Mechanical properties of double-base propellant at high strain rates and its damage-modified ZWT constitutive model

To obtain the mechanical properties and constitutive behaviors of double-base propellant under impact loading, uniaxial compression experiments were performed on the material test machine and the split Hopkinson pressure bar (SHPB) device. The availability of the experimental data was examined, and the stress-strain curves were obtained by using the two-wave method. The experimental results indicate that the double-base propellant is a significant strain-rate-dependent material, the yield strength increases obviously at high strain rates compared with that under quasi-static loading, and the relationship between yield strength and logarithm of strain rate is bilinear. The yield strain of the doublebase propellant behaves in the effect of ductile-brittle transition, and it behaves in ductility at low strain rates as well as impact brittleness at high strain rates. The damage-modified ZWT constitutive model was used to fit the experimental data, and the parameters in the constitutive equation were obtained. Moreover, the damage factor was analyzed. Comparisons of the model-predicted curves with the experimental ones show that the damagemodified ZWT model can well predict the mechanical properties of the double-base propellant in the strain range from 0 to 0.14.