关键词: 成形极限, 冲压成形, 集中缩颈, 剪切破裂, 韧性破裂, 弯曲强化

Abstract: Criterions of ductile fracture (with or without obvious localized necking) and shear fracture of sheet metal forming are analyzed respectively. Advantages and disadvantages of forming limit diagrams and ductile fracture criterions are also compared. The research progress on bending-enhanced forming limit with tight features and shear fracture occurring before necking of advanced high-strength steels (AHSS) are mainly analyzed. These two problems can’t be predicted exactly by the conventional failure criterions embedded in finite element analysis software. The paper presents that it will be more universally significant to predict bending-enhanced forming limit with tight features when bending is assumed along the transverse & longitudinal principle loading direction respectively. And it is also necessary to study the shear fracture mechanism of AHSS to develop a failure criterion that can be used in finite element simulation. It will help to develop the plastic forming theory and guide the engineering applications.

Key words: Bending-enhanced, Ductile fracture, Forming limit, Localized necking, Shear fracture, Stamping