58th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference at AIAA SciTech 2017 Grapevine, Texas, USA 9 - 13 January 2017

AIAA 2017-0348

Multiscale Modeling of Effective Piezoresistivity and Damage Response in Nanocomposite Bonded Explosives

Krishna Kiran Talamadupula, Adarsh K. Chaurasia, Gary D. Seidel
Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061-0203, USA

The current work proposes the numerical modeling of an NCBX material reinforced with CNTs. Numerical modeling of a sample RVE is done using 2D electromechanical finite elements. The microscale RVE generated for numerical studies is obtained from an SEM micrograph of a surrogate explosive pullout. The piezoresistive nature of the nanocomposite binder is simulated with microscale gage factors. Grain and binder interfacial damage is accounted for with the use of coupled electromechanical cohesive laws. Nanocomposite binder damage is simulated with the help of element deletion techniques based on a phenomenological continuum damage law governed by a local damage variable for binder elements within the overall mesh. The effective piezoresistive response of the NCBXs is evaluated using a micromechanics based 2-scale hierarchical model linking the nanoscale (CNT and polymer binder) to the microscale (explosive grain structure). The framework developed is used to study essential features of the NCBX microstructure such as the effect of conductivity, stiffness and strength of the grain, nanocomposite binder microscale damage and interfacial response with respect to both strain and damage sensing.