研究者詳細 - 多田　直哉

MISC - 多田　直哉

分割表示 283 件中 161 - 180 件目／全件表示 >>

1105 引張試験中における塑性変形場の発展が結晶性高分子材料の応力ひずみ関係に及ぼす影響(OS11. 材料の組織・強度に関するマルチスケールアナリシス(1),オーガナイズドセッション講演)

内田真, 多田直哉

計算力学講演会講演論文集 2010 ( 23 ) 127 - 128 2010年9月

C204 直流電位差法を用いたステンレス鋼平板表面に存在する応力腐食割れの検知(亀裂の検査・モニタリング技術-(1),OS5 保全・設備診断技術),動力エネルギーシステム部門20周年,次の20年への新展開)

前田浩輝, 多田直哉, 内田真

動力・エネルギー技術の最前線講演論文集 : シンポジウム 2010 ( 15 ) 329 - 332 2010年6月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

In order to examine the applicability of the direct-current potential difference method to detection of stress corrosion cracking, the potential difference was measured on the surface of stainless steel plates with simulated cracking. Potential difference was measured near the cracking and at the points distant from the crack to evaluate the degree of increase in the potential difference by the crack. The potential difference near the cracking area was higher than that in the other area. The normalized potential difference, which is the ratio of potential difference near the cracking to that far from the area, was 1.03 to 1.50. The result suggests that stress corrosion cracking was able to be detected by direct-current potential difference method.

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107 ポリカーボネート基板上に蒸着した金薄膜試験片の圧縮負荷と除荷に伴う変形の観察(材料力学II)

橋本和基, 多田直哉, 清水一郎, 佐藤直行

講演論文集 2010 ( 48 ) 13 - 14 2010年2月

106 異種材料積層構造体の変形挙動評価(材料力学I)

成瀬文雄, 多田直哉

講演論文集 2010 ( 48 ) 11 - 12 2010年2月

214 直流電位差法を用いたはんだボール/銅接合界面き裂評価に及ぼす銅線はく離とボイドの影響に関する3次元有限要素解析(材料力学V)

吉田直人, 中原亮一, 多田直哉

講演論文集 2010 ( 48 ) 59 - 60 2010年2月

高温環境下での材料寿命予測

多田直哉

日本機械学會誌 = Journal of the Society of Mechanical Engineers 113 ( 1094 ) 8 - 11 2010年1月

239 非晶性高分子材料の微視的な不均一性がくびれ伝ぱ挙動に及ぼす影響(微視効果・不均一性,塑性挙動のモデリングとシミュレーション-ナノからマクロまで-,オーガナイスドセッション5)

内田真, 多田直哉

学術講演会講演論文集 59 283 - 284 2010年

226 双晶主体で変形するTi-14Mo合金結晶粒の押込み挙動(HCP・結晶塑性,塑性挙動のモデリングとシミュレーション-ナノからマクロまで-,オーガナイスドセッション5)

清水一郎, 木村訓明, 多田直哉, 竹元嘉利

学術講演会講演論文集 59 257 - 258 2010年

J0301-1-3 AZ31マグネシウム合金押出し材の比例ひずみ経路二軸圧縮における成形限界([J0301-1]工業材料の変形特性とそのモデル化(1))

岡田浩輔, 清水一郎, 多田直哉

年次大会講演論文集 2010 255 - 256 2010年

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

The deformation twinning of magnesium alloys is known to induce compressive fracture at room temperature. However, the formability in multi-axial compressive stress conditions has scarcely been investigated, nevertheless their importance for plastic working processes such as forging and extrusion. In the present study, biaxial compressive plastic behavior and compressive forming limit of AZ31 magnesium alloy at room temperature were investigated using a unique biaxial compression testing machine. The uniaxial and biaxial compression tests along proportional strain paths were conducted, and thus the influence of strain path upon the mechanical properties and the forming limit were discussed. The compressive forming limit indicated clear strain path dependency. It was also found that the forming limit was influenced by the plastic anisotropy. The adaptability of the typical forming limit criterion to the compressive forming limit was also discussed.

DOI： 10.1299/jsmemecjo.2010.6.0_255

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S0305-3-2 加硫天然ゴムの亀裂進展速度に与えるカーボンブラック含有量の影響([S0305-3]き裂進展)

ソーマプラバーカー, 多田直哉, 内田真, 中原一成, 片山稔

年次大会講演論文集 2010 141 - 142 2010年

記述言語：英語出版者・発行元：一般社団法人日本機械学会

The effect of carbon black loading on fatigue crack growth rate of vulcanized natural rubber used in automotive applications such as engine mounts was studied using pure shear specimens. Tearing energy was calculated from uncut specimens while crack growth rate was calculated from cyclic tests of cut specimens. Finally the fatigue crack growth rate as a function of tearing energy was determined. The fatigue crack growth rate of natural rubber at a given tearing energy was decreased with the increase in fraction of carbon black.

