Explosive-Train Technology

As has been indicated earlier the function of the azide in an explosive train is to respond to an external mechanical, thermal, or electrical stimulus release more energy and transfer this with sufficient power and intensity to initiate the next element in the train. Each of the functions must be performed within a limited geometry (fractions of an inch), with minimal input energies, and with the maximum of assurance that the sequence will function upon demand but will remain quiescent until then. 

The tests are again useful and have permitted the development of sophisticated fuzes for advanced military and aerospace systems. For limited-production items success may always be achieved by overdesign mass production tolerates a certain dud rate, and quality assurance may often be based on no more than the subjective assessment of whether or not a component goes bang at a customary level. 

In considering the advanced diagnostics it should be remembered that the advances presented are concerned only with the azides, their properties and confinement, and the role of the substance earlier or later in the functioning sequence. Most of the work reported was done on production materials, and representative data that relate to the materials, rather than actual explosive-train components, is presented. 

It should, however, be clear that we are far removed from the desirable goal of being able to select the energy of an initial stimulus and, on the basis of a required output, design the explosive elements from first principles. 

Johansson, P. A. Persson, Detonics of High Explosives, Academic Press, London, 1970. 

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Available from NTIS AD 742150) G) R.K, Warner D.L. Overman, " Explosive Train Technology for Electronic Fuzes", Harry Diamond Laboratories HDL-PR—71-7(Nov 1971)... 

W. Voreck, T. Costain, E. Dalrymple, Advances in Explosive Train Technology, Ninth Army Science Conference, West Point, New York, 1974. 

This method of initiation is particularly important because of the function of detonators and booster explosives as discussed under the topic of explosives train technology in Volume 2, Chapter 5. In the larger context of secondary explosives it is often associated with the premature or unwanted functioning of explosives subjected to mechanical and other forms of shock. 

The trend in detonator and explosive-train design, which has continued into the 1970s, has been to smaller components, requiring decreased amounts and diameters of more efficient explosives. This trend itself has tended to emphasize the technological importance first of lead and then silver azide and to assure the continued modification of their properties by process development and control. 

Sensitivity plays a pivotal role in explosives technology, because on the one hand it is indicative of the hazards associated with handling a material, and on the other hand it is a key parameter determining the effectiveness of an explosive in an explosive train. In the former case occurrences of low probability are of interest, while in the latter case reliable functioning of an azide demands certainty that it will detonate in response to a given stimulus. 

The technology in this context was first transferred to NPA who named it explosive vapor detection (EVD), and then later Havard Bach renamed and broadened the concept to REST. MEDDS was more scientifically controllable because the training and use of the dogs were separated from the field and sampling problems. 

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