A ratio of 2T/D of unity corresponds to a solid steel missile.
CEA-EDF Formula (1977).
Based on an empirical fit to data from 52 tests with solid cylindrical missiles
impacting at velocities greater and less than the critical perforation velocity, the
CEA-EDF formula (Reference 7) was developed in France and presented in
1977. It gives the perforation velocity, Vp, as:
Later, tests by CEA-EDF indicated that a realistic residual velocity is given by
using a factor of 1.29 instead of 1.43 in Equation C 6-11. Thus, for reinforced
concrete with a density of 156 lb/ft3 (2500 Kg/m3), the perforation thickness (tp) is
ultimate compressive strength of concrete (lb/in2);
missile nominal diameter (in.);
missile weight (lb);
missile impact velocity (ft/sec).
To prevent perforation, minimum concrete thickness, td, shall be