단층 그래핀판의 초기 균열조건에 따른 파괴거동의 분자동역학적 평가

Abstract

Graphene is an advanced material which is 0.33 nm thin and flexible, and has a strength 200 times higher than steel and a thermal conductivity 10 times higher than copper or aluminium. Due to these characteristics, researches are already underway to utilize and commercialize the excellent properties of graphene to improve the performance of existing materials or products in various fields such as displays, batteries, gas sensors, and wearable devices. However, a thin graphene is more likely to cause cracks in the manufacturing process at various positions, leading to deterioration of the product. For this reason, studies have been conducted to evaluate cracks and defects in graphene, but few studies have been accomplished to evaluate the failure behavior as the change of initial crack conditions, such as the position and shape of the crack. Therefore, this study evaluated molecular fracture behavior of graphene to single layer graphene sheet under various initial crack conditions. The tool of analysis is used LAMMPS, which can analyze atomic and molecular units of microscopic dimensions, such as a graphene. The analysis models were classified into three types according to the position, distance, and angle. As results of the analysis, the initial crack in the single graphene sheet tended to break at the same time as it started to grow, and the model analysis considering the position showed that the fracture strength of the initial crack located at the upper center was 101 GPa. The results of this study may provide a criterion to help solving problems for the defects and cracks in the manufacturing process to improve the performance and commercialization of graphene.