In-plane dynamic crushing and energy absorption of three-dimensional graphene

Abstract

Combining molecular dynamics simulations and theoretical modeling, impact dynamic behaviors of honeycomb three-dimensional (3D), triangle-like 3D and non-equilateral hexagon 3D graphene were investigated to elucidate the dependence of deformation modes, plateau stress, peak stress and energy absorption capacity of three kinds of 3D graphene on impact velocity and graphene sidewall width. The expressions of plateau stress and critical velocity between different deformation modes were given to analyze impact response. The results show that there are four deformation modes which are affected by impact velocity and sidewall width. During impact process, the stress-strain curve and energy absorption curve of 3D graphene can be divided into two stages, namely the stress plateau stage and van der Waals (vdW) hardening stage. The dynamic plateau stress at stress plateau stage increases with increasing impact velocity, and decreases with increasing sidewall width. The energy absorption at the stress plateau stage increases linearly with the increase of strain, and increases sharply at the vdW hardening stage. In addition, it is found that the peak stress is significantly affected by the impact velocity. The maximum energy absorption per unit volume at the end of impact increases with increasing impact velocity, and decreases with increasing sidewall width.