【作者】 杨志； 马飞； 徐可为；

【Author】 Zhi Yang;Fei Ma;Kewei Xu;State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University;Department of Physics and Opt-electronic Engineering, Xi’an University of Arts and Science;

【机构】 西安交通大学； 西安文理学院；

【摘要】 本文采用分子模拟方法探讨了双层石墨烯单轴压缩/拉伸变形的动力学过程。研究表明,单层石墨烯弯曲刚度取决于加载方向,而双层石墨烯弯曲刚度依赖于双层石墨烯层间相对取向。弯曲刚度的相对大小影响压缩变形中面外弯曲的方向。从两个相互垂直的方向压缩时,弯曲方向往往相反。层间距随压缩应变增加变大表明,层间相互作用逐渐弱化。双层石墨烯拉伸变形行为同样与双层石墨烯层间相对取向有关。沿扶手椅方向拉伸时,双层石墨烯断裂应力与应变均随取向角度差的变化先减小后增加。层间取向角度差的变化促使层间相对断裂强度的分化,导致双层石墨烯的失效按逐层断裂的方式进行。更多还原

【Abstract】 Molecular dynamics(MD) simulations are conducted to study the deformation behaviors of bilayer graphene sheets under in-plane uniaxial loading. It is found that the bending direction of the bilayer graphene sheet is related to the compression direction. The bending curvatures are seriously affected by the mixture edges, but usually opposite when compressed from the two orthogonal directions. The separation between layers increases with compressive strain,which is inferred that the interlayer bonding becomes weaker and weaker. As a comparison, the tensile behavior, however, is remarkably related to the misorientation angle. When tensile loaded along zigzag direction, the fracture stress and strain reduces before misorientation angle reaches 30°, and recovers later with the increasing misorientation, which is reverse to that along AC direction. However, it is interesting to note that a high strength differentiation between graphene layers causes a step-by-step fracture mechanism, especially when loaded along armchair direction.更多还原