Failure mechanism of monolayer graphene under hypervelocity impact of spherical projectile

TL;DR

This study investigates how monolayer graphene deforms and fails under hypervelocity impacts, revealing crack patterns, the influence of boundary conditions, and shape effects, which are vital for designing impact-resistant protective shields.

Contribution

It provides new insights into the deformation mechanisms and failure modes of monolayer graphene under hypervelocity impacts through in silico simulations.

Findings

Cracks form preferentially in zigzag directions.

Circular graphene has the best impact resistance.

Higher projectile kinetic energy results in more cracks.

Abstract

The excellent mechanical properties of graphene have enabled it as appealing candidate in the field of impact protection or protective shield. By considering a monolayer graphene membrane, in this work, we assessed its deformation mechanisms under hypervelocity impact (from 2 to 6 km/s), based on a serial of in silico studies. It is found that the cracks are formed preferentially in the zigzag directions which are consistent with that observed from tensile deformation. Specifically, the boundary condition is found to exert an obvious influence on the stress distribution and transmission during the impact process, which eventually influences the penetration energy and crack growth. For similar sample size, the circular shape graphene possesses the best impact resistance, followed by hexagonal graphene membrane. Moreover, it is found the failure shape of graphene membrane has a strong relationship with the initial kinetic energy of the projectile. The higher kinetic energy, the more number the cracks. This study provides a fundamental understanding of the deformation mechanisms of monolayer graphene under impact, which is crucial in order to facilitate their emerging future applications for impact protection, such as protective shield from orbital debris for spacecraft.