Dynamical Performance of Graphene Aerogel with Ductile and Brittle Characteristics

Current research regarding the efficiency of ultra-light graphene aerogel (GA) energy dissipation is limited to quasi-static tests and simulations. The lack of direct dynamical experiments has impeded its utilization in fields of energy dissipation. Therefore, in this study, the high dynamic energy dissipation capability of GA with ultra-low density is obtained directly from the experiment. It is found that the porous and anisotropic properties of GA render the projectile deflected hierarchically and further induce gradually cascaded failure with asymmetry expansion in the GA. This feature, taking advantage of ductile materials, facilitates energy dissipation capability. Failure morphologies of rippled graphene flakes involve brittle features such as micron-size cracks and local broken flakes. In addition, these coarse-grained molecular dynamics (CGMD) simulation results imply kinetic energy changes due to movement, and fluctuations of graphene flakes are effective ways to dissipate energy. Moreover, the stiffness increase of graphene flakes plays a weakened role in energy dissipation because reduced contact area impedes the effectiveness of stress wave and thermal transfer while also increasing the brittle characteristics of GA. Combining the failure characteristics of brittle materials with the benefits of ductile network materials, GA shows great promise in impact protection applications.