Cookoff
For a munition filled with energetic materials exposed to heat (such as from a pool fire), we developed an engineering model that predicts the time to ignition and casing temperature at cookoff. The model also tracks the combustion front propagation in the material with time and concomitant pressure buildup and casing deformation. We validated this model using data from small scale slow cookoff tests (Navy's pipe bomb and Lawrence Livermore National Laboratories' STEX setup) and full scale tests (Navy's Heavy Wall Penetrator and 500 lb GP bomb), all for an RDX based relatively plastic bonded explosive formulation called PBXN-109. Efforts are currently underway to expand the capabilities of this model and validate for additional materials and scenarios.
