The application of a modified constitutive model of metals in the simulation of hypervelocity impact

To accurately calculate the hypervelocity impact of 93 tungsten alloy projectile on Q345 steel plate, a modified constitutive model of metals is established. The GRAY three-phase equation of state is introduced to describe the phase change of the material, while the Johnson-Cook strength model is used to describe the mechanical behavior of the material in the late stage of impact process. Combined with the Feng’s damage evolution model and Johnson-Cook failure model, the tensile and shear failure behavior of materials under different stress triaxiality are represented. The fracture evolution model proposed by Cao Xiang is adopted to describe the process of stress vanishing after material failure. The applicability of the constitutive model is then verified by comparing the numerical simulation results with the experimental ones. Furthermore, the spatial distribution characteristics of fragment group in a typical process of a projectile impacting target are analyzed. The results show that based on the modified metal constitutive model, the perforation diameter of the target, the erosion length of projectile and the expansion velocity of fragment group of the hypervelocity impact are consistent with the experimental results. The GRAY three-phase equation of state can relatively accurately give the melting situation of the projectile and target materials when the projectile impacts the first layer of the target plate and the remaining projectile and fragment group impact the second layer of the target plate. The Feng’s damage evolution model can accurately judge whether spallation occurs during the hypervelocity impact. After integrating Feng’s damage evolution model, Johnson-Cook failure model and fracture evolution model proposed by Cao Xiang, the statistical curve of perforation area and cumulative number of aftereffect target plate impacted by fragment group obtained from the numerical simulation are consistent with the experiment data. The spatial distribution results of fragment group of cylindrical 93 tungsten projectile hypervelocity impacting Q345 target plate under typical conditions are obtained, and the front part of fragment group possesses high mass, high axial momentum and high transverse momentum by their absolute values. © 2022 Explosion and Shock Waves. All rights reserved.