The explosive performance of ϵ‐CL‐20 was found to be approximately 14% greater than HMX as determined by cylinder expansion and tantalum plate acceleration experiments. This makes it the most powerful explosive ever tested at small volume expansions of the detonation products. In general CL‐20 is more sensitive than HMX. However, the sensitivity of CL‐20 to one‐dimensional shock loading was found to be similar to HMX.

The thermal and shock sensitivities of plastic bonded explosive formations based on 2,6-diamino-3,5-dinitropyrazine-1-oxide (commonly called LLM-105 for Lawrence Livermore Molecule #105) are reported. The One Dimensional Time to Explosion (ODTX) apparatus was used to generate times to thermal explosion at various initial temperatures. A four-reaction chemical decomposition model was developed to calculate the time to thermal explosion versus inverse temperature curve. Three embedded manganin pressure gauge experiments were fired at different initial pressures to measure the pressure buildup and the distance required for transition to detonation. An Ignition and Growth reactive model was calibrated to this shock initiation data. LLM-105 exhibited thermal and shock sensitivities intermediate between those of triaminotrinitrobenzene (TATB) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX).

Shock initiation is one of the most important properties of energetic materials, which must transition to detonation exactly as intended when intentionally shocked and not detonate when accidentally shocked. The development of Manganin pressure gauges that are placed inside the explosive charge and record the buildup of pressure upon shock impact has greatly increased the knowledge of these reactive flows. This experimental data, together with similar data from electromagnetic particle velocity gauges, has allowed us to formulate the Ignition and Growth model of shock initiation and detonation in hydrodynamic computer codes for predictions of shock initiation scenarios that cannot be tested experimentally. An important problem in shock initiation of solid explosives is the change in sensitivity that occurs upon heating (or cooling). Experimental Manganin pressure gauge records and the corresponding Ignition and Growth model calculations are presented for two solid explosives, LX-17 [92.5% triaminotrinitrobenzene (TATB) with 7.5% Kel-F binder] and LX-04 [85% octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine (HMX) with 15% Viton binder] at several initial temperatures.Key words: detonation, shock initiation at different initial temperatures, energetic materials, plastic-bonded explosives, modeling of initiation, LX-04, LX-17.Energetic materials (EMs) are widely used in both industrial applications and at defense oriented establishments. Initiation of such materials is of particular interest for reason of safety as well as for control of the desired effect during their application. Energetic materials exist in gaseous state as well as condensed phase in homogeneous form, such as liquids and pastes, and in heterogeneous form, such as solid compositions consisting of granular mixtures of energetic materials with either energetic or inert binders.There are various possible ways to initiate energetic materials. Gaseous mixtures, such as hydrogen and oxygen, can easily be initiated with a spark, a heating element or an open flame. Condensed EM can be initiated by either mechanical or thermal heating or by any other kind of dynamic loading such as shock loading. Of all the initiation mechanisms, shock loading lends itself to the best quantitative analysis of the phenomenon be-

Thermal conduction processes at material interfaces representative of those produced by shock compression are studied in order to understand the temperature history at the interface. The transient effects due to small gaps and thin layers are calculated, as well as the modifications due to a melting transition in one of the materials.

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