Experimental and numerical investigation of the effect of graphene nanoparticles on the strength of sandwich structures under low-velocity impact

The effect of graphene nanoparticles on the strength of a sandwich panel structure based on foam core, which is inspired by the microstructure characteristics of dragonfly wings, has been investigated experimentally and numerically under low-velocity impact. Sandwich panel structures are made of E-glass/epoxy layers, and different percentages of graphene nanoparticles and combined with their resin. Also, polyurethane foam was used for its central core. For numerical modeling, a nonlinear progressive damage model of composite and nano-composite shells is incorporated into the finite element (FE) code by VUMAT subroutine. The numerical results were compared with the collected experimental data and it shows that there is a good compatibility between them. To check the damage in the structures, the images of the cut view of the samples were taken from the damaged area, and the results were reported. In order to evaluate the distribution of graphene nanoparticles in the polymer structure, the manufactured samples were analyzed using the FE-scanning electron microscopy analysis device. It was concluded that this type of sandwich structure inspired by dragonfly wings can limit damage propagation and keep the rest of the structure healthy under low-velocity impact.