Computational and Numerical Analysis of Ductile Damage Evolution under a Load-Unload Tensile Test in Dual-Phase Steel

Dual-phase (DP) sheet steels are used in the automotive industry. They have a microstructure that consists of a ferrite matrix with dispersed martensite islands giving a combination of good formability and high strength. However, they also exhibit ductile failure caused mainly by high strain incompatibility in both phases, which continues to be an issue of discussion among researchers. To capture the mechanical degradation of a DP sheet steel, this research focuses on the damage characterization using a continuum damage model and loading-unloading uniaxial tensile tests to quantify ductile failure without incurring expensive and difficult mechanical tests, which has the potential to provide an understanding of the identification of damage parameters in the metal-forming industry. By comparing experimental tests and computation simulations, the model presents minimum errors considering triaxiality as a constant value.