Effects of microscale damage evolution on piezoresistive sensing in nanocomposite bonded explosives under dynamic loading via electromechanical peridynamics

Abstract

Polymer bonded explosives can sustain microstructural damage due to accidental impact, which may reduce their operational reliability or even cause unwanted ignition leading to detonation of the explosive. Therefore a nanocomposite piezoresistivity based sensing solution is discussed here that employs a carbon nanotube based nanocomposite binder in the explosive material by which in situ real-time sensing can be obtained. A coupled electromechanical peridynamics code is used to numerically obtain the piezoresistive response of such a material under dynamic conditions, which allows one to capture damage initiation and propagation mechanisms due to stress waves. The relative change in resistance at three locations along the length of the microstructure is monitored, and found to correlate well with deformation and damage mechanisms within the material. This response can depend on many factors, such as carbon nanotube content, electrical conductivity of the grain, impact velocity and fracture properties, which are explored through numerical simulations. For example, it is found that the piezoresistive response is highly dependent on preferential pathways of electrical current , i.e. the phase through which the current flows, which is in turn affected by the conductivity of the grain and the specific pattern of damage. It is found that the Modelling and Simulation in Materials Science and Engineering

Modeling Microstructural Effects on Heterogeneous Temperature Fields within Polycrystalline Explosives

“…Fluctuations including both increases and decreases from the average grain temperature associated with the regions near crystal boundaries are attributed to local wave dynamics from the impedance differences across the interface between RDX and binder, as well as local stress concentrations due to the corners of the grains. Our observations are consistent with results from previous mesoscale simulations including approximately 1 GPa impacts using a single crystal plasticity model of RDX from LaBarbera and Zikry [10], and using a peridynamics representation of isotropic RDX behavior by Prakash and Seidel [31]. In these cases, heat transfer by conduction was included in the calculations.…”

A Review of Peridynamics (PD) Theory of Diffusion Based Problems

“…On the other hand, Prakash and Seidel [83] explained the effectiveness of PD model in examining the piezoresistive composite materials. e same authors further developed an electromechanical PD model to predict the deformation and damage of explosive materials [84,85]. Zeleke et al [86][87][88] on the other hand developed a PD formulation for thermoelectric phenomena.…”

A Peridynamic Computational Scheme for Thermoelectric Fields

“…More contributions from J. Zhao et al [33] introduced the transient advection-diffusion PD model by utilizing the approach developed by Bobaru and Duangpanya [27]. Some other applications of PD for thermomechanical and electromechanical coupling can be found in [23,[34][35][36][37][38][39][40][41][42]. Chen et al [25] applied implicit PD formulation in the framework of MOOSE to study coupled thermomechanical problems.…”

“…In the peridynamic perspective of coupled electromechanical and electrical conduction models, Prakash and Seidel [37] explored the beauty of PD to investigate the piezoresistive and electrical response of composite materials at nano scale by introducing electron hopping. Further Prakash and Seidel [38,39] employed a coupled electromechanical PD framework to model the damage-and deformation-sensing capabilities of explosive materials without considering electron hopping. A recent work of Diana and Carvelli [40] implemented micropolar PD (MPPD) formulation to solve electromechanical problems by coupling the electrical conduction PD model with the mechanical micropolar formulation which removed Poisson's ratio restrictions.…”