船用921A钢高温、高应变率下动态本构模型研究

921A steel is important ship structural steel in China. It is of great significance to study the dynamic mechanical properties of 921A steel at high temperature and high strain rate for ship structural protection design and safety evaluation. By using electronic universal testing machine and a high temperature Hopkinson pressure bar with a synchronous assembly system, the quasi-static and dynamic mechanical properties of 921A steel were studied over a wide range of strain rates (from 0.001 s_1 to 4 000 s_1 ) and temperatures (from 25 °C to 500 °C ). The results show that 921A steel has obvious strain rate strengthening effect and thermal softening effect. The strain rate strengthening effect decreases gradually with the increase of temperature, and the thermal softening effect is not sensitive to the change of strain rate. Considering the effects of strain, strain rate and temperature on mechanical properties, the Johnson - Cook constitutive model parameters of 921A steel were obtained byfitting experimental data. The average diameter of the projectile hole and the damage morphology of the double-layer 921A steel plate obtained by numerical simulation are in agreement with the experimental results. It is verified that the parameters of the constitutive model can describe the dynamic mechanical behaviors of 921A steel under the condition of high-speed impact.