New technique for determining the shock initiation sensitivity of explosives
A new technique for determining the shock initiation sensitivity of explosives is described. It involves a flyer plate impinging upon the test explosive to induce initiation of detonation. An electrically exploded foil propels the flyer plate, which is a thin disk of polyimide (Kapton) 1 mm in dia; the charging voltage applied to the capacitor discharge fireset is used to preselect the desired velocity of the flyer plate. Its impact on the explosive introduces a rectangular pressure plus, P, whose amplitude depends on the velocity of the flyer at impact and the shock properties of the flyer and the explosive. The duration of the pulse, tau, depends upon flyer thickness. The test objective is to establish the critical pressure at a given duration which results in a 50 percent probability of detonating the explosive. The data, presented in a log P-log tau plot, generate a demarcation line between detonation and nondetonation regions. In the experiments the impact pressure was in the range of 1 to 10 GPa and the duration from 0.039 to 0.070 ..mu..s. Pentaery-thritol tetranitrate (PETN) and three forms of hexanitrostilbene (HNS) were evaluated. For both materials and variation of the threshold stimulus with initial compaction density was measured. Since a single flyer thickness was used in all but one of the experiments, the data for each explosive give only a single value (P, tau) on the demarcation line which separates detonation from nondetonation. Additional tests with other flyer thicknesses are needed to define this line over a broad range of tau. This new technique employs conventional laboratory equipment and a simple, inexpensive test device. The initiation stimulus may be expressed in a clearly defined form which is directly applicable to safety or performance computations.
- Research Organization:
- Sandia Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- EY-76-C-04-0789
- OSTI ID:
- 7098211
- Report Number(s):
- SAND-77-0416C; CONF-770635-1
- Resource Relation:
- Conference: Conference on the standardization of safety and performance tests for energetic materials, Dover, NJ, USA, 21 Jun 1977
- Country of Publication:
- United States
- Language:
- English
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