HEATING IN MICROSTRUCTURES OF HMX/ESTANE PBX DURING DYNAMIC DEFORMATION

Numerical studies of PBXs are important for understanding the relationship between their mechanical properties and explosive behavior. The objective of this research is to analyze the thermomechanical response of HMX/Estane, a Polymer-Bonded Explosive (PBX), over a range of grain volume fractions at room temperature (300 K) and (epsilon) over dot = 16,667 s(-1). The analysis focuses on the correlation between grain-level failure mechanisms and the overall response using a Lagrangian cohesive finite element method (CFEM) framework. Digitized micrograph of an actual PBX is used in the analysis. The results indicate a transition in heating mechanism from viscoelastic dissipation in the binder to frictional heating at fractured surfaces. The delay time which signifies the time at which the transition occurs, is found to decrease linearly with increases in grain volume fraction. The results are useful in obtaining microstructure-performance relations that can be used in the design of advanced energetic materials.