Investigating the Penetration of Aluminum Targets by a Spherical Impactor in the Range from 460 to 700 m/s

The paper numerically studies the penetration of a spherical impactor through monolithic and reinforced aluminum targets at initial velocities ranging from 460 to 700 meters per second. Aluminum samples with overestimated values of yield strength, spall strength, and specific work of shear plastic deformation are considered as hardened samples. The material is modeled as an elasto-plastic, porous, compressible medium taking into account its strength properties, shock wave phenomena, and fracture formation through spall-induced and shear-induced modes. The governing equations are based on the Prandtl–Reiss equations under the Mises flow condition. The state equation is formulated in Walsh form. Numerical methods are used to solve the problem, with a Lagrangian approach serving as the primary research tool. The computational part is supplemented with mechanisms for splitting nodes and erosion elements. The calculations were carried out in a two-dimensional, axisymmetric model using the latest version of the “Udar.Os.2” finite element solver. The sensitivity of the mesh was analyzed, and the most efficient finite element model was selected. In all cases, hardening of the specimens led to an increase of impact resistance. Although the targets were penetrated, specimens with an overestimated shear strength value provided greater impact resistance. At certain stages of the process, the ballistic curves aligned, but the impactor was not destroyed, leaving behind a target’s debris cloud.