High-Explosive Shock Devices

Optical devices or optical systems have provided most of the available strong shock data and were the primary tools used in the early shock-compression investigations. They are still the most widely used systems in fundamental studies of high explosives. The earliest systems, the flash gap and mirror systems on samples, provided discrete or continuous measurements of displacement versus time. 

Primers used for nonmilitary (commercial or industrial) purposes are devices which initiate high explosive charges (such as Dynamites) by shock produced on detonation of primary charges and not by a flash or flame as in the case of igniters... 

Primary explosives (also known as primary high explosives) differ from secondary explosives in that they undergo a very rapid transition from burning to detonation and have the ability to transmit the detonation to less sensitive explosives. Primary explosives will detonate when they are subjected to heat or shock. On detonation the molecules in the explosive dissociate and produce a tremendous amount of heat and/or shock. This will in turn initiate a second, more stable explosive. For these reasons, they are used in initiating devices. The reaction scheme for the decomposition of the primary explosive lead azide is given in Reaction 2.2. 

Primary explosives explode from shock, from friction, and from heat. They are used in primers where it is desired by means of shock or friction to produce fire for the ignition of powder, and they arc used in detonators where it is desired to produce shock for the initiation of the explosion of high explosives. They are also used in toy caps, toy torpedoes, and similar devices for the making of noise. Indeed, certain primary explosives were used for this latter purpose long before the history of modern high explosives had yet commenced. 

High Explosive Devices and the Reduction of Accumulated Data , DRI-4089-6903-F (1969) (ConO M) F.V. Youngblood, Contributions to the North Atlantic Treaty Organization M72 Light Antitank Weapon Co—Production Program , PATR 3904 (1969) (ConO N)H.D. Jones, et al, The Detonation Properties and Unreacted Shock States of Otto Fuel , NOLTR-69-111 (1969) (ConO O) Anon, Tripartite Anti-Tank Trials and Lethality Evaluation. Part II. Volume I. 1. Warhead Design Data. 

Regarding the pressure duration, the electrical discharge technique forms a bridge between laser ( nanoseconds) and high-explosive (—microseconds) shock experiments. Our electrical discharge device produces shock waves that last between —10 and 100 ns (Fig. 1.1). The shorter lime limit is valid for the highest pressure and reflects the need to use thinner projectiles to achieve the higher flyer-plate velocities. 

Especially with valve switching techniques quite high pressure shocks are initiated which will lead to a distortion of the layer of particles especially in that part of the column which is connected with the valve switching device. The actual inlet pressure which is used to operate the column is also present between the particles. If there is a quick change of pressure above the particle layer, the pressure between the particles will cause a mini-explosion of the adsorbent layer which will generate individual particles which are transported with the carrier gas and may cause clogging or spikes in the detector. 

Detonator An explosive device used to produce a detonation in a high explosive material. Detonators typically contain an ignition mixture, a sensitive primary explosive that detonates from the ignition stimulus, and a high explosive output charge that is taken to detonation by the shock from the detonation of the small amount of primary explosive (which is usually lead azide, Pb(N3)2>. Detonators are used with explosive devices—they are not components of propellant and pyrotechnic systems. The blasting cap is a common type of detonator. 

The earliest tables were compiled from data collected from nuclear weapon tests, in which very high yield devices produced sharp-peaked shock waves with long durations for the positive phase. However, these data are used for other types of blast waves as well. Caution should be exercised in application of these simple criteria to buildings or structures, especially for vapor cloud explosions, which can produce blast waves with totally different shapes. Application of criteria from nuclear tests can, in many cases, result in overestimation of structural damage. 

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