O-012 About the Misuse of Detonation Velocities for the Characterization of High Explosives

In the characterization process of an explosive, there is a certain tendency to use the detonation velocity D as the main parameter because it is easier to measure than the detonation pressure or energy, whereas the main quality generally required is a high release of mechanical energy during the expansion of the detonation products. These parameters are obviously correlated but not strictly related. Typical examples of discrepancies are presented and explained: adding water to a granular explosive (in order to fill the porosity) or adding hydrogen to the stoichiometric mixture 2H2 + O2, (in condensed phases) increases D; adding inert solids to an explosive does not vary its detonation pressure if these solids can be considered incompressible. However, all these additions obviously decrease the specific energy of the explosive by dilution.

The last example emphasizes the importance of the compressibility of the detonation products: the greater this compressibility, the greater the specific energy of the explosive for a given value of D. This may suggest selection criteria for new explosive molecules, especially if used in shaped charges. Both this compressibility and the detonation energy are easily accessible experimentally by measuring the angles of expansion of these products on both sides of an explosive slab coated on one side and initiated at its end;