基于分子动力学的多晶石墨烯拉伸力学性能的应变率相关性

发布时间：2018-06-26 07:23

本文选题：分子动力学 + 多晶石墨烯　；参考：《西安建筑科技大学学报(自然科学版)》2017年04期

【摘要】：应变率是材料力学性能和变形机制的重要影响因素.利用维诺图理论,创建了不同晶粒尺寸的多晶石墨烯模型;利用分子动力学(MD)法,研究了不同拉伸应变率下多晶石墨烯的弹性模量、拉伸强度、极限应变等与拉伸应变率之间的关系.结果表明,多晶石墨烯的拉伸强度随拉伸应变率的增大而呈线性增大的趋势.对同一应变率而言,拉伸强度随晶粒尺寸的增大而增大,但对拉伸应变率的敏感度呈减小趋势.随拉伸应变率的增大,弹性模量呈增大趋势,但其受影响程度取决于应变率与阈值的关系.随着拉伸应变率的增大,极限应变呈增大趋势.对同一应变率而言,随晶粒尺寸的减小,极限应变呈增大趋势.研究结果对明确拉伸应变率与多晶石墨烯拉伸力学性能之间的相关性具有一定的参考价值和意义.
[Abstract]:Strain rate is an important factor affecting mechanical properties and deformation mechanism of materials. The polycrystalline graphene models with different grain sizes were established by using the theory of Vinograph, and the elastic modulus and tensile strength of polycrystalline graphene at different tensile strain rates were studied by molecular dynamics (MD) method. The relationship between limit strain and tensile strain rate. The results show that the tensile strength of polycrystalline graphene increases linearly with the increase of tensile strain rate. For the same strain rate, the tensile strength increases with the increase of grain size, but the sensitivity to tensile strain rate decreases. The elastic modulus increases with the increase of tensile strain rate, but its influence degree depends on the relationship between strain rate and threshold value. With the increase of tensile strain rate, the limit strain increases. For the same strain rate, the ultimate strain tends to increase with the decrease of grain size. The results have some reference value and significance for determining the relationship between tensile strain rate and tensile mechanical properties of polycrystalline graphene.
【作者单位】：西安建筑科技大学土木工程学院;西安建筑科技大学理学院;
【基金】：国家自然科学基金(51641809) 陕西省工业科技攻关项目(2015GY141) 西安建筑科技大学人才基金(RC1601)
【分类号】：TQ127.11

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