Pressure-sensitive dissipation in elastomers and its implications for the detonation of plastic explosives

Abstract

The role of binder deformation and the associated energy dissipation on the detonation sensitivity of plastically bonded explosives is considered by accounting for dilatation-sensitive viscoelastic shear response. Following the observation that pressurization can prolong the relaxation and retardation times of a viscoelastic elastomer tremendously, the implications of this phenomenon are considered for a thin layer of a model elastomer, sheared between two blocks of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine under deformation rates typical in detonation scenarios. The consequences of concurrent pressurization on heat generation are examined using small deformation as well as finite deformation analyses. While a dilatation-insensitive viscoelastic behavior generates notable temperature increases, they are insufficient to cause ignition of the explosive. However, taking into account the increased dissipation associated with the pressure-induced changes in the intrinsic time scale and viscosity of the elastomer leads to temperature rises on the order of 1000degreesC, which are consistent with "hot spots" held responsible for the initiation of detonation in the adjacent explosive grains.

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