研究者詳細 - 上森　武

論文 - 上森　武

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Springback Simulation of High Strength Steel Sheets Calculated by Yoshida-Uemori Model 査読

Takeshi Uemori, Satoshi Sumikawa, Shohei Tamura, Hiroyuki Akagi, Tetsuo Naka, Fusahito Yoshida

STEEL RESEARCH INTERNATIONAL 81 ( 9 ) 825 - 828 2010年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

For the accurate simulation of springback on high strength steel sheets, the use of an appropriate material model is of vital importance. In general, major aspects of material modelling are on the yield function and the hardening law. In the present work, using the framework of Yoshida-Uemori model (F. Yoshida and T. Uemori, Int J Plasticity, 18, 2002, 661-686), which is an advanced kinematic hardening model incorporating with a selected anisotropic yield function, FE simulations of springback in draw bending and S-rail forming (Numisheet'96 model) of 590 and 980MPa levels high strength steel sheets were performed, and the results were compared with the corresponding experimental observations. From the results, it is concluded that the modelling of the Bauschinger effect, including the plastic-strain dependent Young's modulus, is essential for accurate simulation of springback of high strength steel sheets, but the selection of an anisotropic yield function would be of minor effect since most of HSSs have weak anisotropies.

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Elasto-Plasticity Behavior of Type 5000 and 6000 Aluminum Alloy Sheets and Its Constitutive Modeling 査読

Shohei Tamura, Satoshi Sumikawa, Hiroshi Hamasaki, Takeshi Uemori, Fusahito Yoshida

NUMIFORM 2010, VOLS 1 AND 2 1252 630 - + 2010年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AMER INST PHYSICS

To examine the deformation characteristic of type 5000 and 6000 aluminum alloy sheets, uniaxial tension, biaxial stretching and in-plane cyclic tension-compression experiments were performed, and from these, r-values (r(0), r(45) and r(90)), yield loci and cyclic stress-strain responses were obtained. For the accurate description of anisotropies of the materials, high-ordered anisotropic yield functions, such as Gotoh's biquadratic yield function and Barlat's Yld2000-2d, are necessary. Furthermore, for the simulation of cyclic behavior, an advanced kinematic hardening model, such as Yoshida-Uemori model (Y-U model), should be employed. The effect of the selection of material models on the accuracy of the springback prediction was discussed by performing hat bending FE simulation using several yield functions and two types of hardening laws (the isotropic hardening model and Y-U model).

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プレス成形シミュレーションにおける材料モデルの検討

上森武

2010年

G0300-5-2 高張力鋼板のスプリングバック解析([G0300-5]材料力学部門一般講演(5):弾塑性解析)

赤木宏行, 田村翔平, 澄川智史, 上森武, 吉田総仁

年次大会講演論文集 2010 217 - 218 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

High tensile strength steel sheets have been widely used in the automobile industries to produce the light weight constructions. However the large springback deformation due to the high flow stress makes it difficult to the final shapes of car parts. In order to solve the problem, we propose the most accurate constitutive equation "Yoshida-Uemori model". In the present report, we evaluated usefulness of the constitutive equation.

DOI： 10.1299/jsmemecjo.2010.1.0_217

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G0300-5-1 均質化手法による金属の繰返し応力-ひずみ関係の数値シミュレーション([G0300-5]材料力学部門一般講演(5):弾塑性解析)

影山貴大, 上森武, 吉田総仁

年次大会講演論文集 2010 215 - 216 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

With the great development of computer hard technologies, there is a great demand for the accurate finite element analysis which can deal with the morphology of materials. There were so many reports that the complicated plastic deformation behaviors such as "Work hardening", "Bauschinger effect" and "Permanent softening" is related to morphology. We have introduced the Homogenization theory into the commercial finite element code "Marc" in order to research how different stress-strain responses were obtained.

DOI： 10.1299/jsmemecjo.2010.1.0_215

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FLD OF AZ31 SHEET UNDER WARM STRETCHING AND ITS PREDICTION 査読

Tetsuo Naka, Yasuhide Nakayama, Takeshi Uemori, Ryutaro Hino, Fusahito Yoshida

ENGINEERING PLASTICITY AND ITS APPLICATIONS: FROM NANOSCALE TO MACROSCALE 638 - 643 2009年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：WORLD SCIENTIFIC PUBL CO PTE LTD

Forming Limit Diagrams (FLDs) of a magnesium alloy (AZ31) sheet at various forming speeds (3 to 300 mm.mm(-1)) at several temperatures of 100-250 degrees C were investigated by performing a punch stretch-forming test. The forming limit strains increased with temperature rise and with decreasing forming speed, where the effect of forming speed was stronger at higher temperatures. To describe such a characteristic of FLD of AZ31, the Marciniak-Kucznski type forming limit analysis was conducted using the Backofen-type constitutive equation (sigma = C epsilon(n) (epsilon) over dot(m)). In this analysis, the damage evolution in the necking zone was taken into account based on Oyane's ductile fracture criterion. The numerical results of the FLD show a good agreement with the corresponding experimental observations.

