DEFINING GTN PARAMETERS OF DP STEELS OF DIFFERENT ROLLING DIRECTIONS AND AT DIFFERENT STRAIN RATES

The microstructure of Dual Phases steel is known to be mostly composed of the ferrite phase, which offers ductility, and the martensite phase, which provides strength. However, the shapes, orientations and directions of the grains of these two phases are different and vary depending on the degree of observation. Therefore, the objective of this research was to compare the stress and strain distribution at different strain rates of standard specimens of DP steels, namely DP600 and DP800 steels. Besides, in this study, the finite element modeling method is used through optimization to determine the GTN fracture failure, constitutive and nucleation parameters of the mentioned steels based on their rolling directions and strain rates. The experimental and numerical simulation results are also compared, and are in good agreement.