编织结构复合材料的动态损伤与断裂行为研究

In this project, dynamic failure and fracture behavior on braided structural.material are studied. Some fracture characteristics on the evolution of crack tip, crack propagation and stress singularity of composites are shown by means of modern optical experimental technology. The deformation field on crack tip local zone are measured using digital speckle correlation method; The stress singular filed of the crack tip are studied by means of optical caustic pattern; Dynamic large deformation of composites under tensile load are shown by means of dynamic optical fiber displacement system; Dynamic propagation behavior of composite are analyzed using multi-spark high speed camera; Some microscopic mechanism on fracture surface.are shown by SEM.In the meantime, the stress singularities on composite crack tip are modeled numerically combining dynamic fracture mechanics theory with optical caustic principle. On the other hand, 3D fine cell model of braided composite are studied by means of Finite element method. The microscopic cell on composites is introduced to 3D finite element on macroscopic level. Some mechanics behaviors of braided composites.are analyzed. These research works will provide dynamic optical mechanics visualization on failure and fracture on braided composites. It will be useful for the fine design, properties estimation and strength analysis of composites, and put forward further application and development on this kind of textile material in the field of aeronautic engineering.

通过对纤维编织复合材料在冲击下动态损伤与断裂行为的实验与数值模拟研究，得到损伤演化、裂纹萌生及扩展的动态变形分布，确定破坏区尺寸、裂尖局域信息、震荡奇异异性、裂纹速度、断裂模式等特征，分析应力波在纤维网络结构中的传播以及与裂尖的相互作用，建立动态损伤破坏准则，为编织复合材料的抗冲击性设计、动态断裂研究提供实验和理论依据。