研究者詳細 - 多田　直哉

1922 はんだボール/銅接合界面き裂の成長とその評価(J16-3 電子情報機器,電子デバイスの熱制御と強度・信頼性評価(3),J16 電子情報機器,電子デバイスの熱制御と強度・信頼性評価)

江崎佑輔, 多田直哉, 安藤貴宏, 堀和彦

年次大会講演論文集 2007 209 - 210 2007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

Growth of crack on the interface between lead-free solder ball and copper was monitored by means of the direct current potential difference method. The solder balls were jointed on the surface of a plate specimen of pure copper and cyclic tension test was carried out. The change in the potential difference of the solder ball increased with the number of cycles and the interface crack was initiated and grew. The relationship between the increase in the potential difference and the cracked area was evaluated and the results were compared with those obtained by the previous electric field analysis. Both results agreed with each other and this suggests that the interface crack can be monitored by the proposed method.

DOI： 10.1299/jsmemecjo.2007.7.0_209

2440 シリンダブロック隅部の静ひずみ評価とヘッドボルト締付荷重の影響(G03-10 ひずみ・応力解析,G03 材料力学)

井口克之, 多田直哉, 清水一郎

年次大会講演論文集 2007 453 - 454 2007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 static strain at the fillet of cylinder block was evaluated by the finite element method based on a single model of a cylinder block. The fillet is stress concentration part of a cylinder block that is used internal combustion engine. The strain along the fillet varied depending on the position, which was mainly attributed to the stiffness of the cylinder block and the location of cylinder head bolts. An appropriate range of the tightening force of cylinder head bolts for fixing was also evaluated. The minimum force was determined from the minimum pressure on the head packing not to leak the combustion gas. The maximum force was determined from the maximum static strain at the fillet of cylinder block above which cracks could be initiated. This method can be used for optimum designing of cylinder block.

DOI： 10.1299/jsmemecjo.2007.1.0_453

253 ゴム強化型結晶性ポリマーブレンド材の微視およびメゾ領域における変形挙動の数値シミュレーション(マルチスケール解析,OS06 ポリマの変形と破壊に関するモデリングとシミュレーション)

内田真, 北乘吉晴, 多田直哉

計算力学講演会講演論文集 2006 ( 19 ) 401 - 402 2006年11月

107 繰返し負荷によって生じたはんだボール/銅接合界面損傷への直流電位差法の適用(材料力学I)

安藤貴宏, 多田直哉

講演論文集 2006 ( 44 ) 13 - 14 2006年2月

108 直流電位差法を用いたはんだボール/銅接合界面き裂のモニタリングに関する3次元有限要素法解析(材料力学I)

神谷徹, 多田直哉, 安藤貴宏

講演論文集 2006 ( 44 ) 15 - 16 2006年2月

402 微小圧痕形状を用いた純チタンの結晶学的方位評価(GS5(1) 実験,計測,モニタリング)

清水一郎, 多田直哉, 寺内大地

材料力学部門講演会講演論文集 2006 199 - 200 2006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 crystal orientation is one of important factors that affect the mechanical properties of single- and poly-crystalline metals in deformation processes. X-ray diffraction method and electron back scatter diffraction method are the typical ways to identify the crystal orientation of grains. Although these methods are possible to give accurate results, they need relatively expensive instruments and operation trainings. The present study aims to show the possibility to use an indentation shape made on a grain's surface for the identification of it's crystal orientation in polycrystalline titanium, which is hexagonal close-packed crystal structure. The strong correlation between the indention shape and the crystal orientation was found for the grain of pure titanium. The results also show the possibility to evaluate the direction of c-axis to a fairly good accuracy by introduced procedures.

DOI： 10.1299/jsmezairiki.2006.0_199

3326 工業用純チタンのひずみ経路変化を伴う二軸圧縮塑性変形における力学的挙動(S18-2 結晶塑性解析,S18 材料の強度と組織)

清水一郎, 多田直哉, 渋谷享佑

年次大会講演論文集 2006 481 - 482 2006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 understanding of the multiaxial flow behavior of polycrystalline metals is important not only for the process planning but also for the quality assurance of metal working products. In the present study, the biaxial compression experiments with strain path change were performed on industrial pure titanium using a newly developed testing apparatus. The influences of strain path and abrupt path change upon the mechanical behavior were then investigated. The results show that both the strain level at path change and the directional relation between the sequential paths affect the stress-strain relation of the material. It is also found that the plastic anisotropy has influences on the mechanical behavior with regard to the strain histories.

DOI： 10.1299/jsmemecjo.2006.1.0_481

506 二軸圧縮塑性変形に伴う多結晶金属材の変形挙動に関する検討(OS-5B 金属の変形と損傷,OS-5 材料の塑性挙動の構成式のモデル化とシミュレーション)

清水一郎, 多田直哉

計算力学講演会講演論文集 2005 ( 18 ) 827 - 828 2005年11月

715 多結晶金属の引張り塑性変形に伴う微視的変形挙動(GS-3 変形挙動,研究発表講演)

王暁群, 阿部武治, 多田直哉, 鳥居太始之

関西支部講演会講演論文集 2005 ( 80 ) "7 - 29"-"7-30" 2005年3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

It is well-known that the hardness of material is related to its mechanical characteristics. The microscopic inhomogeneity of polycrystalline pure titanium is evaluated by testing the micro hardness of the grain for various grain orientation. Namely, the change in the hardness associated with plastic deformation, and the relation between the deformation of grain and the change of the hardness are studied, by measuring hardness before and after tensile deformation. The strains of respective grains are also measured and the effect of grain size is discussed.