Tokyo University of Agriculture and Technology

Institute of Global Innovation Research

グローバルイノベーション研究院

公開セミナー

Institute of Global Innovation Research Open Seminar

International Seminar on Material Modelingof High Strength Steel Sheets
Thursday, January 16 2020, 15:00~16:30

東京農工大学 小金井キャンパス 6号館 5階 501セミナー室
Seminar Room 501, 5F, Building 6, Koganei Campus TUAT
Program
15:10~16:00

Opening remarks

言語/英語
Language/English

どなたでもご聴講
いただけますEveryone is welcome
to attend.

Prof. Toshihiko Kuwabara, Institute of Engineering, TUAT

15:10~16:00“HAH20 DISTORTIONAL PLASTICITY FRAMEWORK INCLUDING PRESSURE
Prof. Frédéric Barlat,EFFECT”
Graduate Institute of Ferrous Technology,
Pohang University of Science and Technology, Korea

A distortional plasticity framework describing the anisotropic hardening effects that occur during strain
path changes, such as the Bauschinger and cross-loading effects, is developed. This approach,called HAH20, is a modified version of the homogeneous anisotropic hardening (HAH) framework
proposed almost a decade ago (Barlat et al., 2011, Int. J. Plast. 27, 1309–1327). Like the HAH
approach, HAH20 does not include any form of kinematic hardening. In the present formulation, theHAH20 yield condition provides an alternative description of the distortion suggested by crystal
plasticity simulation results (Jeong et al., 2017, Int. J. Plast. 93, 212-228). In addition, it incorporates
the influence of the hydrostatic pressure, which manifests itself by a higher flow stress in uniaxial
compression compared to tension. The state variable evolutions in HAH20 are modified compared to the previous HAH
version for a smoother transition between pure cross-loading cases and pure reversals. The model is calibrated for a DP780
dual-phase steel sheet sample using the data of a tension-compression test with three full cycles, as well as a sequence oftwo uniaxial tension segments in different directions. After calibration, the stress-strain curves predicted for independentloading sequences are compared with experimental results. Finally, theoretical predictions using the constitutive coefficientsof DP780 are discussed in view of the features offered by this new framework.

16:00~16:30“PRACTICAL USAGE OF ADVANCED MATERIAL MODELS FOR PRESSFORMING SIMULATION IN AUTOMOTIVE INDUSTRY” Dr. Nobuyasu NomaUNIPRERS R&D CO., LTD

Stamping manufactures are required to complete the die modification quickly to gain a cost advantage
in vehicle development. However, dramatic increase of strength of steels for automotive stamping partsraise the difficulty of die modification. To reduce the die modification cost and time, virtual design andmodification using FEM simulation is a key technique. Naturally, to enhance the accuracy of FEM
simulation, accurate material model is very important. In UNIPRESS, crush forming without blankholding is a major processing method due to the strength of steels. In this processing, twisting and wall
opening, which are different types of springback, are severe problem. To predict those defects
accurately, both the SD effect and the unloading behavior after pre-strain were investigated. We
concluded that the consideration of the SD effect is effective for twist prediction as well as wall openingprediction. Modeling method of unloading behavior is also crucial because the amount of springback is greatly affected by
the Young’ s modulus and the stress at the bottom dead center. In this presentation, summary of those results and practicalusage of advanced material models used in UNIPRES are introduced.
参加費 / Registration fee
講演会：無料 / Seminar: free

技術懇談会：無料 / Post-seminar party: free
■共催 / Co-organized By※懇談会参加希望の方は 1/14( 火 ) までにご連絡ください/ Post-seminar party registration by Jan.14
日本塑性加工学会板材成形分科会
Committee of Sheet Metal Forming, The Japan Society for Technology of Plasticity

グローバルイノベーション研究院 エネルギー分野 小笠原チーム
Institute of Global Innovation Research, “Energy” Ogasawara Team
卓越大学院プログラム
Excellent Leader Development for Super Smart Society
by New Industry Creation and Diversity■お問い合わせ / Contact
グローバルイノベーション研究院 工学研究院 桑原 俊彦
Institute of Global Innovation Research, Institute of Engineering
Prof. Toshihiko Kuwabara
Email: kuwabara ( ここに＠を入れてください）cc.tuat.ac.jp
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Please refer to our website for more information

小金井キャンパス
Koganei Campus

西門West Gate

講演会場 /Venue→ 東門
East Gate

正門
Main Gate

URL: https://www.tuat-global.jp
https://www.tuat-global.jp/english/