Abstract:

The applicability of the model with strain-rate dependence was investigated in view of the strain rate effect of high strength steel. Using hydraulic-servo high speed testing machine, the tension tests of low alloy high strength cold rolled steel HC340LA were carried out at the intermediate-to-high strain rate (0.1~500 s-1). Finite element simulation of the material at different loading speeds was performed with non-linear dynamic explicit code LS-DYNA. Different constitutive models (e.g., Johnson-Cook, Cowper-Symonds) for depicting strain rate effect and plastic yield stress of steel material were compared. The results show that Swift-HockettSherby hardening law is preferable for characterizing the plastic flow stress behavior of high strength steel, and interpolation method is better than constitutive modeling for accurate simulation of strain rate effect of the material.

Key words: mechanics of materials, high strength steel, strain rate, dynamic tension, finite element, constitutive model