Penetration of a rigid projectile into a finite thickness elastic-plastic target - comparison between theory and numerical computations

Recently, two different analytical solutions have been developed for penetration of a rigid projectile into an elastic-plastic target of finite thickness. One solution satisfies the balance of linear momentum pointwise in target region, but it satisfies the free-surface boundary conditions only in an integrated sense. The second solution satisfies the balance of linear momentum only along a finite number of instantaneous streamlines, but it satisfies the boundary conditions exactly at each intersection of the streamlines with the boundary. The first solution is valid only for normal penetration whereas the second solution has been generalized for oblique penetration. The main objective of the present paper is to compare the predictions of these two theoretical approaches with a numerical solution obtained using the hydrocode Autodyn2D. By modifying the boundary condition used in the first method it is possible to obtain a reasonably accurate description of the penetration process (including the exit stage) with the computational time reduced from a few hours for Autodyn2D to only a few minutes for the analytical solution.