Parameter determination of the dynamic constitutive equation for polycrystal copper

By using MTS (mechanical threshold stress) model and the experimental technique of the split Hopkinson bar with the synchronization assemblage, we determined theoretically the parameters of the dynamic constitutive equation of the continuous casting polycrystal copper. Optimizing the parameters of the dynamic constitutive equation with application to polycrystal copper, we obtained the theoretical stress-strain curves of polycrystal copper. In the narrow heating furnace designed and manufactured by Northwestern Polytechnical University, the dynamic impact experiments at temperature from 285 K to 1100 K were accomplished and we determined the experimental stress-strain curves of polycrystal copper. The theoretical stress-strain curves are in good agreement with experimental curves, except for the range of temperature from 485 K to 585 K. The concept of restoration threshold energy was proposed and the restoration threshold of the continuous casting polycrystal copper is about 545 K. The parameters of MTS model were also discussed in detail. The results show that only seven parameters in the parameters of MTS model are independent.