Application of Piezoresistive Nanocomposite Binders for Real Time Embedded Sensing of Strain and Damage in Energetic Materials

摘要

In-situ structural health monitoring in polymer bonded energetic materials through the introduction of carbon nanotubes into the binder phase is investigated through piezoresistive response under quasi-static and low velocity impact loading in order to provide the basis for deformation and damage sensing for real-time self-diagnostic functionalities in energetic materials. The experimental effort herein is focused on mock energetics using 70 wt% ammonium perchlorate (AP) and 70 wt% sugar crystals embedded into epoxy binder having concentrations of 0.1 and 0.5 wt% MWCNTs relative to the entire hybrids. Electrical conductivity, mechanical properties and piezoresistive sensitivities of mock energetics are quantitatively and qualitatively evaluated. Electrical conductivity was improved ~3 and ~5 orders of magnitude for 0.1 and 0.5 wt% MWCNTs mock energetics from that of the baseline neat mock energetics. Incorporating MWCNTs into local binder improved tensile modulus of AP mock and sugar mock energetics, ~15% and ~70% respectively, and tensile strength of mock sugar mock energetics ~40% compared to neat mock energetics. Significant piezoresistive response was obtained both for MWCNT AP mock and MWCNT sugar mock energetics, which may be the first experimental study in the literature demonstrating the electro-mechanical characterization of inert mock energetic materials which provides proof of concept for strain and damage sensing under quasi-static and low velocity impact loading for real time structural health monitoring in energetics.