Graphene-Like Nanoflakes for Shock Absorption Applications

The effects of high-pressure shock waves generated by the detonation of explosives are of major interest to the strategic sector. We report interaction of transonic shock waves (1.1 Mach speed; peak pressure >1.5 GPa) with graphene-like nanoflakes (GNFs). GNF samples, obtained after chemical vapor deposition of a biomass, were studied using optical/ electron, force microscopy, Raman, and Brunauer-Emmett-Teller/Barrett Joyner Halenda studies. Following this, GNF samples were subjected to high-strain-rate measurements, using a split Hopkinson pressure bar technique to measure variations in the stress, strain, and strain rate. Numerous dynamic mechanical parameters are derived under a classical Lagrange Rankian Hugoniot framework together with collecting statistics on the lateral flake size, number of layers, defect density, wrinkle, slip characteristics, etc. Broadly, the incident shock energy was dampened by similar to 65% of absorption loss with similar to 15% transmittance. It has implications on the GNF microstructure by reducing the flake squareness, area (by similar to 50%), and exfoliating layer conjugation by around 5 times. The in-plane impact was more profound compared to the out of-plane. Dislocation/slip dynamics showed significant modification in prismatic loops (from buckled to ruck and tuck), with twinning exhibiting a lowering of the Peierls-Nabarro stress to make disorder glissile. At the molecular level, dynamic deformation dramatically modified the force constants with bond elongation at -C-C- by similar to 80% and at -C=C by >150% compared to pristine. An interactive model is presented.