The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical method, respectively. An ellipse assumption for the cross-section of yarn was proposed in this analysis method with considering the yarn size and yarn-packing factor. Two types of local unit cell structures were identified for 4-step braided composites by considering the nature of the braiding processes and by observing the sample cross-sections. The relationship between the braiding procedure and the properties for 3-D braided structural shapes was established. This method provides the basis for analyzing stiffness and strength of 3-D braided composites.%分别通过实验与控制体积方法系统地研究了采用四步法1×1方型编织工艺编织的预成形件的纱线结构.提出了纱线椭圆形横截面假设,考虑了编织纱线的细度和编织纱线填充因子的影响.根据编织过程中携纱器的运动轨迹特点,将预成形件划分为内部、表面和棱角3个不同的区域,分别定义了不同的控制体积单元,识别了预成形件的两种局部单胞模型,分析了预成形件的纱线构造,并导出了编织结构参数之间的关系.为编织复合材料的刚度、强度性能分析提供了充分的条件.
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机译：The yarn architecture of 3-D braided composites products by the four-step 1×1 braiding technique has been studied by means of a control volume method in conjunction with experimental investigation and a numerical method, respectively. An ellipse assumption for the cross-section of yarn was proposed in this analysis method with considering the yarn size and yarn-packing factor. Two types of local unit cell structures were identified for 4-step braided composites by considering the nature of the braiding processes and by observing the sample cross-sections. The relationship between the braiding procedure and the properties for 3-D braided structural shapes was established. This method provides the basis for analyzing stiffness and strength of 3-D braided composites.%分别通过实验与控制体积方法系统地研究了采用四步法1×1方型编织工艺编织的预成形件的纱线结构.提出了纱线椭圆形横截面假设,考虑了编织纱线的细度和编织纱线填充因子的影响.根据编织过程中携纱器的运动轨迹特点,将预成形件划分为内部、表面和棱角3个不同的区域,分别定义了不同的控制体积单元,识别了预成形件的两种局部单胞模型,分析了预成形件的纱线构造,并导出了编织结构参数之间的关系.为编织复合材料的刚度、强度性能分析提供了充分的条件.
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