HEARTS" developed by one of the authors. The system is available to consider the coupling effect among metallurgical change due to phase transformation, temperature and inelastic stress/strain. In the quenching process of the Japanese sword, a special kind of clay is pasted on the surface to control the heat transfer coefficient between metal and water. The dependence of the coefficient on the thickness of clay and also the surface temperature is experimentally evaluated first by using a cylindrical rod of silver. The results show a relatively higher value with thin-pasted clay than that without clay at a high temperature range. The data are then applied to simulate the variation of temperature coupled with the structural change from austenite to martensite and pearlite as well as the variation of stress. It gives an attractive result that the sword is bent two times to the direction opposite to the normal shape due to the complicated time difference between martensitic and pearlitic transformation and thermal contraction. The simulated results of residual stress distributions are compared with the measured data by X-ray diffraction technique.

著者

堀川 教世 中山 英明 境田 彰芳 田中 道七

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.49, no.4, pp.426-432, 2000-04-15 (Released:2009-06-03)

参考文献数

12

被引用文献数

3 4

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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 Pmax with three different stress ratios of R(=Pmix/Pmax)=0.1, 0.5 and 0.7. The maximum load Pmax 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 Pmax-Nf diagram. In order to evaluate the fatigue strength behavior more precisely, the fatigue strength data must be plotted on S-N diagram by using the maximum tensile stress σmax determined from the cross-sectional 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 σmax and the stress amplitude σa, and that the combined stress parameter σmax(1-α)×σaα is useful to describe the fatigue strength behaviors of the different stress ratios.

著者

浅田 和雄 高橋 浩昭 高橋 尚志

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.468, pp.1396-1402, 1992-09-15

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When a projectile with high velocity impacts onto a target, several fracture modes (such as spall fracture, plug fracture, penetration fracture and so forth) appear in the target. Therefore, in order to identify an impact fracture strength of materials, a particular type of impact experiments should be undertaken. For example, an impact experiment for flying plate is suitable to determine the spall fracture strength. Different impact conditions, however, may bring in different fracture strength even for the same target material. For the purpose of clarifying perforation dynamics (mechanism) by means of computer code, it is necessary to provide a unified fracture condition which enables to explain all modes of spall fracture, plug fracture and penetration fracture. Under this fracture condition, fracture takes place when the strain has attained its critical value, which may be affected by pressure and temperature. In the present study, the unified fracture condition was examined through comparison between the back surface velocity of flying plate impact experiment and the velocity calculated from computer code by using Ni-Cr-Mo steel (SNCM-630 steel). The computer code used here was that of one -dimensional large deformation stress wave propagation by finite-difference-method. The experimental results and computer code results were well in accord with each other, confirming the applicability of the unified fracture condition to perforation dynamics.

著者

木村 宣夫 楠本 韶 内田 武 安藤 司文 越智 利彦

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.38, no.434, pp.1261-1267, 1989-11-15 (Released:2009-06-03)

参考文献数

15

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A method to express the distribution of the experimental results of fracture toughness of ice was investigated by postulating the Weibull distribution with three parameters. The data were taken from the previous experiments conducted to study the effect of loading rate on the fracture toughness9), 10). Weibull parameters were estimated by several estimation methods11), 12) and the parameters obtained were compared with each other. The effect of loading rate together with that of specimen size on the parameters were discusssd at three loading rate ranges. It was confirmed that the parameters estimated were closely related to the experimental value of fracture toughness.

著者

座古 勝 辻上 哲也 北村 貴典

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.44, no.499, pp.390-394, 1995-04-15

被引用文献数

1

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It is well known that the mechanical properties of laminated composites depend on the stacking sequences. As the bending modulus of elasticity is affected remarkably by the stacking sequences, the stress and strain analyses for laminated composite structures require a special technique. Therefore, a new analytical method has been proposed in order to calculate the mechanical behavior of laminated structures in this paper. The proposed method has been applied for a laminated composite structure as a numerical example. As a result, it has been recognized that the numerical behavior of the composite structure with anisotropic properties under mixed loads of bending and tension can be analyzed by the proposed method, even if it has two different moduli of elasticity of bending and tension. In addition, CPU time of FEM based on the proposed method can be reduced remarkably as compared with ordinary FEM.

