Penetration of rigid projectiles into concrete based on improved cavity expansion model

The main objective of the present work is to develop an approximate approach for nondeformable projectile normal penetration into concrete targets with clear mechanics concepts. The normal/tangential stress acting at the projectile–target interface in the tunnel region is obtained according to the spherical cavity expansion penetration model, where the fractured target medium near the expansion cavity is perfectly described by Tresca's law. Then, the penetration resistances on projectile with spherical nose, ogive nose, and conical nose are further derived by composing stress along the projectile's axis respectively. The prediction formula of penetration depth for nondeformable projectile normal into concrete targets is presented according to Newton's second law. Comparisons between the predicted penetration depth and the experimental data are in reasonable good agreement in a broad range of projectile geometry, impact velocity, and concrete target. Moreover, the results of this prediction model are very close to those of Forrestal et al's analytical model, and the parameters of presented model have important mechanics concepts that are easy to obtain.