Molecular dynamics simulations of silica aerogel nanocomposites reinforced by glass fibers, graphene sheets and carbon nanotubes: A comparison study on mechanical properties

Abstract Silica aerogel is a brittle as well as a low-tensile strength highly porous solid. Therefore, the primary goal of the present work is to incorporate glass fibers, graphene sheets and carbon nanotubes into the silica aerogel matrix using molecular dynamics (MD) simulations to improve not only the mechanical properties, e. g., tensile strength, elastic modulus, and toughness, but also the deformation characteristics due to the pre-existing cracks. This work investigates and compares the mechanical properties obtained from tension and compression tests of native silica aerogels and their nanocomposites. The results show that the axial and lateral direction mechanical properties of carbon-based nanocomposites are significantly higher than the native and glass fibers reinforced silica aerogels. For example, in the axial loading, the elastic modulus of the proposed glass fibers, graphene sheets, and carbon nanotubes reinforced nanocomposites were ∼  3.5, ∼  9.5 and ∼  11.5 times higher than the native silica aerogels, respectively. Moreover, the influence of crack depth has been studied in the tensile fracture simulations, and we found that in nanocomposites, the tensile load bearing candidates are mainly reinforced materials. The outcome of this work is a vital step in the process of designing advanced nanocomposites.