A modified Johnson-Cook model of dynamic tensile behaviors for 7075-T6 aluminum alloy

The dynamic mechanical behaviors of 7075-T6 aluminum alloy at various strain rates were measured by dynamic tensile tests using the electronic universal testing machine, high velocity testing system and split Hopkinson tensile bar (SHTB). Stress-strain curves at different rates were obtained. The results show that the strain rate hardening effect of 7075-T6 aluminum alloy is significant. By modifying the strain rate hardening term in the Johnson-Cook constitutive model, a new Johnson-Cook (JC) constitutive model of 7075-T6 aluminum alloy was obtained. The improved Johnson-Cook model matched the experiment results very well. With the Johnson-Cook constitutive model, numerical simulations of tensile tests at different rates for 7075-T6 aluminum alloy were conducted. According to tensile loading and stress-strain relation of 7075-T6 aluminum alloy, calculation results were compared with experimental results. Accuracy of the modified Johnson-Cook constitutive equation was further proved. (C) 2014 Elsevier B.V. All rights reserved.