2-SCALE HIERARCHICAL MULTISCALE MODELING OF PIEZORESISTIVE AND DAMAGE RESPONSE IN POLYMER NANOCOMPOSITE BONDED EXPLOSIVE

This paper builds on previous work done [1, 2] to explore the effective piezoresistive response of polymer bonded explosive (PBX) materials where the polymer medium is reinforced with carbon nanotubes (CNTs). In the present work, the nanocomposite binder is modeled explicitly as a piezoresistive material whose properties are determined from the nanoscale through a micromechanics based 2-scale hierarchical model connecting the nanoscale to the microscale grain structure. Electromechanical cohesive zones are used to model the interface between the grains and nanocomposite binder in order to characterize interface separation and the resulting piezoresistive effect. The overall microscale piezoresistive effect is measured by using the volume averaged properties of the microscale RVE. The hierarchical framework developed here is used to explore key features of the NCBX microstructure such as the effect of grain conductivity, weight percentage of CNTs used and nanocomposite gage factor.