A THERMOMECHANICAL ANALYSIS OF HOT-SPOT FORMATION IN CONDENSED-PHASE, ENERGETIC MATERIALS

This article discusses the mechanics of shock-induced hot spot formation in porous, energetic materials. A hollow sphere configuration is used to simulate the dynamic and thermodynamic response of a single void centered in a field of condensed-phase energetic material. In addition to treating pore dynamics, the hot spot model includes energy balances for the pore gas and surrounding material. Important thermal processes such as viscoplastic heating, finite rate chemical effects, and heat exchange between the pore gas and surrounding material are also evaluated. The governing conservation equations together with the initial and interface conditions are solved numerically for a series of test cases for a nitramine material. The results show that viscoplastic heating is an effective mechanism for shock initiation of Porous, energetic materials, In addition, it is demonstrated that the initial porosity of the material, the initial pore size and the material viscosity have strong influences on hot spot formation.