著者

中島 道七 出納 真平

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.19, no.202, pp.629-634, 1970-07-15

被引用文献数

1 6

著者

時國 裕也 上野 沙也加 牛尾 祐大 福本 直 吉武 勇

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.10, pp.710-715, 2014-10-15 (Released:2014-10-20)

参考文献数

15

被引用文献数

1

---

Thermal power plant has occupied 90% of electric power supply after the earthquake disaster in Japan. Hence amount of coal-ash has increased gradually. Coal-ash, especially fly-ash, should be used for civil infrastructures, and concrete pavement must be a typical application using fly-ash. Fly-ash is a pozzolanic material, so it can contribute to various properties, such as strength development at mature age. The strength development at early age, however, is significantly slow and may negatively affect traffic service. Early strength may be improved when limestone filler is mixed in fly-ash concrete. In addition, the fly-ash concrete made with limestone aggregate may be recyclable as raw material for cement production. This study aims at developing the fly-ash pavement concrete which can make a traffic opening early and can be recycled. The paper describes the flexural strength properties of pavement concrete made with fly-ash of 40% replacement of cement. The result indicates the flexural strength at early age can be improved by using limestone filler, and assures sufficient strength development for traffic service at age of 2 days. In addition, the report shows flexural fatigue strength of the fly-ash pavement concrete is equal to or higher than the durability of conventional concrete pavement.

著者

攝津 暢浩 高橋 学 松下 正史 岡部 永年

出版者

The Society of Materials Science, Japan

雑誌

材料 (ISSN:05145163)

巻号頁・発行日

vol.61, no.6, pp.530-536, 2012

被引用文献数

6

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We investigate the mechanical strength of ceramic/metal composites subjected to cyclic thermal loading. First, test samples of Cu/AlN systems are prepared via brazing. Next, short-term thermal cycle tests (25, 50, and 100cycles) are conducted at temperatures ranging from -40 to 125°C. Four-point bending tests are conducted to evaluate the residual strength. Further, thermal stress analysis is performed using the finite element method in order to examine the thermal stress behaviors during cyclic heating. The results reveal that the residual strength increases during 0∼20cycles because of residual thermal stress relaxation. This relaxation is generated by the cyclic softening of the metals owing to combined hardening. In contrast, relatively long-term thermal cycling (20∼100cycles) reduces the residual strength owing to damage growth to AlN. The AlN plates exhibit variability in residual strength, and the distribution of the residual strength for each cycle number conforms to the two-parameter Weibull curve. The variability in residual strength increases with the cycle number, and it is attributed to variabilities in the pre-existing crack size and damage accumulation. We conclude that the residual strength of the Cu/AlN composites depends on the thermal stress behavior and damage growth to the AlN plates.

著者

若杉 三紀夫 山本 高広

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.457, pp.1372-1378, 1991-10-15

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The effects of three types of polymer modification on both hydration characteristics and physical properties of the gypsum pastes and mortars originated from anhydrite plaster have been studied at various polymer-gypsum ratios. The polymer dispersions used were ethylene-vinyl acetate (EVA), polyacrylic ester and styrene-butadiene rubber. The degree of hydration of the gypsum pastes and mortars was examined by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and porosity measurement. The setting time of fresh gypsum mortars (polymer-modified and unmodified) as well as the physical properties of hardened gypsum mortars were also measured. The hydration was complete in about 3 days, and the degree of hydration of the polymer-modified gypsum mortars was smaller than that of unmodified mortar. The setting time of gypsum mortars was retarded by the addition of polymer, and was affected by the chemical structure of polymer. The flexural and tensile strengths of the EVA-modified mortar with a polymer-gypsum ratio of 5% were higher than those of unmodified mortar. Its elastic modulus was the smallest of all, and further EVA-modified mortars showed small linear expansion. From the above test results, the EVA-modified gypsum mortar with a polymer-gypsum ratio of 5% was shown to be one of the candidates of the better plastering materials for polystyrene and polyurethane foams.

著者

大内田 久 西岡 章夫 岩崎 勤

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.12, no.117, pp.451-456, 1963-06-15 (Released:2009-06-03)

参考文献数

6

被引用文献数

1

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The present investigation has been made in order to determine the influence of induction-hardening on the fatigue strength of shrink-fitted specimens. Cyclic direct stress fatigue tests were made on shrink-fitted specimens 20mm in diameter of NiCrMo steel.The results obtained were summarized as follows:1. The reduction ratio 2.3 was obtained by comparing the endurance limit for a shrink-fitted specimen with that of a plain specimen.2. The endurance limit of a shrink-fitted specimen was increased by about 2.1 times by induction-hardening.3. The fatigue strength of the induction-hardened specimen with a shink-fitted member may be estimated approximately from the modified Goodman diagram, in which the residual compressive stress on the surface layer of specimen is assumed to be mean stress.