Resistance to Detonation and Explosion

An interpretation of the fact that, for some explosives at least, the detonation velocity does not continue to rise with rise in density, but goes thru a maximum and detonation finally fails when the density exceeds a critical value is reptd by Dunkle (Ref 5) and Price Refs 9 10). Roth (Ref 4), on the basis of results reported in Refs 1, 2 St 3, suggests the existence of a property he calls Widerstand ( resistance or impedance ) of value equal to the product of loading density and detonation velocity, analogous to acoustic impedance and shock impedance (See abstract of Roth s paper at the end of this item) 

Gordon (Ref 8) attributes the effect of density to its strong influence on the detonation pressure. The log of the diffusion coefficient is approximately proportional to the inverse cube of the density. Thus, in composite explosives the reaction slows 

Other evidence indicates that the pre-compression need have no dynamic character, to cause quenching of the detonation. All that is required is the achievement of an initial density above a critical value. In general, this critical value depends on the charge dimensions the smaller the charge, the lower the critical density. For some explosives this density may be lower than the TMD at atmospheric pressure for instance, MF 8t LA,under certain conditions, will not support a high-velocity detonation at densities near crystal (See Dead-Pressed Explosives in Vol 3 of Encycl, p D20) 

For many military explosives the critical density is roughly 8% above the .voidless density, and can be reached by dynamic compressing of the explosive with 

Dr Langhans (Ref 4a) gave a comment (in German) on Dr Roth s paper (Ref 4), which can be approx translated as follows  

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