Textile composites are applied to aerospace and automotive industries because they have good fatigue characteristics, and higher specific stiffness and strength compared to metallic materials. In addition, textile composites have better out-of-plane performances such as the resistance of impact and inter-laminar delamination, in addition to greater structural flexibility than the traditional unidirectional composite materials. In this paper, we studied a stiffness prediction method for the effective stiffness of triaxial braided composites accounting for manufacturing parameters such as fiber volume fraction, number of filaments in a yarn, braiding angle, and gap between fiber yarns. The repeating unit cell (RUC) of the triaxial braided composites and the geometric model of yarn architecture were defined in consideration of the gap between adjacent yarns. The gap size between yarns was measured from the photographic image of the cross-section of the triaxial braided composite specimens. The fiber yarn discretization method and the stress averaging method were applied to predict the effective mechanical properties of triaxial braided composites. The predicted properties by the proposed model have good agreement with experimental results.

纺织复合材料具有良好的疲劳特性，与金属材料相比具有更高的比刚度和强度，因此可用于航空航天和汽车工业。此外，与传统的单向复合材料相比，纺织复合材料具有更好的面外性能，例如抗冲击性和层间分层性，并且具有更大的结构灵活性。在本文中，我们研究了一种三轴编织复合材料有效刚度的刚度预测方法，该方法考虑了制造参数，例如纤维体积分数，纱线中的细丝数量，编织角度和纤维纱线之间的间隙。考虑到相邻纱线之间的间隙，定义了三轴编织复合材料的重复单位单元（RUC）和纱线结构的几何模型。纱线之间的间隙尺寸是从三轴编织复合样品的横截面的摄影图像测量的。应用纤维纱离散化法和应力平均法预测了三轴编织复合材料的有效力学性能。该模型的预测性能与实验结果吻合良好。应用纤维纱离散化法和应力平均法预测了三轴编织复合材料的有效力学性能。该模型的预测性能与实验结果吻合良好。应用纤维纱离散化法和应力平均法预测了三轴编织复合材料的有效力学性能。该模型的预测性能与实验结果吻合良好。