纤维增强树脂基复合材料拼接结构拉伸性能

Tensile properties of fiber reinforced epexy resin composite with ply splice structures

为了解拼接结构的力学特性,更好地设计高强度的拼接结构,测试了三种含拼接结构的单向碳纤维增强环氧树脂基(CF/EP)层合板复合材料的拉伸性能,通过监测结构在拉伸过程中的形态分析其破坏特点,并利用有限元软件对不同拼接结构的拉伸过程进行模拟,分析拼接结构受拉过程中的受力特点。所有材料均采用真空辅助灌注工艺(VARTM)获得。结果表明,拼接结构的引入大大降低了CF/EP材料的拉伸强度;由于拼接位置产生明显的应力集中,结构破坏从拼接位置开始,最终破坏模式为层间破坏;拼接位置处的剪切应力和侧向拉伸应力是结构发生初始破坏的主要因素;为了尽可能避免产生拼接位置处的剪切应力和侧向拉伸应力以提高结构强度,应尽可能设计为对称结构。

In order to understand the mechanical property of the fiber reinforced epexy resin composite with ply splice structure and get strong ply splice structures,the tensile properties of three kinds of unidirectional CF/EP with ply splice structures were tested.The tensile specimens were monitored during the loading process to analyze the fracture process,and finite element method （FEM）was used to study the character of the stress distributions when the ply splice structures were under a tensile load.All the CF/EP materials were prepared through vacuum as-sisted resin transfer molding （VARTM）process.The results show that,inducing ply splices into CF/EP materials, the tensile strength decreases evidently.Due to the ply splice,stress concentrations occur,and the initial fracture happens in the ply splice position,leading to the final fracture on the interfaces between different plies.The inter-laminar shear stress and the tensile stress in the through-thickness direction near the ply splice position are the key factors leading to the initial failure.In order to get stronger ply splice structures,symmetric structures should be adopted.