Based on the mesostructure, a parametric finite element (FE) model of the 3D6d braided composites was developed considering the real cross-sectional shape of the yarn and its contact relationship. The 3D Hashin criterion and maximum stress criterion were used for failure determination and periodic displacement boundary conditions were imposed on the model to numerically simulate the initiation, propagation and final failure of yarns and matrix damage. The FE model accurately predicts the longitudinal tensile strength of 3D6d braided composites and simulates the progressive damage process associated with the stress-strain behavior. The longitudinal mechanical properties of the 3D6d braided composites decrease with increasing braiding angle, while increasing the fiber volume fraction leads to enhancement of these properties. Furthermore, the change rate of longitudinal mechanical properties with braiding angle is relatively stable, and the influence of fiber volume fraction on longitudinal properties decreases with the increase of braiding angle. For the damage mode, the increase of braiding angle makes the damage of braiding and sixth-directional yarns gradually change from single direction to multiple directions, and the decrease of fiber volume fraction makes the damage of braiding and fifth-directional yarns at the peak stress more serious.

基于细观结构，考虑纱线的真实横截面形状及其接触关系，开发了3D6d编织复合材料的参数有限元（FE）模型。采用 3D Hashin 准则和最大应力准则确定失效，并在模型上施加周期性位移边界条件，以数值模拟纱线的起始、传播和最终失效以及基体损伤。有限元模型准确地预测了 3D6d 编织复合材料的纵向拉伸强度，并模拟了与应力-应变行为相关的渐进损伤过程。3D6d编织复合材料的纵向力学性能随着编织角的增加而降低，而纤维体积分数的增加导致这些性能的增强。此外，纵向力学性能随编织角的变化率比较稳定，纤维体积分数对纵向性能的影响随着编织角的增大而减小。对于损伤模式，编织角度的增加使编织和六向纱线的损伤逐渐由单向向多向转变，纤维体积分数的减小使得编织和五向纱线的损伤在峰值应力处更认真。