A CDM-based unified viscoplastic constitutive model of FLCs and FFLCs for boron steel under hot stamping conditions

Forming limit curves (FLCs), which are constructed using the strains at localised necking, most widely used tools for evaluation of formability sheet metals. Fracture forming (FFLCs) more recently developed, complementary instead fracture. Since depends strongly on conditions such as strain state, temperature and rate, models predicting FLCs FFLCs essential optimisation further application hot processes in these vary significantly with both position time. However, no model has so far been developed to predict either alone or conjunction metals boron steel under stamping conditions. In this study, a set unified viscoplastic constitutive equations prediction based continuum damage mechanics (CDM) formulated from dislocation-based hardening, combination two novel coupled variables characterising accumulated leading necking The take into account effects rate material constants CDM-based have calibrated experimental data comprising true stress-true 22MnB5 obtained range temperatures rates. Investigation effect varying selected parameters resulting computed demonstrated flexibility enabling different shapes numerical values be constructed. This indicates potential other materials warm processes.