纳米级石墨晶体层片力学性能的等效模型及分析

Equivalent models and mechanical analysis of nano-graphite crystal sheet

石墨晶体是由碳原子以sp2杂化轨道和邻近的三个碳原子形成共价键,在其平面内再构成网状层片结构。文中对基于原子键合力能关系的CCBE等效模型和经典的BEAM单元等效模型作了比较分析。其中CCBE包括两个节点,每个节点包含三个平移自由度。与经典BEAM单元相比,其两个节点均没有转动自由度。CCBE和BEAM单元的各个参数可以通过石墨晶体的相关实验获得。通过对石墨晶体层片的拉伸、剪切等效模型的柔度(刚度)系数计算分析,并与实验数据相对比,验证了CCBE等效建模方法的正确性和合理性。该等效建模方法为研究石墨的微观结构、性能等提供了一种有效的数值模拟方法。

The carbon atom has a hybridized orbital and forms covalent bonds with neighborhood C atoms in graphite. The graphite crystals contain the stacks of parallel hexagonal net planar sheets. Based on the principle of bonding theory, the CCBE （C-C Bonding Element） equivalent model and Beam equivalent model for graphite crystal sheet have been built. The CCBE has two nodes and each node has three translation freedoms. Compared with BEAM element, the CCBE hasn＇t rotation freedoms. Parameters of CCBE and BEAM element can be obtained from the correspondent experiments of crystal graphite.Stiffness effects of these equivalent models have been analyzed under the loadcases of tension and shearing. The results were also compared with the experimental data. The analysis verified the correctness and rationality of CCBE equivalent model. It has a potential to provide an effective numerical simulation approach to study the microstructure and micro-properties of graphite crystals and other similar structure materials.