Generation of detonation in solid explosives

• Published in: Symposium, International, on Combustion Vol. 12; no. 1; pp. 745 - 751
• Main Authors: Fauquignon, C., Cheret, R.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1969
• ISSN: 0082-0784
• DOI: 10.1016/S0082-0784(69)80455-8

It is well known that, before a constant-velocity explosion occurs, a transient regime is always observed. The structure and the length of this region depend upon the nature and the intensity of the perturbation brought to the explosive. This transient phenomenon obviously involves complex mechanical and chemical processes and thus offers a large field for theoretical and experimental research. Emphasis is placed on the large amount of work associated with the initiation of detonation by a plane shock wave generated by a donor explosive through an inert barrier, or by a flying plate. The influence of the intensity and the history of the shock on the one hand, and of the structure of the explosive acceptor on the other, are considered. It is found that two processes of chemical energy release are successively involved, the relative importance of each depending on the degree of heterogeneity of the explosive: The plane induced shock is broken into multiple grain-sized waves interacting in the grains (high-intensity reflected waves) and at the free boundaries (high-velocity jets through the voids). As a consequence, a high chemical reaction rate and fast energy release are observed in the neighborhood of the shock front. A lower reaction rate, partially controlled by the shock history, will result in a smooth and progressive energy release in the mass of the acceptor; this second energy supply is responsible for the observed overshoot.