Abstract The paper investigates the processing technology and mechanical properties of a novel type of 3D-braided composite material, named as one-carry-two full five directional braided composite (1C2 3DF5d). The material differs from the conventional 3D-braided composites by doubling the number of braiding yarns in the cross section. This unique yarn architecture is achieved by the introduction of a novel yarn carrier path planning method and side (support) gear design on a rotary braiding machine. The proposed braiding machine and the preform manufacturing process are first compared to the established approaches in textile composite industry, namely the one-carry-one (1C1) method under a new classification scheme. A parametric representative unit cell (RUC) model of the new material is then established which reveals that the cross-section area is increased more than 58% compared to 1C1 braiding materials under the same braiding angle, and the fiber volume fraction is lower by 14%–16%. Damage propagation of the material under tensile and compressive loading conditions are simulated using finite element method based on the 3-d Hashin failure criterion. The longitudinal stiffness and strength of 1C2 3DF5d are compared to 1C1 3DF5d composites and demonstrate a reduction of more than 20% for both due to the lower fiber volume fractions. However, the loading carrying capability of the material is increased by 10%–20% due to the increased cross section area. The technology may serve as a new way to manufacture 3D-braided materials with large cross section and high load-carrying capabilities.

中文翻译：

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新型三维（3D）编织复合材料的新型加工工艺和细观几何建模及其纵向力学性能研究

摘要 研究了一种新型3D编织复合材料——一载二全五向编织复合材料(1C2 3DF5d)的加工工艺和力学性能。该材料与传统 3D 编织复合材料的不同之处在于，其横截面中的编织纱线数量增加了一倍。这种独特的纱线结构是通过在旋转编织机上引入新颖的导纱器路径规划方法和侧（支撑）齿轮设计来实现的。所提出的编织机和预制件制造工艺首先与纺织复合材料行业的既定方法进行比较，即新分类方案下的单运一 (1C1) 方法。然后建立了新材料的参数代表晶胞（RUC）模型，结果表明在相同编织角度下，与1C1编织材料相比，横截面积增加了58%以上，纤维体积分数降低了14 %–16%。材料在拉伸和压缩载荷条件下的损伤传播使用基于 3-d Hashin 失效准则的有限元方法进行模拟。1C2 3DF5d 的纵向刚度和强度与 1C1 3DF5d 复合材料相比，由于较低的纤维体积分数，两者均降低了 20% 以上。然而，由于横截面积的增加，材料的承载能力增加了 10%–20%。