Dimensionless formulae for penetration depth of concrete target impacted by a non-deformable projectile

Based on the dimensional analysis of concrete penetration by a non-deformable projectile and an analytical penetration model, two dimensionless numbers, i.e., the impact function I and the geometry function of projectile N are defined and used in a dimensionless formula to predict the penetration depth. It is shown that experimental data on shallow, medium and deep penetrations in a broad range of concrete strength, impact velocity and projectile geometry can be uniquely represented by these two dimensionless numbers. It is also shown that the formula based on these two dimensionless numbers is comparable to the unit-dependent empirical formulae on penetration depth.