Modeling High Explosives with the Method of Cells and Mori-Tanaka Effective Medium Theories

The Method of Cells (MOC) has been applied to a PBX 9501 composite, consisting of large explosive grains embedded in a small grain‐binder mixture, to determine its thermal‐mechanical properties. To treat the bimodal size distribution of grains, in the framework of the MOC, we assign one of eight MOC cells to model the effects of large grains and the remaining seven cells to model the small grain‐binder mixture. We have applied a modified Mori‐Tanaka effective medium theory to model the small grain‐binder mixture. Spherical as well as randomly oriented ellipsoidal grains can be treated. This theory allows us to model the individual properties of the constituents: binder viscoelasticity, and grain elastic‐plastic‐damage behavior. Interfacial debonding between the grains and binder can be incorporated as needed. The method’s predictions are compared to uniaxial measurements. [Research supported by the USDOE under contract W‐7405‐ENG‐36.]