Controllable dynamic mechanical behavior of graphene under impact through pre-strain/pre-stress: adhesion, rebound, and penetration

Abstract

Graphene exhibits distinguished impact resistance and specific energy dissipation, and has enormous application in the field of protective engineering. Herein, based on molecular dynamics simulation and theoretical models, we propose that pre-strain/pre-stress can dynamic control the dynamic mechanical behavior of graphene under the impact. Phase diagrams are presented to illustrate three typical responses: adhesion, rebound, and penetration. These responses rely on the pre-strain direction in the graphene noticeable. Both the critical rebound velocity and the ballistic limit velocity decrease significantly with the increasing pre-strain. The critical rebound velocity of the projectile can be adjusted about 36 % (60 %) under armchair (zigzag) direction tensile pre-strain, which means control the mutual conversion between adhesion and rebound behavior. The ballistic limit velocity of the graphene can be adjusted about 63 % (49 %) under armchair (zigzag) direction pre-strain, which means control the level of difficulty to break/perforate the graphene. The failure modes of graphene can be controlled by the pre-strain direction. In addition, the relations between the residual velocity of projectile and the pre-strain of graphene are revealed with different initial impact velocity of projectile. The specific energy dissipation is unveiled in phase diagrams with the variation of pre-strain in graphene. This work not only opens up frontiers for adjusting the impact behavior, but also provides a key theoretical basis for the optimization design of graphene in impact and protective engineering.