The effect of target inertia on the penetration of aluminum targets by rigid ogive-nosed long rods

• Equations for final depth of penetration that neglect and include target inertia were examined.
• Target inertia needs to eventually be included in cavity-expansion approximation penetration models at some striking velocity.
• Target inertia effects depend on striking velocity, projectile properties, and target properties.
• Large strain, compression, stress–strain data for the target material are essential for modeling.

In this article, we investigate in further detail the differences between quasi-static and dynamic penetration models based on the spherical cavity-expansion approximation for rigid ogive-nose long rod steel projectiles that penetrate aluminum targets at normal impact over a range of striking velocities. Comparisons of experimental data with predictions from a preveously published incompressible power-law strain hardening penetration model that includes target inertia effects derived from a spherical cavity-expansion solution show excellent agreement for striking velocities to 1800 m/s. However, predictions from a previously published incompressible penetration model derived from a quasi-static spherical cavity-expansion solution that neglects target inertia effects loses accuracy with increasing striking velocity. In this work, we illustrate the effects that target inertia has on the deep penetration of rigid ogive-nosed long rod steeel projectiles that strike aluminum targets with normal impact over a range of striking velocities. This comparison is achieved by employing the cavity-expansion approximation with solutions for quasi-static and dynamic incompressible power-law strain hardeniong spherical cavity expansion solutions. These results indicate that the magnitude of the target inertia effects depends on striking velocity, projectile geometry and nose shape, projectile density, and target material properties.