氧化石墨烯/多壁碳纳米管协同改性复合材料层合板的冲击损伤特性研究

The fibre-reinforced epoxy composite is widely used in the aerospace structures and mechanical engineering because of their high specific stiffness, high specific strength and outstanding designability characteristic. The composites have poor interfacial properties and interlaminar mechanical properties, and therefore exhibit low impact damage resistance and damage tolerance. The interlaminar fracture toughness and damage resistance of fibre-reinforced composite was improved when the composite is modified by graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs). In this project, the fibre/epoxy composite modified by GO and MWCNTs will be prepared by three methods, including adding the resin with GO/MWCNTs directly, spraying the prepregs surface with GO/ MWCNTs and making fiber modification by GO/MWCNTs. Followed that, the interlaminar fracture toughness, interlaminar shear strength and impact damage resistance of the modified composite laminates will be evaluated. The action law of the interlaminar toughening and impact damage caused by adding GO/MWCNTs will be discussed. Then the enhancement mechanism of impact damage resistance for composite laminates modified with GO/MWCNTs synergistically will be revealed. In the end, the optimized design scheme for the laminated composite plate structures with better impact performance will be proposed, which will offer useful reference for the engineering application of this composite material.

纤维增强环氧树脂复合材料因具有较高的比强度和比刚度、较好的可设计性等众多优点，在航空、航天和机械工程等领域得到广泛应用。复合材料界面性能和层间力学性能较差，表现出低的冲击损伤阻抗和损伤容限特征。加入氧化石墨烯(GO)、多壁碳纳米管(MWCNTs)对纤维增强复合材料改性是改善其层间断裂韧性和抗冲击性的有效手段。本项目拟研究直接在环氧树脂中加入GO/MWCNTs、将GO/MWCNTs喷涂在预浸料表面、直接用GO/MWCNTs对纤维进行改性3种GO/MWCNTs加入方式对改性复合材料层合板层间断裂韧性、层间剪切强度及抗冲击性能的影响。研究GO/MWCNTs对复合材料层合板层间增韧及冲击损伤形式的作用规律，试图揭示GO/MWCNTs协同作用对复合材料层合板抗冲击性能的增强机制。提出了一种GO/MWCNTs协同改性复合材料层合板抗冲击性能的结构优化设计方案，为该复合材料的工程应用提供有益的参考。

本项目利用石墨烯和碳纳米管对复合材料进行了改性，研究了石墨烯、碳纳米管增强复合材料的力学性能及增韧机制。通过取一个代表性体积单元（RVE）对石墨烯增强复合材料的力学性能进行有限元模拟计算。结果表明，复合材料的杨氏模量和剪切模量随着石墨烯体积分数的增加几乎呈线性增加，但是，对于不同的夹角，复合材料杨氏模量和剪切模量增加的快慢程度不同。石墨烯和碳纳米管都可以分为锯齿型和扶手椅型，通过将其两两之间的结合，得到四组新型的石墨烯柱结构（PGS），分析计算了手性和碳纳米管的距离对PGS结构力学性能的影响。基于分子结构力学和多尺度方法，针对石墨烯存在的几种缺陷，构建了含有不同数量的双原子空缺缺陷和Stone-Wales（S-W）缺陷的石墨烯增强复合材料的有限元模型。研究了石墨烯的缺陷在不同石墨烯体积分数下对复合材料弹性模量以及界面层应力传递的影响。使用Abaqus建立表面带金属层的复合材料层合板和复合材料裸板低速冲击的有限元模型，通过分析计算复合材料层合板的低速冲击损伤规律，提出了一种抗冲击的结构优化设计方案。