Piezoresistive detection of simulated hotspots and the effects of low velocity impact at the mesoscale in nanocomposite bonded energetic materials via multiphysics peridynamics modeling

Structural engineering from an inverse problems perspective

“…Here, however, we will instead focus on materials that have been engineered to be selfsensing; that is, an additional constituent has been added to the material system without which it does not exhibit piezoresistivity. This is most commonly done by adding a conductive phase to a non-conductive matrix such as polymers (including structural polymers such as epoxy vinyl ester [250], polymeric thin films for use as sensing skins [251], laser-induced graphene inter-layers in continuous fibre composites [252,253] and even polymer binders in energetic materials [254,255]), cements [256] or ceramics [257]. Electrical transport is then a consequence of percolation-the composite conducts electricity when enough fillers have been added to form an electrically connected network.…”

“…Considerable effort has also been devoted to the development of piezoresistivity modelscomputational and/or analytical means of predicting how conductivity changes for a prescribed strain. These efforts can be broadly categorized as (i) equivalent resistor network models [260][261][262], (ii) computational micro-mechanics models [254,[263][264][265], or (iii) homogenized macroscale models [266][267][268]. In (i) equivalent resistor network models, high aspect ratio fillers such as CNTs are represented as either straight or wavy/curved sticks in a micro-domain [260][261][262].…”

“…Second, (ii) computational micro-mechanics models use computational means to simulate both phases of the composite-the non-conductive matrix and the conductive fillers [254,[263][264][265]. Because of this, and unlike equivalent resistor network models, computational micro-mechanics models can incorporate nuanced effects such as nanofiller-to-matrix debonding, nanofiller deformation, etc.…”

“…Both examples leverage knowledge of conductivity change bounds to build constraints into the solution space. Beyond these advantages for structural imaging, the pairing of EIT/ERT with self-sensing materials may also have keen, as-of-yet unrealized potential for extreme loading (particularly self-sensing energetic materials [254,255]). That is, it may be illuminating to image energetic materials as they detonate.…”

Viscoplastic flow of functional cellular materials with use of peridynamics

“…In literature, coupled formulations involving peridynamics have been developed to analyse thermal, chemical, diffusion, and electrical problems as well as for porous flow [4][5][6][7][8][9][10][11][12][13]. As the peridynamics formulation can inherently account for discontinuities in the displacement field, peridynamics has been predominantly used to solve fracture and damage problems [14,15].…”