Effect of confinement and thermal cycling on the shock initiation of LX-17
- Lawrence Livermore National Lab., CA (United States). Energetic Materials Center
The shock initiation of the insensitive high explosive LX-17, which contains 92.5% triaminotrinitrobenzene (TATB) and 7.5% Kel-F binder, was studied under two simulated accident conditions: initially confined charges were heated to 250 C and shocked; and unconfined charges were thermally cycled between 25 and 250 C and shocked. Previous research on unconfined TATB-based explosives heated to 250 C revealed increased shock sensitivity. This increase was attributed to both the increased porosity caused by the unsymmetrical thermal expansion of TATB, which resulted in more hot spot ignition sites, and the faster growth of hot spot reactions due to the increased surrounding temperature. In this study, aluminum confinement was used to decrease the thermal expansion of LX-17. The shock sensitivity of confined LX-17 at 250 C was observed to be less than that of unconfined charges at 250 C but greater than that of unconfined, ambient temperature LX-17. The thermal cycling results showed that the LX-17 heated to 250 C and then shocked at 25 C was more sensitive than pristine LX-17, because irreversible growth had produced more ignition sites. LX-17 held at 250 C for an hour or fired at 250 C after two thermal cycles did not appear to be significantly more shock sensitive than LX-17 heated to 250 C and shocked immediately. Therefore, it is unlikely that TATB is thermally decomposing into less stable intermediate species at 250 C. The Ignition and Growth reactive flow model for shock initiation of LX-17 was normalized to these experimental results to provide a predictive capability for other accident scenarios that cannot be tested directly.
- OSTI ID:
- 215668
- Journal Information:
- Combustion and Flame, Vol. 105, Issue 1-2; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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