The influence of a steel rear barrier on the detonation response of a steel covered explosive struck by a steel projectile

Experiments by Weickert showed that the critical impact velocity of a shaped charge jet, required to cause detonation of a steel/explosive/steel laminate, reduced when the explosive thickness reduced. This paper examines the cause of this change using hydrocode simulations with and without a temperature based burn model. The simulations show that the change in critical impact velocity is caused by the reflected shock from the rear plate exceeding the shock at the cover plate. At this point the site of the detonation moves from the cover plate to the rear plate. Further reduction in explosive thickness causes further reduction in critical impact velocity due to the reduced dissipation of the shock reaching the back plate. The change in critical velocity for hemispherical-nosed projectiles is predicted to be not as sharply defined as for flat-nosed projectiles. This is due to a later, third stage reflection from the bulge of the advancing cover plate.