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 penetr ation of a rigid projectile into an elastic-plastic target of finite thickn ess. One solution satisfies the balance of linear momentum pointwise in tar get region, but it satisfies the free-surface boundary conditions only in a n integrated sense. The second solution satisfies the balance of linear mom entum only along a finite number of instantaneous streamlines, but it satis fies the boundary conditions exactly at each intersection of the streamline s with the boundary. The first solution is valid only for normal penetratio n whereas the second solution has been generalized for oblique penetration. The main objective of the present paper is to compare the predictions of t hese two theoretical approaches with a numerical solution obtained using th e hydrocode Autodyn2D. By modifying the boundary condition used in the firs t 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 analyt ical solution. (C) 2001 Elsevier Science Ltd. All rights reserved.