冲击载荷下复合材料层间断裂特性研究

Fiber-reinforced resin-matrix composites have been considered as the most potential structural materials in the use of advanced airplanes. However, up to now, the failure mechanism of this kind of materials under impact loads remains unclear and an effective failure model is eagerly needed. This limits the development of composites in the field of aeronautics and aerospace, and has attracted much interest of researchers. This project will foucus on carbon fiber-reinforced epoxy-matrix composites.Firstly,the I/II modes dynamic fracture experiments will be designed and the delamination fracture mechanism of this composites under impact load will be carefully examined by means of high speed photography and microscopic observation.Method of dynamic fracture toughness evaluation will be developed based on the dynamic J-integral; Secondly, a delamination model will be established taking into account the strain rate effect as well as the fiber-bridging effect. A program based on this delamination moded will be developed and embedded into the comericial simulation software for easier application. This study is of great importance for understanding the strain rate effect on the delamination failure of composite materials and also for the safety design of composite structures in industrial applications.

纤维增强树脂基复合材料因为其优异的性能在先进飞机结构中有着重要的前景，然而其在冲击载荷作用下的失效机理和失效模型还未完全澄清，成为制约其在航空航天领域应用的一个瓶颈，同时也引起国内外学者的广泛关注。本项目拟针对碳纤维增强环氧树脂基复合材料开展研究，通过设计层间I/II型裂纹动态断裂试验，结合高速摄像和显微分析技术，研究复合材料层合板在冲击载荷下的层间失效机理，发展基于动态J积分的断裂韧性评估方法，建立考虑应变率效应和纤维桥连机制的复合材料层间断裂失效模型，形成一套可用于数值计算的模型程序，并将其集成到已有仿真软件中。本项目的研究不仅对全面认识复合材料层间断裂行为的应变率效应有重要的科学意义,而且对于复合材料结构安全性设计具有重要的工程应用价值。

碳纤维增强树脂基复合材料因为其优异的性能在先进飞机结构中有着重要的前景，然而在冲击载荷作用下的分层损伤的起始和扩展严重制约其应用前景。我们针对某碳纤维增强环氧树脂基复合材料开展了层间动态断裂试验研究，结合高速摄像,显微分析技术，电磁加载，数字图像相关分析以及霍普金森杆技术，研究了复合材料层合板在冲击载荷下的层间失效机理。在动态加载下，裂纹扩展应变片和高速摄像得到动态裂纹扩展，结合实验和数值模拟方法通过动态J积分和虚拟裂纹扩展技术，得到了I型层间起始断裂韧性GIC随加载速率变化的一般趋势。通过建立用户单元子程序模拟高速裂纹的扩展，得到I型层间断裂韧性与裂纹扩展速度、裂纹扩展加速之间的关系，得到I型层间断裂的止裂韧性。研制新型加载装置——双向电磁霍普金森杆，该装置能够同步同幅值加载双悬臂梁试样，进而保证在动态加载下DCB试样为纯I型破坏。本项目的研究得到了层间裂纹动态扩展的一般规律，对全面认识复合材料层间断裂行为的应变率效提供了有效的研究手段,对于复合材料结构安全性设计具有重要的工程应用价值。