著者

森 和也 陳 玳〓 西谷 弘信

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 A編 (ISSN:03875008)

巻号頁・発行日

vol.57, no.544, pp.2987-2991, 1991-12-25 (Released:2008-02-21)

参考文献数

8

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The authers have developed a method for satisfying resultant boundary conditions on each divided boundary by discrete point forces. This method stands high accuracy and short calculating time at the same time. However, to obtain highly accurate solutions, it is necessary to put the point forces at the optimum locations. In this paper, the optimum location of point forces were obtained through several problems in 2D or 3D. The optimum location, that is, the optimum ratio of devided boundary length to distance between point force and boundary is 0.5∼0.7 in the case of notch problems and is 1.5 in the case of crack problems.

著者

後藤 真宏 西谷 弘信 宮川 浩臣 柳川 恭広

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 A編 (ISSN:03875008)

巻号頁・発行日

vol.54, no.499, pp.497-502, 1988-03-25 (Released:2008-02-21)

参考文献数

13

被引用文献数

2 2

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Using a series of base oils of different viscosity grades, rotating bending fatigue tests of 0.34 % C steel plain specimens were carried out to examine the effect of oil environments on the fatigue behavior. Although the effect of oil is hardly observed in one grain size crack initiation process, its effect appears in the crack propagation process. As the main effects of oil, two actions are considered ; that is, the isolation of the atmosphere and the oil wedging action. The propagation of a crack smaller than 0.1mm is controlled mainly by the former effect. For a crack larger than 0.1mm, its behavior is controlled mainly by the latter effect. On the other hand, the effect of oil on the fatigue limit is very small.

著者

西谷 弘信 尾田 安司

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.46, no.407, pp.745-755, 1980-07-25

被引用文献数

1 10

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半無限板の直線縁またはその付近に存在するき裂同志またはき裂と切欠きの干渉効果を体積力法によって計算した. 取扱った問題は, (a)遠方で引張りを受ける半無限板中の, (i)V形切欠き底のき裂, (ii)2個の縁き裂, (iii)先行き裂を伴う縁き裂, (iv)先端にだ円孔を有する縁き裂, および(b)き裂面に多項式で表される分布荷重を受ける縁き裂である. 最後の問題は切欠き底のき裂, 複数個の縁き裂などの応力拡大係数を近似的に求めるのに有効である.

著者

宮川 浩臣 西谷 弘信

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.51, no.462, pp.445-449, 1985-02-25

被引用文献数

3 1

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This paper is concerned with the beneficial effects due to additional holes or indentations. Two indentations facing each other with the tip of a crack is especially effective in retardation of crack propagation. The effects of the indentations can be estimated approximately from the existence of residual stresses produced by the indentations.

著者

皮籠石 紀雄 西谷 弘信 後藤 真宏 豊廣 利信 北山 智

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. A編 (ISSN:03875008)

巻号頁・発行日

vol.59, no.557, pp.57-61, 1993-01-25

被引用文献数

2 2

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Statistical analysis is necessary in evaluating the fatigue life of structures. In the present study, rotating bending fatigue tests were carried out on specimens with two small blind holes of a 5052 A1 alloy in order to investigate the distribution characteristics of the fatigue crack growth life based on the small-crack growth law dl/dN= C_1σ^n_al. The crack growth rate in each specimen was determined uniquely by σ^n_al, therefore the crack growth life can be predicted by the small-crack growth law. On the assumption that the value of n is a fixed one and the value of C_1 is a random variable, the distribution of the crack growth rate can be evaluated through the value of C_3 in the relationship dl/dN=C_3l. C_3 follows a Weibull distribution approximately. The calculated distribution of the ocracy growth life based on the small-crack growth law and the distribution of C_3 was in good agreement with the experimental results.