The high strain rate impact effect and failure behavior of three-dimensional six-directional (3D6d) braided composites with different braiding angles are reported in this paper. The results show that 3D6d braided composites exhibit typical strain rate sensitivity. Under out-of-plane dynamic compression, the stress–strain curves rise linearly and present obvious softening characteristics. With the increase of strain rate, both the strength and modulus of composites increase, while the failure strain decreases. Moreover, the composites with larger braiding angle exhibit higher dynamic curves and better out-of-plane high strain rate properties. The fracture morphology shows that composites exhibit different dynamic damage and failure modes at different strain rates and braiding angles. As the strain rate increases, the composites show clearer shear fracture feature and more severe brittle failure. The damage is mainly manifested as shear of the sixth and braiding fibers, tear of the fifth fibers on the shear plane, interfacial debonding and matrix cracking. As the braiding angle increases, the damage and fracture of composites are reduced obviously and the composites become less brittle failure at high stain rates.

本文报道了不同编织角度的三维六向（3D6d）编织复合材料的高应变率冲击效应和破坏行为。结果表明，3D6d编织复合材料表现出典型的应变速率敏感性。在平面外动态压缩下，应力-应变曲线呈线性上升，并表现出明显的软化特性。随着应变率的增加，复合材料的强度和模量均增加，而破坏应变减小。此外，具有较大编织角的复合材料表现出更高的动态曲线和更好的面外高应变速率特性。断裂形态表明，复合材料在不同的应变速率和编织角度下表现出不同的动态破坏和破坏模式。随着应变率的增加，复合材料表现出更清晰的剪切断裂特征和更严重的脆性破坏。损伤主要表现为第六和编织纤维的剪切，第五纤维在剪切面上的撕裂，界面剥离和基体开裂。随着编织角度的增加，复合材料的损伤和断裂明显减少，并且在高污染率下复合材料的脆性破坏减少。