三维五向管状织物纱束轨迹及纤维体积分数的分析与研究

针对四步法编织的三维五向管状织物,基于圆形编织的纱束运动过程及机理分析,研究了织物内部与表面纱束的几何拓扑关系,继而提出三维五向管状织物的单胞结构模型。在此基础上,分别用阿基米德螺旋线段和圆弧段近似预成型内部与表面的纱束轨迹投影,并给出相应的数学描述。根据单胞几何特征,提出了织物横截面上不同位置处的纤维体积分数计算方法。通过建立纱束数据结构及运用计算机可视化技术,对纱束空间轨迹及横截面纤维体积分数进行了模拟显示。这对表征三维五向管状织物的结构性质、实现编织参数优化设计有着重要的意义。 

CALCULATION MODEL OF 3D FIVE-DIRECTION TUBULAR BRAID'S YARN TRAJECTORY AND FIBER VOLUME FRACTION

For the 3D five-direction tubular preform produced by four-step braiding, the yarn geometric topologies in the interior and the surface regions were studied, and a unit-cell structure model was presented on the basis of (tubular) braiding process and principles. Under these conditions, the yarn trajectory projection was simulated as the Archimedean screw in the interior region or the circular arc in the surface region and characterized with a corresponding mathematical formula. On the other hand, the fiber volume fraction of different zones in the fabric's cross-section was computed in terms of the unit-cell's geometric feature. Then the preform's architecture and the fiber volume fraction in a cross-section were simulated by building the yarn's data structure and using the computer visualization techniques, which may have a great meaning to characterize the structure of the 3D five-direction tubular preform and optimize the braiding parameters.