Prediction of Forming Limit of Dual-Phase 500 Steel Sheets Using the GTN Ductile Damage Model in an Innovative Hydraulic Bulging Test

摘要

Advanced high-strength steel has great potential for application in automotive and high-speed rail industries owing to its excellent mechanical properties. To predict the forming limit of dual-phase 500 steel sheets (DP500), Banabic's innovative hydraulic bulging test was conducted on them, and the Gurson-Tvergaard-Needleman (GTN) ductile damage model was used to determine their failure under different strain paths. GTN damage parameters were identified using a hybrid experimental-numerical method based on the equal biaxial hydraulic bulging test. The results show that fracture of all of the DP500 specimens occurred in their polar region in experiments under different strain paths from uniaxial to equal biaxial tension. Moreover, the GTN ductile damage model could not only provide an accurate prediction of the fracture position, but also give an appropriate evaluation of the sheet forming limit under different loading paths.