The mirror buckling analysis of freestanding graphene membranes based on the coarse-grained molecular dynamics method

Abstract

For now, just few researchers have analyzed the thermal-mechanical mirror buckling behavior of freestanding graphene membranes discovered in scan tunneling microscope experiments. Ones of the potential applies of the out-of-plane deformational behavior of graphene membranes are energy harvesting systems. Whatever in the experiments, or for energy harvesting systems, the graphene membranes are micron order. According to previous researches, traditional molecular dynamics method is an appropriate approach to express mirror buckling with nano scale. However, due to the limit of algorithm, when dealing with micro size model by molecular dynamics method, the problems of low computational efficiency and too long calculational time may arise. Therefore, for analyzing the mirror buckling of micro size graphene membranes, the coarse-grained molecular dynamics method is utilized in this paper. Graphene membranes with a fan-shaped cross section and various depth-span ratios are under mechanical or thermal loads. Influences of every factor on the mirror buckling are explored. The calculations indicated that for graphene membranes with various depth-span ratios under mechanical load mirror buckling could be observed. And the critical loading increases with the depth-span ratio. Under thermal load graphene membranes only with low depth-span ratios could totally overturn. For high depth-span ratio graphene, the center height decreases with temperature rise. However, it is hard to overturn completely. Understanding the influences of various factors on the mirror buckling phenomenon of graphene membranes provides theoretical guidance for the design of energy harvesting systems.