SUMMARY

The ignition of Polymer-bonded explosives (PBXs) is a topic of great interest in the shock physics community. Major challenges in the development of PBXs involve determining how to microstructure of PBX affects its sensitivity to ignition. Since PBX is inherently heterogeneous, a multitude of factors contribute to the heat generation in the microstructure as a direct result of shock loading, including fracture, friction, viscoplastic deformation, bulk compression, and pore collapse. The resulting heat generation influences the time scale of chemical reaction, and influences whether or not the chemical reaction becomes self-sustaining, thereby leading to ignition.

The goal of the proposed research is to delineate the relative importance of each mechanism as it relates to ignition sensitivity. Specifically, the effects of incorporating aluminum particles as well as other microstructural changes (varying grain size, material type, constitutive behavior, etc.) will be discussed. Finally, the thermomechanical transition from heat generation into the evolution of temperature “hotspots”, and eventually into the onset of chemistry will be analyzed. The results of this research will provide a new understanding regarding the importance of microstructure, as well as the interaction among physical mechanisms during shock loading, and will guide the future direction of PBX experiments.