Precise understanding of concrete target behavior when subjected to high velocity impact of an eroding projectile involves analysis and studying the plastic flow field around the penetrating projectile. In this paper, the flow field around an eroding projectile is reviewed and the main equations of it are presented. Assuming viscoplastic behavior and solving these equations results in determination of the thickness of plastic layer ahead of penetrating projectile. Results show that the strength of the target is proportional to the size of the incompressible zone. Furthermore, there is a direct relation between penetration velocity and pressure gradient at the beginning and end of the incompressible zone; the lesser the pressure gradient the smaller the penetration velocity which means the higher resistance of the target against penetration. Comparison between the results of the presented analysis and experimental data corroborates acceptable accuracy of the model.
