Penetration of eroding projectiles into concrete

Concrete is an important material when building protective structures. To calculate what happens to these structures when they are hit by a projectile, we need to have a solid understanding of their behavior. Moreover, the projectile itself will be severely deformed upon impact. Even though this is difficult to handle analytically, several attempts have been made in the literature to describe both the penetrator and the target as fluids. In this report, we present a review of these models as well as some procedures for solving the governing equations. The models are divided into two main categories: The first is based on pure hydrodynamics, while the other utilizes a predefined velocity profile. Our review does not include every possible model, but gives an overview of which physical processes are relevant when the projectile is deformed during the penetration process. These processes are therefore relevant when constructing military facilities. Some calibration by additional experiments should be performed. The models are mainly valid for high impact velocities. For low impact velocities, the projectile can be considered a rigid body. Some of the models cover this situation, and the level of concrete model complexity determine which of the models one should choose. The models with predefined velocity give a smoother velocity profile. This, in turn, gives the governing equations better numerical properties.