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PLASTIC DEFORMATION BEHAVIOR OF HIGH STRENGTH STEEL SHEET UNDER NON-PROPORTIONAL LOADING AND ITS MODELING 査読

Takeshi Uemori, Yuji Mito, Satoshi Sumikawa, Ryutaro Hino, Fusahito Yoshida, Tetsuo Naka

ENGINEERING PLASTICITY AND ITS APPLICATIONS: FROM NANOSCALE TO MACROSCALE 22 - + 2009年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：WORLD SCIENTIFIC PUBL CO PTE LTD

This paper deals with plastic deformations of a high tensile strength steel sheet (HTSS sheet) under biaxial stress condition including strain path. Using a cruciform specimen of a HTSS sheet of 780MPa-TS, experiments under proportional and non-proportional loadings were investigated. Numerical simulations of stress-strain responses for several strain paths after biaxial stretching were conducted using a large-strain cyclic plasticity model (Yoshida-Uemori model). The results of numerical simulation agrees well the corresponding experimental results, which is attributed to the accurate modeling of the backstress evolution of the anisotropic yield function.

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二軸応力経路が変化する場合の高張力鋼板の弾塑性変形挙動

上森武

塑性と加工 50 ( 576 ) 39 - 43 2009年

記述言語：日本語出版者・発行元：The Japan Society for Technology of Plasticity

The elastopasticity behavior of a high-strength steel sheet was investigated by performing biaxial tension experiments. To evaluate the accuracy of constitutive models in describing such elastoplasticity behavior, numerical simulations of stress-strain responses were conducted for the same stress paths as those in the experiments using two types of models: the isotropic hardening model (IH model) and the kinematic hardening model proposed by the present authors (Yoshida-Uemori model). In this work, special emphasise is placed in the cases of stress-path change. In experiments on radial loadings after equibalanced tension preloading, it was found that flow stresses are considerably lower than uniaxial tension flow stress. The IH model hardly describes this phenomenon, although it is sufficient for stress-strain analysis of proportional loading cases. In contrast, the Yoshida-Uemori model can well predict every stress-strain response in biaxial stress-path changes.

DOI： 10.9773/sosei.50.39

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00324822128?from=CiNii

板材の引張試験，変形特性と成形性の評価試験

上森武

2009年

ショットピーニングによるコールドバットジョイント

上森武, 兵庫県立大

2009年

高張力鋼板と異種金属のショットピーニングによるバットジョイント

上森武, 兵庫県立大

2009年

非比例変形時における高張力鋼板の塑性変形挙動とそのモデル化

上森武

22 ( 31-32 ) 5394 - 5399 2008年12月

温間ストレッチ下におけるAZ31板FLDとその予測

上森武, 弓削商船高等専門学校

22 ( 31-32 ) 6010 - 6015 2008年12月

調質圧延における鋼板の不均一塑性変形と降伏点除去過程のFEMシミュレーション(<特集>調質圧延のミクロ変形解析および実機操業技術の最近の進歩)

吉田総仁, 上森武, 金田佑也, 山本茂雄, 後藤良孝, 酒井岳人

鐵と鋼 : 日本鐡鋼協會々誌 94 ( 10 ) 384 - 390 2008年10月

記述言語：日本語出版者・発行元：社団法人日本鉄鋼協会

Finite element simulations of temper rolling of a steel sheet were performed using a model of elasto-viscoplasticity that describes the yield-point phenomena such as a high upper yield point, the rate-dependent Luders strain at the yield plateau and the subsequent workhardening. From the simulations of uniaxial tension of temper-rolled sheets, the mechanism of elimination of the yield point by rolling has been clarified. For the purpose of the elimination of the yield point, the roughness of the roll plays an important role. During the temper rolling with rough surface rolls, a number of plastic zones are non-uniformly formed on the surfaces of the sheet, and from these numerous Luders bands will start to propagate simultaneously. Consequently, macroscopic plastic deformation more likely to occur in the temper-rolled sheet under a comparatively low load without showing the yield point.

DOI： 10.2355/tetsutohagane.94.384

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00319515370?from=CiNii

FE Simulation of Non-uniform Plastic Deformation of Steel Sheet and Elimination of Yield Point in Temper Rolling 査読

Fusahito Yoshida, Takeshi Uemori, Yuya Kaneda, Shigeo Yamamoto, Yoshitaka Goto, Gakuto Sakai

TETSU TO HAGANE-JOURNAL OF THE IRON AND STEEL INSTITUTE OF JAPAN 94 ( 10 ) A384 - A390 2008年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：IRON STEEL INST JAPAN KEIDANREN KAIKAN

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ひずみ速度，温度，板厚の影響がAZ31マグネシウム合金板の降伏曲面に与える影響