DOI： 10.1299/jsmemecjo.2010.1.0_141

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G0300-6-2 片状黒鉛の分布を考慮した鋳鉄製シリンダブロックの強度評価に関する有限要素解析([G0300-6]材料力学部門一般講演(6):強度解析)

井口克之, 多田直哉, 清水一郎, 今津知裕

年次大会講演論文集 2010 225 - 226 2010年

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

The stress distribution in gray cast iron used for diesel engine cylinder block was calculated by the finite element method. The distribution of flaky graphite on the surface of the gray cast iron was observed by microscope and it was reproduced in the analysis model. Three models, (I) multiple graphite model, (II) multiple hole model, and (III) single hole model, were used and the stress distribution near the tip of flaky graphite was discussed. The stress intensity factor for critical flaky graphite was approximately calculated. The results of the present analysis suggested that the stress intensity factor for the critical flaky graphite was found to be about 3.7 times as high as that of a single crack with the same length. Furthermore, critical graphite length to the fracture of cylinder block of diesel engine was calculated based on the proposed method. The length was much larger than that of actual graphite.

DOI： 10.1299/jsmemecjo.2010.1.0_225

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S0304-1-3 微少押込み試験によるTi-Mo合金の結晶方位評価([S0304-1]応力・ひずみ測定)

木村訓明, 清水一郎, 多田直哉, 竹元嘉利

年次大会講演論文集 2010 265 - 266 2010年

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

In recent years, β-type Ti alloys have been attracting much attention for industrial applications, not only by its high specific strength and superior formability but also by special features such as low elastic modulus and extraordinary plastic deformation behavior. However, the studies on β-Ti alloys are still less than those on other types of Ti alloys. Hence, the evaluation processes of various properties of β-Ti alloys have still not been established nevertheless of their importance for industrial applications. The aim of the present study is to evaluate the crystal orientation of grains of β-Ti alloys by means of micro indentation technique. Ti-14Mo and Ti-20Mo alloys, whose primary deformation mechanisms are mechanical twin and coarse slip, respectively, were employed as typical β-Ti alloys. The detailed investigations were performed on the relationship between the crystal orientation and the indentation behavior. The results revealed that the lines which appeared around the indentation of Ti-14Mo almost corresponded to twin boundaries, while those of Ti-20Mo were slip lines. The distortion of indentation shapes also appeared on both Ti-Mo alloys. Based on these results, the procedure of crystal orientation evaluation by micro indentation test was discussed.

DOI： 10.1299/jsmemecjo.2010.1.0_265

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G0300-9-3 異種材料積層構造体の圧縮における変形挙動と密度変化([G0300-9]材料力学部門一般講演(9):構造強度)

成瀬文雄, 多田直哉

年次大会講演論文集 2010 255 - 256 2010年

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

A lot of multilayer ceramic electric devices, for example MLCCs, are manufactured by stacking the ceramic sheets with printed internal electrodes and pressing it to make a monolithic structure. However, the pressing process also causes non-uniform deformation in the ceramic block and it hinders the realization of MLCCs' downsizing. Therefore, the development of highly accurate press technology has been desired. In this study, experimental study on the compression of block of stacked ceramic sheets was carried out and the change in density of side-gap and the local deformation in the block were investigated. It was found that the change in density of side-gap begins to increase at the onset of compression and become constant at the compressive strain of 10%.

DOI： 10.1299/jsmemecjo.2010.1.0_255

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1511 直流電位差法を用いたはんだボール/銅接合界面き裂評価における銅線位置とボイドの影響(OS15.電子デバイス・電子材料と計算力学(3),オーガナイズドセッション)

中原亮一, 吉田直人, 多田直哉

計算力学講演会講演論文集 2009 ( 22 ) 724 - 725 2009年10月

903 巨視的ひずみ勾配下にある多結晶金属材料の力学的挙動に関する数値シミュレーション(OS9.材料の組織・強度に関するマルチスケールアナリシス(1),オーガナイズドセッション)

内田真, 清水一郎, 多田直哉

計算力学講演会講演論文集 2009 ( 22 ) 330 - 331 2009年10月

OS0317 双晶変形を伴う最密六方晶金属の二軸圧縮塑性挙動(非立方晶型金属材料の変形現象とそのモデル化,オーガナイズドセッション)

清水一郎, 多田直哉, 出井準也

M&M材料力学カンファレンス 2009 734 - 735 2009年7月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Uniaxial and biaxial compression tests with proportional strain paths were preformed on industrial pure titanium and AZ31 magnesium alloy, in order to investigate the plastic behavior of hexagonal close-packed metals. Those distinctive features were clarified by comparing with the results of industrial pure iron. The true stress-true strain curves of pure titanium and AZ31 alloy showed constant or increasing strain hardening ratio within a certain range of applied strain, due to deformation twinning. The work contours, namely contours of the equal expenditure of plastic work, were obtained by biaxial compressive stress-strain relations for the study of yielding behavior. The deviation of work contour plots in biaxial compression region became large with the progress of plastic deformation. This fact implies the evolution of anisotropy during biaxial compressions of hexagonal close-packed metals.

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205 同期型スピニング加工による非軸対称成形に及ぼす被加工材性質の影響(材料力学V)

田中秀一, 清水一郎, 多田直哉

講演論文集 2009 ( 47 ) 55 - 56 2009年2月