Energy of Impact or Shock in Detonation

Critical Energy of Impact (or Shock) in Detonation (or Explosion). This term signifies the minimum available energy of the falling hammer to produce explosions in impact sensitivity tests. It is designated as Ac and expressed 

Kistiakowsky (Ref 1) suggested that for the success of detonation by impact two sets of conditions must be met a) A hot spot, as defined by Bowden, must be first produced and b) The initial deflagration must be given the opportunity to develop and to produce a shock wave within the minute charge and the short time defined by the usual conditions of explns by impact (See also Ref 3) Refs 1) G.B. Kistiakowsky, p 565 in the 6thSympCombstn (1957) 2) Cook (1958), 

In examining the process of initiation of expls, ic is of importance to determine not only the critical density, p, and critical diameter, dc, of a detonator (or booster), but also its critical length, lc, which is the shortest length required for steady state detonation. It is known that if the initial velocity of shock wave of an initiator is equal to or lower than the velocity of sound, C0, in the charge to be initiated, no detonation can take place even with a large initiator. This means that the critical detonation velocity of an initiator, Dc, must be higher than a certain value which is different for each explosive to be initiated. Another requirement for successful detonation is that pressure at the front of a detonation wave produced by initiator at the expense of chemical energy, must be maintained at a certain minimum level 

If the charge were cast (such as TNT), a booster was required in addition to a decona-tor. By initiating a cast cylinder of TNT, 

Explosive Charge 2. Electric Detonator 3. Thin Brass Plate  

---