The Deflagration-to-Detonation Transition

Violent cookoff reactions in HMX-based explosives in DDT tubes: Tracking luminous waves with streak imaging

“…Classic DDT tube experiments taught us that porous beds of explosive powders contained in strong, heavy confinement will undergo DDT and that DDT run length was inversely related to the degree of porosity [1]. These experiments also laid the framework for explaining the mechanics of DDT.…”

HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

“…Small fragment size and large porosity result in a fast burn up for a relatively large volume of broken material. Our model can describe this feature, but does not describe the heterogeneous compaction observed for weak assemblies of highly porous material [46]. For the most part, the porosity that develops by mechanical damage is limited, and in our test simulations only grows large as a result of burn-up.…”

“…The latter category includes both the applicap 21 tion of mesoscale simulations and carefully designed and executed experiments. As noted by McAfee [46] in the context of DDT, the results of many experiments on energetic materials are difficult to interpret unambiguously. The advantage of simulations with HERMES and with mesoscale simulations is that the calculational results can help interpret the experimental results.…”

“…The present DDT model using CREST is appropriate for Type I DDT [46] where the initiation of detonation is the result of a sufficiently strong shock in under-dense explosive. This DDT type is observed for HMX explosives at low to moderate porosity (less than 40% porosity).…”

“…This DDT type is observed for HMX explosives at low to moderate porosity (less than 40% porosity). For some other explosives, and at high porosity, Type II DDT can occur [46]. Small fragment size and large porosity result in a fast burn up for a relatively large volume of broken material.…”