A numerical study on the detonation behaviour of double reactive cassettes by impacts of projectiles with different nose shapes

The detonation behaviours of two layers of reactive cassettes by the impact of cylindrical steel projectiles with different nose shapes were numerically simulated at 1800 m s−1 based on the forest fire explosive reaction rate model. When a projectile with a flat-ended nose impacted the target, a run distance-induced detonation took place at the bulk of the first cassette. In the case of a cone-ended projectile impact, however, a back plate-assisted detonation took place via the superposition of incident and reflective shock waves at the region near the back plate of the first cassette. Since such a mechanism was not observable in the conventional critical initiation criteria (CIC) test, the previously developed CIC models were suggested to be inadequate to predict the detonation sensitivity of a reactive cassette. When a hemispherically nosed projectile impacted the target, none of the detonation mechanisms were triggered, resulting in the failure of detonation. The detonation of the second reactive cassette was not directly influenced by the impact shock of the projectile, but it was achieved only when the first cassette was successfully detonated thereby transferring sufficient energy to the second one.