This paper numerically investigated the effects of manufacturing defects and braiding angle on the impact compressive properties of three-dimensional (3D) carbon fiber/epoxy resin circular braided composite tubes. Based on the realistic geometrical architecture of 3D tubular braided preform, the full-size microstructural finite element analysis (FEA) models of the braided composite tubes with different braiding angles were established for the axial impact compression behavior at the split Hopkinson pressure bar apparatus. The manufacturing defects including fiber breakages and voids in the resin matrix were generated with Monte Carlo method in fiber tows and resin, respectively. The numerical results show the effects of defects in fiber tows and resin on the compressive strength, initial modulus, and failure strain of the braided composite tubes are both dependent on the braiding angle. The random defects have a negative influence on compressive failure mechanisms of the braided tubes. Comparing the failure morphologies of FEA models with experimental results, we found the non-ideal models containing random defects of appropriate content in fiber tows are more accurate than ideal models to simulate the dynamic compressive failure evolution process of 3D braided composite tubes.

本文数值研究了制造缺陷和编织角度对三维（3D）碳纤维/环氧树脂圆形编织复合管冲击压缩性能的影响。基于3D管状编织预成型坯的实际几何构架，建立了具有不同编织角度的编织复合管的全尺寸微观结构有限元分析模型，以用于剖分式Hopkinson压力棒装置的轴向冲击压缩行为。用蒙特卡罗法分别在纤维束和树脂中产生包括纤维断裂和树脂基质中的空隙在内的制造缺陷。数值结果表明纤维束和树脂中的缺陷对抗压强度，初始模量，编织复合管的破坏应变都取决于编织角度。随机缺陷对编织管的压缩破坏机理有负面影响。将FEA模型的破坏形态与实验结果进行比较，我们发现在纤维束中包含适当含量的随机缺陷的非理想模型比模拟3D编织复合管动态压缩破坏演化过程的理想模型更为准确。