NCJ Number
218753
Date Published
April 2002
Length
11 pages
Annotation
This paper explores the fundamental mathematical and physical principles determining the distribution of explosives residue.
Abstract
During a detonation there is an interface at the charge surface where unreacted or partly reacted explosives material may survive and become residue. It has been estimated that explosives residue is derived from a thin, partly reacted, outer layer of the charge and can thus be considered as fragments of a container in which the residue corresponds to the shell of the container. If this estimate is correct, the mathematical consequences are that the proportion of explosives residue that survives as residue will: (1) decrease with increasing charge weight; (2) decrease with increasing velocity of detonation; (3) increase with increasing curvature of the shock front with smaller diameter charges; and (4) increase with an increasing number of interfaces. In addition to exploring the origin of explosives residue, the author also considers the distribution of explosives residue associated with fragments or with bare or lightly encased charges. The mathematical relationships of the distribution of explosives residue is presented as the author demonstrates how a local particle velocity is linked to the detonation velocity and the bulk sound speed, which does not vary widely among a range of common explosive materials. Two different models of residue distribution patterns are shown before the author considers how residue distribution is affected by air resistance, wind, charge size, and fragmentation. It is estimated that the distribution of explosives fragments and residue does not follow a simple inverse square distribution but instead may be found in relatively high concentrations further from the blast seat than would be expected. Figures, references