Graphene in Edge-Carboxylated Graphite by Ball Milling and Analyses Using Finite Element Method

Abstract

Edge-carboxylated graphite (ECG) was produced by grinding pristine graphite in a planetary ball-mill machine. Transmission electron microscope was used to confirm the layers of graphene in ECG. The elemental analyses showed that the oxygen contents are different between ECG samples. The vibrational analysis of single- and five-layered graphene was conducted using finite element method within ANSYS. The vibrational behaviors of cantilevered and fixed graphene with one or five layers were modeled using three-dimensional elastic beams of carbon bonds and point masses. The dynamic analysis was conducted using nonlinear elastic elements within LS-DYNA. The natural frequencies, strain and kinetic energy of the beam elements were calculated considering the van der Waals forces between the carbon atoms in the hexagonal lattice. The natural frequencies, strain and kinetic energy of the graphene sheets were estimated based on the geometrical type and the layered sheets with boundary conditions. In the dynamic analysis, the change in displacement over time appears larger along the x- and y-axes than along the z-axis, and the value of the displacement vector sum appears larger in the five-layer graphene than in the single-layer graphene.