Relationship between out-of-plane shear and springback in press forming of tailored CFRTP

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06100
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Production engineering/Processing studies
• Research Institution: Gunma National College of Technology
• Principal Investigator: KUROSE Masashi 群馬工業高等専門学校, 機械工学科, 教授 (10280356)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: プレス成形 / 金型 / 弾性力学 / 塑性力学 / 異方性 / 成形温度 / ねじり

Outline of Final Research Achievements

In this study, I focused on the tailored blank material in CFRP and aimed to investigate the influence of the difference thickness position on the press formability of the blank material and the torsional strength of the molded product. Hat bending of CFRP tailored blanks with different thickness difference positions was performed by analysis and experiment, and the strain distribution, forming shape, and torsional strength were evaluated.In the analysis and experiment, the CFRP tailored blank material had a local constriction on the vertical wall surface on the thick side in press forming as the difference thickness position was set to the free side. Therefore, it was shown that the press formability of the tailored blank becomes better as the difference thickness position was closer to the side where the cross-sectional area was larger, and it was necessary to secure a large clearance.

Free Research Field

工学

Academic Significance and Societal Importance of the Research Achievements

炭素繊維強化樹脂(CFRP)は鋼や軽合金よりも比剛性かつ比強度に優れることから，航空機体だけでなく自動車ボディの材料として注目されている．また，近年では，自動車産業において自動車ボディへの最適な材料配置を可能にするために，異なる厚さの板材を接合したテーラードブランク材をプレス成形して使用する試みも行われている．テーラードブランク材は差厚位置によって成形性が変化するため，差厚位置と成形性の関係性を明らかにする必要があった．さらに，自動車ボディは面内荷重だけでなくねじりによる面外荷重を受けるため，差厚位置の異なる成形品のねじり強度を把握することができた．