A Modified Johnson-Cook Model for Sheet Metal Forming at Elevated Temperatures and Its Application for Cooled Stress-Strain Curve and Spring-Back Prediction

Journal Article · Mon Aug 22 00:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3623666· OSTI ID:21611545

Duc-Toan, Nguyen ^[1]; Tien-Long, Banh ^[2]; Young-Suk, Kim ^[3]; Dong-Won, Jung ^[1]

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1. Department of Mechanical Engineering, Jeju National University, Jeju-Do 690-756 (Korea, Republic of)
2. School of Mechanical Engineering, Hanoi University of Science and Technology, lA-Dai Co Viet Street, Hai Ba Trung District, Hanoi City (Viet Nam)
3. Department of Mechanical Engineering, Kyungpook National University, Daegu 702-701 (Korea, Republic of)

In this study, a modified Johnson-Cook (J-C) model and an innovated method to determine (J-C) material parameters are proposed to predict more correctly stress-strain curve for tensile tests in elevated temperatures. A MATLAB tool is used to determine material parameters by fitting a curve to follow Ludwick's hardening law at various elevated temperatures. Those hardening law parameters are then utilized to determine modified (J-C) model material parameters. The modified (J-C) model shows the better prediction compared to the conventional one. As the first verification, an FEM tensile test simulation based on the isotropic hardening model for boron sheet steel at elevated temperatures was carried out via a user-material subroutine, using an explicit finite element code, and compared with the measurements. The temperature decrease of all elements due to the air cooling process was then calculated when considering the modified (J-C) model and coded to VUMAT subroutine for tensile test simulation of cooling process. The modified (J-C) model showed the good agreement between the simulation results and the corresponding experiments. The second investigation was applied for V-bending spring-back prediction of magnesium alloy sheets at elevated temperatures. Here, the combination of proposed J-C model with modified hardening law considering the unusual plastic behaviour for magnesium alloy sheet was adopted for FEM simulation of V-bending spring-back prediction and shown the good comparability with corresponding experiments.

• OSTI ID: 21611545
• Journal Information: AIP Conference Proceedings, Vol. 1383, Issue 1; Conference: NUMISHEET 2011: 8. international conference and workshop on numerical simulation of 3D sheet metal forming processes, Seoul (Korea, Republic of), 21-26 Aug 2011; Other Information: DOI: 10.1063/1.3623666; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BENDING
BORON
COMPUTERIZED SIMULATION
COOLING
FINITE ELEMENT METHOD
HARDENING
MAGNESIUM ALLOYS
METALS
PLASTICS
SHEETS
SPRINGS
STEELS
STRAINS
STRESSES
TENSILE PROPERTIES
V CODES
ALLOYS
CALCULATION METHODS
CARBON ADDITIONS
COMPUTER CODES
DEFORMATION
ELEMENTS
IRON ALLOYS
IRON BASE ALLOYS
MACHINE PARTS
MATERIALS
MATHEMATICAL SOLUTIONS
MECHANICAL PROPERTIES
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
POLYMERS
SEMIMETALS
SIMULATION
SYNTHETIC MATERIALS
TRANSITION ELEMENT ALLOYS