L-287 Mixing Rules for Energetic Materials Elastic Constants

Many properties of energetic composite materials are rarely experimentally determined and instead estimated through the use of models established in the technical literature. Schrama and Jaansalu examined the electrical properties of composite energetic materials and their models. This report continues this line of research, examining the elastic constants of composite energetic materials and assessing the models available within the technical literature for these properties. 

Many models are examined; however, the majority of them are unable to provide accurate estimations for the elastic moduli when compared to data for energetic materials found in the literature. In addition, there is a serious paucity of experimental data in the available literature for energetic composites when it comes to the elastic constants. Despite this, several initial conclusions can be drawn on why the majority of models fail to provide accurate estimations, mainly relating to particle-particle interactions at high volume fractions of filler as well as the high phase stiffness ratios of the energetic composites examined. 

One model which outperforms the rest is the logarithmic sum as described by Agari and Uno. It is found that this model provides accurate estimations for composites with volume fractions of filler >0.5 and phase stiffness ratios of 0.5 and phase stiffness ratios >100. 

In addition to these conclusions, the recommendation is to perform more experimentation on energetic composites to allow for better verification of the available models within the technical literature and the results obtained in this paper.