Numerical Prediction Model of Temperature Effect on DP1000 Steel Damage during Warm Formability

In this work experimental tensile tests were performed on a DP1000 steel at different temperature levels in the range (293-600) K. This experimental database was used for the identification of a Johnson-Cook constitutive model taking into account temperature effects. A critical void area fraction and a corresponding critical equivalent plastic strain were also identified from each temperature using a metallographic analysis previously described. This critical equivalent plastic strain was considered as a fracture criterion instead of the traditional fracture strain of the Johnson-Cook model and a corresponding damage parameter was determined in these specific conditions. Finally numerical simulations were carried out to analyze the influence of the temperature on the macroscopic critical fracture during a forming operation by bending.