Characterization of plasticity and fracture of an QP1180 steel sheet

Experiments are designed to experimentally characterize the plastic behaviour and fracture limits of an QP1180 steel sheet under complex loading conditions. The plastic behaviour is modelled by the Drucker yield function, while the fracture behaviour is illustrated the DF2016 [1] fracture criterion. The pressure-coupled Drucker yield function is calibrated by inverse engineering approach. The predicted load-stroke curves are compared with experimental results, which shows that the prediction matches with the experimental results with good agreement. Then the fracture data are then extracted from experiments and numerical simulations to calibrated two fracture criteria. The predicted fracture loci are compared with experimental results. The comparison demonstrates that both fracture criterion matches with the experimental results very well. Therefore, the Drucker function together with the Swift-Voce hardening law is recommended to model plastic deformation up to large plastic strain for various loading conditions. The fracture behaviour from shear to plane strain tension is recommended to be modelled by the DF2016 criterion and the pressure-coupled Drucker functions of sheet metal forming processes.